Advertisement

Associations between days on close-up diets and immune responses prepartum, metabolites peripartum, and risk of postpartum diseases in Jersey cows

Open ArchivePublished:March 24, 2021DOI:https://doi.org/10.3168/jds.2020-19700

      ABSTRACT

      Nutritional strategies during the final weeks prepartum, the close-up period, aim to reduce immune suppression and metabolic imbalances. This paper reports results of 2 observational studies. Data from 2 previous experiments (study 1) were used to investigate the associations between days fed close-up diets (DINCUD) and uterine diseases (n = 1,230). In study 2, retrospective data from animals not used in study 1 (n = 11,962) were used to investigate the associations between DINCUD and removal from the herd and long-term reproductive and productive responses. Nulliparous (lactation = 0) and parous (lactation ≥1) cows were moved to close-up pens 28 d before expected calving date, but only parous cows were fed rations with negative dietary cation-anion difference. In study 1, study personnel diagnosed retained fetal membranes, metritis, and acute metritis postpartum. Length of the close-up period was tested for its linear and quadratic effects. The β-coefficients from the multivariable analyses were used to calculate the predicted outcome for each cow. In addition, the mean (±SEM) for cows with <10, 28 ± 3, and 42 ± 3 DINCUD are reported. Metritis was associated with the interaction between DINCUD and parity-diet (nulliparous: <10 d = 31.8 ± 9.2, 28 ± 3 d = 21.8 ± 0.7, 42 ± 3 d = 29.8 ± 2.1%; parous: <10 d = 81.7 ± 2.9, 28 ± 3 d = 11.1 ± 0.3, 42 ± 3 d = 14.8 ± 1.3%). The interaction between DINCUD and parity-diet was associated with total energy-corrected milk yield (nulliparous: ≤10 d = 7.91 ± 0.03, 28 ± 3 d = 8.17 ± 0.01, 42 ± 3 d = 8.15 ± 0.01 kg × 103; parous: ≤10 d = 7.99 ± 0.05, 28 ± 3 d = 9.79 ± 0.01, 42 ± 3 d = 9.52 ± 0.03 kg × 103) and percentage of cows pregnant by 305 days in milk (DIM; nulliparous: ≤10 d = 80.4 ± 0.4, 28 ± 3 d = 83.3 ± 0.1, 42 ± 3 d = 82.8 ± 0.2%; parous: ≤10 d = 59.5 ± 0.7, 28 ± 3 d = 78.3 ± 0.1, 42 ± 3 d = 73.1 ± 0.5%). Furthermore, the interaction between DINCUD and parity-diet was associated with removal from the herd by 305 DIM (nulliparous: ≤10 d = 27.0 ± 0.5, 28 ± 3 d = 20.7 ± 0.1, 42 ± 3 d = 21.8 ± 0.1%; parous: ≤10 d = 45.1 ± 0.7, 28 ± 3 d = 31.1 ± 0.1, 42 ± 3 d = 28.1 ± 0.3%). Jersey cows that are managed to achieve 28 DINCUD may have reduced odds of uterine diseases and improved reproductive and productive performances.

      Key words

      INTRODUCTION

      Despite a large body of research investigating management and nutritional strategies to improve the health and performance of peripartum cows, the morbidity during the postpartum period in US dairy herds is approximately 45% and the first AI pregnancy per AI is less than 40% (
      • Pinedo P.
      • Santos J.E.P.
      • Chebel R.C.
      • Galvão K.N.
      • Schuenemann G.M.
      • Bicalho R.C.
      • Gilbert R.O.
      • Rodriguez-Zas S.L.
      • Seabury C.M.
      • Rosa G.
      • Thatcher W.
      Associations of reproductive indices with fertility outcomes, milk yield, and survival in Holstein cows.
      ). The transition from the nonlactating, pregnant state to the lactating state is marked by several hormonal, metabolic, and behavioral changes. To address these changes and prepare the cow for the new lactation, different diets are fed from drying off to approximately 21 d before calving, and from 21 d before expected calving to calving (
      • Grummer R.R.
      Impact of changes in organic nutrient metabolism on feeding the transition dairy cow.
      ;
      • Drackley J.K.
      Biology of dairy cows during the transition period: The final frontier?.
      ). During the last weeks of gestation, DMI decreases progressively to a nadir on the day of calving (
      • Pérez-Báez J.
      • Risco C.A.
      • Chebel R.C.
      • Gomes G.C.
      • Greco L.F.
      • Tao S.
      • Thompson I.M.
      • do Amaral B.C.
      • Zenobi M.G.
      • Martinez N.
      • Staples C.R.
      • Dahl G.E.
      • Hernández J.A.
      • Santos J.E.P.
      • Galvão K.N.
      Association of dry matter intake and energy balance prepartum and postpartum with health disorders postpartum: Part I. Calving disorders and metritis.
      ); therefore, diets fed during the close-up period usually have a slightly greater concentration of energy compared with diets fed in the early stages of the dry period (
      • Rabelo E.
      • Bertics S.J.
      • Mackovic J.
      • Grummer R.R.
      Strategies for increasing energy density of dry cow diets.
      ). In a recent meta-analysis,
      • Husnain A.
      • Santos J.E.P.
      Meta-analysis of the effects of prepartum dietary protein on performance of dairy cows.
      demonstrated that supplying increased amounts of metabolizable protein to nulliparous cows during the close-up period is beneficial to their lactational performance. Furthermore,
      • Gaynor P.J.
      • Mueller F.J.
      • Miller J.K.
      • Ramsey N.
      • Goff J.P.
      • Horst R.L.
      Parturient hypocalcemia in jersey cows fed alfalfa haylage-based diets with different cation to anion ratios.
      demonstrated that acidogenic salts fed during the prepartum period improve mineral balance peripartum and reduce the risk of hypocalcemia postpartum. Thus, exposure of cows to close-up diets for an appropriate period of time is believed to be critical to ensure good health peripartum and production postpartum, but the ideal duration of the close-up period is unknown.
      With the greater penetration of acidogenic salts in diets of prepartum cows in the US, the question of the ideal length of feeding close-up diets needs to be addressed.
      • Lopera C.
      • Zimpel R.
      • Vieira-Neto A.
      • Lopes F.R.
      • Ortiz W.
      • Poindexter M.
      • Faria B.N.
      • Gambarini M.L.
      • Block E.
      • Nelson C.D.
      • Santos J.E.P.
      Effects of level of dietary cation-anion difference and duration of prepartum feeding on performance and metabolism of dairy cows.
      demonstrated that acidogenic diets (−180 and −70 mEq/kg of DM) fed for 42 versus 21 d were detrimental to reproductive and productive performances.
      • DeGaris P.J.
      • Lean I.J.
      • Rabiee A.R.
      • Heuer C.
      Effects of increasing days of exposure to prepartum transition diets on milk production and milk composition in dairy cows.
      reported a quadratic association between days on the close-up diet (DINCUD) and yield of 4.0% fat, 3.2% protein-corrected milk, and between DINCUD and protein yield in Holstein and Holstein × Jersey grazing, parous cows. In addition,
      • DeGaris P.J.
      • Lean I.J.
      • Rabiee A.R.
      • Heuer C.
      Effects of increasing days of exposure to prepartum transition diets on reproduction and health in dairy cows.
      reported a positive association between DINCUD and the risk of pregnancy to first service and hazard of pregnancy during the lactation. The close-up diets fed in the studies by
      • DeGaris P.J.
      • Lean I.J.
      • Rabiee A.R.
      • Heuer C.
      Effects of increasing days of exposure to prepartum transition diets on milk production and milk composition in dairy cows.
      ,
      • DeGaris P.J.
      • Lean I.J.
      • Rabiee A.R.
      • Heuer C.
      Effects of increasing days of exposure to prepartum transition diets on reproduction and health in dairy cows.
      ,
      • DeGaris P.J.
      • Lean I.J.
      • Rabiee A.R.
      • Stevenson M.A.
      Effects of increasing days of exposure to prepartum diets on the concentration of certain blood metabolites in dairy cows.
      ) had DCAD ranging from −305 to −35 mEq/kg of DM. It is worth noting that the negative effects of extended DINCUD was also observed when cows were not fed acidogenic salts.
      • Contreras L.L.
      • Ryan C.M.
      • Overton T.R.
      Effects of dry cow grouping strategy and prepartum body condition score on performance and health of transition dairy cows.
      demonstrated that cows fed a diet containing higher NEL and CP and lower NDF during the last 60 d of gestation had reduced fat and protein content in milk and greater interval from calving to first AI compared with cows fed this diet only in the last 21 d of gestation. These data indicate that the length of feeding of close-up diets, generally containing higher NEL and CP and lesser NDF, is associated with the performance of dairy cows.
      The hypotheses of the current studies were that cows fed close-up diets for a shorter period have greater risk of uterine diseases, reduced yield of ECM, and reduced risk of pregnancy. In addition, it was hypothesized that DINCUD is associated with function and phenotype of PMN prepartum and metabolites peripartum. The objectives of the current studies were to determine the associations between DINCUD and the risks of uterine diseases and pregnancy and yield of ECM. Furthermore, it was the objective of this study to evaluate the association between DINCUD and prepartum function and phenotype of PMN and concentrations of nonesterified fatty acids (NEFA) and BHB peripartum of Jersey cows.

      MATERIALS AND METHODS

      These were retrospective cohort studies. Cows used in these studies were from 1 commercial dairy herd located in south central Minnesota. During the period in which studies 1 and 2 were conducted, there were approximately 6,500 lactating and 800 pregnant, nonlactating Jersey cows (first lactation = 38.4%, second lactation = 26.9%, third lactation or greater = 34.6%). The rolling herd average milk yield was 9,439.9 kg/305 d, parous cows remained in the dry period (mean ± SD) for 55.4 ± 13.7 d, and the mean (±SD) DINCUD was 28.2 ± 13.5. Cows were housed in 1 of 3 dairies located in an 8-mile radius. Two of the dairies had low-profile, cross-ventilated barns, with 2 rows of recycled sand-bedded freestalls per pen. In the third dairy, pregnant cows in later stages of lactation were housed in 2-row freestall, compost-bedded, naturally ventilated barns.
      In study 1, data from 1,290 Jersey animals (nulliparous = 323, parous = 967) that had been used in 2 previous experiments (experiment 1:
      • Silva P.R.
      • Moraes J.G.
      • Mendonça L.G.
      • Scanavez A.A.
      • Nakagawa G.
      • Fetrow J.
      • Endres M.I.
      • Chebel R.C.
      Effects of weekly regrouping of prepartum dairy cows on metabolic, health, reproductive, and productive parameters.
      ,
      • Silva P.R.
      • Moraes J.G.
      • Mendonça L.G.
      • Scanavez A.A.
      • Nakagawa G.
      • Ballou M.A.
      • Walcheck B.
      • Haines D.
      • Endres M.I.
      • Chebel R.C.
      Effects of weekly regrouping of prepartum dairy cows on innate immune response and antibody concentration.
      ; experiment 2:
      • Silva P.R.
      • Dresch A.R.
      • Machado K.S.
      • Moraes J.G.
      • Lobeck-Luchterhand K.
      • Nishimura T.K.
      • Ferreira M.A.
      • Endres M.I.
      • Chebel R.C.
      Prepartum stocking density: Effects on metabolic, health, reproductive, and productive responses.
      ,
      • Silva P.R.
      • Lobeck-Luchterhand K.M.
      • Cerri R.L.
      • Haines D.M.
      • Ballou M.A.
      • Endres M.I.
      • Chebel R.C.
      Effects of prepartum stocking density on innate and adaptive leukocyte responses and serum and hair cortisol concentrations.
      ) were used to investigate the associations between DINCUD and PMN function and phenotype prepartum, uterine health, BCS, NEFA, and BHB concentrations, locomotion score, return to cyclicity, and first postpartum AI outcomes. Cows used in study 1 calved between February 2011 and October 2011 (
      • Silva P.R.
      • Moraes J.G.
      • Mendonça L.G.
      • Scanavez A.A.
      • Nakagawa G.
      • Fetrow J.
      • Endres M.I.
      • Chebel R.C.
      Effects of weekly regrouping of prepartum dairy cows on metabolic, health, reproductive, and productive parameters.
      ,
      • Silva P.R.
      • Moraes J.G.
      • Mendonça L.G.
      • Scanavez A.A.
      • Nakagawa G.
      • Ballou M.A.
      • Walcheck B.
      • Haines D.
      • Endres M.I.
      • Chebel R.C.
      Effects of weekly regrouping of prepartum dairy cows on innate immune response and antibody concentration.
      ) and between October 2012 and March 2013 (
      • Silva P.R.
      • Dresch A.R.
      • Machado K.S.
      • Moraes J.G.
      • Lobeck-Luchterhand K.
      • Nishimura T.K.
      • Ferreira M.A.
      • Endres M.I.
      • Chebel R.C.
      Prepartum stocking density: Effects on metabolic, health, reproductive, and productive responses.
      ,
      • Silva P.R.
      • Lobeck-Luchterhand K.M.
      • Cerri R.L.
      • Haines D.M.
      • Ballou M.A.
      • Endres M.I.
      • Chebel R.C.
      Effects of prepartum stocking density on innate and adaptive leukocyte responses and serum and hair cortisol concentrations.
      ). Experiments 1 and 2 focused on housing strategies for the close-up period, and only 2 and 4 pens (44 stalls and 48 headlocks) were used, respectively, leaving 4,808 and 3,622 contemporaneous cows out of experiments 1 and 2, respectively. A detailed description of the eligibility criteria for enrollment in experiments 1 and 2 are described by
      • Silva P.R.
      • Moraes J.G.
      • Mendonça L.G.
      • Scanavez A.A.
      • Nakagawa G.
      • Fetrow J.
      • Endres M.I.
      • Chebel R.C.
      Effects of weekly regrouping of prepartum dairy cows on metabolic, health, reproductive, and productive parameters.
      ,
      • Silva P.R.
      • Dresch A.R.
      • Machado K.S.
      • Moraes J.G.
      • Lobeck-Luchterhand K.
      • Nishimura T.K.
      • Ferreira M.A.
      • Endres M.I.
      • Chebel R.C.
      Prepartum stocking density: Effects on metabolic, health, reproductive, and productive responses.
      ).
      In study 2, data from 16,834 Jersey animals (nulliparous = 6,843, parous = 9,991) that calved between February 2011 and March 2013, but were not enrolled in experiments 1 (
      • Silva P.R.
      • Moraes J.G.
      • Mendonça L.G.
      • Scanavez A.A.
      • Nakagawa G.
      • Fetrow J.
      • Endres M.I.
      • Chebel R.C.
      Effects of weekly regrouping of prepartum dairy cows on metabolic, health, reproductive, and productive parameters.
      ,
      • Silva P.R.
      • Moraes J.G.
      • Mendonça L.G.
      • Scanavez A.A.
      • Nakagawa G.
      • Ballou M.A.
      • Walcheck B.
      • Haines D.
      • Endres M.I.
      • Chebel R.C.
      Effects of weekly regrouping of prepartum dairy cows on innate immune response and antibody concentration.
      ) and 2 (
      • Silva P.R.
      • Dresch A.R.
      • Machado K.S.
      • Moraes J.G.
      • Lobeck-Luchterhand K.
      • Nishimura T.K.
      • Ferreira M.A.
      • Endres M.I.
      • Chebel R.C.
      Prepartum stocking density: Effects on metabolic, health, reproductive, and productive responses.
      ,
      • Silva P.R.
      • Lobeck-Luchterhand K.M.
      • Cerri R.L.
      • Haines D.M.
      • Ballou M.A.
      • Endres M.I.
      • Chebel R.C.
      Effects of prepartum stocking density on innate and adaptive leukocyte responses and serum and hair cortisol concentrations.
      ), were used to investigate the associations between DINCUD and risk of diseases, yield of milk and milk components, reproductive outcomes, and survival. Only cows with DINCUD between 1 and 45 and gestation length between 256 and 296 were used. The numbers of cows used in study 1 for the analyses of PMN activity and phenotype, uterine health, concentrations of NEFA and BHB, BCS, and lameness are depicted in Table 1.
      Table 1Number of cows used according to experiment
      Experiment 1: Silva et al. (2013a,b); experiment 2: Silva et al. (2014, 2016).
      and parity for each of the outcomes evaluated (study 1)
      ItemExperiment 1Experiment 2
      ParousNulliparousParous
      Overall
      Cows with data referent to health, reproductive, and productive outcomes.
      560272398
      BCS and locomotion score
       −28 d relative to calving560272398
       1 ± 1 DIM551272396
       31 ± 6 DIM525257370
       58 ± 5 DIM504253374
      Resumption of ovarian cycles
      Experiment 1: cows with a corpus luteum at 39 ± 3 or 53 ± 3 DIM were considered to have resumed ovarian cycles by 53 ± 3 DIM. Experiment 2: cows with progesterone concentration ≥1 ng/mL at 32 ± 6 or 45 ± 3 DIM were considered to have resumed ovarian cycles by 45 ± 3 DIM.
      504242362
      Nonesterified fatty acid504260386
      BHB503263392
      PMN683546
      1 Experiment 1:
      • Silva P.R.
      • Moraes J.G.
      • Mendonça L.G.
      • Scanavez A.A.
      • Nakagawa G.
      • Fetrow J.
      • Endres M.I.
      • Chebel R.C.
      Effects of weekly regrouping of prepartum dairy cows on metabolic, health, reproductive, and productive parameters.
      ,
      • Silva P.R.
      • Moraes J.G.
      • Mendonça L.G.
      • Scanavez A.A.
      • Nakagawa G.
      • Ballou M.A.
      • Walcheck B.
      • Haines D.
      • Endres M.I.
      • Chebel R.C.
      Effects of weekly regrouping of prepartum dairy cows on innate immune response and antibody concentration.
      ); experiment 2:
      • Silva P.R.
      • Dresch A.R.
      • Machado K.S.
      • Moraes J.G.
      • Lobeck-Luchterhand K.
      • Nishimura T.K.
      • Ferreira M.A.
      • Endres M.I.
      • Chebel R.C.
      Prepartum stocking density: Effects on metabolic, health, reproductive, and productive responses.
      ,
      • Silva P.R.
      • Lobeck-Luchterhand K.M.
      • Cerri R.L.
      • Haines D.M.
      • Ballou M.A.
      • Endres M.I.
      • Chebel R.C.
      Effects of prepartum stocking density on innate and adaptive leukocyte responses and serum and hair cortisol concentrations.
      ).
      2 Cows with data referent to health, reproductive, and productive outcomes.
      3 Experiment 1: cows with a corpus luteum at 39 ± 3 or 53 ± 3 DIM were considered to have resumed ovarian cycles by 53 ± 3 DIM. Experiment 2: cows with progesterone concentration ≥1 ng/mL at 32 ± 6 or 45 ± 3 DIM were considered to have resumed ovarian cycles by 45 ± 3 DIM.
      Animals with 0 lactations at the start of the close-up and 1 lactation during the study period are named “nulliparous” throughout, whereas cows with ≥1 lactation at the start of the close-up and ≥2 lactations during the study period are named “parous” throughout.

      Feeding, Housing, Disease Definition, and Data Collection

      From dry-off to −28 ± 3 d before expected calving date, cows were housed in sand-bedded, freestall, naturally ventilated barns. Animals were moved to the close-up pens 28 ± 3 d before expected calving date. Expected calving date was calculated by the on-farm software (DairyComp305, Valley Ag Software) according to the recorded date of establishment of pregnancy. During the close-up period through the end of the gestation, cows were housed in sand-bedded, freestall, cross-ventilated 10-row barns (2-row pens). At all phases of lactation and gestation, nulliparous and parous cows were housed in separate pens.
      Cows were fed prepartum diets to meet or exceed the requirements of the
      • NRC
      Nutrient Requirements of Dairy Cattle.
      according to parity and stage of gestation and postpartum diets according to stage of lactation, milk yield, and stage of gestation. During the close-up period, parous cows were fed acidogenic salts (Bio-Chlor, Arm and Hammer Animal Nutrition) to result in negative DCAD, but nulliparous cows were fed TMR with positive DCAD. During experiments 1 and 2, samples of the TMR fed to nulliparous and parous cows prepartum (far-off and close-up) and postpartum (calving to 21 DIM) were collected weekly, and, at the conclusion of the experiments, 1 sample per pen was submitted for wet chemistry analysis. Detailed information on the diets fed during the prepartum and postpartum periods is depicted in Table 2. Generally, prepartum diets were based on wheat straw, wheatlage, corn and soybean meal, and cotton seed. Conversely, postpartum diets were based on corn silage, alfalfa hay, corn and soybean meal, and cotton seed.
      Table 2Composition of diets (% of DM unless otherwise noted) formulated for the far-off (dry-off to 28 ± 3 d before expected calving date), close-up (28 ± 3 d before expected calving date), and postpartum (calving to 21 ± 3 DIM) periods during the experiments
      Experiment 1: Silva et al. (2013a,b); experiment 2: Silva et al. (2014, 2016).
      (study 1)
      VariableExperiment 1
      Only parous cows were enrolled in experiment 1.
      Experiment 2
      NulliparousParous
      Close-upPostpartumFar-offClose-upPostpartumFar-offClose-upPostpartum
      DM, %44.949.642.943.045.442.340.446.1
      NEL, Mcal/kg1.311.611.371.431.651.451.391.64
      CP13.4316.2014.3814.9817.6415.0514.6219.49
      ADF32.9021.7534.5532.2420.6633.3332.7921.44
      NDF44.8331.1149.8347.6632.9347.0547.3832.40
      NFC
      Calculated as DM − (CP + NDF + ether extract + ash).
      28.941.222.024.435.923.824.834.5
      Ether extract2.434.043.853.885.354.823.365.10
      Ash10.437.509.969.098.219.249.808.52
      Ca1.440.870.990.811.080.911.241.03
      P0.410.490.340.360.480.330.330.42
      Mg0.410.340.400.360.350.420.350.35
      K1.171.431.471.191.251.461.091.40
      Na0.130.370.230.130.370.230.150.47
      Cl1.210.380.620.470.330.600.970.48
      S0.340.270.250.260.310.250.310.30
      DCAD,
      Calculated as [(mEq of K) + (mEq of Na)] − [(mEq of Cl) + (mEq of S)].
      mEq/kg of DM
      −197.8251.4145.566.4194.4148.6−123.1240.2
      1 Experiment 1:
      • Silva P.R.
      • Moraes J.G.
      • Mendonça L.G.
      • Scanavez A.A.
      • Nakagawa G.
      • Fetrow J.
      • Endres M.I.
      • Chebel R.C.
      Effects of weekly regrouping of prepartum dairy cows on metabolic, health, reproductive, and productive parameters.
      ,
      • Silva P.R.
      • Moraes J.G.
      • Mendonça L.G.
      • Scanavez A.A.
      • Nakagawa G.
      • Ballou M.A.
      • Walcheck B.
      • Haines D.
      • Endres M.I.
      • Chebel R.C.
      Effects of weekly regrouping of prepartum dairy cows on innate immune response and antibody concentration.
      ); experiment 2:
      • Silva P.R.
      • Dresch A.R.
      • Machado K.S.
      • Moraes J.G.
      • Lobeck-Luchterhand K.
      • Nishimura T.K.
      • Ferreira M.A.
      • Endres M.I.
      • Chebel R.C.
      Prepartum stocking density: Effects on metabolic, health, reproductive, and productive responses.
      ,
      • Silva P.R.
      • Lobeck-Luchterhand K.M.
      • Cerri R.L.
      • Haines D.M.
      • Ballou M.A.
      • Endres M.I.
      • Chebel R.C.
      Effects of prepartum stocking density on innate and adaptive leukocyte responses and serum and hair cortisol concentrations.
      ).
      2 Only parous cows were enrolled in experiment 1.
      3 Calculated as DM − (CP + NDF + ether extract + ash).
      4 Calculated as [(mEq of K) + (mEq of Na)] − [(mEq of Cl) + (mEq of S)].
      Information regarding lactation number, previous lactation 305-d milk yield, gestation length, days dry, DINCUD, calving difficulty (1 = unassisted parturition; 2 = minimal assistance; 3 = moderate assistance; 4 = severe assistance; 5 = cesarean section or fetotomy), calf sex, twins, and stillbirth were recorded by farm personnel on DairyComp305 software and retrieved.

      Clinical Examination and Disease Definition

      Stillbirth was defined as calves that were dead at delivery or that died within 24 h of delivery. In study 1, study personnel examined cows starting 24 h after calving to determine and record the occurrence of retained fetal membranes (RFM; presence of fetal membranes >12 h after calving;
      • Kelton D.F.
      • Lissemore K.D.
      • Martin R.E.
      Recommendations for recording and calculating the incidence of selected clinical diseases of dairy cattle.
      ). In addition, study personnel palpated cows per rectum on d 4 ± 1, 7 ± 1, 10 ± 1, and 13 ± 1 postpartum for diagnosis of metritis, which was defined as watery, pink or brown, and fetid uterine discharge (adapted from
      • Chenault J.R.
      • McAllister J.F.
      • Chester T.
      • Dame K.J.
      • Kausche F.M.
      • Robb E.J.
      Efficacy of ceftiofur hydrochloride sterile suspension administered parenterally for the treatment of acute postpartum metritis in dairy cows.
      ). Cows diagnosed with metritis that had rectal temperature >39.5°C, anorexia, or depression were classified as having acute metritis (
      • LeBlanc S.
      Monitoring metabolic health of dairy cattle in the transition period.
      ). In study 2, farm personnel were trained to diagnose and record RFM (
      • Kelton D.F.
      • Lissemore K.D.
      • Martin R.E.
      Recommendations for recording and calculating the incidence of selected clinical diseases of dairy cattle.
      ) and acute metritis (
      • LeBlanc S.
      Monitoring metabolic health of dairy cattle in the transition period.
      ). Upon identification of a cow with anorexia, depression, or empty udder at milking, farm personnel determined the vaginal discharge through palpation per rectum and the rectal temperature. Cows with watery, pink or brown, and fetid uterine discharge, and rectal temperature >39.5°C, anorexia, or depression, were classified as having acute metritis (
      • LeBlanc S.
      Monitoring metabolic health of dairy cattle in the transition period.
      ).
      In studies 1 and 2, all cows were observed once daily by farm personnel for signs of anorexia, depression, empty udder at milking, and indigestion, and thrice daily during milking for mastitis. Cows with signs of anorexia, depression, and empty udder at milking were examined for displacement of abomasum, which was characterized by a metallic sound between the 7th and 13th intercostal space on the left or right side during auscultation and percussion. Herd managers were trained to identify cows with mastitis based on alterations of milk appearance and redness and firmness of the udder. Cows with scant manure, lack of appetite, and rumen stasis were diagnosed with indigestion. Incidences of displacement of abomasum, indigestion, and mastitis within 30 and 60 DIM were recorded. Percentages of cows that died and were sold within 60 and 305 DIM were calculated.

      Body Condition and Locomotion Scores (Study 1).

      Cows were scored for body condition (1 = emaciated, and 5 = obese; 0.25-unit increments;
      • Ferguson J.D.
      • Galligan D.T.
      • Thomsen N.
      Principal descriptors of body condition score in Holstein cows.
      ) and locomotion (1 = normal locomotion, and 5 = severely lame, as described by
      • Sprecher D.J.
      • Hostetler D.E.
      • Kaneene J.B.
      A lameness scoring system that uses posture and gait to predict dairy cattle reproductive performance.
      ) at 28 d before expected calving date, 1 ± 1, 32 ± 6, and 56 ± 3 DIM. Cows with a locomotion score (LS) ≥3 were considered lame. Within experiment, body condition and locomotion were scored by the same individual.

      Milk Yield and Milk Components.

      Cows were milked thrice daily and started to receive recombinant bST (500 mg of sometribove zinc suspension; Elanco Animal Health) 57 ± 3 d postpartum, at 11-d intervals, until 223 ± 3 d of gestation. The herd was enrolled in the official DHIA monthly test. Based on the monthly test data and the DIM at the completion of the lactation, the total milk yield, total yields of fat and protein, and total yields of 3.5% FCM and ECM were calculated. Test data collected between 5 and 34 DIM were used for the first test in the lactation, and so forth.
      The formulas used to calculate FCM and ECM were as follows:
      3.5% FCM (kg) = (0.432 × kg of milk) + (16.23 × kg of fat); and


      ECM (kg) = (kg of milk × 0.327) + (kg of fat × 12.95) + (kg of protein × 7.2).


      In study 1, ECM yield and MUN in the first test were analyzed. In study 2, first test yield of milk and ECM, protein and fat content, MUN, SCC, and percentage of cows with SCC >200,000 cells/mL were analyzed. In addition, in study 2, the lactational yield of milk, fat, protein, and ECM were analyzed.

      Resumption of Ovarian Cycles and Reproductive Management and Outcomes.

      In study 1, a subset of cows (experiment 1, n = 504;
      • Silva P.R.
      • Moraes J.G.
      • Mendonça L.G.
      • Scanavez A.A.
      • Nakagawa G.
      • Fetrow J.
      • Endres M.I.
      • Chebel R.C.
      Effects of weekly regrouping of prepartum dairy cows on metabolic, health, reproductive, and productive parameters.
      ) had their ovaries examined by ultrasound (5 MHz, Ibex Lite, E. I. Medical Imaging) at 39 ± 3 and 53 ± 3 DIM. Cows with a corpus luteum at either of the exams were considered to have resumed ovarian cycles by 53 ± 3 DIM. Furthermore, a different subset of cows (experiment 2, n = 604;
      • Silva P.R.
      • Dresch A.R.
      • Machado K.S.
      • Moraes J.G.
      • Lobeck-Luchterhand K.
      • Nishimura T.K.
      • Ferreira M.A.
      • Endres M.I.
      • Chebel R.C.
      Prepartum stocking density: Effects on metabolic, health, reproductive, and productive responses.
      ) had blood samples collected at 32 ± 6 and 45 ± 3 DIM, to determine progesterone concentration by solid-phase RIA using a commercial kit (Coat-a-Count Progesterone, Siemens Medical Solutions Diagnostics;
      • Kothari K.
      • Lal R.
      • Pillai M.R.A.
      Development of a direct radioimmunoassay for serum progesterone.
      ). The assay sensitivity was 0.10 ng/mL, and the intra- and interassay CV were 4.9 and 7.1%, respectively. Cows with at least 1 sample with progesterone concentration ≥1 ng/mL were considered to have resumed ovarian cycles by 45 ± 3 DIM. Using these data, the percentage of cows that had resumed cyclicity was calculated.
      Cows were presynchronized with 3 injections of PGF at 39 ± 3, 53 ± 3, and 67 ± 3 DIM. Cows observed in estrus after 50 DIM were inseminated, and those not observed in estrus by 79 ± 3 DIM were enrolled in the 5-d Cosynch protocol (d 0: GnRH, d 5: PGF, d 6: PGF, d 8: GnRH and timed AI). Cows that had not been re-AI were examined for pregnancy 31 ± 3 d after AI using ultrasound, and pregnant cows were re-examined 66 ± 3 and 178 ± 3 d after AI through palpation per rectum of the uterine contents. From February 2011 to October 2011, cows diagnosed not pregnant were immediately enrolled in the Ovsynch56 protocol (d 0: GnRH, d 7: PGF, d 9: PGF, d 10: GnRH and timed AI). From November 2011 to March 2013, cows diagnosed not pregnant at 31 ± 3 d after AI that had a corpus luteum received a PGF injection 2 d later and, if not reinseminated in estrus within 12 d, were enrolled in the 5-d Cosynch protocol for fixed-time reinsemination. Cows diagnosed not pregnant at 31 ± 3 d after AI that did not have a corpus luteum received a GnRH injection on the same day and, if not reinseminated within 7 d, were enrolled in the 5-d Cosynch protocol for fixed-time reinsemination.
      In study 1, sex-sorted semen was used in 20.1% of first services of nulliparous cows, whereas sex-sorted semen was used in 5.7% of first services of parous cows. In study 2, sex-sorted semen was used in 44.4% of first services of nulliparous cows, whereas sex-sorted semen was used in 25.5% of first services of parous cows. In study 2, sex-sorted semen was used in 16.8% of ≥ second services of nulliparous cows, whereas sex-sorted semen was used in 9.1% of ≥ second services of parous cows. The decision on the type of semen used was based solely on cows' lactation and DIM.

      Concentrations of NEFA and BHB (Study 1).

      Blood samples were collected from the coccygeal vein or artery into empty evacuated tubes and evacuated tubes containing K2 EDTA (Becton Dickinson Vacutainer Systems). Tubes were placed on ice until centrifugation for serum and plasma separation (1,200 × g for 15 min at 4°C). Plasma was aliquoted into microcentrifuge tubes and stored at −32°C until analysis.
      Blood samples collected weekly from −21 ± 3 d before expected calving date to 21 ± 3 DIM were used to determine NEFA concentrations. Concentrations of NEFA were determined using a colorimetric assay (Wako Chemicals USA;
      • Ballou M.A.
      • Gomes R.C.
      • Juchem S.O.
      • DePeters E.J.
      Effects of dietary supplemental fish oil during the peripartum period on blood metabolites and hepatic fatty acid compositions and total triacylglycerol concentrations of multiparous Holstein cows.
      ) using control serum (Randox Control Sera, Randox Laboratories). The intra- and interassay CV were 7 and 4%, respectively. Blood samples collected weekly from 3 ± 3 to 21 ± 3 DIM were used to determine concentrations of BHB using an enzymatic assay (Ranbut, Randox Laboratories;
      • Ballou M.A.
      • Gomes R.C.
      • Juchem S.O.
      • DePeters E.J.
      Effects of dietary supplemental fish oil during the peripartum period on blood metabolites and hepatic fatty acid compositions and total triacylglycerol concentrations of multiparous Holstein cows.
      ). The intra- and interassay CV were 11 and 8%, respectively.
      Data from wk −2 (−14 to −8 d relative to calving), −1 (−7 to −1 d relative to calving), 0 (0 to 6 DIM), 1 (7 to 14 DIM), and 2 (15 to 21 DIM) relative to calving were analyzed. Prepartum and postpartum data were analyzed separately. Concentrations of NEFA on wk −2 and −1 were analyzed separately because the range of DINCUD of cows that had blood sampled on wk −2 and −1 was different than the range of DINCUD of cows that had blood sampled only on wk −1.

      PMN Function and Phenotype (Study 1).

      A subsample of cows enrolled in experiments 1 (
      • Silva P.R.
      • Moraes J.G.
      • Mendonça L.G.
      • Scanavez A.A.
      • Nakagawa G.
      • Ballou M.A.
      • Walcheck B.
      • Haines D.
      • Endres M.I.
      • Chebel R.C.
      Effects of weekly regrouping of prepartum dairy cows on innate immune response and antibody concentration.
      ) and 2 (
      • Silva P.R.
      • Lobeck-Luchterhand K.M.
      • Cerri R.L.
      • Haines D.M.
      • Ballou M.A.
      • Endres M.I.
      • Chebel R.C.
      Effects of prepartum stocking density on innate and adaptive leukocyte responses and serum and hair cortisol concentrations.
      ) were used to determine PMN unction and phenotype. On the first day of each replicate, a subsample of cows (n = 5 to 6 cows per treatment per replicate) was chosen based on gestation length, to ensure that sampling occurred on the same date for all cows, for determination of PMN function and phenotype. Blood samples collected into 10-mL heparinized evacuated tubes on d −14 ± 1 and −7 ± 1 before expected calving date and at 0 ± 1, 7 ± 1, 14 ± 1, and 21 ± 1 DIM were used for determination of ex vivo PMN function (
      • Hulbert L.E.
      • Carroll J.A.
      • Burdick N.C.
      • Randel R.D.
      • Brown M.S.
      • Ballou M.A.
      Innate immune responses of temperamental and calm cattle after transportation.
      ). Data referent to PMN function and phenotype on wk −1 relative to calving were analyzed. The ranges of DINCUD were 19 to 44 d for nulliparous and 8 to 39 d for parous, from which samples were collected to determine PMN function and phenotype. Therefore, the data from nulliparous and parous animals were analyzed separately.
      Details of the assays are described in detail in
      • Silva P.R.
      • Moraes J.G.
      • Mendonça L.G.
      • Scanavez A.A.
      • Nakagawa G.
      • Ballou M.A.
      • Walcheck B.
      • Haines D.
      • Endres M.I.
      • Chebel R.C.
      Effects of weekly regrouping of prepartum dairy cows on innate immune response and antibody concentration.
      ,
      • Silva P.R.
      • Lobeck-Luchterhand K.M.
      • Cerri R.L.
      • Haines D.M.
      • Ballou M.A.
      • Endres M.I.
      • Chebel R.C.
      Effects of prepartum stocking density on innate and adaptive leukocyte responses and serum and hair cortisol concentrations.
      ). Indirect immunofluorescence staining was used to determine expression of adhesion molecules CD62L (L-selectin) and CD18 (β2-integrin) by peripheral PMN. Hemograms of all cows were performed before PMN function assays, and blood from cows presenting normal total blood count was used as positive and negative controls in all assays. Negative controls were incubated with 200 μL of PBS solution instead of monoclonal antibodies. Phagocytic and oxidative burst activities of peripheral PMN were determined upon challenge with enteropathogenic bacteria (Escherichia coli 0118:H8). Briefly, the assay consisted of incubating 200 µL of whole blood with 100 µM dihydrorhodamine 123 (Molecular Probes/Invitrogen), an oxidative-sensitive indicator, and 40 µL of fluorescently labeled bacteria (109 cfu/mL) at 38.5°C for 15 min, with surface bacteria fluorescence removed using Trypan Blue solution (0.4%; Sigma-Aldrich). Blood from cows presenting normal hemogram was used as positive and negative controls. Unlabeled bacteria were used as negative controls for the phagocytosis assay, and samples that received no dihydrorhodamine 123 served as negative controls for the oxidative burst assay. Flow cytometry was carried out on a Facscanto II (BD Biosciences) and analyzed using FlowJo 7.6.4 software (Tree Star Inc.). The PMN population was identified on the basis of forward- and side-scatter properties. After strictly gating the PMN population, forward scatter, side scatter, and log fluorescence data were recorded.
      Data reported herein is referent to percentages of PMN positive for phagocytosis and oxidative burst, and expressing CD18 and CD62L molecules. Furthermore, data referent to intensity of phagocytosis, oxidative burst, and expression of CD18 and CD62L molecules are reported herein as geometric mean fluorescence intensity (GMFI). Intensity of phagocytosis and intensity of expression of adhesion molecules are indirect indicators of the number of bacteria phagocytized by PMN and number of adhesion molecules expressed by PMN. However, oxidative burst intensity is an indirect indicator of the amount of reactive oxygen species produced via oxidation of dihydrorhodamine 123.

      Statistical Analyses

      These were retrospective cohort studies. Two key variables had to be accounted for (DINCUD and parity-diet), and their interaction had to be included in all models. Thus, post hoc sample size calculations were carried out for nulliparous and parous cows. Sample sizes of 255 nulliparous and 925 parous cows were sufficient to prevent types I (α = 0.05) and II (β = 0.20) errors when the differences in the incidences of metritis are, respectively, 7 percentage points (e.g., 18 vs. 25%) and 3.5 percentage points (e.g., 16.5 vs. 20%). Furthermore, 34 nulliparous cows were needed to detect a 6-percentage-point difference in PMN positive for phagocytosis and oxidative burst (SD = 12%; α = 0.05, β = 0.20), a 475-GMFI difference in phagocytosis (SD = 940; α = 0.05, β = 0.20), and a 1,775-GMFI difference in oxidative burst (SD = 3,600; α = 0.05, β = 0.20). Conversely, 109 parous cows were needed to detect a 3.25-percentage-point difference in PMN positive for phagocytosis and oxidative burst (SD = 12%; α = 0.05, β = 0.20), a 255-GMFI difference in phagocytosis (SD = 940; α = 0.05, β = 0.20), and a 975-GMFI difference in oxidative burst (SD = 3,600; α = 0.05, β = 0.20).
      All statistical analyses were conducted using SAS version 9.3 (SAS STAT, SAS Institute Inc.). Binary outcomes (male calf, twins, stillbirth, dystocia, calving problems, RFM, metritis, acute metritis, resumption of ovarian cycles, LS ≥3, displaced abomasum, mastitis, morbidity, removal from the herd, first AI in estrus, and pregnancy outcomes) were analyzed by logistic regression using the LOGISTIC procedure (study 1) and the GLIMMIX (study 2) procedure, with logit function and binomial distribution. Continuous outcomes (gestation length, days dry, DINCUD, NEFA and BHB concentrations, PMN responses, BCS, MUN concentration, SCC, and productive responses) were analyzed by ANOVA using the MIXED procedure. Continuous outcomes with repeated measures (e.g., NEFA and BHB postpartum) were analyzed with ANOVA for repeated measures via the MIXED procedure using the repeated statement and the cow as the random effect. The structure of covariance with the lowest Bayesian information criterion was compound symmetry. Ordinal data (e.g., BCS) were analyzed via the GENMOD procedure using a multinomial distribution and the cumulative logit link function. Using the regression coefficients of the final multivariable models, SAS was used to generate an estimate for each individual used in the statistical analysis. The estimates generated for each individual used in the multivariable models, in which DINCUD was used as a continuous variable, were also used to calculate the mean (±SEM) for cows that spent ≤10, 25 to 31 (28 ± 3), and 39 to 45 (42 ± 3) DINCUD. The data were presented in this manner to facilitate the discussion of the results of groups of cows with extreme DINCUD compared with cows with moderate DINCUD.
      In study 1, the models included parity-diet (nulliparous vs. parous), DINCUD (linear and quadratic), interactions between parity-diet and DINCUD (linear and quadratic), gestation length class (short ≤269 d, normal = 270–282 d, long ≥283 d), season of calving (hot vs. cold), offspring sex, calving-related problems (at least 1 reported case of stillbirth, twin calving, or dystocia), BCS (linear and quadratic), and LS ≥3 (yes vs. no) at 28 d before expected calving date, and a dummy variable that identified the experiment and treatment (4 levels). When analyzing outcomes of first insemination, technician inseminating the cow, type of insemination (estrus vs. fixed-time AI), and type of semen (sex-sorted vs. conventional) were included in the model. In study 2, 135 and 2,802 cows contributed with 3 and 2 lactations, respectively. Thus, for all statistical analyses referent to study 2, cow was used a random effect nested within lactation. The models used to analyze the data from study 2 included parity-diet (nulliparous vs. parous), DINCUD (linear and quadratic), the interactions between parity-diet and DINCUD (linear and quadratic), gestation-length class (short, normal, long), season of calving (hot vs. cold), offspring sex, and calving-related problems. In both studies, DIM on the day of the test (linear and quadratic) was added to the models to analyze data referent to the first postpartum milk test.
      All variables in the statistical models were tested for collinearity using the REG procedure and the VIF and COLLIN statements, and no variables had a variance inflation factor >1.5. In all models, a backward stepwise elimination procedure was adopted, and variables with P > 0.05 were removed until all variables that remained in the model had P ≤ 0.05. Statistical significance was declared when P ≤ 0.01, and a tendency was declared when 0.01 < P ≤ 0.05. Data are reported as least squares means ± SEM, unless otherwise stated. The best-fit line (linear or quadratic) was included in the figures when the DINCUD (linear or quadratic) was (P ≤ 0.01) or tended to be (0.01 < P ≤ 0.05) associated with the outcome of interest. When quadratic associations were depicted in figures, the peak and nadir of the association were assessed visually.

      RESULTS

      In study 1, data from 29 nulliparous and 7 parous cows were not used because of gestation length, and data from 22 nulliparous and 2 parous cows were not used because of DINCUD. In study 2, data from 2,112 nulliparous and 1,426 parous cows were not used because of gestation length, and data from 843 nulliparous and 491 parous cows were not used because of DINCUD.
      Descriptive statistics of cows enrolled in studies 1 and 2 are depicted in Table 3. In Table 4, Table 5, the estimated means (±SEM) for outcomes of interest are depicted for cows that spent ≤10, 28 ± 3, and 42 ± 3 DINCUD. Results presented herein are referent to the final multivariable analyses.
      Table 3Descriptive statistics according to study and parity
      Variable (±SD)Study 1
      Experiment 1: Silva et al. (2013a,b); experiment 2: Silva et al. (2014, 2016).
      Study 2
      Experiment 1Experiment 2
      Parous (n = 560)Nulliparous (n = 272)Parous (n = 398)Nulliparous (n = 3,888)Parous (n = 8,074)
      Previous lactation number1.73 ± 0.901.84 ± 1.121.95 ± 1.08
      Previous lactation 305-d ME,
      BCS: 1 = emaciated, 5 = obese, 0.25-unit increments (Ferguson et al., 1994).
      kg
      9,897.6 ± 4,712.710,224.6 ± 3,710.09,543.2 ± 2,284.1
      Previous lactation DIM323.4 ± 52.5312.2 ± 43.0322.1 ± 52.8
      Gestation length, d280.8 ± 5.7278.8 ± 5.9282.6 ± 5.2278.2 ± 6.6281.6 ± 5.3
      Days dry49.5 ± 14.658.8 ± 5.955.8 ± 7.3
      Days on the close-up diet period25.5 ± 6.229.0 ± 7.626.6 ± 5.527.0 ± 9.124.1 ± 6.4
      BCS
      BCS: 1 = emaciated, 5 = obese, 0.25-unit increments (Ferguson et al., 1994).
       28 d before expected calving date3.04 ± 0.413.16 ± 0.212.95 ± 0.3
       1 ± 1 DIM2.86 ± 0.383.01 ± 0.162.96 ± 0.24
       32 ± 6 DIM2.70 ± 0.362.96 ± 0.192.90 ± 0.27
       56 ± 3 DIM2.76 ± 0.412.99 ± 0.242.91 ± 0.28
      Locomotion score
      Locomotion score: 1 = normal locomotion, 5 = severely lame (Sprecher et al., 1997).
       ≥3 prepartum, %1.240.00.0
       ≥3 at 1 ± 1 DIM, %4.510.00.50
       ≥3 at 32 ± 6 DIM, %8.880.984.80
       ≥3 at 56 ± 3 DIM, %7.690.334.49
      Male calf, %48.832.754.240.054.6
      Twins, %3.20.04.80.74.6
      Stillbirth, %2.53.72.83.72.7
      Dystocia, %2.71.53.33.34.3
      Retained fetal membrane, %11.24.48.30.93.3
      Metritis,
      Metritis = cows with watery, pink or brown, and fetid uterine discharge. Acute metritis = cows with watery, pink or brown, and fetid uterine discharge, and rectal temperature >39.5°C, anorexia, or depression.
      %
      18.324.012.6
      Acute metritis,
      Metritis = cows with watery, pink or brown, and fetid uterine discharge. Acute metritis = cows with watery, pink or brown, and fetid uterine discharge, and rectal temperature >39.5°C, anorexia, or depression.
      %
      8.213.26.56.66.0
      Displaced abomasum by 60 DIM, %2.30.01.60.22.0
      Mastitis by 60 DIM, %11.75.43.46.76.8
      Morbidity by 60 DIM,
      Any of the following diseases: retained fetal membranes, metritis, displacement of the abomasum, mastitis, indigestion.
      %
      29.230.519.4
      Removed by 60 DIM, %8.95.95.35.08.6
      Removed by 305 DIM, %30.519.526.421.532.1
      Pregnant at 305 DIM, %74.376.174.183.176.8
      305-d milk yield, kg7,817.5 ± 2,816.46,437.5 ± 2,365.58,489.8 ± 2,892.56,857.2 ± 2,574.68,099.9 ± 3,138.7
      1 Experiment 1:
      • Silva P.R.
      • Moraes J.G.
      • Mendonça L.G.
      • Scanavez A.A.
      • Nakagawa G.
      • Fetrow J.
      • Endres M.I.
      • Chebel R.C.
      Effects of weekly regrouping of prepartum dairy cows on metabolic, health, reproductive, and productive parameters.
      ,
      • Silva P.R.
      • Moraes J.G.
      • Mendonça L.G.
      • Scanavez A.A.
      • Nakagawa G.
      • Ballou M.A.
      • Walcheck B.
      • Haines D.
      • Endres M.I.
      • Chebel R.C.
      Effects of weekly regrouping of prepartum dairy cows on innate immune response and antibody concentration.
      ); experiment 2:
      • Silva P.R.
      • Dresch A.R.
      • Machado K.S.
      • Moraes J.G.
      • Lobeck-Luchterhand K.
      • Nishimura T.K.
      • Ferreira M.A.
      • Endres M.I.
      • Chebel R.C.
      Prepartum stocking density: Effects on metabolic, health, reproductive, and productive responses.
      ,
      • Silva P.R.
      • Lobeck-Luchterhand K.M.
      • Cerri R.L.
      • Haines D.M.
      • Ballou M.A.
      • Endres M.I.
      • Chebel R.C.
      Effects of prepartum stocking density on innate and adaptive leukocyte responses and serum and hair cortisol concentrations.
      ).
      2 BCS: 1 = emaciated, 5 = obese, 0.25-unit increments (
      • Ferguson J.D.
      • Galligan D.T.
      • Thomsen N.
      Principal descriptors of body condition score in Holstein cows.
      ).
      3 Locomotion score: 1 = normal locomotion, 5 = severely lame (
      • Sprecher D.J.
      • Hostetler D.E.
      • Kaneene J.B.
      A lameness scoring system that uses posture and gait to predict dairy cattle reproductive performance.
      ).
      4 Metritis = cows with watery, pink or brown, and fetid uterine discharge. Acute metritis = cows with watery, pink or brown, and fetid uterine discharge, and rectal temperature >39.5°C, anorexia, or depression.
      5 Any of the following diseases: retained fetal membranes, metritis, displacement of the abomasum, mastitis, indigestion.
      Table 4Estimated probabilities of uterine diseases, locomotion score (LS) ≥3, BCS, nonesterified fatty acid (NEFA), and first test yield of milk and milk components according to parity-diet and days on the close-up diet (DINCUD) calculated based on the β-coefficients of the final multivariable models (study 1)
      Retained fetal membranes, metritis, acute metritis, BCS, and LS were diagnosed or evaluated by study personnel.
      Variable (means ± SEM)NulliparousParousP-value
      ≤10 d28 ± 3 d42 ± 3 d≤10 d28 ± 3 d42 ± 3 dDINCUDParity- dietDINCUD × Parity-diet
      Retained fetal membranes, %22.2 ± 4.82.9 ± 0.16.5 ± 0.566.4 ± 3.96.1 ± 0.24.0 ± 0.3<0.01
      Quadratic effect of DINCUD.
      <0.010.03
      Linear effect of DINCUD.
      Metritis,
      Metritis = cows with watery, pink or brown, and fetid uterine discharge. Acute metritis = cows with watery, pink or brown, and fetid uterine discharge, and rectal temperature >39.5°C, anorexia, or depression.
      %
      81 ± 2.810.9 ± 0.316 ± 1.331.9 ± 6.922.5 ± 0.729.3 ± 1.9<0.01
      Quadratic effect of DINCUD.
      <0.010.02
      Quadratic effect of DINCUD.
      Acute metritis,
      Metritis = cows with watery, pink or brown, and fetid uterine discharge. Acute metritis = cows with watery, pink or brown, and fetid uterine discharge, and rectal temperature >39.5°C, anorexia, or depression.
      %
      15.2 ± 6.59.1 ± 0.615.7 ± 2.262.5 ± 5.44.0 ± 0.26.4 ± 0.8<0.01
      Quadratic effect of DINCUD.
      <0.010.02
      Quadratic effect of DINCUD.
      NEFA wk −1, mmol/L0.21 ± 0.050.22 ± 0.020.24 ± 0.020.13 ± 0.020.14 ± 0.020.15 ± 0.02<0.01
      Linear effect of DINCUD.
      <0.010.72
      NEFA postpartum, mmol/L0.22 ± 0.020.29 ± 0.010.34 ± 0.010.21 ± 0.010.26 ± 0.010.30 ± 0.01<0.01
      Linear effect of DINCUD.
      0.100.65
      BHB postpartum, mmol/L0.41 ± 0.020.46 ± 0.010.47 ± 0.010.36 ± 0.010.44 ± 0.010.45 ± 0.010.730.990.49
      BCS
      BCS: 1 = emaciated, 5 = obese, 0.25-unit increments (Ferguson et al., 1994).
       1 ± 1 DIM2.99 ± 0.013.01 ± 0.013.00 ± 0.022.90 ± 0.062.90 ± 0.012.80 ± 0.060.02
      Linear effect of DINCUD.
      <0.010.67
       32 ± 6 DIM2.94 ± 0.042.96 ± 0.012.99 ± 0.022.83 ± 0.052.76 ± 0.012.76 ± 0.080.150.08<0.01
      Linear effect of DINCUD.
       56 ± 3 DIM2.80 ± 0.043.00 ± 0.013.01 ± 0.022.97 ± 0.052.80 ± 0.012.87 ± 0.070.22<0.010.02
      Quadratic effect of DINCUD.
      LS
      LS: 1 = normal locomotion, 5 = severely lame (Sprecher et al., 1997).
       ≥3 1 ± 1 DIM, %6.2 ± 0.41.7 ± 0.00.7 ± 0.06.0 ± 0.22.0 ± 0.10.8 ± 0.00.03
      Linear effect of DINCUD.
      0.950.99
       ≥3 32 ± 6 DIM, %1.6 ± 0.51.2 ± 0.01.2 ± 0.111.1 ± 5.17.0 ± 0.45.4 ± 0.00.23<0.010.31
       ≥3 56 ± 3 DIM, %0.5 ± 0.20.4 ± 0.00.4 ± 0.09.8 ± 4.75.8 ± 0.34.5 ± 0.00.350.010.19
      First test ECM, kg/d22.6 ± 0.0222.5 ± 0.122.6 ± 0.224.4 ± 1.033.1 ± 0.138.8 ± 0.7<0.01
      Linear effect of DINCUD.
      0.70<0.01
      Linear effect of DINCUD.
      First test MUN, mg/dL15.6 ± 1.013.1 ± 0.113.7 ± 0.27.3 ± 0.711.2 ± 0.213.3 ± 0.70.07
      Quadratic effect of DINCUD.
      0.010.02
      Quadratic effect of DINCUD.
      First AI at estrus, %95.8 ± 0.881.0 ± 0.192 ± 0.498.0 ± 0.290.5 ± 0.295.7 ± 0.20.02
      Quadratic effect of DINCUD.
      <0.010.08
      Pregnancy 31 ± 3 d after first AI, %35.4 ± 4.051.0 ± 1.041.1 ± 1.923.7 ± 1.446.8 ± 0.438.7 ± 2.60.02
      Quadratic effect of DINCUD.
      0.690.42
      Linear effect of DINCUD.
      Pregnancy 66 ± 3 d after first AI, %26.4 ± 4.941.6 ± 1.528.1 ± 2.416.0 ± 2.440.6 ± 0.529.4 ± 2.10.06
      Quadratic effect of DINCUD.
      0.540.63
      1 Retained fetal membranes, metritis, acute metritis, BCS, and LS were diagnosed or evaluated by study personnel.
      2 Metritis = cows with watery, pink or brown, and fetid uterine discharge. Acute metritis = cows with watery, pink or brown, and fetid uterine discharge, and rectal temperature >39.5°C, anorexia, or depression.
      3 BCS: 1 = emaciated, 5 = obese, 0.25-unit increments (
      • Ferguson J.D.
      • Galligan D.T.
      • Thomsen N.
      Principal descriptors of body condition score in Holstein cows.
      ).
      4 LS: 1 = normal locomotion, 5 = severely lame (
      • Sprecher D.J.
      • Hostetler D.E.
      • Kaneene J.B.
      A lameness scoring system that uses posture and gait to predict dairy cattle reproductive performance.
      ).
      Linear effect of DINCUD.
      Quadratic effect of DINCUD.
      Table 5Estimated probabilities of nonuterine diseases and culling, and yield of milk and milk components (±SEM) according to parity-diet and days on the close-up diet (DINCUD), calculated based on the β-coefficients of the final multivariable models (study 2)
      Variable (means ± SEM)NulliparousParousP-value
      ≤10 d28 ± 3 d42 ± 3 d≤10 d28 ± 3 d42 ± 3 dDINCUDParity- dietDINCUD × Parity-diet
      Retained fetal membranes, %2.5 ± 0.20.6 ± 0.10.4 ± 0.126.1 ± 1.91.5 ± 0.10.5 ± 0.1<0.01
      Linear effect of DINCUD.
      <0.01<0.01
      Linear effect of DINCUD.
      Acute metritis,
      Cows diagnosed with metritis (watery, pink or brown, and fetid uterine discharge) that had rectal temperature >39.5°C, anorexia, or depression.
      %
      14.3 ± 0.85.4 ± 0.18.6 ± 0.234.8 ± 1.33.4 ± 0.12.0 ± 0.1<0.01
      Quadratic effect of DINCUD.
      <0.01<0.01
      Linear effect of DINCUD.
      Displaced abomasum by 30 DIM, %0.22 ± 0.010.23 ± 0.010.24 ± 0.011.78 ± 0.031.75 ± 0.011.84 ± 0.030.70<0.010.41
      First test SCC >200,000 cells/mL, %34.0 ± 0.140.5 ± 0.141.7 ± 0.163.4 ± 0.933.8 ± 0.144.7 ± 0.50.03
      Quadratic effect of DINCUD.
      <0.01<0.01
      Quadratic effect of DINCUD.
      Mastitis by 60 DIM, %7.5 ± 0.16.6 ± 0.19.1 ± 0.17.6 ± 0.16.6 ± 0.19.0 ± 0.20.02
      Quadratic effect of DINCUD.
      0.310.48
      Indigestion
      Cows with scant manure, lack of appetite, and rumen stasis.
      by 60 DIM, %
      6.6 ± 0.32.4 ± 0.14.4 ± 0.111.4 ± 0.53.8 ± 0.16.5 ± 0.2<0.01
      Quadratic effect of DINCUD.
      <0.010.30
      Dead by 60 DIM, %1.14 ± 0.040.89 ± 0.010.79 ± 0.012.93 ± 0.101.98 ± 0.011.75 ± 0.060.42<0.010.61
      Sold by 60 DIM, %4.7 ± 0.23.4 ± 0.14.7 ± 0.117.1 ± 0.95.7 ± 0.14.4 ± 0.10.99<0.01<0.01
      Linear effect of DINCUD.
      Removed by 305 DIM, %27.0 ± 0.520.7 ± 0.121.8 ± 0.145.1 ± 0.731.1 ± 0.128.1 ± 0.30.32<0.01<0.01
      Linear effect of DINCUD.
      First test milk, kg/d20.7 ± 0.222.9 ± 0.122.7 ± 0.124.5 ± 0.231.6 ± 0.133.1 ± 0.3<0.01
      Quadratic effect of DINCUD.
      0.690.01
      Quadratic effect of DINCUD.
      First test fat, %4.11 ± 0.023.92 ± 0.013.86 ± 0.014.34 ± 0.024.25 ± 0.014.16 ± 0.03<0.01
      Linear effect of DINCUD.
      <0.010.13
      First test protein, %3.43 ± 0.023.39 ± 0.013.39 ± 0.013.71 ± 0.023.65 ± 0.013.55 ± 0.03<0.01
      Linear effect of DINCUD.
      <0.010.02
      Linear effect of DINCUD.
      First test ECM, kg/d23.7 ± 0.0225.3 ± 0.125.3 ± 0.128.5 ± 0.235.9 ± 0.136.6 ± 0.3<0.01
      Quadratic effect of DINCUD.
      0.47<0.01
      Quadratic effect of DINCUD.
      First test SCC118.0 ± 2.4120.9 ± 1.0134.4 ± 1.8150.5 ± 3.499.0 ± 0.5112.3 ± 3.9<0.01
      Quadratic effect of DINCUD.
      <0.01<0.01
      Quadratic effect of DINCUD.
      First test MUN, mg/dL11.03 ± 0.0611.53 ± 0.0211.16 ± 0.0310.91 ± 0.0511.78 ± 0.0110.36 ± 0.07<0.01
      Quadratic effect of DINCUD.
      0.380.03
      Quadratic effect of DINCUD.
      Total milk yield, kg × 1036.52 ± 0.036.88 ± 0.016.98 ± 0.016.70 ± 0.048.29 ± 0.018.13 ± 0.02<0.01
      Quadratic effect of DINCUD.
      0.13<0.01
      Quadratic effect of DINCUD.
      Total fat yield, kg300.8 ± 0.1308.7 ± 0.1305.7 ± 0.1302.7 ± 0.1370.2 ± 0.1354.3 ± 0.1<0.01
      Quadratic effect of DINCUD.
      0.04<0.01
      Quadratic effect of DINCUD.
      Total protein yield, kg235.1 ± 0.1245.5 ± 0.1245.0 ± 0.1243.0 ± 0.1297.6 ± 0.1293.7 ± 0.1<0.01
      Quadratic effect of DINCUD.
      0.14<0.01
      Quadratic effect of DINCUD.
      Total ECM, kg × 1037.91 ± 0.038.17 ± 0.018.15 ± 0.017.99 ± 0.059.79 ± 0.019.52 ± 0.03<0.01
      Quadratic effect of DINCUD.
      0.05<0.01
      Quadratic effect of DINCUD.
      Pregnant by 305 DIM, %80.4 ± 0.483.3 ± 0.182.8 ± 0.259.5 ± 0.778.3 ± 0.173.1 ± 0.50.03
      Quadratic effect of DINCUD.
      <0.01<0.01
      Quadratic effect of DINCUD.
      1 Cows diagnosed with metritis (watery, pink or brown, and fetid uterine discharge) that had rectal temperature >39.5°C, anorexia, or depression.
      2 Cows with scant manure, lack of appetite, and rumen stasis.
      Linear effect of DINCUD.
      Quadratic effect of DINCUD.

      Association Between DINCUD and Uterine Health and PMN Function and Phenotype (Study 1)

      The interaction between DINCUD (linear) and parity-diet tended to be (P = 0.03) associated with the odds of RFM, and a quadratic association between DINCUD and the odds of RFM (Figure 1) was detected (P < 0.01). The odds of metritis tended to be (P = 0.02) associated with the interaction between DINCUD (quadratic) and parity-diet (Figure 1). The interaction between DINCUD (quadratic) and parity-diet tended to be (P = 0.02) associated with the odds of acute metritis (Figure 1). In general, more dramatic increases in the probability of uterine diseases (RFM, metritis, and acute metritis) were observed among parous cows with shorter DINCUD, and the odds of uterine diseases among nulliparous were associated with shortened and extended DINCUD.
      Figure thumbnail gr1
      Figure 1Association between days on the close-up diet (DINCUD) and the probability of uterine diseases. Retained fetal membranes: DINCUD (quadratic) P < 0.01, parity-diet P < 0.01, and DINCUD (linear) × parity-diet P = 0.03. Metritis: DINCUD (quadratic) P < 0.01, parity-diet P < 0.01, and DINCUD (quadratic) × parity-diet P = 0.02. Acute metritis: DINCUD (quadratic) P < 0.01, parity-diet P < 0.01, and DINCUD (quadratic) × parity-diet P = 0.02. Retained fetal membranes = presence of fetal membranes >12 h after calving. Metritis = watery, pink or brown, and fetid uterine discharge. Acute metritis = cows with metritis and rectal temperature >39.5°C, anorexia, or depression. Dashed lines = 95% CI.
      Number of days on the close-up diet was (P < 0.01) positively associated with the percentage of PMN from parous cows positive for phagocytosis and oxidative burst prepartum (Figure 2), but not (P = 0.39) in nulliparous cows. Similarly, among parous cows, DINCUD was (P < 0.01) positively associated with the intensity of phagocytosis by PMN prepartum, but not (P = 0.56) in nulliparous cows (Figure 2). The association between DINCUD and intensity of oxidative burst by PMN prepartum was (P < 0.01) positive among parous cows (Figure 2), but such association was not (P = 0.07) detected among nulliparous cows. Length of time in the close-up diet was not (P ≥ 0.42) associated with the intensity of expression of CD18 and CD62L by PMN prepartum among nulliparous cows. Although, among parous cows, DINCUD was not (P = 0.90) associated with the intensity of expression of CD18, a positive association (P = 0.01) was detected between DINCUD and the intensity of expression of CD62L by PMN prepartum (Figure 2).
      Figure thumbnail gr2
      Figure 2Association between days on the close-up diet (DINCUD) and percentage of PMN positive for phagocytosis and oxidative burst (phago. oxid.) and intensity of phagocytosis, oxidative burst, and expression of CD62L in wk −1 relative to calving among parous cows. Association of DINCUD with percentage of PMN positive for phagocytosis and oxidative burst P < 0.01 (linear), intensity of phagocytosis P < 0.01 (linear), intensity of oxidative burst P < 0.01 (linear), and intensity of expression of CD62L P = 0.01 (linear). GMFI = geometric mean fluorescence intensity. Dashed lines = 95% CI.

      Association Between DINCUD and NEFA and BHB Concentrations, BCS, and Lameness (Study 1)

      Although DINCUD was not (P = 0.28) associated with NEFA concentrations in wk −2, a positive association (P < 0.01) was detected between DINCUD and NEFA concentrations in wk −1 (Figure 3), independent of parity. The association between DINCUD and NEFA concentration postpartum was (P = 0.01) positive (Figure 3) and independent of parity and week postpartum. The interaction between DINCUD (quadratic) and week postpartum tended to be (P = 0.02) associated with BHB concentrations in wk 0, 1, and 2 postpartum (Figure 3). Greater differences in BHB concentrations between the extremes of DINCUD were observed in wk 1 and 2.
      Figure thumbnail gr3
      Figure 3Association between days on the close-up diet (DINCUD) and concentrations of nonesterified fatty acid (NEFA) peripartum and BHB postpartum. NEFA week −1: DINCUD (linear) P < 0.01, NEFA postpartum: DINCUD (linear) P < 0.01. BHB: DINCUD (quadratic) P = 0.73, week P = 0.61, DINCUD (quadratic) × week P = 0.02. Dashed lines = 95% CI.
      A tendency (P = 0.02) was detected for a linear association between DINCUD and BCS at 1 ± 1 DIM (Table 4). The interaction between DINCUD (linear) and parity-diet was (P < 0.01) associated with BCS at 32 ± 6 DIM as, among nulliparous cows, BCS increased with increasing DINCUD, but among parous cows, BCS decreased with increasing DINCUD, reaching a plateau at approximately 28 DINCUD. The interaction between DINCUD (quadratic) and parity-diet tended to be (P = 0.02) associated with BCS at 56 ± 3 DIM because BCS increased with increasing DINCUD in nulliparous cows, but, among parous cows, the estimated BCS was lowest for cows spending approximately 28 ± 3 DINCUD (Table 3). Although DINCUD tended (P = 0.03) to be negatively associated with the odds of LS ≥3 at 1 ± 1 DIM, no associations were detected (P ≥ 0.23) between DINCUD and the odds of LS ≥3 at 32 ± 6 and 56 ± 3 DIM.

      Association Between DINCUD and Estrous Cyclicity and First Service Outcomes (Study 1)

      No associations were detected (P ≥ 0.29) between DINCUD and resumption of cyclicity and between DINCUD and hazard of first AI. The interaction between DINCUD (quadratic) and parity-diet, however, tended (P = 0.02) to be associated with the odds of first AI in estrus, as cows with approximately 28 DINCUD had the lowest odds of first AI in estrus. There tended (P = 0.02) to be a quadratic association between DINCUD and the odds of pregnancy 31 ± 3 d after the first AI, but DINCUD was not (quadratic, P = 0.06) associated with the odds of pregnancy 66 ± 3 d after the first AI (Figure 4). Number of days on the close-up diet was not (P = 0.28) associated with the odds of pregnancy loss from 31 to 66 d after the first AI.
      Figure thumbnail gr4
      Figure 4Association between days on the close-up diet (DINCUD) and the probability of pregnancy at 31 ± 3 and 66 ± 3 d after the first AI and the probability of pregnancy by 305 DIM. Pregnant to the first AI: 31 ± 3 d after AI | DINCUD (quadratic) P = 0.02; 66 ± 3 d after AI | DINCUD (quadratic) P = 0.06. Pregnancy by 305 DIM: DINCUD (quadratic) P = 0.03, parity-diet P < 0.01, DINCUD (quadratic) × parity-diet P < 0.01. Dashed lines = 95% CI.

      Association Between DINCUD and Diseases and Removal from the Herd (Study 2)

      The odds of RFM and acute metritis were (P < 0.01) negatively associated with the interaction between DINCUD and parity-diet. The highest odds of RFM and acute metritis were observed when DINCUD was reduced but, among nulliparous cows, a slight increase in the odds of acute metritis was detected as DINCUD increased beyond 28 d.
      The interaction between DINCUD (quadratic) and parity-diet was (P < 0.01) associated with the odds of SCC >200,000 cells/mL in the first test. Among nulliparous cows, the probability of having SCC >200,000 cells/mL in the first test varied minimally according to DINCUD, but among parous cows, the lowest probability of SCC >200,000 cells/mL in the first test was associated with approximately 28 DINCUD (Figure 5). Regardless of parity-diet, DINCUD had a positive (P < 0.01) association with the odds of mastitis by 30 DIM and tended (P = 0.02) to have a quadratic association with the odds of mastitis by 60 DIM. The lowest probability of mastitis by 60 DIM was associated with approximately 21 DINCUD (Figure 5).
      Figure thumbnail gr5
      Figure 5Associations between days on the close-up diet (DINCUD) and the probability of SCC >200,000 cells/mL on the first test, mastitis by 30 and 60 DIM, and indigestion by 60 DIM. SCC >200,000 cells/mL: DINCUD (quadratic) P = 0.03, parity-diet P < 0.01, DINCUD (quadratic) × parity-diet P < 0.01. Mastitis: 30 DIM | DINCUD (linear) P < 0.01; 60 DIM | DINCUD (quadratic) P = 0.02. Indigestion: DINCUD (quadratic) P < 0.01. Dashed lines = 95% CI.
      Although DINCUD was not associated with the odds of displaced abomasum by 30 and 60 DIM (P ≥ 0.27), a quadratic association (P < 0.01) was detectable between DINCUD and the odds of indigestion by 60 DIM. The lowest probability of indigestion was observed when cows had approximately 28 DINCUD (Figure 5). Number of days on the close-up diet was not (P = 0.42) associated with the odds of cows dying by 60 DIM, but the interaction between DINCUD and parity-diet was (P < 0.01) associated with the odds of being sold by 60 DIM. A negligible association occurred between DINCUD and the odds of nulliparous cows being sold by 60 DIM, but the odds of parous cows being sold by 60 DIM increased when DINCUD was <15. Finally, the interaction between DINCUD (linear) and parity-diet was (P < 0.01) associated with the odds of a cow being removed from the herd by 305 DIM. Shorter DINCUD was associated with a slight increase in the probability of nulliparous cows being removed by 305 DIM, but shorter DINCUD was associated with an accentuated increase in the odds of parous cows being removed by 305 DIM (Figure 6).
      Figure thumbnail gr6
      Figure 6Associations between days on the close-up diet (DINCUD) and removal from the herd by 305 DIM and 305-d yield of ECM. Removed by 305 DIM: DINCUD (quadratic) P = 0.32, parity-diet P = 0.01, DINCUD (linear) × parity-diet P < 0.01. ECM yield (305-d): DINCUD (quadratic) P < 0.01, parity-diet P = 0.05, DINCUD (quadratic) × parity-diet P < 0.01. Dashed lines = 95% CI.

      Association Between DINCUD and Productive Outcomes in the First Postpartum Test

      In study 1, the yield of ECM was (P < 0.01) associated with the interaction between DINCUD (linear) and parity-diet. Length of time in the close-up diet was not associated with the yield of ECM of nulliparous cows in the first test, but for every 1 extra DINCUD the yield of ECM of parous cows in the first test increased by 0.43 kg/d. The concentration of MUN in the first test tended (P = 0.02) to be associated with the interaction between DINCUD (quadratic) and parity-diet. Milk urea nitrogen increased as DINCUD of nulliparous cows decreased, but MUN of parous cows increased as DINCUD increased.
      In study 2, first test milk yield was (P < 0.01) associated with the interaction between DINCUD (quadratic) and parity-diet. The first test milk yield of nulliparous cows increased up to approximately 28 DINCUD, when it reached a plateau, whereas the first test milk yield of parous cows continuously increased until 45 DINCUD. A negative association (P < 0.01) occurred between DINCUD and milk fat content in the first test. The interaction between DINCUD (linear) and parity-diet tended (P = 0.02) to be associated with milk protein content in the first test because the nadir for nulliparous cows was reached at approximately 28 DINCUD but milk protein content continued to decrease for parous cows until 45 DINCUD. The interaction between DINCUD (quadratic) and parity-diet was (P < 0.01) associated with the first test ECM yield. The highest estimated ECM yield was associated with 42 ± 3 DINCUD, but the changes in the estimated ECM yield associated with an increase in DINCUD from 28 ± 3 to 42 ± 3 d were 0.008 and 0.702 kg/d for nulliparous and parous cows, respectively. The interaction between DINCUD (quadratic) and parity-diet was (P < 0.01) and tended to be (P = 0.03) associated with the first test somatic cell count and MUN, respectively. Among nulliparous cows, SCC increased as DINCUD increased, but, among parous cows, DINCUD of approximately 28 d was associated with the lowest SCC. Regardless of parity, DINCUD of approximately 28 d was associated with higher MUN.

      Association Between DINCUD and Long-Term Productive and Reproductive Responses (Study 2)

      In study 2, the total yield of milk, fat, protein, and ECM (Figure 6) were (P < 0.01) associated with the interaction between DINCUD (quadratic) and parity-diet. A progressive increase in total milk yield of nulliparous cows was detectable up to 45 DINCUD, whereas total milk yield of parous cows reached a peak at approximately 28 ± 3 DINCUD and slightly decreased up to 45 DINCUD. As DINCUD increased from ≤10 to 28 ± 3 d, the total yields of fat, protein, and ECM of nulliparous cows increased by approximately 7.9, 10.4, and 260 kg. The total yields of fat, protein, and ECM of parous cows increased by approximately 67.5, 54.6, and 1,800 kg as DINCUD increased from ≤10 to 28 ± 3 d. Among nulliparous cows, the decreases in the estimated total fat, protein, and ECM yields when DINCUD increased from 28 ± 3 to 42 ± 3 d were approximately 3.0, 0.5, and 23.3 kg, respectively, but among parous cows these decreases were approximately 15.8, 3.9, 275.6 kg, respectively.
      The odds of cows becoming pregnant by 305 DIM was (P < 0.01) associated with the interaction between DINCUD (quadratic) and parity-diet. The highest probability of cows becoming pregnant by 305 DIM was observed at approximately 28 DINCUD, regardless of parity-diet (Figure 4). Among nulliparous cows, a decrease in DINCUD from 28 ± 3 to ≤10 d was associated with a decrease in the probability of 0.029, and an increase in DINCUD from 28 ± 3 to 42 ± 3 DINCUD was associated with a decrease in the probability of 0.005. The probability of parous cows being pregnant by 305 DIM decreased by 0.188 when DINCUD decreased from 28 ± 3 to ≤10 d, whereas it decreased by 0.052 when DINCUD increased from 28 ± 3 to 42 ± 3 DINCUD.

      DISCUSSION

      The importance of metabolic and immune adaptations during the transition from the nonlactating to the lactating state cannot be overstated. In the past decades, an increasing amount of research has focused on nutritional, hormonal, and management strategies to reduce the risk of health disorders peripartum, improve lactation performance, and ensure the prompt establishment of pregnancy after the end of the voluntary waiting period. Among nutritional strategies, growing evidence demonstrates that in the latter weeks of gestation, adequate mineral (
      • Gaynor P.J.
      • Mueller F.J.
      • Miller J.K.
      • Ramsey N.
      • Goff J.P.
      • Horst R.L.
      Parturient hypocalcemia in jersey cows fed alfalfa haylage-based diets with different cation to anion ratios.
      ), protein (
      • Husnain A.
      • Santos J.E.P.
      Meta-analysis of the effects of prepartum dietary protein on performance of dairy cows.
      ), and energy (
      • Rabelo E.
      • Bertics S.J.
      • Mackovic J.
      • Grummer R.R.
      Strategies for increasing energy density of dry cow diets.
      ) supplies are needed. As a result of such research, herds generally adopt 2 diets during the dry period, and the diets fed in the last 3 to 4 wk prepartum generally have slightly greater energy and protein contents than the diets fed earlier in the dry period. Some herds also adopt the feeding of acidogenic salts and reduce concentrations of strong cations to create a negative DCAD to prevent hypocalcemia (
      • Goff J.P.
      • Horst R.L.
      • Mueller F.J.
      • Miller J.K.
      • Kiess G.A.
      • Dowlen H.H.
      Addition of chloride to a prepartal diet high in cations increases 1,25-dihydroxyvitamin D response to hypocalcemia preventing milk fever.
      ;
      • Santos J.E.P.
      • Lean I.J.
      • Golder H.
      • Block E.
      Meta-analysis of the effects of prepartum dietary cation-anion difference on performance and health of dairy cows.
      ). In the current studies, diets fed to parous cows in the close-up period contained acidogenic salts and, according to the samples collected during study 1, had DCAD between −200 and −120 mEq/kg, which is within the range considered adequate to improve production and reduce the incidence of postpartum diseases (
      • Lean I.J.
      • Santos J.E.P.
      • Block E.
      • Golder H.M.
      Effects of prepartum dietary cation-anion difference intake on production and health of dairy cows: A meta-analysis.
      ;
      • Santos J.E.P.
      • Lean I.J.
      • Golder H.
      • Block E.
      Meta-analysis of the effects of prepartum dietary cation-anion difference on performance and health of dairy cows.
      ).
      In the current studies, the odds of uterine diseases were associated with the interaction between DINCUD and parity-diet. A more dramatic increase in the odds of uterine diseases was observed when DINCUD was shorter among parous than nulliparous cows, and, regardless of parity-diet, a slight increase in the odds of uterine diseases was observed as DINCUD increased beyond 28 to 35 d.
      • Vieira-Neto A.
      Mineral metabolism in transition dairy cows: The role of acid-base status and vitamin D metabolites.
      demonstrated that the probabilities of RFM and metritis were lowest among parous Holstein cows with approximately 28 DINCUD and that short and long DINCUD were associated with pronounced increases in the probability of uterine diseases. Among nulliparous cows, the probability of RFM was lowest for those with approximately 28 DINCUD, but the probability of metritis was minimally associated with DINCUD (
      • Vieira-Neto A.
      Mineral metabolism in transition dairy cows: The role of acid-base status and vitamin D metabolites.
      ). In the current studies, increased DINCUD was associated with greater intensity of phagocytosis, oxidative burst, and expression of CD62L by PMN from parous cows. Conversely, DINCUD was not associated with function and phenotype of PMN from nulliparous cows in the prepartum. In a recent study using data from Holstein and Jersey cows,
      • Chebel R.C.
      Predicting the risk of retained fetal membranes and metritis in dairy cows according to prepartum hemogram and immune and metabolic status.
      demonstrated that greater intensity of phagocytosis, oxidative burst, and expression of CD62L by PMN were associated with reduced odds of RFM and metritis. These findings may help explain the dramatic differences in the odds of uterine diseases between parous cows with DINCUD ≤10 and 28 ± 3 and the small differences between those with 28 ± 3 and 42 ± 3 DINCUD. Conversely, in the current studies, the association between DINCUD and uterine diseases among nulliparous cows may not be explained by PMN function and phenotype.
      Although the positive association between DINCUD and NEFA concentration in the week preceding calving may lead to speculation that the energy balance of pregnant, nonlactating cows became more negative as they remained on the close-up diet longer, this cannot be asserted from the current studies. The negligible associations between DINCUD and BCS of nulliparous cows at 1 ± 1, 32 ± 6, and 56 ± 3 DIM may reflect the minute association between DINCUD and first test ECM yield. Conversely, the negative associations between DINCUD and BCS of parous cows at 1 ± 1 and 32 ± 6 DIM may be a consequence of the positive association between DINCUD and yield of ECM at first test. In fact, when first test ECM yield was included as an independent variable in the analyses of factors associated with BCS at 32 ± 6 DIM, only a tendency was detected for the association between DINCUD and this outcome (data not shown).
      • DeGaris P.J.
      • Lean I.J.
      • Rabiee A.R.
      • Stevenson M.A.
      Effects of increasing days of exposure to prepartum diets on the concentration of certain blood metabolites in dairy cows.
      observed positive associations between DINCUD and prepartum concentrations of BHB and cholesterol, and suggested that this was associated with lesser nutrient availability as DINCUD increased. In the current studies, prolonged DINCUD in parous cows meant a prolonged intake of an acidogenic diet.
      • Lopera C.
      • Zimpel R.
      • Vieira-Neto A.
      • Lopes F.R.
      • Ortiz W.
      • Poindexter M.
      • Faria B.N.
      • Gambarini M.L.
      • Block E.
      • Nelson C.D.
      • Santos J.E.P.
      Effects of level of dietary cation-anion difference and duration of prepartum feeding on performance and metabolism of dairy cows.
      did not detect an effect of prolonged feeding of acidogenic diets on DMI, but they observed that cows fed diets with −180 mEq/kg of DM had lower DMI than those fed diets with −70 mEq/kg of DM. Because in the current studies both nulliparous and parous cows had greater NEFA concentration in the week preceding calving as DINCUD increased, it is not possible to make the association between length of time feeding acidogenic diets and metabolic status. Longer DINCUD was associated with greater first test yields of milk and ECM in nulliparous and parous cows; thus, one may speculate that the onset of colostrogenesis and lactogenesis may explain the positive association between DINCUD and NEFA concentration in the week preceding calving and during the postpartum. Although greater concentration of NEFA peripartum is a predisposing factor for clinical ketosis (
      • Ospina P.A.
      • Nydam D.V.
      • Stokol T.
      • Overton T.R.
      Evaluation of nonesterified fatty acids and beta-hydroxybutyrate in transition dairy cattle in the northeastern United States: Critical thresholds for prediction of clinical diseases.
      ), the quadratic association between DINCUD and BHB concentration from calving to 21 DIM suggests that the uptake of NEFA by the liver during the periparturient period was sufficient to increase its incomplete oxidation (
      • Grummer R.R.
      Etiology of lipid-related metabolic disorders in periparturient dairy cows.
      ). Increased concentration of NEFA is a predisposing factor for displacement of abomasum (
      • Ospina P.A.
      • Nydam D.V.
      • Stokol T.
      • Overton T.R.
      Evaluation of nonesterified fatty acids and beta-hydroxybutyrate in transition dairy cattle in the northeastern United States: Critical thresholds for prediction of clinical diseases.
      ;
      • Chapinal N.
      • Carson M.
      • Duffield T.F.
      • Capel M.
      • Godden S.
      • Overton M.
      • Santos J.E.
      • LeBlanc S.J.
      The association of serum metabolites with clinical disease during the transition period.
      ), but, in the current studies, DINCUD was not associated with the odds of displaced abomasum. The increase in NEFA concentration associated with increased DINCUD in the current studies was likely insufficient to impair the health of Jersey cows and may simply reflect their greater milk yield.
      Days on the close-up diet tended to be negatively associated with the probability of LS ≥3 at 1 ± 3 DIM.
      • Vieira-Neto A.
      Mineral metabolism in transition dairy cows: The role of acid-base status and vitamin D metabolites.
      observed a positive association between DINCUD and lameness recorded by herd managers such that DINCUD ≥28 was associated with greater probability of lameness. Early postpartum lameness may be associated with the thickness of the digital cushion, which in turn is positively associated with BCS (
      • Bicalho R.C.
      • Machado V.S.
      • Caixeta L.S.
      Lameness in dairy cattle: A debilitating disease or a disease of debilitated cattle? A cross-sectional study of lameness prevalence and thickness of the digital cushion.
      ). In the current studies, however, the associations between DINCUD and BCS postpartum were quite small. Controlled experiments resulting in differing DINCUD and with more detailed evaluation of hoof lesions are necessary to determine how DINCUD affects the odds of LS ≥3.
      Shorter DINCUD among nulliparous cows was associated with decreasing odds of cows having SCC >200,000 cells/mL between 5 and 34 DIM. Among parous cows, shorter DINCUD was associated with greater odds of cows having SCC >200,000 cells/mL between 5 and 34 DIM, whereas longer DINCUD was associated with a slight increase in the odds of cows having SCC >200,000 cells/mL between 5 and 34 DIM. It is reasonable to speculate that the association between DINCUD and the odds of SCC >200,000 cells/mL in the first test may be a consequence of the association between DINCUD and PMN responses. Conversely, greater odds of mastitis by 60 DIM were associated with shorter and longer DINCUD, independent of parity. Obviously, the discrepancy in the association between DINCUD and odds of SCC >200,000 cells/mL compared with the association between DINCUD and odds of mastitis by 60 DIM may be explained by the fact that SCC was measured once between 5 and 34 DIM, whereas cows were examined thrice daily for mastitis. Furthermore, mastitis diagnosis is somewhat subjective, whereas SCC >200,000 cells/mL is an objective measure of udder health.
      • DeGaris P.J.
      • Lean I.J.
      • Rabiee A.R.
      • Heuer C.
      Effects of increasing days of exposure to prepartum transition diets on reproduction and health in dairy cows.
      reported a positive association between DINCUD and the odds of mastitis by 150 DIM, whereas
      • Vieira-Neto A.
      Mineral metabolism in transition dairy cows: The role of acid-base status and vitamin D metabolites.
      reported a slight increase in the odds of mastitis by 60 DIM among nulliparous cows when DINCUD increased, and the odds of mastitis by 60 DIM among parous cows reached a peak at approximately 28 DINCUD. In the studies reported herein, Jersey cows were housed in freestall barns bedded with recycled sand from 60 d prepartum through their lactation, whereas
      • DeGaris P.J.
      • Lean I.J.
      • Rabiee A.R.
      • Heuer C.
      Effects of increasing days of exposure to prepartum transition diets on milk production and milk composition in dairy cows.
      ,
      • DeGaris P.J.
      • Lean I.J.
      • Rabiee A.R.
      • Heuer C.
      Effects of increasing days of exposure to prepartum transition diets on reproduction and health in dairy cows.
      ,
      • DeGaris P.J.
      • Lean I.J.
      • Rabiee A.R.
      • Stevenson M.A.
      Effects of increasing days of exposure to prepartum diets on the concentration of certain blood metabolites in dairy cows.
      ) used Holstein grazing cows, and
      • Vieira-Neto A.
      Mineral metabolism in transition dairy cows: The role of acid-base status and vitamin D metabolites.
      used Holstein cows housed, during the close-up period, in dry-lots. Experiments that subject cows to different DINCUD and carefully evaluate udder health before dry-off and at calving should provide explanations on why DINCUD is associated with SCC and mastitis incidence.
      In study 1, first test (between 5 and 34 DIM) yield of ECM of parous cows was positively associated with DINCUD, and, in study 2, this association was quadratic. Generally, the total lactation performance in study 2 reflected the results observed for the first test with quadratic associations between DINCUD and total fat, protein, and ECM yield. It is worth noting that the changes in lactation responses associated with DINCUD were more pronounced in parous than in nulliparous cows.
      • DeGaris P.J.
      • Lean I.J.
      • Rabiee A.R.
      • Heuer C.
      Effects of increasing days of exposure to prepartum transition diets on milk production and milk composition in dairy cows.
      also observed a quadratic association between DINCUD and total yields of fat- and protein-corrected milk, protein, and fat in grazing Holstein cows. Furthermore,
      • Vieira-Neto A.
      Mineral metabolism in transition dairy cows: The role of acid-base status and vitamin D metabolites.
      demonstrated a quadratic association between DINCUD and total milk yield in confined Holstein cows. In a controlled experiment,
      • Contreras L.L.
      • Ryan C.M.
      • Overton T.R.
      Effects of dry cow grouping strategy and prepartum body condition score on performance and health of transition dairy cows.
      detected an effect of the interaction between BCS and length of feeding of the close-up diet on milk yield such that cows with BCS ≤3 and fed the close-up diet for 21 d had greater milk yield than those with BCS ≥3.25. In the same experiment, the average yield of 3.5% FCM in the first 5 mo postpartum of cows fed the close-up diet during the entire dry period (~62 d) tended to be 1.7 kg/d lower than those fed the close-up diet for 21 d, regardless of BCS (
      • Contreras L.L.
      • Ryan C.M.
      • Overton T.R.
      Effects of dry cow grouping strategy and prepartum body condition score on performance and health of transition dairy cows.
      ).
      • Rabelo E.
      • Rezende R.L.
      • Bertics S.J.
      • Grummer R.R.
      Effects of transition diets varying in dietary energy density on lactation performance and ruminal parameters of dairy cows.
      demonstrated that nulliparous and parous cows fed high-energy diets prepartum had greater DMI and more positive energy balance in the last 30 d prepartum, but nulliparous cows fed prepartum diets with greater NDF and reduced NFC concentrations had greater yield of 3.5% FCM.
      • Contreras L.L.
      • Ryan C.M.
      • Overton T.R.
      Effects of dry cow grouping strategy and prepartum body condition score on performance and health of transition dairy cows.
      and
      • Rabelo E.
      • Rezende R.L.
      • Bertics S.J.
      • Grummer R.R.
      Effects of transition diets varying in dietary energy density on lactation performance and ruminal parameters of dairy cows.
      fed diets that varied between 1.40 and 1.65 Mcal/kg of NEL and 12.8 and 16.3% of CP. The prepartum diets fed during experiments 1 and 2 (study 1) contained 1.31 to 1.45 Mcal/kg of NEL and 13.4 to 15.1% of CP. In the collaborating herd, the content of NEL, CP, and NDF in the close-up diet of nulliparous cows was slightly higher than in the far-off diet. Thus, among nulliparous cows, shorter DINCUD and the consequent shortened exposure to the close-up diet necessary to support the final growth of the mammary gland before calving (
      • Capuco A.V.
      • Akers R.M.
      • Smith J.J.
      Mammary growth in Holstein cows during the dry period: Quantification of nucleic acids and histology.
      ;
      • Bell A.W.
      • Burhans W.S.
      • Overton T.R.
      Protein nutrition in late pregnancy, maternal protein reserves and lactation performance in dairy cows.
      ) may explain their reduced yield. Conversely, this hypothesis is not valid for parous cows with short DINCUD, because their close-up diet had slightly reduced NEL and CP compared with the far-off diet. It is possible that the increased morbidity of parous cows with shorter DINCUD partially explains their impaired lactation performance, but, when health disorders were added to the models evaluating productive responses, the associations between DINCUD and lactation performance were still observed (data not shown). A critical flaw of these epidemiological studies is the fact that DMI was not measured, making it impossible to determine whether DINCUD had an effect on total daily intake of NEL and CP.
      Number of days on the close-up diet was not associated with resumption of ovarian cyclicity postpartum in study 1. In study 1, a quadratic association between DINCUD and odds of pregnancy to first service was detected. In study 2, the interaction between DINCUD and parity-diet was associated with the odds of pregnancy by 305 DIM. Among parous cows, DINCUD less than approximately 28 d was associated with reduced odds of pregnancy by 305 DIM, and DINCUD greater than approximately 28 d was associated with a slight decrease in the odds of pregnancy by 305 DIM. Among nulliparous cows, however, the association between DINCUD and odds of pregnancy by 305 DIM was negligible. When diseases were added to the models to analyze the odds of pregnancy after the first AI and the odds of pregnancy by 305 DIM, only an interaction between DINCUD and parity-diet was detected for the odds of pregnancy by 305 DIM (data not shown). This leads to the speculation that the associations between DINCUD and reproductive responses are mediated in part by the association between DINCUD and health disorders. Although
      • DeGaris P.J.
      • Lean I.J.
      • Rabiee A.R.
      • Heuer C.
      Effects of increasing days of exposure to prepartum transition diets on reproduction and health in dairy cows.
      demonstrated a positive association between DINCUD and the odds of pregnancy to first service,
      • Vieira-Neto A.
      Mineral metabolism in transition dairy cows: The role of acid-base status and vitamin D metabolites.
      detected a quadratic association between DINCUD and odds of pregnancy by 300 DIM. It is worth noting that
      • Vieira-Neto A.
      Mineral metabolism in transition dairy cows: The role of acid-base status and vitamin D metabolites.
      detected a greater difference in odds of pregnancy by 300 DIM between cows with 28 versus 45 DINCUD than the one observed in the current studies.
      The associations of the interactions between DINCUD and parity-diet and odds of cows being sold by 60 DIM and being removed from the herd by 305 DIM likely reflect the associations between DINCUD and health, productive, and reproductive outcomes. Among nulliparous cows, for every 1-d increase in DINCUD, the probability of cows being sold by 60 DIM and being removed by 305 DIM decreased by 0.00003 and 0.002 units, respectively. Among parous cows, for every 1-d increase in DINCUD, the probability of cows being sold by 60 DIM and being removed by 305 DIM decreased by 0.004 and 0.005 units, respectively. As discussed previously, shorter DINCUD had negative associations with the outcomes evaluated herein, particularly among parous cows, whereas increased DINCUD was associated with relatively small increases in odds of health disorders and decreases in pregnancy and yield of ECM. The negative association between DINCUD and odds of cows being sold or dying by 305 DIM corroborates the findings from
      • DeGaris P.J.
      • Lean I.J.
      • Rabiee A.R.
      • Heuer C.
      Effects of increasing days of exposure to prepartum transition diets on reproduction and health in dairy cows.
      but contradicts the findings by
      • Vieira-Neto A.
      Mineral metabolism in transition dairy cows: The role of acid-base status and vitamin D metabolites.
      , who demonstrated a steeper increase in the odds of removal from the herd by 300 DIM as DINCUD increased. The decision to sell a cow is complex. Although impaired reproductive and productive performances are predisposing factors for a cow to be sold, factors such as availability of replacements, milk price, income over feed-cost, and stocking density of the herd play significant roles on decisions regarding culling (
      • De Vries A.
      • Dechassa H.
      • Hogeveen H.
      Economic evaluation of stall stocking density of lactating dairy cows.
      ).
      It is important to discuss the limitations of the studies presented herein. Associations between DINCUD and outcomes of nulliparous and parous cows were confounded by the fact that nulliparous cows were not fed acidogenic salts to achieve a negative DCAD in the close-up diet, whereas parous cows were. Thus, any association between DINCUD and parity is in fact an association between DINCUD and parity-diet. The studies were conducted in 1 large south central Minnesota herd, limiting its external validity. Finally, the of range of DINCUD was limited to 1 to 45 d, and few nulliparous and parous cows had ≤10 DINCUD, and few parous cows had ≥40 DINCUD. Therefore, the findings of the current studies should be tested in randomized controlled experiments with large sample sizes, multiple herds, and a wider range of DINCUD. In the current studies, the associations between days dry and the outcomes of interest were not evaluated, because one of the hypotheses was that length of exposure to a diet containing acidogenic salts would be associated with health and performance. Among parous cows used in studies 1 and 2, the correlation (r2) between days dry and DINCUD was 0.20. Thus, among parous cows, it is not possible to discard the importance of days dry for the outcomes evaluated herein. Cows with a 56-d dry period had greater milk yield from 6 to 10 wk postpartum and had more negative energy balance postpartum than cows with a 0- and 28-d dry period (
      • Rastani R.R.
      • Grummer R.R.
      • Bertics S.J.
      • Gümen A.
      • Wiltbank M.C.
      • Mashek D.G.
      • Schwab M.C.
      Reducing dry period length to simplify feeding transition cows: Milk production, energy balance, and metabolic profiles.
      ). In addition, cows with a 56-d dry period were less likely to have ovulation of the follicle from the first follicular and had a longer interval from calving to first ovulation compared with cows with a 0-d dry period (
      • Gümen A.
      • Rastani R.R.
      • Grummer R.R.
      • Wiltbank M.C.
      Reduced dry periods and varying prepartum diets alter postpartum ovulation and reproductive measures.
      ). Finally, cows with a 55-d dry period had greater milk yield up to 100 DIM and reduced BCS up to 63 DIM compared with those with a 34-d dry period (
      • Watters R.D.
      • Guenther J.N.
      • Brickner A.E.
      • Rastani R.R.
      • Crump P.M.
      • Clark P.W.
      • Grummer R.R.
      Effects of dry period length on milk production and health of dairy cattle.
      ). These data suggest that days dry may play a role in some of the outcomes reported herein.

      CONCLUSIONS

      In these observational retrospective studies, DINCUD was associated with several health, reproductive, and productive responses of Jersey cows. It is reasonable to conclude that, in parous cows, extended DINCUD may have a positive influence on immune responses, reducing the odds of infectious diseases. In the current studies, however, few parous cows had ≤10 DINCUD, and none had ≥45 DINCUD, limiting these studies' relevance for very extreme DINCUD. The association between DINCUD and health disorders was less dramatic among nulliparous cows, with no associations between DINCUD and immune responses. It is not possible to conclude that the difference in close-up nutrition strategy between nulliparous (no acidogenic salts) and parous (acidogenic salts) cows caused this discrepancy in responses; randomized control experiments with large samples sizes are needed. Furthermore, these studies were conducted in 1 large Minnesota herd, limiting external validity. These epidemiological studies suggest that to achieve a successful transition period, measured by low incidence of diseases and elevated milk yield and odds of pregnancy, nulliparous and parous Jersey cows may need to be fed close-up diets for approximately 28 ± 3 d. Controlled, randomized experiments with large sample size are necessary to corroborate the conclusions from these studies.

      ACKNOWLEDGMENTS

      The author thanks Mitch Davis, Tom Jinkinson, and the staff of Davis Family Dairies (Nicollet, MN). The author has not stated any conflicts of interest.

      REFERENCES

        • Ballou M.A.
        • Gomes R.C.
        • Juchem S.O.
        • DePeters E.J.
        Effects of dietary supplemental fish oil during the peripartum period on blood metabolites and hepatic fatty acid compositions and total triacylglycerol concentrations of multiparous Holstein cows.
        J. Dairy Sci. 2009; 92: 657-669
        • Bell A.W.
        • Burhans W.S.
        • Overton T.R.
        Protein nutrition in late pregnancy, maternal protein reserves and lactation performance in dairy cows.
        Proc. Nutr. Soc. 2000; 59 (10828181): 119-126
        • Bicalho R.C.
        • Machado V.S.
        • Caixeta L.S.
        Lameness in dairy cattle: A debilitating disease or a disease of debilitated cattle? A cross-sectional study of lameness prevalence and thickness of the digital cushion.
        J. Dairy Sci. 2009; 92 (19757545): 3175-3184
        • Capuco A.V.
        • Akers R.M.
        • Smith J.J.
        Mammary growth in Holstein cows during the dry period: Quantification of nucleic acids and histology.
        J. Dairy Sci. 1997; 80 (9098797): 477-487
        • Chapinal N.
        • Carson M.
        • Duffield T.F.
        • Capel M.
        • Godden S.
        • Overton M.
        • Santos J.E.
        • LeBlanc S.J.
        The association of serum metabolites with clinical disease during the transition period.
        J. Dairy Sci. 2011; 94 (21943741): 4897-4903
        • Chebel R.C.
        Predicting the risk of retained fetal membranes and metritis in dairy cows according to prepartum hemogram and immune and metabolic status.
        Prev. Vet. Med. 2020; (33257005)105204
        • Chenault J.R.
        • McAllister J.F.
        • Chester T.
        • Dame K.J.
        • Kausche F.M.
        • Robb E.J.
        Efficacy of ceftiofur hydrochloride sterile suspension administered parenterally for the treatment of acute postpartum metritis in dairy cows.
        J. Am. Vet. Med. Assoc. 2004; 224 (15154734): 1634-1639
        • Contreras L.L.
        • Ryan C.M.
        • Overton T.R.
        Effects of dry cow grouping strategy and prepartum body condition score on performance and health of transition dairy cows.
        J. Dairy Sci. 2004; 87 (14762095): 517-523
        • De Vries A.
        • Dechassa H.
        • Hogeveen H.
        Economic evaluation of stall stocking density of lactating dairy cows.
        J. Dairy Sci. 2016; 99 (26923039): 3848-3857
        • DeGaris P.J.
        • Lean I.J.
        • Rabiee A.R.
        • Heuer C.
        Effects of increasing days of exposure to prepartum transition diets on milk production and milk composition in dairy cows.
        Aust. Vet. J. 2008; 86 (18782415): 341-351
        • DeGaris P.J.
        • Lean I.J.
        • Rabiee A.R.
        • Heuer C.
        Effects of increasing days of exposure to prepartum transition diets on reproduction and health in dairy cows.
        Aust. Vet. J. 2010; 88 (20402690): 84-92
        • DeGaris P.J.
        • Lean I.J.
        • Rabiee A.R.
        • Stevenson M.A.
        Effects of increasing days of exposure to prepartum diets on the concentration of certain blood metabolites in dairy cows.
        Aust. Vet. J. 2010; 88 (20402701): 137-145
        • Drackley J.K.
        Biology of dairy cows during the transition period: The final frontier?.
        J. Dairy Sci. 1999; 82 (10575597): 2259-2273
        • Ferguson J.D.
        • Galligan D.T.
        • Thomsen N.
        Principal descriptors of body condition score in Holstein cows.
        J. Dairy Sci. 1994; 77 (7814740): 2695-2703
        • Gaynor P.J.
        • Mueller F.J.
        • Miller J.K.
        • Ramsey N.
        • Goff J.P.
        • Horst R.L.
        Parturient hypocalcemia in jersey cows fed alfalfa haylage-based diets with different cation to anion ratios.
        J. Dairy Sci. 1989; 72 (2600220): 2525-2531
        • Goff J.P.
        • Horst R.L.
        • Mueller F.J.
        • Miller J.K.
        • Kiess G.A.
        • Dowlen H.H.
        Addition of chloride to a prepartal diet high in cations increases 1,25-dihydroxyvitamin D response to hypocalcemia preventing milk fever.
        J. Dairy Sci. 1991; 74 (1757627): 3863-3871
        • Grummer R.R.
        Etiology of lipid-related metabolic disorders in periparturient dairy cows.
        J. Dairy Sci. 1993; 76 (8132893): 3882-3896
        • Grummer R.R.
        Impact of changes in organic nutrient metabolism on feeding the transition dairy cow.
        J. Anim. Sci. 1995; 73 (8582873): 2820-2833
        • Gümen A.
        • Rastani R.R.
        • Grummer R.R.
        • Wiltbank M.C.
        Reduced dry periods and varying prepartum diets alter postpartum ovulation and reproductive measures.
        J. Dairy Sci. 2005; 88 (15956303): 2401-2411
        • Hulbert L.E.
        • Carroll J.A.
        • Burdick N.C.
        • Randel R.D.
        • Brown M.S.
        • Ballou M.A.
        Innate immune responses of temperamental and calm cattle after transportation.
        Vet. Immunol. Immunopathol. 2011; 143 (21726904): 66-74
        • Husnain A.
        • Santos J.E.P.
        Meta-analysis of the effects of prepartum dietary protein on performance of dairy cows.
        J. Dairy Sci. 2019; 102 (31495616): 9791-9813
        • Kelton D.F.
        • Lissemore K.D.
        • Martin R.E.
        Recommendations for recording and calculating the incidence of selected clinical diseases of dairy cattle.
        J. Dairy Sci. 1998; 81 (9785242): 2502-2509
        • Kothari K.
        • Lal R.
        • Pillai M.R.A.
        Development of a direct radioimmunoassay for serum progesterone.
        J. Radioanal. Nucl. Chem. 1995; 196: 331-338
        • Lean I.J.
        • Santos J.E.P.
        • Block E.
        • Golder H.M.
        Effects of prepartum dietary cation-anion difference intake on production and health of dairy cows: A meta-analysis.
        J. Dairy Sci. 2019; 102 (30594362): 2103-2133
        • LeBlanc S.
        Monitoring metabolic health of dairy cattle in the transition period.
        J. Reprod. Dev. 2010; 56 (20629214): S29-S35
        • Lopera C.
        • Zimpel R.
        • Vieira-Neto A.
        • Lopes F.R.
        • Ortiz W.
        • Poindexter M.
        • Faria B.N.
        • Gambarini M.L.
        • Block E.
        • Nelson C.D.
        • Santos J.E.P.
        Effects of level of dietary cation-anion difference and duration of prepartum feeding on performance and metabolism of dairy cows.
        J. Dairy Sci. 2018; 101 (29885896): 7907-7929
        • NRC
        Nutrient Requirements of Dairy Cattle.
        7th rev. ed. Natl. Acad. Sci, 2001
        • Ospina P.A.
        • Nydam D.V.
        • Stokol T.
        • Overton T.R.
        Evaluation of nonesterified fatty acids and beta-hydroxybutyrate in transition dairy cattle in the northeastern United States: Critical thresholds for prediction of clinical diseases.
        J. Dairy Sci. 2010; 93 (20105526): 546-554
        • Pérez-Báez J.
        • Risco C.A.
        • Chebel R.C.
        • Gomes G.C.
        • Greco L.F.
        • Tao S.
        • Thompson I.M.
        • do Amaral B.C.
        • Zenobi M.G.
        • Martinez N.
        • Staples C.R.
        • Dahl G.E.
        • Hernández J.A.
        • Santos J.E.P.
        • Galvão K.N.
        Association of dry matter intake and energy balance prepartum and postpartum with health disorders postpartum: Part I. Calving disorders and metritis.
        J. Dairy Sci. 2019; 102 (31326177): 9138-9150
        • Pinedo P.
        • Santos J.E.P.
        • Chebel R.C.
        • Galvão K.N.
        • Schuenemann G.M.
        • Bicalho R.C.
        • Gilbert R.O.
        • Rodriguez-Zas S.L.
        • Seabury C.M.
        • Rosa G.
        • Thatcher W.
        Associations of reproductive indices with fertility outcomes, milk yield, and survival in Holstein cows.
        J. Dairy Sci. 2020; 103 (32359989): 6647-6660
        • Rabelo E.
        • Bertics S.J.
        • Mackovic J.
        • Grummer R.R.
        Strategies for increasing energy density of dry cow diets.
        J. Dairy Sci. 2001; 84 (11699456): 2240-2249
        • Rabelo E.
        • Rezende R.L.
        • Bertics S.J.
        • Grummer R.R.
        Effects of transition diets varying in dietary energy density on lactation performance and ruminal parameters of dairy cows.
        J. Dairy Sci. 2003; 86 (12703628): 916-925
        • Rastani R.R.
        • Grummer R.R.
        • Bertics S.J.
        • Gümen A.
        • Wiltbank M.C.
        • Mashek D.G.
        • Schwab M.C.
        Reducing dry period length to simplify feeding transition cows: Milk production, energy balance, and metabolic profiles.
        J. Dairy Sci. 2005; 88 (15738235): 1004-1014
        • Santos J.E.P.
        • Lean I.J.
        • Golder H.
        • Block E.
        Meta-analysis of the effects of prepartum dietary cation-anion difference on performance and health of dairy cows.
        J. Dairy Sci. 2019; 102 (30612801): 2134-2154
        • Silva P.R.
        • Dresch A.R.
        • Machado K.S.
        • Moraes J.G.
        • Lobeck-Luchterhand K.
        • Nishimura T.K.
        • Ferreira M.A.
        • Endres M.I.
        • Chebel R.C.
        Prepartum stocking density: Effects on metabolic, health, reproductive, and productive responses.
        J. Dairy Sci. 2014; 97 (24952785): 5521-5532
        • Silva P.R.
        • Lobeck-Luchterhand K.M.
        • Cerri R.L.
        • Haines D.M.
        • Ballou M.A.
        • Endres M.I.
        • Chebel R.C.
        Effects of prepartum stocking density on innate and adaptive leukocyte responses and serum and hair cortisol concentrations.
        Vet. Immunol. Immunopathol. 2016; 169 (26827837): 39-46
        • Silva P.R.
        • Moraes J.G.
        • Mendonça L.G.
        • Scanavez A.A.
        • Nakagawa G.
        • Ballou M.A.
        • Walcheck B.
        • Haines D.
        • Endres M.I.
        • Chebel R.C.
        Effects of weekly regrouping of prepartum dairy cows on innate immune response and antibody concentration.
        J. Dairy Sci. 2013; 96 (24140318): 7649-7657
        • Silva P.R.
        • Moraes J.G.
        • Mendonça L.G.
        • Scanavez A.A.
        • Nakagawa G.
        • Fetrow J.
        • Endres M.I.
        • Chebel R.C.
        Effects of weekly regrouping of prepartum dairy cows on metabolic, health, reproductive, and productive parameters.
        J. Dairy Sci. 2013; 96 (23660147): 4436-4446
        • Sprecher D.J.
        • Hostetler D.E.
        • Kaneene J.B.
        A lameness scoring system that uses posture and gait to predict dairy cattle reproductive performance.
        Theriogenology. 1997; 47 (16728067): 1179-1187
        • Vieira-Neto A.
        Mineral metabolism in transition dairy cows: The role of acid-base status and vitamin D metabolites.
        (PhD thesis.) Department of Animal Science, University of Florida, Gainesville2020
        • Watters R.D.
        • Guenther J.N.
        • Brickner A.E.
        • Rastani R.R.
        • Crump P.M.
        • Clark P.W.
        • Grummer R.R.
        Effects of dry period length on milk production and health of dairy cattle.
        J. Dairy Sci. 2008; 91 (18565918): 2595-2603