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Effects of feeding rumen-protected methionine pre- and postpartum in multiparous Holstein cows: Health disorders and interactions with production and reproduction
Study objectives were to evaluate the effects of feeding rumen-protected Met (RPM) in pre- and postpartum total mixed rations (TMR) on health disorders and the interactions of health disorders with lactation and reproductive performance. Multiparous Holstein cows [470; 235 cows at University of Wisconsin (UW) and 235 cows at Cornell University (CU)] were enrolled at approximately 4 wk before parturition and housed in close-up dry cow (n = 6) and replicated lactation pens (n = 16). Pens were randomly assigned to treatment diets (pre- and postpartum, respectively): (1) control (CON): basal diet = 2.30% and 2.09% Met as % of metabolizable protein (MP) (UW) or 2.22% and 2.19% Met as % of MP (CU); (2) RPM: basal diet fed with RPM with 2.83% and 2.58% Met (Smartamine M, Adisseo Inc.; 12 g prepartum and 27 g postpartum), as % of MP (UW) or 2.85% and 2.65% Met (Smartamine M; 13 g prepartum and 28 g postpartum), as % of MP (CU). Total serum Ca was evaluated at the time of parturition and on d 3 ± 1 postpartum. Daily rumination was monitored from 7 d before parturition until 28 d postpartum. Health disorders were recorded during the experimental period until the time of first pregnancy diagnosis (32 d after timed artificial insemination; 112 ± 3 d in milk). Uterine health was evaluated on d 35 ± 3 postpartum. Time to pregnancy and herd exit were evaluated up to 350 d in milk. Treatment had no effect on the incidence of most health disorders and did not alter daily rumination. Cows fed RPM had reduced subclinical hypocalcemia (13.6 vs. 22%; UW only) on day of parturition relative to CON. Percentage of cows culled (13.1 vs. 19.3%) and hazard of herd exit due to culling [hazard ratio = 0.65, 95% confidence interval (CI): 0.42–1.02] tended to be reduced for cows fed RPM compared with CON. Moreover, cows fed RPM had greater milk protein concentration and protein yield overall, although retrospective analysis indicated that RPM only significantly increased protein yield in the group of cows with one or more health disorders (1.47 vs. 1.40 kg/d), not in cows without health disorders (1.49 vs. 1.46 kg/d) compared with CON. Overall, treatment had no effect on pregnancy per timed artificial insemination; however, among cows with health disorders, those fed RPM had reduced time to pregnancy compared with CON (hazard ratio = 0.71, 95% CI: 0.53–0.96). Thus, except for subclinical hypocalcemia on the day of parturition, feeding RPM in pre- and postpartum TMR did not reduce the incidence of health disorders, but our retrospective analysis indicated that it lessened the negative effects of health disorders on milk protein production and time to pregnancy.
). The onset of lactation in dairy cows increases nutrient demands for milk production that may not be compensated for by nutrient intake, creating multiple nutrient deficiencies (
). Although most research has focused on the effects of negative energy balance during the periparturient period, the effects of negative protein and AA balance (
) may also affect cow performance and health. Indeed, some studies have suggested that during the early postpartum period, cows require greater amounts of MP and AA to support mammary gland requirements, as evidenced by the greater yields of milk, fat, and protein, and health parameters in response to increased supply of MP or AA (
Concurrent and carryover effects of feeding blends of protein and amino acids in high-protein diets with different concentrations of forage fiber to fresh cows. 1. Production and blood metabolites.
). For example, Met—generally considered an AA that can limit production in most dairy diets—has been shown to improve lactation performance, particularly during early lactation (
In addition to their effects on synthesis of proteins, AA can affect physiological processes. Such effects have led to the classification of some AA, including Met, as “functional AA” (
Functional roles of arginine during the peri-implantation period of pregnancy. III. Arginine stimulates proliferation and interferon tau production by ovine trophectoderm cells via nitric oxide and polyamine-TSC2-MTOR signaling pathways.
). Some of the functional roles of Met include DNA methylation, regulation of translation [mammalian target of rapamycin (mTOR) activation], and synthesis of molecules involved in hepatic lipid metabolism (e.g., choline, polyamines, and carnitine), antioxidant balance (e.g., glutathione and taurine) (
). As a result, improvements in production or health by feeding Met could be related not only to optimization of protein synthesis but also to several of the functional roles of Met in dairy cattle. Indeed, recent studies provided some evidence that feeding rumen-protected Met (RPM) during the periparturient period improved lactation performance and had modest effects on health outcomes; namely, a reduction in the incidence of some clinical health disorders such as ketosis and retained placenta (
). These benefits might have been associated with positive shifts for some indicators of immune function, inflammation, oxidative stress, and liver metabolism (
Therefore, we hypothesized that feeding RPM pre- and postpartum would reduce the incidence of health disorders from parturition until 112 ± 3 DIM. In addition, we hypothesized that feeding RPM would interact with health status categories such that feeding RPM would alleviate some of the negative effects of health disorders on lactation and reproductive performance. To test these hypotheses, we used data from a recent experiment conducted to evaluate the effects of RPM feeding on reproductive and productive performance in multiparous dairy cows (
Effects of feeding rumen-protected methionine pre- and postpartum in multiparous Holstein cows: Lactation performance and plasma amino acid concentrations.
). Our objective was to explore the effect of feeding RPM in pre- and postpartum TMR on the incidence of health disorders, and the interaction of health disorders with lactation and reproductive performance of multiparous dairy cows.
MATERIALS AND METHODS
The Animal Care and Use Committee of Cornell University and the University of Wisconsin-Madison College of Agricultural and Life Sciences Animal Care and Use Committee approved all procedures performed with cows.
Experimental Design and Treatments
This experiment was conducted from June 2016 to April 2017 at the Dairy Unit of the Cornell University Ruminant Center located in Harford, New York (Cornell University; CU), and from January 2016 to May 2017 at the University of Wisconsin – Emmons Blaine Dairy Research Center in Arlington, Wisconsin (University of Wisconsin; UW). Details about animals and study design are provided elsewhere (
Effects of feeding rumen-protected methionine pre- and postpartum in multiparous Holstein cows: Lactation performance and plasma amino acid concentrations.
). Briefly, a total of 470 multiparous Holstein cows (CU: n = 235; UW: n = 235) were enrolled in the experiment. At each farm, a list of all cows eligible for enrollment in the experiment (i.e., dry cows between 250 and 256 d of gestation) was generated weekly and transferred to Excel (Microsoft Corp.). Cows were stratified by lactation number and randomly allocated to close-up and lactation pens following parturition (CU: 2 close-up pens, 1 CON and 1 RPM; UW: 4 close-up pens, 2 CON and 2 RPM; CU: 12 pens of 16 cows each, 6 CON and 6 RPM; UW: 6 pens of 16 cows each, 3 CON and 3 RPM). Pens were randomly assigned to control (CON; 9 pens, and 118 and 119 cows, respectively, at CU and UW) or fed with RPM (RPM; 9 pens, 117 and 116 cows, respectively, at CU and UW) groups, with the only difference being the inclusion rate of RPM (Smartamine M; Adisseo) in the diets. After calving, cows were moved to the lactation pens where they remained for the rest of the experimental period. Cows pregnant at first service remained in the experiment until reconfirmation of pregnancy at 67 d of gestation (i.e., 147 ± 3 DIM). Cows not pregnant after first service remained in their respective experimental pens until either the day of the second AI service at detected estrus or timed AI (TAI) at CU and until the day of nonpregnancy diagnosis 32 d after first-service TAI (i.e., 112 ± 3 DIM; Figure 1).
Figure 1Graphical depiction of experimental procedures. At approximately −28 and −22 d before parturition, cows were randomly allocated to pens that were assigned to receive a control diet (CON), or the same diet fed with rumen-protected Met (RPM; 12 and 27 g pre- and postpartum, respectively). CON: basal diet = 2.30 and 2.09% Met as % of MP (University of Wisconsin; UW) or 2.22 and 2.19% Met (Cornell University; CU); RPM: basal diet fed with rumen-protected Met with 2.83 and 2.58% Met as % of MP (UW) or 2.85 and 2.65% Met as % of MP (CU), all pre- and postpartum, respectively. All veterinary and management procedures were based on standard operating procedures at UW and CU. tCa = total calcium; TAI = timed AI.
Cows had ad libitum access (amount of feed delivered estimated for 5% refusals) to diets formulated to meet or exceed requirements of energy, MP, minerals, and vitamins based on the Cornell Net Carbohydrate and Protein System (CNCPS, v. 6.5.5;
). At UW, RPM cows were fed a TMR containing the basal diet and, during the prepartum period, fed 12 g of RPM (Smartamine M, Adisseo) mixed with 215 g of distillers grains (dried distillers grains with solubles; DDGS) (RPM prepartum: 1,193 g of MP and 2.83% of MP) and during the postpartum period fed 27 g of RPM mixed with 200 g DDGS (RPM postpartum: 3,120 g of MP and 2.58% of MP). The CON cows were fed the basal diet and 227 g of DDGS (1,188 g and 2.30% of MP prepartum and 3,135 g and 2.09% of MP postpartum for CON cows). At CU, cows in the CON group were fed 1.4 and 1.2% DM (pre- and postpartum, respectively) LysAAmet (Perdue Agribusiness) containing no RPM (1,291 g and 2.22% of MP and 3,491 g and 2.19% of MP postpartum). The RPM cows were fed 1.4 and 1.2% DM of LysAAmet containing RPM [7% DM of Smartamine M (13 g and 28 g respectively pre- and postpartum; Adisseo) (1,292 g of MP and 2.85% of MP prepartum and 3,497 g and 2.65% of MP postpartum)]. The LysAAmet supplements of each treatment were mixed with the basal diet and fed as TMR. For both treatments, dietary levels of other AA such as Lys and His were similar between treatments within each period (Supplemental Tables S3 and S4, https://figshare.com/articles/online_resource/Toledo_et_al_SUPPLEMENTAL_TABLES/21893127;
Characterization and Definition of Health Disorders
All veterinary and management procedures were based on standard operating procedures at CU and UW. Health events were recorded by farm personnel in the dairy herd management software (DairyComp305, ValleyAg Software) from initiation of the treatment period until the time of first pregnancy diagnosis (32 d after TAI; 112 ± 3 DIM) and were extracted and analyzed at the end of the trial. Specific health disorders that were recorded included the following:
(1)
Retained placenta: characterized by lack of expulsion of the fetal membranes within 24 h after calving.
(2)
Displaced abomasum: diagnosis of a left or right side displacement of abomasum based on auscultation of a characteristic metallic “ping” sound, and confirmed by surgery.
(3)
Clinical ketosis: defined as cows with decreased appetite, decreased milk yield, and urinary ketone-acetoacetic acid at or above “moderate” (≥40 mg/dL; Mission Urine Reagent Strips, ACON). All cows were examined daily from 1 to 10 DIM and then in cows suspected of ketosis.
(4)
Clinical mastitis: diagnosed by the presence of abnormal milk or signs of inflammation in one or more quarters.
(5)
Respiratory problems: defined as increased respiratory rate, fever, and increased lung sounds at auscultation.
(6)
Lameness: defined as cows that stood and walked with arched back and an abnormal gait or avoidance of bearing weight on one or more limbs (
In addition, evaluation of uterine health was performed at 35 ± 3 DIM. Uterine cytology samples were collected to determine the percentage of PMN using the cytobrush technique. Samples were collected using a stainless-steel gun attached to a sterile brush following the technique described by
Extending the duration of the voluntary waiting period from 60 to 88 days in cows that received timed artificial insemination after the Double-Ovsynch protocol affected the reproductive performance, herd exit dynamics, and lactation performance of dairy cows.
. Smears on glass slides were air-dried and stained with Dip Quick kit (Jorgensen Laboratories Inc.) at CU and with Protocol-Hema3 (Fisher Scientific) at UW. A single observer evaluated slides from both farms at 400× magnification. The percentage of PMN cells in each slide was averaged from 2 counts of 100 cells (PMN and endometrial cells) each in 2 different locations of the slide. A third count was conducted if the difference between the 2 counts was greater than 10 percentage points. Cows with >10% PMN in the sample were considered to have cytological endometritis (
In addition, blood samples (∼8 to 9 mL) were collected by puncture of the caudal vein or artery using evacuated tubes containing K2-EDTA (BD Vacutainer) at the time of parturition and d 3 ± 1 postpartum for determination of total serum calcium (tCa) concentrations (UW cows only; d 0: n = 213; d 3 ± 1: n = 221). Samples were immediately placed on ice and transported to the laboratory for further processing (centrifugation at 1,900 × g for 20 min at 5°C) and stored at −20°C until assayed for tCa. Samples were analyzed using a colorimetric calcium assay kit (#700550, Cayman Chemical) per the manufacturer's instructions (https://www.caymanchem.com/product/701220). The intra- and interassay coefficients of variation for 13 plates analyzed were 2.6 and 2.7%, respectively. Subclinical hypocalcemia (SCH) was defined as cows with tCa <1.77 mM at the time of parturition or <2.20 mM on d 3 ± 1 postpartum (
Based on health records available for both farms, cows were retrospectively classified into different categories of health status (without or with one or more health disorders: displaced abomasum, ketosis, SCH, clinical mastitis, retained placenta, respiratory problems, lameness, and cytological endometritis) monitored from start of treatment until 112 ± 3 DIM [i.e., day of pregnancy diagnosis after first service (32 d after TAI)]. Repeated cases of the same health disorder per cow were considered a single event.
Lactation Performance, BW, BCS, and Rumination
Methods for collection of milk yield and composition data for both farms are described elsewhere (
Effects of feeding rumen-protected methionine pre- and postpartum in multiparous Holstein cows: Lactation performance and plasma amino acid concentrations.
). Briefly, milk yield for individual cows was recorded daily and milk samples were collected every other week until 112 ± 3 DIM. Milk energy content (NEL; Mcal/d) was calculated by the equation described by the
: [(0.0929 × % milk fat) + (0.0563 × % milk true protein/0.93) + (0.0395 × % milk lactose)] × milk yield from the week when milk was sampled. Data from parturition until 112 ± 3 DIM were averaged as a single measurement per cow per day before statistical analysis for yields of milk, fat, and protein, and milk composition to evaluate the association with health categories and treatment effects within each health status group. In addition, BW change was calculated from 4 to 39 ± 3 DIM and BCS change was determined from parturition to 49 ± 3 DIM. Cows were fitted with a neck-mounted electronic rumination and activity monitoring tag (HR Tags; SCR Dairy) approximately 4 wk before parturition to monitor rumination time from at least 7 d before calving until 28 d after calving. Rumination raw data were recorded in minutes per 2 h. Data were summarized as total minutes of rumination per day. Similarly, averaged data from 7 d before parturition until 6 d postpartum and from 7 d until 28 d postpartum were used to evaluate the association with health categories and treatment effects within each health categories.
) (first day: GnRH–7 d later: PGF–3 d later: GnRH–7 d later: GnRH–7 d later: PGF–24 h later: PGF–32 h later: GnRH–16 to 20 h later: TAI). At both sites, cows were enrolled in the Double-Ovsynch protocol weekly on Fridays at 53 ± 3 DIM. For second and greater AI services, cows at CU were submitted for insemination after detection of estrus through a combination of visual observation and physical activity monitoring using neck-mounted activity tags (HR Tags, SCR Dairy). Cows not pregnant after a previous insemination that were not re-inseminated at detected estrus at CU and all open cows at UW were resynchronized with the Ovsynch protocol (first day: GnRH–7 d later: PGF–24 h later: PGF–32 h later: GnRH–16 to 20 h later: TAI) initiated 25 ± 3 d after AI. Cows without a corpus luteum ≥15 mm in diameter and a follicle ≥10 mm in diameter at the time of nonpregnancy diagnosis (32 d after AI) received a CIDR (controlled intravaginal drug release)-Synch protocol and TAI at 42 d after previous AI (first day: GnRH+CIDR–7 d later: CIDR removal+PGF–24 h later: PGF–32 h later: GnRH–16 to 20 h later: TAI), as described in
A resynchronization of ovulation program based on ovarian structures present at nonpregnancy diagnosis reduced time to pregnancy in lactating dairy cows.
Determination of Pregnancy Status and Embryo Mortality
During the experiment, pregnancy diagnosis was performed at 25 and 29 d after AI by circulating concentrations of pregnancy-specific protein-B (PSPB), as described in
, and at 32, 39, and 67 d after first service through transrectal ultrasonography (Ibex Pro, E.I. Medical Imaging) of the reproductive tract using a 7.5-MHz linear array transducer. A cow was considered pregnant if a viable conceptus (presence of amniotic vesicle with a live embryo; i.e., heartbeat) was observed. After the end of the treatment period and until 350 DIM, pregnancy diagnosis after subsequent insemination was also performed at 32 ± 3 d and at 67 ± 3 d after TAI through transrectal ultrasonography.
Herd Exit
At the end of the treatment period (i.e., 112 or 147 ± 3 DIM), cows were moved to common pens, fed a common diet, and followed the standard herd management for each farm. The herd exit dynamics of cows was recorded up to 350 DIM. This included cows that were coded as culled (including cows sold for any reason), died, and the total percentage of cows that left the herd (culled + died;
Reproductive performance and herd exit dynamics of lactating dairy cows managed for first service with the Presynch-Ovsynch or Double-Ovsynch protocol and different duration of the voluntary waiting period.
The experiment followed a complete randomized design, performed at 2 farms, with lactation number as the stratification factor. Because the experimental treatments were applied at the pen level, pen was the experimental unit, and individual cows within pens were considered observational units (
). Thus, for all statistical analyses of our treatment effects and interactions with treatment, the error term is based on number of pen replicates, not number of cows (df = 14 for all health disorders; df = 9 to 15 for interactions between production, reproduction and health disorders; df = 7 for subclinical hypocalcemia). The sample size available (i.e., number of pens per treatment) was sufficient to detect a difference of at least 15 percentage points in the incidence of all health events (proportion of cows with one or more health disorders), assuming the incidence of health events would be 30 versus 45% for CON and RPM, respectively. The method for sample size estimation was based on the approach described in
Dichotomous outcomes [i.e., occurrence of health disorders, pregnancy per AI (P/AI), and pregnancy loss] were analyzed by logistic regression using the GLIMMIX procedure of SAS, whereas continuous outcomes (i.e., lactation performance, rumination) were analyzed by ANOVA using the MIXED procedure of SAS (version 9.4, SAS Institute Inc.). Treatment (CON or RPM), farm (CU or UW), and treatment × farm interaction were offered to all models as fixed effects; pen nested within treatment and farm were included as random effects. In addition, the model to evaluate daily rumination contained the effect of time and the treatment × time interaction, and cow within pen, treatment, and farm was the subject of the repeated measures. Daily rumination was evaluated separately for 2 periods (−7 to 6 d relative to parturition, and from 7 to 28 d postpartum), due to the expected effect of parturition on the pattern of rumination time. The proportion of cows with SCH and serum tCa concentrations (UW only) were evaluated separately (on the day of parturition and d 3 ± 1 after parturition), and the model contained the fixed effect of treatment and pen nested within treatment as a random effect.
For response variables with repeated measurements, the covariance structure (compound symmetry or autoregressive) to account for measures from the same animal was selected based for each model based on the Bayesian information criterion. Calculations of degrees of freedom were obtained using the Kenward-Roger option. Overdispersion of the data was analyzed by the ratio of the generalized chi-squared statistic and its degrees of freedom, looking at fit statistic (χ2/df) using the Laplace method. All variables had χ2/df ≤1.2. Analyses of studentized residuals were performed to evaluate model assumptions for normality. Daily rumination data for cows with <10 measurements (0.6%) and data with studentized residuals >3 or < −3 and not meeting model assumptions were excluded from the analysis (1.0 and 1.5% for the 2 periods analyzed: −7 d to 6 d and 7 d to 28 d relative to parturition).
Time-to-event data (i.e., time to pregnancy and sold) were analyzed using Cox proportional hazards regression calculated with the PHREG procedure of SAS. Treatment (CON or RPM) and farm (CU or UW) were included as fixed effects, whereas pen was included as a random effect. For the analysis of time-to-culled, cows were right censored (cows identified as culled at any given time during the analysis due to any reason) if they left the herd due to death before 350 DIM. For time-to-pregnancy analysis, only cows that maintained pregnancy up to 150 d of gestation were considered pregnant. Cows were right censored (cows identified as not pregnant at any given time during the analysis due to any reason) if they left the herd due to culling and death, or if coded as “do not breed” before 350 DIM. Cows not pregnant at 350 DIM were also right censored (
Reproductive performance and herd exit dynamics of lactating dairy cows managed for first service with the Presynch-Ovsynch or Double-Ovsynch protocol and different duration of the voluntary waiting period.
). The median and mean days to an event were obtained from the LIFETEST procedure of SAS. Survival plots were generated using SigmaPlot version 13.0 (Systat Software Inc.).
In addition to evaluating the overall effect of dietary treatments on outcomes of interest, analyses were conducted to explore the interaction between the occurrence of health disorders and RPM feeding. Cows were grouped based on the occurrence of no health disorders or one or more health disorders during the observation period. Models contained treatment, health status group, health status group × treatment interaction, and farm as fixed effects. Pen nested within treatment and farm, and pen nested within health status group were random effects. For lactation performance, health status groups were created based on occurrence of disorders up to 112 DIM, whereas for BW, BCS change, and daily rumination, groups were formed based on occurrence of health disorders up to 28 DIM. Preplanned contrasts were used to evaluate additional questions of interest. Specifically, we evaluated the contrasts between CON and RPM within each health status group.
All initial models included lactation number used as a covariate, but it was removed from the model if not significant (P > 0.10). All explanatory variables and their interactions were considered significant if P ≤ 0.05, whereas 0.05 < P ≤ 0.10 was considered a tendency. All proportions and quantitative variables reported are presented as least squares means ± standard error of the mean (LSM ± SEM; largest SEM is shown if only a single value is presented) obtained with the LSMEANS option of PROC MIXED or GLIMMIX of SAS. When appropriate, the Tukey post hoc mean separation test was used to determine differences between LSM.
RESULTS
Health Disorders and Rumination
Table 1 summarizes the effect of treatment on the proportion and number of health disorder events recorded. Overall, the proportion of cows with one or more health disorders (49.7 vs. 47.9%, respectively, for RPM and CON) did not differ (P = 0.61) between treatments or farm (49.5 vs. 48.1%, respectively, for UW and CU), and there was no treatment × time interaction (P = 0.61; Table 1). There was no effect of treatment or treatment × farm interaction on the proportion of cows with displaced abomasum (3.3 vs. 2.9% for RPM and CON, respectively), ketosis (9.7 vs. 13.0%), mastitis (13.9 vs. 18.6%), retained placenta (9.7 vs. 7.8%), respiratory problems (10.9 vs. 9.4%), or lameness (2.6 vs. 1.8%) (P > 0.10; Table 1). Moreover, there was no treatment effect on cytological endometritis (23.6 vs. 20.2%, P = 0.39) or average number of health disorder events (1.57 vs. 1.51, P = 0.72). The incidence of some health disorders differed by farm. The proportion of cows with lameness was greater (5.5 vs. 0.8%, P = 0.02) and the proportion of cows with respiratory problems (13.3 vs. 7.6%, P = 0.06) tended to be greater at UW than CU. Conversely, a smaller proportion of cows had cytological endometritis at UW than at CU (16.0 vs. 29.2%, P < 0.01).
Table 1Effect of feeding rumen-protected Met (RPM) diet or a control diet (CON) pre- and postpartum on incidence of health disorders
CON: basal diet = 2.30 and 2.09% of MP (University of Wisconsin; UW) or 2.22 and 2.19% of MP (Cornell University; CU); RPM: basal diet fed with rumen-protected Met (12 and 27 g pre- and postpartum, respectively) with 2.83 and 2.58% Met as % of MP (UW) or 2.85 and 2.65% Met as % of MP (CU), pre- and postpartum, respectively.
Defined as cows with decreased appetite, decreased milk yield, and urinary ketone-acetoacetic acid at or above “moderate” (≥40 mg/dL). All cows were examined daily from 1 to 10 DIM and then in cows suspected of ketosis.
LSM ± SEM; only cows with at least one health event.
1.57
1.51
0.12
—
0.72
0.52
1 CON: basal diet = 2.30 and 2.09% of MP (University of Wisconsin; UW) or 2.22 and 2.19% of MP (Cornell University; CU); RPM: basal diet fed with rumen-protected Met (12 and 27 g pre- and postpartum, respectively) with 2.83 and 2.58% Met as % of MP (UW) or 2.85 and 2.65% Met as % of MP (CU), pre- and postpartum, respectively.
2 Trt = treatment effect; Trt × farm P > 0.10.
3 Includes clinical health disorders + cytological endometritis.
4 Defined as left or right side displacement of abomasum based on auscultation of a characteristic metallic “ping” sound; confirmed by surgery.
5 Defined as cows with decreased appetite, decreased milk yield, and urinary ketone-acetoacetic acid at or above “moderate” (≥40 mg/dL). All cows were examined daily from 1 to 10 DIM and then in cows suspected of ketosis.
6 Defined as presence of abnormal milk or signs of inflammation in one or more quarters.
7 Defined as lack of expulsion of the fetal membranes within 24 h after calving.
8 Defined as increased respiratory rate, fever, and increased lung sounds at auscultation.
9 Defined as defined as cows that stood and walked with arched back and an abnormal gait or avoidance of bearing weight on one or more limbs.
10 Cytological endometritis = cows with PMN >10%. Final number of cows evaluated: CON = 211; RPM = 209.
11 LSM ± SEM; only cows with at least one health event.
Table 2 summarizes the effect of treatment on tCa concentrations and on proportion of cows with SCH at the time of parturition and on d 3 ± 1 postpartum at UW. There was no treatment effect on tCa at the time of parturition (2.12 vs. 2.07 mM for RPM and CON, respectively; P = 0.50) or on d 3 ± 1 postpartum (2.12 vs. 2.07 mM, P = 0.91). However, we observed a lower (P = 0.05) proportion of cows with SCH (13.6 vs. 22.0%) for the RPM treatment at the time of parturition but no differences (P = 0.83) on d 3 ± 1 postpartum (33.6 vs. 31.4%).
Table 2Effect of feeding rumen-protected Met (RPM) diet or a control diet (CON) pre- and postpartum on total calcium concentrations (tCa) and subclinical hypocalcemia (SCH) at the time of parturition and on d 3 ± 1 postpartum
SCH is defined as a total serum Ca concentration <1.77 mM at parturition or <2.20 mM on d 3 ± 1 postpartum. University of Wisconsin (UW) data only; n at parturition: CON = 107, RPM = 107 and d 3: CON = 110 and RPM = 111.
CON: basal diet = 2.30 and 2.09% of MP (UW) or 2.22 and 2.19% of MP (Cornell University; CU); RPM: basal diet fed with rumen-protected Met (12 and 27 g pre- and postpartum, respectively) with 2.83 and 2.58% Met as % of MP (UW) or 2.85 and 2.65% Met as % of MP (CU), pre- and postpartum, respectively.
CON: basal diet = 2.30 and 2.09% of MP (UW) or 2.22 and 2.19% of MP (Cornell University; CU); RPM: basal diet fed with rumen-protected Met (12 and 27 g pre- and postpartum, respectively) with 2.83 and 2.58% Met as % of MP (UW) or 2.85 and 2.65% Met as % of MP (CU), pre- and postpartum, respectively.
SEM
Odds ratio (95% CI)
P-value
tCa, mM
At parturition
2.07
2.12
0.05
0.50
Day 3
2.37
2.38
0.06
0.91
SCH, %
At parturition
22.0
13.6
2.2
0.56 (0.31–1.01)
0.05
Day 3
31.4
33.6
7.0
1.11 (0.32–3.83)
0.83
1 SCH is defined as a total serum Ca concentration <1.77 mM at parturition or <2.20 mM on d 3 ± 1 postpartum. University of Wisconsin (UW) data only; n at parturition: CON = 107, RPM = 107 and d 3: CON = 110 and RPM = 111.
2 CON: basal diet = 2.30 and 2.09% of MP (UW) or 2.22 and 2.19% of MP (Cornell University; CU); RPM: basal diet fed with rumen-protected Met (12 and 27 g pre- and postpartum, respectively) with 2.83 and 2.58% Met as % of MP (UW) or 2.85 and 2.65% Met as % of MP (CU), pre- and postpartum, respectively.
The effects of treatments on daily rumination are presented in Figure 2. There was no effect (P > 0.05) of treatment from 7 d before parturition until 6 d postpartum (469.3 vs. 471.5 min/d) or from 7 to 28 d postpartum (531.6 vs. 544.0 min/d, respectively, for RPM and CON) and no treatment × day or treatment × farm interactions (P > 0.10). However, daily rumination was affected by day (P < 0.01) in both periods. As expected, daily rumination reached a nadir (295.5 min/d, P < 0.01) on the day of parturition and started to increase until d 5 postpartum (523.3 min/d) when it reached levels similar to 7 d before parturition (518.1 min/d). In addition, cows at UW had greater (P < 0.01) daily rumination time than cows at CU (554.2 vs. 521.4 min/d) from 7 d until 28 d postpartum but not from 7 d before parturition until 6 d postpartum.
Figure 2Effect of feeding rumen-protected Met (RPM) or a control diet (CON) pre- and postpartum on daily rumination time. CON: n = 204; RPM: n = 198. CON: basal diet = 2.30 and 2.09% Met as % of MP (University of Wisconsin; UW) or 2.22 and 2.19% Met (Cornell University; CU); RPM: basal diet fed with rumen-protected Met with 2.83 and 2.58% Met as % of MP (UW) or 2.85 and 2.65% Met as % of MP (CU), all pre- and postpartum, respectively. Trt = treatment effect. Values are LSM, with SEM represented by error bars.
Time to Pregnancy After Calving and Herd Exit Dynamics
Figure 3 shows the effect of feeding RPM on time to pregnancy up to 350 DIM. We observed no effect of feeding RPM on time to pregnancy when all cows that had a pregnancy outcome at first-service TAI were included in the analysis [hazard ratio (HR) = 0.88, 95% CI: 0.72–1.07, P = 0.20]. Median and mean days to pregnancy were 103 and 130 for CON and 102 and 119 for RPM. There was no farm effect on time to pregnancy (P = 0.54).
Figure 3Time to pregnancy after parturition for all multiparous cows that had a pregnancy outcome at first-service timed AI (n = 426) and were fed a rumen-protected Met (RPM) diet or a control diet (CON) pre- and postpartum. CON: basal diet = 2.30 and 2.09% Met as % of MP (University of Wisconsin; UW) or 2.22 and 2.19% Met (Cornell University; CU); RPM: basal diet fed with rumen-protected Met with 2.83 and 2.58% Met as % of MP (UW) or 2.85 and 2.65% Met as % of MP (CU), all pre- and postpartum, respectively. The overall time to pregnancy did not differ between treatments (hazard ratio = 0.88, 95% CI = 0.72–1.07, P = 0.20). Median and mean days to pregnancy were 103 and 130 for CON and 102 and 119 for RPM.
The effect of treatment on herd exit [i.e., culled, died, and total cows that left the herd (culled + died)] for all cows is summarized in Table 3, and time to herd exit for cows culled up to 350 DIM is presented in Figure 4. There was no effect of treatment (P > 0.10) on the proportion of cows that died or that left the herd. However, the overall proportion of cows culled as sold (P = 0.08; Table 3) and the hazard of culling by 350 DIM (Figure 4) tended to differ as fewer cows were culled and cows were culled at a slower rate (HR = 0.65, 95% CI: 0.42–1.02, P = 0.06) for cows fed RPM versus CON. Mean days to culling were 319 for both treatments. In addition, there was a tendency for a farm effect for both the proportion of cows culled and dead. Specifically, the proportion of cows culled tended to be greater for UW than for CU (19.3 vs. 13.0%, P = 0.08), but the proportion of cows dead tended to be greater for CU than for UW (4.8 vs. 0.5%, P = 0.10). No effect of farm (P = 0.77) or treatment × farm interaction (P > 0.05) was observed for the total proportion of cows that left the herd.
Table 3Effect of feeding rumen-protected Met (RPM) diet or a control diet (CON) pre- and postpartum on herd exit up to 350 DIM
CON: basal diet = 2.30 and 2.09% of MP (University of Wisconsin; UW) or 2.22 and 2.19% of MP (Cornell University; CU); RPM: basal diet fed with rumen-protected Met (12 and 27 g pre- and postpartum, respectively) with 2.83 and 2.58% Met as % of MP (UW) or 2.85 and 2.65% Met as % of MP (CU), pre- and postpartum, respectively.
CON: basal diet = 2.30 and 2.09% of MP (University of Wisconsin; UW) or 2.22 and 2.19% of MP (Cornell University; CU); RPM: basal diet fed with rumen-protected Met (12 and 27 g pre- and postpartum, respectively) with 2.83 and 2.58% Met as % of MP (UW) or 2.85 and 2.65% Met as % of MP (CU), pre- and postpartum, respectively.
1 CON: basal diet = 2.30 and 2.09% of MP (University of Wisconsin; UW) or 2.22 and 2.19% of MP (Cornell University; CU); RPM: basal diet fed with rumen-protected Met (12 and 27 g pre- and postpartum, respectively) with 2.83 and 2.58% Met as % of MP (UW) or 2.85 and 2.65% Met as % of MP (CU), pre- and postpartum, respectively.
Figure 4Time of cows being culled after parturition for all multiparous cows (n = 470) fed a rumen-protected Met (RPM) diet or a control diet (CON) pre- and postpartum. CON: basal diet = 2.30 and 2.09% Met as % of MP (University of Wisconsin; UW) or 2.22 and 2.19% Met (Cornell University; CU); RPM: basal diet fed with rumen-protected Met with 2.83 and 2.58% Met as % of MP (UW) or 2.85 and 2.65% Met as % of MP (CU), all pre- and postpartum, respectively. The overall hazard of being sold tended (P = 0.06) to be reduced for RPM compared with CON (hazard ratio = 0.65, 95% CI: 0.42–1.02). Mean days-to-sold was 319 d for both treatments.
Interaction of Health Disorders and Feeding RPM With Lactation Performance, BW Change, BCS Change, and Rumination
Milk and component yields, and milk composition were evaluated for health status groups and treatments within each health status group (Table 4). Cows without health disorders tended to have greater (P = 0.09) NEL in milk (36.0 vs. 35.2 Mcal/d) and had greater (P < 0.05) milk protein concentration (2.99 vs. 2.93%) and yield (1.48 vs. 1.44 kg/d), lactose concentration (4.90 vs. 4.86%), MUN (10.6 vs. 10.2 mg/dL), and lower SCC (73.7 vs. 121.3 × 103 cells/mL) than cows with health disorders. Milk yield (49.9 vs. 49.4 kg/d), ECM (50.6 vs. 49.7 kg/d), fat concentration (3.79 vs. 7.76%) and yield (1.88 vs. 1.86), and lactose yield (2.45 vs. 2.40 kg/d for cows without and with health disorders, respectively) were unaffected (P > 0.10) by health status.
Table 4Interaction of feeding rumen-protected Met (RPM) or a control diet (CON) pre- and postpartum with health disorder groups on milk yield and milk composition during the first 112 ± 3 DIM
CON: basal diet = 2.30 and 2.09% of MP (University of Wisconsin; UW) or 2.22 and 2.19% of MP (Cornell University; CU); RPM: basal diet fed with rumen-protected Met (12 and 27 g pre- and postpartum, respectively) with 2.83 and 2.58% Met as % of MP (UW) or 2.85 and 2.65% Met as % of MP (CU), pre- and postpartum, respectively.
Health disorder groups: Without = group of cows that did not experience health disorders; With = group of cows that experienced one or more health disorders.
P-values for preplanned treatment contrast within health group. Farm: P < 0.05 for milk protein and lactose concentration, milk lactose yield, MUN, and SCC.
Back transformed data: 95% CI: Without: CON (62.4, 101.4); RPM (53.4, 87.1); With: CON (96.2, 156.8); RPM (93.2, 153.8).
×103 cells/mL
73.7
121.3
—
<0.01
79.6
68.2
122.8
119.7
—
0.35
0.88
1 CON: basal diet = 2.30 and 2.09% of MP (University of Wisconsin; UW) or 2.22 and 2.19% of MP (Cornell University; CU); RPM: basal diet fed with rumen-protected Met (12 and 27 g pre- and postpartum, respectively) with 2.83 and 2.58% Met as % of MP (UW) or 2.85 and 2.65% Met as % of MP (CU), pre- and postpartum, respectively.
2 Health disorder groups: Without = group of cows that did not experience health disorders; With = group of cows that experienced one or more health disorders.
3 P-values for preplanned treatment contrast within health group. Farm: P < 0.05 for milk protein and lactose concentration, milk lactose yield, MUN, and SCC.
4 Without: CON n = 108, RPM n = 111; With: CON n = 104, RPM n = 103.
5 Back transformed data: 95% CI: Without: CON (62.4, 101.4); RPM (53.4, 87.1); With: CON (96.2, 156.8); RPM (93.2, 153.8).
We observed no effects of treatments (P > 0.05) on milk yield, ECM, NEL in milk, milk fat yield, lactose concentration and yield, MUN, or SCC within any of the health status groups evaluated (Table 4). However, cows fed RPM had greater (P < 0.01) milk protein concentration within the group of cows with (3.00 vs. 2.87%) and without (3.04 vs. 2.93%) health disorders compared with CON cows. Cows fed RPM had greater (P = 0.02) milk protein yield than CON cows within the group with health disorders (1.47 vs. 1.40 kg/d), but this effect was not detected within the group of cows without health disorders (P = 0.27). This difference was more dramatic in cows with multiple health disorders (1.44 vs. 1.36 kg/d; P = 0.01) than in cows with a single health disorder (1.48 vs. 1.43 kg/d; P = 0.07; data not shown in table). In addition, cows fed RPM had greater (P = 0.04) milk fat concentration (3.85 vs. 3.73%) within the group of cows without health disorders, but not within the group of cows with health disorders (P = 0.19).
Table 5 shows the effect of health disorders groups during the first 28 DIM on BW change, BCS change, and average rumination time and effect of feeding RPM within each health group. There was no effect (P > 0.05) of health status groups on BW change or BCS change. Rumination time was affected by health status groups, with rumination time being greater for cows without health disorders than for those with disorders (P < 0.01) from 7 d before parturition until 6 d postpartum (479.5 vs. 445.7 min/d) and from 7 to 28 d postpartum (543.5 vs. 518.3 min/d). There was no effect of treatment (P > 0.10) on rumination within health status groups.
Table 5Interaction of feeding rumen-protected Met (RPM) or a control diet (CON) pre- and postpartum with health disorder (first 28 DIM) groups on BW change (4 to 39 ± 3 DIM), BCS change (0 to 49 ± 1 DIM), and daily rumination
CON: basal diet = 2.30 and 2.09% of MP (University of Wisconsin; UW) or 2.22 and 2.19% of MP (Cornell University; CU); RPM: basal diet fed with rumen-protected Met (12 and 27 g pre- and postpartum, respectively) with 2.83 and 2.58% Met as % of MP (UW) or 2.85 and 2.65% Met as % of MP (CU), pre- and postpartum, respectively.
Health disorder group: Without = group of cows that did not experience health disorders; With = group of cows that experienced one or more health disorders.
P-values for preplanned treatment contrast within health groups. Farm: P < 0.05 for daily rumination from 7 to 28 d postpartum period, BW change, and BCS change.
Without: CON n = 145, RPM n = 145; With: CON n = 55, RPM n = 53.
min/d
543.5
518.3
7.7
<0.01
549.8
537.2
524.5
512.1
11.0
0.21
0.43
1 CON: basal diet = 2.30 and 2.09% of MP (University of Wisconsin; UW) or 2.22 and 2.19% of MP (Cornell University; CU); RPM: basal diet fed with rumen-protected Met (12 and 27 g pre- and postpartum, respectively) with 2.83 and 2.58% Met as % of MP (UW) or 2.85 and 2.65% Met as % of MP (CU), pre- and postpartum, respectively.
2 Health disorder group: Without = group of cows that did not experience health disorders; With = group of cows that experienced one or more health disorders.
3 P-values for preplanned treatment contrast within health groups. Farm: P < 0.05 for daily rumination from 7 to 28 d postpartum period, BW change, and BCS change.
4 Without: CON n = 153, RPM n = 150; With: CON n = 53, RPM n = 55.
5 Without: CON n = 145, RPM n = 145; With: CON n = 55, RPM n = 53.
Interaction of Health Disorders and Feeding RPM with Reproductive Performance
Reproductive performance was evaluated for health disorder groups (Table 6). Health disorders had a dramatic effect on reproductive performance; regardless of treatments, cows without health disorders had greater (P < 0.05) P/AI than cows with health disorders at all time points (e.g., P/AI at 67 d after TAI: without = 54.5%; with = 33.9%). Except for pregnancy loss between d 25 and 29 (P = 0.24), pregnancy loss was reduced (P < 0.05) for cows without health disorders for all periods (e.g., pregnancy loss between 25 and 67 d after TAI: without = 15.6%; with: = 34.3%). There was no effect of feeding RPM on P/AI within each health status group at any timepoint and no difference in pregnancy loss for all periods evaluated (P > 0.10).
Table 6Interaction of feeding rumen-protected Met (RPM) or a control diet (CON) pre- and postpartum with health disorder groups on pregnancies per AI and pregnancy loss after first-service timed AI (TAI) and proportion of cows pregnant or pregnancy loss
CON: basal diet = 2.30 and 2.09% of MP (University of Wisconsin; UW) or 2.22 and 2.19% of MP (Cornell University; CU); RPM: basal diet fed with rumen-protected Met (12 and 27 g pre- and postpartum, respectively) with 2.83 and 2.58% Met as % of MP (UW) or 2.85 and 2.65% Met as % of MP (CU), pre- and postpartum, respectively.
Health disorder group: Without = group of cows that did not experience health disorders; With = group of cows that experienced one or more health disorders.
All cows enrolled in the experiment that had a pregnancy outcome at first-service TAI were included in the analysis. Includes clinical health disorders + cytological endometritis. Without: n = 212 (CON, 108; RPM, 104); With: n = 214 (CON, 111; RPM, 103).
All cows enrolled in the experiment that had a pregnancy outcome at first-service TAI were included in the analysis. Includes clinical health disorders + cytological endometritis. Without: n = 212 (CON, 108; RPM, 104); With: n = 214 (CON, 111; RPM, 103).
25 and 29 d after TAI
2.5
5.7
2.3
0.24
4.8
1.3
5.4
6.0
3.2
0.23
0.90
29 and 32 d after TAI
7.5
17.7
3.8
0.03
5.6
9.9
18.7
16.7
5.7
0.35
0.79
25 and 32 d after TAI
11.2
23.6
4.2
0.03
10.9
11.5
24.2
22.9
6.2
0.91
0.88
32 and 67 d after TAI
4.4
13.5
4.3
0.06
6.7
2.8
16.5
11.0
7.0
0.33
0.53
Total 25 and 67 d after TAI
15.6
34.3
5.1
<0.01
17.1
14.2
37.3
31.4
7.5
0.66
0.56
1 CON: basal diet = 2.30 and 2.09% of MP (University of Wisconsin; UW) or 2.22 and 2.19% of MP (Cornell University; CU); RPM: basal diet fed with rumen-protected Met (12 and 27 g pre- and postpartum, respectively) with 2.83 and 2.58% Met as % of MP (UW) or 2.85 and 2.65% Met as % of MP (CU), pre- and postpartum, respectively.
2 Health disorder group: Without = group of cows that did not experience health disorders; With = group of cows that experienced one or more health disorders.
3 All cows enrolled in the experiment that had a pregnancy outcome at first-service TAI were included in the analysis. Includes clinical health disorders + cytological endometritis. Without: n = 212 (CON, 108; RPM, 104); With: n = 214 (CON, 111; RPM, 103).
Figure 5 shows time to pregnancy up to 350 DIM for health status groups. Cows with health disorders had reduced hazard of pregnancy compared with cows without health disorders (HR = 0.67, 95% CI: 0.55–0.82, P < 0.01). Median and mean days to pregnancy for cows without or with health disorders were 83 and 113, and 115 and 137, respectively.
Figure 5Time to pregnancy after parturition for multiparous cows without or with health disorders. Cows with health disorders had delayed time to pregnancy compared with cows without health disorders (hazard ratio = 0.67, 95% CI: 0.55–0.82, P < 0.01). Median and mean days to pregnancy for cows without or with health disorders were 83 and 113 d, and 115 and 137 d, respectively.
Figure 6 shows the effect of treatment (CON or RPM) on time to pregnancy for cows with or without health disorders. There was no effect of treatment on the hazard ratio for pregnancy in cows without health disorders (HR = 1.04, 95% CI: 0.79–1.37, P = 0.77: Figure 6A). Median and mean days to pregnancy for cows without health disorders were 83 and 114 (CON) and 83 and 112 (RPM). Conversely, for cows with one or more health disorders (Figure 6B), cows fed RPM had reduced hazard ratio for time to pregnancy compared with CON (HR = 0.71, 95% CI: 0.53–0.96, P = 0.03). Median and mean days to pregnancy were 129 and 149 for CON and 115 and 125 for RPM. No effect of farm was observed for time to pregnancy in all cows or in any of the health status categories (P > 0.10).
Figure 6Time-to-pregnancy after calving for all multiparous cows (A) without health disorders and (B) with one or more health disorders and fed a rumen-protected Met (RPM) diet or a control diet (CON) pre- and postpartum. CON: basal diet = 2.30 and 2.09% Met as % of MP (University of Wisconsin; UW) or 2.22 and 2.19% Met (Cornell University; CU); RPM: basal diet fed with rumen-protected Met with 2.83%and 2.58% Met as % of MP (UW) or 2.85 and 2.65% Met as % of MP (CU), all pre- and postpartum, respectively. Treatments did not affect cows without health disorder [hazard ratio (HR) = 1.04, 95% CI: 0.79–1.37, P = 0.77]. Median and mean days to pregnancy for cows without health disorders were 83 and 114 d (CON) and 83 and 112 d (RPM). However, cows with one or more health disorders fed RPM had reduced time to pregnancy compared with CON (HR = 0.71, 95% CI: 0.53–0.96, P = 0.03). Median and mean days to pregnancy were 129 and 149 d for CON and 115 and 125 d for RPM.
Our main hypothesis was that feeding RPM pre- and postpartum would decrease the incidence of specific health disorders routinely evaluated in these herds, and incidence of cytological endometritis and subclinical hypocalcemia. To test this hypothesis, the current experiment conducted on 2 university farms (UW and CU) was designed to determine of effects of adding RPM into the diet on health disorders using more than 400 multiparous cows in a pen-based approach. Although this approach did not allow us to control or monitor individual DMI, treatment was effective, as evidenced by the increase in plasma Met concentrations in cows fed RPM (
Effects of feeding rumen-protected methionine pre- and postpartum in multiparous Holstein cows: Lactation performance and plasma amino acid concentrations.
). Nevertheless, this is an important limitation of the current study because an accurate intake of the treatment supplement could not be determined for individual cows. The use of replicated pens allowed incorporation of RPM in the TMR to have sufficient sample size to validly assess binary outcomes, such as incidence of health disorders (
The effect of feeding dairy heifers diets with and without supplemental phosphorus on growth, reproductive efficiency, health, and lactation performance.
). Our data did not support our primary hypothesis: we observed no effect of RPM feeding pre- and postpartum on incidence of all health disorders combined. The only effects observed were a 38% reduction in prevalence of SCH on the day of parturition and a tendency for a reduction in the proportion of cows that left the herd due to sale (32% reduction) for cows fed RPM. Although our current results indicated that feeding RPM in the TMR at the rate used in this experiment did not prevent occurrence of health disorders, it seemed to partially alleviate some of the negative effects of health disorders on productive and reproductive outcomes. For example, feeding RPM increased milk protein production in cows with health disorders (+70 g), but not in cows without health disorders. Similarly, time to pregnancy was reduced (24 d) in cows with health disorders but not in cows without health disorders. Collectively, these data suggested that RPM feeding might improve certain performance and reproductive outcomes but only in lactating dairy cows affected by health disorders. Additional experiments are needed to test this hypothesis.
Our data showed that feeding RPM decreased SCH at the time of parturition (UW) but not other types of health disorders (UW and CU). Previous studies reported improvements for indicators of immune function, inflammation, oxidative stress, and liver metabolism (
Ethyl-cellulose rumen-protected methionine alleviates inflammation and oxidative stress and improves neutrophil function during the periparturient period and early lactation in Holstein dairy cows.
Ethyl-cellulose rumen-protected methionine alleviates inflammation and oxidative stress and improves neutrophil function during the periparturient period and early lactation in Holstein dairy cows.
). Our findings for occurrence of clinical health disorders did not support an effect of RPM on overall incidence of health disorders, and contrast with these previous studies as we observed no differences in the proportion of cows with retained placenta and ketosis. We cannot rule out positive effects of RPM feeding on cow immune, inflammation, oxidative, and metabolic status observed in previous experiments (
Biomarkers of inflammation, metabolism, and oxidative stress in blood, liver, and milk reveal a better immunometabolic status in peripartal cows supplemented with Smartamine M or MetaSmart.
Ethyl-cellulose rumen-protected methionine alleviates inflammation and oxidative stress and improves neutrophil function during the periparturient period and early lactation in Holstein dairy cows.
) because these were not evaluated in our study. However, if RPM feeding did affect these physiologic measures, the magnitude was insufficient to prevent the occurrence of clinical health disorders. Our results are in agreement with some studies that reported no effect of feeding RPM or Met analog during the pre- and postpartum periods on blood metabolites, such as nonesterified fatty acids, BHB, and glucose, or on liver metabolism (
To our knowledge, no previous study has evaluated the effect of feeding RPM on the proportion of cows that develop SCH. Prevalence of SCH in US herds is reported to reach 73% for cows in lactation ≥3 (
The association of subclinical hypocalcemia, negative energy balance and disease with bodyweight change during the first 30 days post-partum in dairy cows milked with automatic milking systems.
). Our observation of reduced incidence of SCH on the day of parturition but not on d 3 is intriguing, and future studies with RPM feeding should be done to determine the repeatability of this finding and potentially the mechanism underlying this effect. Previous studies indicated that SCH, especially during the first 3 DIM, is associated with increased risk of other health disorders (
). However, a recent study indicated that calcium concentrations within 12 h after parturition may be a poor indicator of increased risk of health disorders (except displaced abomasum) or of reproductive performance but do indicate an association with lactation performance (
Association of immediate postpartum plasma calcium concentration with early-lactation clinical diseases, culling, reproduction, and milk production in Holstein cows.
). In our study, we also observed an interaction of RPM feeding with SCH. Cows fed RPM and with SCH had greater milk protein yield (1.58 kg/d) than cows fed RPM without SCH (1.45 kg/d) or CON cows with (1.44 kg/d) or without (1.40 kg/d) SCH on the day of parturition (P = 0.09; data not shown). This agrees with previous studies (
Association of immediate postpartum plasma calcium concentration with early-lactation clinical diseases, culling, reproduction, and milk production in Holstein cows.
) and indicates that synthesis of milk protein by the mammary gland of high-producing multiparous cows may require more calcium and Met than is normally supplied by dietary intake.
Culling in dairy herds is multifactorial (including reproductive problems, health disorders, and low milk production among others), strongly influenced by herd management policies, and poorly standardized (
), most health disorder events in our experiment were recorded during the first 3 to 4 wk postpartum, but negative effects of poor health on reproductive efficiency and culling rates were evident beyond early lactation. Most cows culled in our experiment, 67% (54/81), experienced at least one health disorder, and these cows had increased time to pregnancy compared with cows without health disorders. Of note, we observed that RPM cows tended to be less likely to be culled from the herd and had reduced hazard of herd exit due to sale up to 350 DIM. In agreement,
reported reduced culling up to 60 DIM in a study with 166 cows fed RPM from 3 wk prepartum until 16 d postpartum. As we did not observe effects of RPM feeding on the incidence of health disorders or milk yield, it is unlikely that more cows were sold during the experiment because of poor health, reduced milk yield, or combinations thereof. Conversely, a potential factor that could have influenced the proportion of cows sold was the difference in hazard of pregnancy for cows with health disorders. It is plausible that because of the greater pregnancy rate for cows in the RPM group with health disorders, some cows that would have been otherwise sold remained in the herd because they were pregnant. Indeed, it has been well documented that dairy farms are less likely to sell pregnant than nonpregnant lactating cows (
). This potential association between reproductive performance in cows fed RPM and the culling dynamic, however, should be interpreted with caution because reasons for selling cows in our experiment were not properly standardized. Future experiments should explore the effects of RPM feeding on dairy herd culling dynamics, accounting for possible interactions between reproductive performance and herd exit due to sale.
To evaluate the interaction of health disorders and feeding RPM, lactation performance was evaluated in cows without or with health disorders. As expected, decreased lactation performance was observed in cows with health disorders. More specifically, milk protein yield, milk protein and lactose concentrations, MUN, and SCC were affected by health status. These observations were not surprising because several studies have previously reported negative associations between postpartum health disorders and lactation performance (
Association between the proportion of sampled transition cows with increased nonesterified fatty acids and beta-hydroxybutyrate and disease incidence, pregnancy rate, and milk production at the herd level.
Biomarkers of inflammation, metabolism, and oxidative stress in blood, liver, and milk reveal a better immunometabolic status in peripartal cows supplemented with Smartamine M or MetaSmart.
Ethyl-cellulose rumen-protected methionine alleviates inflammation and oxidative stress and improves neutrophil function during the periparturient period and early lactation in Holstein dairy cows.
), improvements in overall health and lactation performance were partially attributed to increased DMI during the periparturient period for RPM-fed cows. Unfortunately, individual DMI in our study could not be measured and, at the pen level, we observed no effects of RPM on DMI (
Effects of feeding rumen-protected methionine pre- and postpartum in multiparous Holstein cows: Lactation performance and plasma amino acid concentrations.
). Alternatively, it is possible that cows that experienced health disorders were more deficient in Met. For these cows, the supply of extra metabolizable Met provided by RPM feeding could have alleviated some of the negative effects of health disorders (e.g., decrease subclinical or severity of health disorders;
Biomarkers of inflammation, metabolism, and oxidative stress in blood, liver, and milk reveal a better immunometabolic status in peripartal cows supplemented with Smartamine M or MetaSmart.
Regulation of inflammation, antioxidant production, and methyl-carbon metabolism during methionine supplementation in lipopolysaccharide-challenged neonatal bovine hepatocytes.
Ethyl-cellulose rumen-protected methionine alleviates inflammation and oxidative stress and improves neutrophil function during the periparturient period and early lactation in Holstein dairy cows.
), with effects on milk protein production only. Indeed, RPM feeding had no effect on other production measures that were decreased by health disorders.
Consistent with the increased milk protein production response, time to pregnancy was also affected by an interaction of health disorders with RPM feeding. In our study, health disorders had a dramatic effect on P/AI (67 d after TAI: 54.5% vs. 33.9%) and pregnancy loss (15.6% vs. 34.3%). Our data are in agreement with several previous studies that demonstrated reduced reproductive performance in cows that had health disorders during lactation (
Association between the proportion of sampled transition cows with increased nonesterified fatty acids and beta-hydroxybutyrate and disease incidence, pregnancy rate, and milk production at the herd level.
). Interestingly, the detected pregnancy losses for cows with health disorders were greatest between 25 and 32 d after TAI and, within this interval, there was a surprisingly high pregnancy loss between 29 and 32 d after TAI (7.5 vs. 17.7%, without and with health disorders, respectively). This was more dramatic in cows with multiple health disorders (32.8%; data not shown). This is the first study to report an effect of health disorders on this short interval during early pregnancy. Confirmation of these results and determination of the mechanism(s) causing pregnancy loss during this pivotal period will require further research (
). In addition, cows with health disorders (median: 115 d) had delayed time to pregnancy up to 350 DIM compared with cows without health disorders (median: 83 d). Of particular importance, we observed that cows fed RPM became pregnant earlier than CON cows (HR = 0.71). This is the first study showing potential effects of feeding RPM on time to pregnancy in cows with health disorders; thus, future studies are warranted to properly evaluate the interactions between feeding RPM pre- and postpartum with health outcomes and reproductive performance. Some potential explanations for RPM reducing time to pregnancy in cows with health disorders that should be explored in future studies include reduced SCH (
). Epigenetic changes involving methylation of DNA or histones is one obvious potential mechanism because Met participates in the one-carbon pathway and could provide required methyl groups (
). Thus, the link between health disorders and Met on embryonic viability and pregnancy outcomes in lactating dairy cows needs to be confirmed, and the intriguing mechanisms that produce this link remain to be elucidated.
CONCLUSIONS
Our study evaluated the effect of feeding RPM in the TMR using a pen-based approach on prevalence of health disorders, herd exit dynamics, and the interaction of health disorders and feeding RPM in >400 multiparous cows on 2 university farms. We observed no effect of RPM on any type of specific health disorder, although feeding RPM decreased the number of cows with SCH at the time of parturition and tended to reduce the number of cows culled from the herd. Overall, feeding RPM improved milk protein production, but no changes were observed in reproductive efficiency measured by P/AI or pregnancy loss. Nevertheless, feeding RPM alleviated some negative effects of health disorders, such that cows with health disorders and fed RPM had increased milk protein production and earlier time to pregnancy. Collectively, these findings support the idea that feeding RPM in pre- and postpartum diets can affect performance of dairy cows and suggest that these effects may be accentuated in situations of stress, such as during health disorders. Further research is required to confirm this observation and to elucidate the mechanism by which Met can diminish the negative effects of health disorders on lactation and reproduction in high-producing dairy cows.
ACKNOWLEDGMENTS
This research was partially supported by Adisseo USA Inc. (Alpharetta, GA). This research was also supported by the Multistate Regional Research Project NE1727 as USDA (Washington, DC) Hatch Project WIS04041 to MCW and as USDA Project NYC-127813 to JOG. The authors thank the staff at the University of Wisconsin-Madison Blaine Dairy Cattle Center and the staff at the Dairy Unit of the Cornell University Ruminant Center (Harford, NY) for assistance during the trial with milk sampling, management, and animal care. We also thank Sandy Trower, Hattie Weissmann, Susan Murkley, Sandy Bertics, and Faye Nashold (University of Wisconsin), and Susanne Pelton (Cornell University) for assistance with the trial; Jeff Booth at the Feed Mill (University of Wisconsin Madison) for assistance with the rations; and West Central Cooperative (Ralston, IA) for donating the SoyPLUS. The authors have not stated any conflicts of interest.
Ethyl-cellulose rumen-protected methionine alleviates inflammation and oxidative stress and improves neutrophil function during the periparturient period and early lactation in Holstein dairy cows.
The effect of feeding dairy heifers diets with and without supplemental phosphorus on growth, reproductive efficiency, health, and lactation performance.
The association of subclinical hypocalcemia, negative energy balance and disease with bodyweight change during the first 30 days post-partum in dairy cows milked with automatic milking systems.
Association of immediate postpartum plasma calcium concentration with early-lactation clinical diseases, culling, reproduction, and milk production in Holstein cows.
Biomarkers of inflammation, metabolism, and oxidative stress in blood, liver, and milk reveal a better immunometabolic status in peripartal cows supplemented with Smartamine M or MetaSmart.
Association between the proportion of sampled transition cows with increased nonesterified fatty acids and beta-hydroxybutyrate and disease incidence, pregnancy rate, and milk production at the herd level.
Reproductive performance and herd exit dynamics of lactating dairy cows managed for first service with the Presynch-Ovsynch or Double-Ovsynch protocol and different duration of the voluntary waiting period.
Extending the duration of the voluntary waiting period from 60 to 88 days in cows that received timed artificial insemination after the Double-Ovsynch protocol affected the reproductive performance, herd exit dynamics, and lactation performance of dairy cows.
Concurrent and carryover effects of feeding blends of protein and amino acids in high-protein diets with different concentrations of forage fiber to fresh cows. 1. Production and blood metabolites.
Effects of feeding rumen-protected methionine pre- and postpartum in multiparous Holstein cows: Lactation performance and plasma amino acid concentrations.
Functional roles of arginine during the peri-implantation period of pregnancy. III. Arginine stimulates proliferation and interferon tau production by ovine trophectoderm cells via nitric oxide and polyamine-TSC2-MTOR signaling pathways.
A resynchronization of ovulation program based on ovarian structures present at nonpregnancy diagnosis reduced time to pregnancy in lactating dairy cows.
Regulation of inflammation, antioxidant production, and methyl-carbon metabolism during methionine supplementation in lipopolysaccharide-challenged neonatal bovine hepatocytes.
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