Journal of Dairy Science

Journal of Dairy Science®since 1917

2010-03-01

Gary W. Rogers (10)

2010-03-01

Maintenance of breast milk immunoglobulin A after high-pressure processing. By Permanyer et al., page 877. In exceptional circumstances, human milk banks provide a good alternative. This study compares the thermal pasteurization system commonly used to preserve breast milk with a new system using high pressure. The results show that high-pressure treatment eliminates microorganisms as well as thermal treatment while preserving essential defense molecules, some of which are lost with the thermal technique.

ADSA Member News …

2010-03-01

In memoriam: James B. Russell, PhD James B. “Jim” Russell died peacefully at his farm on September 20, 2009. Jim was born on June 30, 1951, in Livermore, California, to the late Lincoln A. and Mary Arlene (Murphy) Russell. In 1953, the Russell family came to New York and purchased the family farm, Burke Meadow Farm, near Manheim, New York. It was there that Russell acquired his lifelong love of dairy cows.

19thADSA Discover Conference on Food Animal Agriculture: Key Issues in Sustainability of the Dairy Industry

2010-03-01

To provide a focused forum for discussion of the key societal, environmental, animal welfare, and economic issues related to dairy food production using science-based approaches

Characterization of wine rennet and its kinetics by gel electrophoresis

T.M. Jiang, L.J. Chen — 2010-03-01

Abstract: The rennet of glutinous rice wine (wine rennet) is an exclusive clotting agent for Chinese Royal cheese production. Some characterizations are reported herein in an attempt to provide evidence about the use of the protease as either a rennet substitute or an accelerator in cheese making and ripening. The results showed that wine rennet was a monomeric and unglycosylated protease. The N-sequencing indicated a high degree of similarity to other fungal rennets. The cleavage sites of wine rennet on oxidized insulin B chain identified by HPLC-mass spectrometry included Gln4-His5, Ala14-Leu15, Leu15-Tyr16, Tyr16-Leu17, and Phe24-Phe25 at pH 6.5, which were similar to those observed for Mucor rennet, but different from calf chymosin except for Leu15-Tyr16. A comparison study of the kinetic properties of wine rennet on bovine caseins with that of rennets from calf and Mucor miehei by gel electrophoresis showed that these rennets had similar coagulation efficiency but different reaction rates. Wine rennet exhibited a higher degree of degradation than the calf and Mucor enzymes at pH 6.5 and 40°C. Therefore, wine rennet would be an adjunct for calf rennet or an accelerator in cheese making.

The effect of storage temperatures and packaging methods on properties of Motal cheese

S. Andiç, H. Gençcelep, Y. Tunçtürk, Ş. Köse — 2010-03-01

Abstract: The effects of storage temperature (+4°C and –18°C) and packaging method (nonvacuum and vacuum) on biogenic amines in Motal cheese during storage periods were investigated. In addition, dry matter, titratable acidity, total nitrogen, water-soluble nitrogen, trichloroacetic acid-soluble nitrogen, phosphotungstic acid-soluble nitrogen, free amino group (proteolysis), electrophoretic patterns of casein, and amounts of lactic acid bacteria and coliforms were determined. Storage period had a significant effect on all of the biogenic amines. When compared with vacuum packaging, normal packaging had higher amounts of putrescine, cadaverine, histamine, and tyramine. Coliforms were not found at detectable levels (<100cfu/g) in all cheese samples. Results of urea-PAGE analysis of cheese samples were in good agreement with biogenic amine results and other proteolysis parameters.

A novel real-time polymerase chain reaction-based method for the detection and quantification of lactose-fermenting Enterobacteriaceae in the dairy and other food industries

M.C. Martín, N. Martínez, B. del Rio, V. Ladero, M. Fernández, M.A. Alvarez — 2010-03-01

Abstract: The presence of lactose-fermenting Enterobacteriaceae and coliforms is routinely assessed to determine the hygienic quality of water and foods, particularly dairy products. This paper reports the use of lacZ-specific primers in an SYBR green I-based real-time PCR method for the easy and rapid detection of coliforms in dairy products. A large number of bacterial species were assayed to establish the specificity of the method. The sensitivity of the method was assessed using artificially contaminated cheeses. The limit of detection was 1 coliform cell in cheese samples enriched for 8h in a culture medium. The entire procedure, including sample processing, enrichment, DNA extraction, and real-time PCR amplification, can be completed within 10 to 12h, making it a single-day assay.

Major proteins of the goat milk fat globule membrane

C. Cebo, H. Caillat, F. Bouvier, P. Martin — 2010-03-01

Abstract: Fat is present in milk as droplets of triglycerides surrounded by a complex membrane derived from the mammary epithelial cell called milk fat globule membrane (MFGM). Although numerous studies have been published on human or bovine MFGM proteins, to date few studies exist on MFGM proteins from goat milk. The objective of this study was thus to investigate the protein composition of the goat MFGM. Milk fat globule membrane proteins from goat milk were separated by 6% and 10% sodium dodecyl sulfate-PAGE and were Coomassie or periodic acid–Schiff stained. Most of MFGM proteins [mucin-1, fatty acid synthase, xanthine oxidase, butyrophilin, lactadherin (MFG EGF-8, MFG-E8), and adipophilin] already described in cow milk were identified in goat milk using peptide mass fingerprinting. In addition, lectin staining provided a preliminary characterization of carbohydrate structures occurring on MFGM proteins from goat milk depending on αS1-casein genotype and lactation stage. We provide here first evidence of the presence of O-glycans on fatty acid synthase and xanthine oxidase from goat milk. A prominent difference between the cow and the goat species was demonstrated for lactadherin. Indeed, whereas 2 polypeptide chains were easily identified by peptide mass fingerprinting matrix-assisted laser desorption/ionization–time of flight analysis within bovine MFGM proteins, lactadherin from goat milk consisted of a single polypeptide chain. Another striking observation was the presence of caseins associated with MFGM preparations from goat milk, whereas virtually no caseins were found in MFGM extracts from bovine milk. Taken together, these observations strongly support the existence of a singular secretion mode previously hypothesized in the goat.

Maintenance of breast milk immunoglobulin A after high-pressure processing

2010-03-01

Abstract: Human milk is considered the optimal nutritional source for infants. Banked human milk is processed using low-temperature, long-time pasteurization, which assures microbial safety but involves heat denaturation of some desirable milk components such as IgA. High-pressure processing technology, the subject of the current research, has shown minimal destruction of food macromolecules. The objective of this study was to investigate the influence of pressure treatments on IgA content. Moreover, bacterial load was evaluated after pressure treatments. The effects of high-pressure processing on milk IgA content were compared with those of low-temperature, long-time pasteurization. Mature human milk samples were heat treated at 62.5°C for 30min or pressure processed at 400, 500, or 600MPa for 5min at 12°C. An indirect ELISA was used to measure IgA in human milk whey obtained after centrifugation at 800×g for 10min at 4°C. All 3 high-pressure treatments were as effective as low-temperature, long-time pasteurization in reducing the bacterial population of the human milk samples studied. After human milk pressure processing at 400MPa, 100% of IgA content was preserved in milk whey, whereas only 72% was retained in pasteurized milk whey. The higher pressure conditions of 500 and 600MPa produced IgA retention of 87.9 and 69.3%, respectively. These results indicate that high-pressure processing at 400MPa for 5min at 12°C maintains the immunological protective capacity associated with IgA antibodies. This preliminary study suggests that high-pressure processing may be a promising alternative to pasteurization in human milk banking.

Identification of angiotensin I-converting enzyme inhibitory peptides from koumiss, a traditional fermented mare's milk

Y. Chen, Z. Wang, X. Chen, Y. Liu, H. Zhang, T. Sun — 2010-03-01

Abstract: Angiotensin I-converting enzyme (ACE) inhibitory activities in untreated koumiss and koumiss digested with ACE, pepsin, trypsinase, and chymotrypsin were compared and analyzed. Four novel ACE inhibitory peptides (PI, PK, PM, and PP) were purified using ultrafiltration and high performance liquid chromatography (HPLC). The classification study showed that these 4 peptides were of the true inhibitor type. The amino acid sequences of these peptides are YQDPRLGPTGELDPATQPIVAVHNPVIV, PKDLREN, LLLAHLL, and NHRNRMMDHVH, respectively. Their individual IC50 (50% inhibitory concentration) values were as follows: 14.53±0.21μM, 9.82±0.37μM, 5.19±0.18μM, and 13.42±0.17μM. From sequence analysis, we determined that PI was part of β-casein in mare's milk. The 3 peptides PK, PM, and PP did not correspond with any known milk protein. The results suggest that koumiss is rich in ACE inhibitory peptides, and the ACE inhibitors in koumiss are of the pro-drug type or a mixture of the pro-drug type and the true inhibitor type. These results may provide evidence about the beneficial effects of koumiss, especially on cardiovascular health.

Short communication: Separation and quantification of caseins and casein macropeptide using ion-exchange chromatography

B. Holland, S. Rahimi Yazdi, G. Ion Titapiccolo, M. Corredig — 2010-03-01

Abstract: The aim of this work was to improve an existing method to separate and quantify the 4 major caseins from milk samples (i.e., containing whey proteins) using ion-exchange chromatography. The separation process was carried out using a mini-preparative cation exchange column (1 or 5mL of column volume), using urea acetate as elution buffer at pH 3.5 with a NaCl gradient. All 4 major caseins were separated, and the purity of each peak was assessed using sodium dodecyl sulfate-PAGE. Purified casein fractions were also added to raw milk to confirm their elution volumes. The quantification was carried out using purified caseins in buffer as well as added directly to fresh skim milk. This method can also be employed to determine the decrease in κ-casein and the release of the casein-macropeptide during enzymatic hydrolysis using rennet. In this case, the main advantage of using this method is the lack of organic solvents compared with the conventional method for separation of macropeptide (using reversed phase HPLC).

Interrelationships between herd-level reproductive performance measures based on intervals from initiation of the breeding program in year-round and seasonal calving dairy herds

J.M. Morton — 2010-03-01

Abstract: In year-round calving herds, reproductive performance has traditionally been described in relation to each cow's calving date. This research described reproductive performance in year-round and seasonal calving dairy herds using herd-level measures based on interval from each cow's initiation of breeding program date, and assessed interrelationships between such measures. A large, prospective, single cohort study, implemented in 1997 and 1998, included 29,327 cows from 167 Australian dairy herds. Herd reproductive performance was described using 2 measures of primary importance to herd managers: the proportion of cows that became pregnant by 6wk after their initiation of breeding program date (6-wk pregnancy rate) and the proportion of cows that were nonpregnant 21wk after their initiation of breeding program date (21-wk nonpregnancy rate). Measures that contribute to these primary measures (secondary measures) were calculated for each herd for both the first and second 3-wk periods of each cow's breeding program; submission rates were calculated as proportions of cows that were inseminated at least once in the 3-wk period, and conception rates were calculated as the proportions of inseminations in the 3-wk period that resulted in pregnancy. The individual herd was the unit of analysis. The study results indicate that high submission rates are essential if herd reproductive performance is to be achieved. Six-week pregnancy rate was predicted to increase by 6 to 8 percentage points following a 10-percentage-point increase in submission rates in both 3-wk periods, and by 6 to 10 percentage points following a 10-percentage-point increase in conception rates. Submission rates were more variable than conception rates, indicating that managers may be able to achieve large increases in submission rates more easily than substantial increases in conception rates. However, the predicted benefits of increasing submission rates were greatest when conception rates were high and vice versa, highlighting the need to improve both submission and conception rates when both are low. The study results indicate that some herd managers can concurrently achieve high submission and conception rates.

Naturally occurring mastitis effects on timing of ovulation, steroid and gonadotrophic hormone concentrations, and follicular and luteal growth in cows

Y. Lavon, G. Leitner, H. Voet, D. Wolfenson — 2010-03-01

Abstract: The effects of naturally occurring subclinical chronic or clinical short-term mastitis on time of ovulation, plasma steroid and gonadotropin concentrations, and follicular and luteal dynamics were examined in 73 lactating Holstein cows. Cows were sorted by milk somatic cell count and bacteriological examination into an uninfected group (n=22), a clinical mastitis group (n=9; events occurring 20±7 d before the study), and a subclinical chronic mastitis group (n=42). In addition, uninfected and mastitic cows were further sorted by their estrus to ovulation (E-O) interval. About 30% of mastitic cows (mainly subclinical) manifested an extended E-O interval of 56±9.2h compared with 28±0.8h in uninfected cows and 29±0.5h in the other 70% of mastitic cows. In mastitic cows with extended E-O interval, the concentration of plasma estradiol at onset of estrus was lower than that of uninfected cows or mastitic cows that exhibited normal E-O intervals (3.1±0.4, 5.8±0.5, and 5.5±0.5 pg/mL, respectively). The disruptive effect of mastitis on follicular estradiol probably does not involve alterations in gonadotropin secretion because any depressive effects of mastitis on pulsatile LH concentrations were not detected. Cortisol concentrations did not differ among groups. The preovulatory LH surge in mastitic cows with delayed ovulation varied among individuals, being lower, delayed, or with no surge noted compared with the normal LH surge exhibited by uninfected cows or mastitic cows with normal E-O interval (6.8±0.7 ng/mL). The diameter of the second-wave dominant follicle was larger and the number of medium follicles was smaller in uninfected and subclinical cows with normal intervals compared with subclinical cows with extended intervals (13.4±0.5 vs. 10.9±0.9mm, and 3.8±0.2 vs. 6.7±0.14 follicles, respectively). Mid-luteal progesterone concentrations were similar in uninfected and mastitic cows. These results indicate for the first time that around 30% of cows with subclinical chronic mastitis exhibit delayed ovulation that is associated with low plasma concentrations of estradiol and a low or delayed preovulatory LH surge.

Supplementation of progesterone via controlled internal drug release inserts during ovulation synchronization protocols in lactating dairy cows1

2010-03-01

Abstract: Our objective was to determine the effect of exogenous progesterone (P4) during a timed artificial insemination (TAI) protocol on pregnancies per AI (P/AI) in dairy cows not previously detected in estrus. Lactating cows (n=3,248) from 7 commercial dairy herds were submitted to a presynchronization protocol (2 injections of PGF2α 14 d apart; Presynch), and cows in estrus after the second PGF2α received AI (EDAI; n=1,583). Cows not inseminated by 12 to 14 d after the second PGF2α injection were submitted to a TAI protocol (GnRH on d 0, PGF2α on d 7, and GnRH+TAI 72h after PGF2α). At onset of the TAI protocol, cows were balanced by parity and days in milk and assigned randomly to receive no exogenous P4 (control, n=803) or a controlled internal drug release (CIDR) insert containing 1.38g of P4 from d 0 to 7 (CIDR, n=862). Blood samples were collected at the second PGF2α injection of the Presynch and on the day of the first GnRH injection of the TAI protocol for P4 determination. When P4 in both samples was <1 ng/mL, cows were classified as anovular, whereas cows having at least 1 sample ≥1 ng/mL were classified as cyclic. Concentration of P4 at 11 to 14 d after AI was determined in a subgroup of cows (n=453) from 2 herds. Pregnancy was diagnosed at 40±5 and 65±5 d after AI. Proportion of cows inseminated on estrus after the second PGF2α injection of the Presynch protocol differed among herds (range=26.7 to 59.8%). Overall P/AI for EDAI cows at 40±5 and 65±5 d were 36.2 and 33.7%, respectively, and pregnancy loss was 8.8%. Proportion of cyclic cows at the onset of the TAI protocol differed among herds (range from 66.5 to 86.3%), but did not differ between treatments (control=72.4%, CIDR=74.1%). Treatment affected P/AI at 40±5 (control=33.3%, CIDR=38.1%) and 65±5 (control=30.0%, CIDR=35.1%) d after AI but did not affect pregnancy loss (8.6%). Cyclic cows had greater P/AI at 40±5 (38.2 vs. 29.3%) and 65±5 d (35.1 vs. 26.1%) after AI, but cyclic status had no effect on pregnancy loss. Treatment affected P4 concentration after AI, with more CIDR cows having P4 ≥1 ng/mL (94.4 vs. 86.9%) and P4 ≥3.2 ng/mL (81.8 vs. 68.0%) at 11 to 14 d after AI compared with control cows. Treatment of cows not previously detected in estrus with a CIDR insert during a TAI protocol increased proportion of cows with functional CL after AI and P/AI.

Assessment of lameness prevalence and associated risk factors in dairy herds in England and Wales

Z.E. Barker, K.A. Leach, H.R. Whay, N.J. Bell, D.C.J. Main — 2010-03-01

Abstract: Visits were made to 205 dairy farms in England and Wales between October 2006 and May 2007 by 1 or more of 4 researchers. At each visit, all milking cows were locomotion scored (lameness scored) using a 4-point scale (0=sound locomotion, 1=imperfect locomotion, 2=lame, 3=severely lame). The mean prevalence of lameness (scores 2 and 3) across the study farms was 36.8% (range=0–79.2%). On each farm, the presence within the housing and grazing environments of commonly reported risks for increased lameness was recorded. Each farmer was interviewed to gauge the ability of the farm staff to detect and treat lameness. A multivariable linear regression model was fitted. Risk factors for increased lameness were the presence of damaged concrete in yards, cows pushing each other or turning sharply near the parlor entrance or exit, cattle grazing pasture also grazed by sheep, the use of automatic scrapers, not treating lame cows within 48h of detection, and cows being housed for 61 d or longer at the time they were locomotion scored by the visiting researcher. Having a herd consisting entirely of a breed or breeds other than Holstein-Friesian was associated with a reduction in lameness prevalence compared with having a herd consisting entirely of Holstein-Friesians.

Increasing the revenues from automatic milking by using individual variation in milking characteristics

G. André, P.B.M. Berentsen, B. Engel, C.J.A.M. de Koning, A.G.J.M. Oude Lansink — 2010-03-01

Abstract: The objective of this study was to quantify individual variation in daily milk yield and milking duration in response to the length of the milking interval and to assess the economic potential of using this individual variation to optimize the use of an automated milking system. Random coefficient models were used to describe the individual effects of milking interval on daily milk yield and milking duration. The random coefficient models were fitted on a data set consisting of 4,915 records of normal uninterrupted milkings collected from 311 cows kept in 5 separate herds for 1 wk. The estimated random parameters showed considerable variation between individuals within herds in milk yield and milking duration in response to milking interval. In the actual situation, the herd consisted of 60 cows and the automatic milking system operated at an occupation rate (OR) of 64%. When maximizing daily milk revenues per automated milking system by optimizing individual milking intervals, the average milking interval was reduced from 0.421 d to 0.400 d, the daily milk yield at the herd level was increased from 1,883 to 1,909 kg/d, and milk revenues increased from €498 to €507/d. If an OR of 85% could be reached with the same herd size, the optimal milking interval would decrease to 0.238 d, milk yield would increase to 1,997 kg/d, and milk revenues would increase to €529/d. Consequently, more labor would be required for fetching the cows, and milking duration would increase. Alternatively, an OR of 85% could be achieved by increasing the herd size from 60 to 80 cows without decreasing the milking interval. Milk yield would then increase to 2,535 kg/d and milk revenues would increase to €673/d. For practical implementation on farms, a dynamic approach is recommended, by which the parameter estimates regarding the effect of interval length on milk yield and the effect of milk yield on milking duration are updated regularly and also the milk production response to concentrate intake is taken into account.

Measures of weight distribution of dairy cows to detect lameness and the presence of hoof lesions

M. Pastell, L. Hänninen, A.M. de Passillé, J. Rushen — 2010-03-01

Abstract: There is increasing interest in automated methods of detecting lame cows. Hoof lesion data and measures of weight distribution from 61 lactating cows were examined in this study. Lame cows were identified with different numerical rating scores (NRS) used as thresholds (NRS >3 and NRS ≥3.5) for lameness. The ratio of weight applied to a pair of legs (LWR) when the cow was standing was calculated using a special weigh scale, and the cows were gait scored using a 1 to 5 NRS. Hoof lesions were scored and the cows placed into 1 of 4 mutually exclusive categories of hoof lesion: a) no lesions, b) moderate or severe hemorrhages, c) digital dermatitis, and d) sole ulcers. Regression analysis and receiver operating characteristic (ROC) curves were used to analyze the relation between hoof lesions and LWR. A clear relationship was found between NRS and LWR for the cows with sole ulcers (R2=0.79). The LWR could differentiate cows with sole ulcers from sound cows with no hoof lesions [area under the curve (AUC)=0.87] and lame cows from nonlame cows with lameness thresholds NRS >3 (AUC=0.71) and NRS ≥3.5 (AUC=0.88). There was no relationship between LWR and NRS for cows with digital dermatitis. Measurement of how cows distribute their weight when standing holds promise as a method of automated detection of lameness.

Effect of heat treatment of bovine colostrum on bacterial counts, viscosity, and immunoglobulin G concentration

J.A. Elizondo-Salazar, B.M. Jayarao, A.J. Heinrichs — 2010-03-01

Abstract: A study was conducted to identify the optimal temperature and time at which heat treatment of bovine colostrum would least change viscosity and IgG concentrations yet reduce bacterial count. First-milking colostrum with >50g of immunoglobulins/L (measured by colostrometer) was collected from 30 Holstein cows. Aliquots of colostrum were heated for 0, 30, 60, or 90min at 57, 60, or 63°C in a water bath. Samples were examined for viscosity, IgG1, and IgG2 concentrations, standard plate count, coagulase-negative staphylococci, environmental streptococci, coliform, gram-negative noncoliform, Streptococcus agalactiae, and Staphylococcus aureus counts. All heat treatments reduced counts of all bacteria groups measured compared with untreated colostrum samples. Heat treatment at ≥60°C denatured IgG1 compared with untreated colostrum; however, colostral IgG2 levels were not reduced when temperature was held at 60°C for <60min. Viscosity was not affected when temperature was held at 60°C for <60min. In this study, heat treatment of bovine colostrum at 60°C for 30 or 60min reduced bacterial count, slightly reduced IgG concentration, and did not affect viscosity.

Effect of days to conception in the previous lactation on the risk of death and live culling around calving

P.J. Pinedo, A. De Vries — 2010-03-01

Abstract: The objective was to quantify the effect of days to conception (days open) in the previous parity on the risk of death and live culling (excluding the disposal reasons “dairy purposes” and “death”) in the proximity of a subsequent calving in Holstein cows enrolled in the Dairy Herd Improvement program. After edits, 2,075,834 observations of cows calving between 2001 and 2007 in herds located in 36 US states primarily east of the Mississippi river were available. The period at risk included the time between 14 d before expected calving to 60 d after calving. Days open were categorized in 6 periods: 0 to 45 d, 46 to 90 d, 91 to 150 d, 151 to 210 d, 211 to 300 d, and 301 to 600 d after calving in the previous parity. Other variables of interest included parity, length of the dry period before calving, relative last test-day milk yield before dry off before calving, season of calving, and the cow's relative 305-d mature equivalent (305ME) milk yield before calving. Control variables were calving year, herd size, and relative herd 305ME milk yield. All variables were categorized. Generalized mixed models were used and included herd as random effect. Interactions between days open and the variables of interest were included in the models. Least squares means for the risk of death between −14 and 60 d after calving were 2.5, 2.5, 2.9, 3.6, 4.4, and 5.8% for increasing categories of days open. Similarly, for the same categories, least squares means for the risk of live culling were 4.5, 5.0, 5.4, 6.1, 6.9, and 8.1%. The effect of days open on the risk of death was slightly greater for third-parity cows, for long dry periods, for cows with low test-day milk yield before dry off before calving, for spring calvings, and for intermediate relative 305ME milk yield before calving. Similar trends for these interactions were found for the risk of live culling, except for relative 305ME milk yield before calving, where the effect of days open was more pronounced for high-producing cows. In conclusion, increased days open in the previous parity were associated with a greater risk of death and live culling around calving.

The effect of injectable butaphosphan and cyanocobalamin on postpartum serum β-hydroxybutyrate, calcium, and phosphorus concentrations in dairy cattle

E. Rollin, R.D. Berghaus, P. Rapnicki, S.M. Godden, M.W. Overton — 2010-03-01

Abstract: The objective of this study was to determine the effect of an injection of 10% butaphosphan and cyanocobalamin (Catosal, Bayer, Shawnee Mission, KS) on the day of calving and 1 d later on the prevalence of subclinical ketosis in dairy cattle in the early postpartum period. Cows from 4 herds (n=1,122) were randomized to receive either 25mL of 10% butaphosphan and cyanocobalamin or 25mL of sterile water subcutaneously on both days. Each milliliter of Catosal contained 0.05mg of cyanocobalamin and 100mg of butaphosphan, which provided 17.3mg of P in the form of [1-(butylamino)-1-methylethyl]-phosphonic acid. Serum was sampled for β-hydroxybutyrate (BHBA) concentration at calving (pretreatment) and again between 3 and 10 d in milk. A subset of samples from mature cows was also evaluated for serum Ca and P concentrations. When cows from all age groups were included in the analysis, there was no difference between the median serum BHBA concentrations of cows in the 2 treatment groups, and no difference in the proportion of hyperketonemic cows (serum BHBA ≥1,200μmol/L) during the first week postpartum. When the analysis was restricted to mature cows (lactation ≥3), both the median BHBA concentration and the proportion of hyperketonemic cows were significantly lower in the treatment group than in the placebo group. Serum Ca and P concentrations did not differ between treatment groups. Our results suggest that injection of butaphosphan and cyanocobalamin on the day of calving and 1 d later may decrease the prevalence of subclinical ketosis during the week after calving in mature dairy cows, but not in first- and second-lactation animals.

Pharmacokinetics of progesterone in lactating dairy cows: Gaining some insights into the metabolism from kinetic modeling

L.N. Turino, R.N. Mariano, M.I. Cabrera, D.E. Scándolo, M.G. Maciel, R.J.A. Grau — 2010-03-01

Abstract: Progesterone pharmacokinetics were analyzed for plasma hormone concentrations ranging from linear to saturated metabolism in lactating Holstein cows with differing daily milk yields. The adequacy of 2-coupled first-order (bi-exponential equation), hyperbolic (Michaelis–Menten equation), and sigmoidal (Hill equation) kinetic models to describe the experimental progesterone pharmacokinetic profiles was examined on a statistical basis. After nonlinear regression and statistical analysis of the data-fitting capability, a simple one-compartment model based on Hill equation proved to be most adequate. This model indicates an enzyme-catalyzed metabolism of progesterone involving cooperative substrate-binding sites, resulting from allosteric effects that yield a sigmoidal saturation rate curve. Kinetic parameters were estimated for 2 groups of lactating Holstein cows with different daily milk yields. We found, for the first time, a remarkable quantitative agreement of the Hill coefficient value with that reported in pharmacokinetic studies involving cytochrome P450, family 3, subfamily A (CYP3A)-mediated reactions in other mammals, humans included. It seems that positive cooperativity makes enzymes much more sensitive to plasma progesterone concentration, and their activities can undergo significant changes in a narrow range of concentration as characteristic of sigmoidal behavior. Therefore, the values of classical pharmacokinetic parameters, such as the elimination constant, half-life, and clearance rate, were found to be highly dependent on the plasma progesterone concentration.

Up-regulation of expression of interferon-stimulated gene 15 in the bovine corpus luteum during early pregnancy

L. Yang, X.L. Wang, P.C. Wan, L.Y. Zhang, Y. Wu, D.W. Tang, S.M. Zeng — 2010-03-01

Abstract: Interferon-τ (IFNT), the pregnancy recognition signal in ruminant species, is secreted by conceptus trophectoderm cells and induces expression of IFN-stimulated gene 15 (ISG15) in the uterus and corpus luteum (CL) in ewes. Expression of ISG15 in ovine CL is speculated to be through an endocrine pathway, but it is unclear whether expression of ISG15 in bovine CL is via such a pathway. In this study, CL were obtained from cows on d 16, 25, 60, 120, 180, and 270 of pregnancy, and endometrium, mammary gland, ovarian stroma, and CL were also collected from cows on d 18 of pregnancy and on d 15 and 18 of the estrous cycle. All tissue explants from d 15 of the estrous cycle were cultured in the absence or presence of 100ng/mL of recombinant bovine IFNT for 24h. The results indicated that ISG15 and conjugated proteins were expressed in CL of both cyclic and pregnant cows regardless of pregnancy status and were upregulated during early pregnancy. The mammary gland from d 18 of pregnancy did not express ISG15, but explants of the mammary gland from d 15 of the estrous cycle did express ISG15 after being treated with IFNT. However, luteal explants from d 15 of the estrous cycle did not express ISG15 after being cultured for 24h. In conclusion, ISG15 expression is upregulated in the bovine CL during early pregnancy. Interestingly, cultured CL cells do not respond to IFNT, suggesting that the pregnancy-dependent stimulation of ISG15 expression is controlled by something other than IFNT in the bloodstream.

Effect of a high cornstarch diet on hepatic cytochrome P450 2C and 3A activity and progesterone half-life in dairy cows1

C.O. Lemley, T.A. Wilmoth, L.R. Tager, K.M. Krause, M.E. Wilson — 2010-03-01

Abstract: In the cow, inadequate concentrations of progesterone during gestation may lead to an abrupt termination of pregnancy. The primary organ involved in progesterone catabolism is the liver, which contains an abundance of cytochrome P450 isozymes (EC 1.14.14.1; mixed-function monooxygenases). The objectives of the current experiment were to determine the effect of feeding 2 isoenergetic and isonitrogenous diets, formulated to cause divergent insulin secretion, on hepatic cytochrome P450 2C (CYP2C) and 3A (CYP3A) activity as well as the resulting biological half-life of progesterone. Twenty-two Holstein cows averaging 80±7 d in milk were randomly assigned to either a high cornstarch diet or a high fiber diet in a crossover experimental design consisting of two 14-d periods. Dry matter intake, milk yield, milk lactose yield, and milk lactose percentage were similar between the 2 diets. Milk fat yield and milk fat percentage were higher in cows fed the high fiber diet, whereas milk protein yield tended to be higher and milk protein percentage was higher in cows fed the high cornstarch diet. Energy balance tended to be improved by 57% in cows consuming the high cornstarch diet. Insulin concentrations at the time of liver biopsy (3.16±0.04h post-feeding) were increased by 44% in cows consuming the high cornstarch diet compared with cows consuming the high fiber diet. Cytochrome P450 2C activity was decreased by 45%, whereas CYP3A activity tended to be lowered by 34% in cows consuming the high cornstarch diet. Cytochrome P450 2C mRNA expression tended to be decreased by 21% in cows fed the high cornstarch diet, whereas CYP3A mRNA expression was not different between the dietary treatments. The fractional rate constant of progesterone decay was not different between the 2 diets; however, the half-life of progesterone tended to be longer in cows fed the high cornstarch diet compared with cows fed the high fiber diet (85 vs. 64min, respectively). In summary, cows consuming the high cornstarch diet had increased insulin concentrations and lower hepatic CYP2C and CYP3A activity and tended to have a longer progesterone half-life compared with cows consuming the high fiber diet. Feeding diets that stimulate insulin secretion could alter progesterone clearance during lactation, when dairy cows have increased rates of progesterone inactivation because of high energy demands and increased DMI.

Contribution of the female reproductive tract to low fertility in postpartum lactating dairy cows

D. Rizos, F. Carter, U. Besenfelder, V. Havlicek, P. Lonergan — 2010-03-01

Abstract: Infertility in dairy cattle is a multifactorial problem that may be linked to follicle development and the quality of the ovulated oocyte, to sperm transport and fertilization, to the reproductive tract environment, or to a combination of these factors. Using a state-of-the-art endoscopic embryo transfer technique, the aim of this study was to compare the ability of the reproductive tract of postpartum dairy cows and nulliparous heifers to support the development of early embryos to the blastocyst stage. Bovine embryos of 2 to 4 cells (n=1,800) were produced by in vitro maturation and fertilization of oocytes derived from the ovaries of slaughtered cattle. The estrus cycles of nulliparous Holstein heifers (n=10) and postpartum Holstein cows (n=8, approximately 60 d postpartum) were synchronized using an 8-d controlled internal drug release device coupled with prostaglandin injection. On d 2, one hundred 2- to 4-cell embryos were endoscopically transferred to the oviduct ipsilateral to the corpus luteum. Five days later, on d 7, the oviduct and uterus were flushed nonsurgically to recover the embryos. The number of embryos developing to the blastocyst stage was recorded immediately at recovery and following overnight culture in vitro. A representative number of blastocysts from heifers and cows were stained to assess cell number. Progesterone concentrations were lower in cows than in heifers on d 5, 6, and 7 (d 7=2.39±0.33 vs. 5.34±0.77ng/mL, respectively). More embryos were recovered from heifers than cows (79.0±7.0 vs. 57.2±11.4%). Of the embryos recovered, 33.9±3.6% had developed to the blastocyst stage in the heifer oviduct compared with 18.3±7.9% in the postpartum cow oviduct. There was no evidence of a difference in blastocyst quality as evidenced by total cell number in the blastocysts (71.2±5.7 vs. 67.0±5.3, respectively). In conclusion, the reproductive tract of the postpartum lactating dairy cow may be less capable of supporting early embryo development than that of the nonlactating heifer, and this may contribute to the lower conception rates observed in such animals.

Association between Mycobacterium avium subspecies paratuberculosis infection and milk production in two California dairies

S.S. Aly, R.J. Anderson, J.M. Adaska, J. Jiang, I.A. Gardner — 2010-03-01

Abstract: The association between Mycobacterium avium ssp. paratuberculosis (MAP) and milk production was estimated on 2 California dairies using longitudinal data from 5,926 cows. Both study herds had moderate MAP seroprevalence, housed cows in freestalls, and had Johne's disease control programs. Cow MAP status was determined using both serum ELISA and fecal culture results from cows tested at dry-off and from whole-herd tests. Potential confounders were evaluated based on a causal diagram. Mixed models with 2 functions (splines) for days in milk (DIM) representing milk production pre- and postpeak used in similar studies were further modified to use each cow's observed DIM at peak and lactation length. Cows that were seropositive produced 2.5kg less 4% fat-corrected milk (FCM) per day than their seronegative herdmates. In addition, cows that were fecal-culture positive by liquid culture and confirmed by PCR produced 2.2kg less 4% FCM per day than their fecal-culture negative herdmates. The decrease in milk production in MAP test-positive compared with test-negative cows started in the second lactation. A switch in MAP status in either ELISA or fecal culture results from positive to negative had no significant association with milk production. Modified DIM functions that used the observed DIM at peak had better model fit than another function that assumed a fixed peak at 60 DIM. Cows that tested positive for MAP on serum ELISA or fecal culture produced less milk than cows that tested negative, and the association between MAP and milk production was not confounded by mastitis, elevated somatic cell counts, or uterine or metabolic cow conditions.

Modulation of the bovine innate immune response by production of 1α,25-dihydroxyvitamin D3 in bovine monocytes

C.D. Nelson, T.A. Reinhardt, T.C. Thacker, D.C. Beitz, J.D. Lippolis — 2010-03-01

Abstract: In cattle, the kidney has been the only known site for production of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] from 25-hydroxyvitamin D3 [25(OH)D3] by 1α-hydroxylase (1α-OHase). Based on human studies, it was hypothesized that bovine monocytes could produce 1,25(OH)2D3 upon activation and 1,25(OH)2D3 would regulate expression of vitamin D–responsive genes in monocytes. First, the effects of 1,25(OH)2D3 on bovine monocytes isolated from peripheral blood were tested. Treatment of nonstimulated monocytes with 1,25(OH)2D3 increased expression of the gene for the vitamin D 24-hydroxylase (24-OHase) enzyme by 51±13 fold, but 1,25(OH)2D3 induction of 24-OHase expression was blocked by lipopolysaccharide (LPS) stimulation. In addition, 1,25(OH)2D3 increased the gene expression of inducible nitric oxide synthase and the chemokine RANTES (regulated upon activation, normal T-cell expressed and secreted) in LPS-stimulated monocytes 69±13 and 40±12 fold, respectively. Next, the ability of bovine monocytes to express 1α-OHase and produce 1,25(OH)2D3 was tested. Activation of monocytes with LPS, tripalmitoylated lipopeptide (Pam3CSK4), or peptidoglycan caused 43±9, 17±3, and 19±3 fold increases in 1α-OHase gene expression, respectively. Addition of 25(OH)D3 to LPS-stimulated monocytes enhanced expression of inducible nitric oxide synthase and RANTES and nitric oxide production in a dose-dependent manner, giving evidence that activated monocytes convert 25(OH)D3 to 1,25(OH)2D3. In conclusion, bovine monocytes produce 1,25(OH)2D3 in response to toll-like receptor signaling, and 1,25(OH)2D3 production in monocytes increased the expression of genes involved in the innate immune system. Vitamin D status of cattle might be important for optimal innate immune function because 1,25(OH)2D3 production in activated monocytes and subsequent upregulation of inducible nitric oxide synthase and RANTES expression was dependent on 25(OH)D3 availability.

Application of one injection of prostaglandin F2α in the five-day Co-Synch+CIDR protocol for estrous synchronization and resynchronization of dairy heifers

2010-03-01

Abstract: The objective was to determine if the 5-d Co-Synch+CIDR (controlled internal drug releasing insert) protocol can be used in dairy heifers for a synchronized timed artificial insemination (TAI) with one injection of PGF2α for first and second services. In experiment 1, heifers were assigned randomly to receive 1 (n=295) or 2 (n=298) injections of PGF2α in the 5-d Co-Synch+CIDR protocol. Corpus luteum (CL) regression was measured in one replicate (n=218). No difference in pregnancy per TAI (P/TAI; 46.1 and 48.6%) or CL regression (86.9 and 92.8%) was detected for 1 versus 2 injections of PGF2α, respectively. In experiment 2, nonpregnant heifers (n=86) were assigned to a resynchronized 5-d Co-Synch+CIDR with 1 PGF2α/TAI or insemination at detected estrus. There was no difference in P/TAI (52.2 and 55%) between groups. In experiment 3, nonpregnant heifers (n=110) were assigned randomly to receive a CIDR (n=54) or no CIDR insert (n=56) in the 5-d Co-Synch protocol for resynchronization of TAI. Pregnancy per TAI was lower without the CIDR device (39.3 vs. 51.8%). In a commercial field evaluation, 416 heifers were synchronized for the first and resynchronized TAI with the 5-d Co-Synch+CIDR protocol with 1 injection of PGF2α. Pregnancy per TAI on d 60 was 58.2 and 47.5% for first and second TAI, respectively; there was a sire effect to the second TAI. In conclusion, the 5-d Co-Synch+CIDR protocol with 1 injection of PGF2α is an effective reproductive management program for first and second TAI in dairy heifers.

Acidification of calf bedding reduces fly development and bacterial abundance

M.S. Calvo, A.C. Gerry, J.A. McGarvey, T.L. Armitage, F.M. Mitloehner — 2010-03-01

Abstract: Environmental stressors, such as high fly density, can affect calf well-being. Sodium bisulfate (SBS) is an acidifier that reduces the pH of flooring and bedding, creating a medium that neither bacteria nor immature flies (also known as larvae or maggots) can thrive in. Two experiments were conducted to investigate the application of SBS to a mixture of rice hull calf bedding and calf slurry (BED) to reduce house fly (Musca domestica L.) larval density and the abundance of bacteria. In experiment 1, dish pans containing 1L of BED and 3,000 house fly eggs were treated with SBS at concentrations of 0, 8.9, 17.7, and 26.5g of SBS/0.05m2 of BED (CON, LOW, MED, and HIGH, respectively), with each SBS concentration applied to 4 individual pans (16 pans total). Reapplication of the same SBS concentrations in each pan occurred 3 times/wk throughout the 23-d trial. Larval house fly survival was significantly reduced in all pans with SBS relative to CON pans, with lowest survival rates in the MED and HIGH pans (99% and 100% reduction, respectively). The mean pH for each treatment was inversely related to the SBS concentration. In experiment 2, pans containing 1L of BED and 3,000 house fly eggs were treated with either 0g of SBS (CON), 8.9g of SBS/0.05m2 of BED with reapplication of the acidifier 3 times/wk (SB3×), or 8.9g of SBS/0.05m2 of BED applied only once at 48h before the end of the 8 d-trial (SB48). Larval house fly survival and bacterial concentrations were reduced (90% larval reduction and 68% bacterial reduction) in the SB3× treatment relative to the CON. Mean pH was also reduced in SB3× pans relative to CON or SB48 pans. Overall, acidification of calf BED using the acidifier SBS resulted in a reduction of bacteria and house fly larval survival. This form of fly control might be expected to reduce adult fly production and, therefore, fly-related stress in calves.

Short communication: Survey of fresh cow management practices of dairy cattle on small and large commercial farms

W. Heuwieser, M. Iwersen, J. Gossellin, M. Drillich — 2010-03-01

Abstract: The objective was to conduct a survey of current fresh cow management practices that have an effect on health and diseases postpartum considering different herd sizes of commercial dairy farms. A mail survey regarding aspects of the fresh cow program including general management issues, calving, diseases, and veterinary service was conducted utilizing a convenience sample. A total of 429 survey forms were returned (12.0% response rate) and could be used for final analysis. Only 21.6% of the farms had a designated fresh cow pen. Almost every farm executed some type of fresh cow examination. Only 18.5% of farm managers documented the observations. Most of the dairy managers used more or less subjective criteria such as general appearance (97.0%) and appetite (69.7%). Only a minority of the responding dairy managers monitored their fresh cows using objective (fever 33.6%) or semiquantitative measures (subclinical ketosis 2.8%; body condition score 36.4%). On most farms, the veterinarian visited the herd only if needed (72.6%). Most cases of retained fetal membranes were treated by manual removal (72.3%) and antibiotic pills (89.5%). Several challenges and opportunities were identified to improve cow management practices.

Technical note: Variation in daily milk yield calculations for dairy cows milked in an automatic milking system

P.P. Nielsen, G. Pettersson, K.M. Svennersten-Sjaunja, L. Norell — 2010-03-01

Abstract: An accurate estimation of the daily milk yield of dairy cows milked in an automatic milking system is not obvious because of variations in milking intervals and frequencies. Daily harvested milk varies substantially, and developing a method to be used for estimating daily milk production is of great importance. Three calculation methods (simple, semiadvanced, and advanced) were used. The simple method calculated rough daily milk production by summing up the yield per day. The semiadvanced used yield in combination with time since last milking to calculate the milk production per hour between milking; an average of the milk production per hour over the day was calculated and multiplied by 24. The advanced method calculated the milk production from midnight to midnight by using information about yield and time since last milking to calculate the exact milk production. The results show a clear preference for the advanced calculation method because the variation [variation for the advanced method=ln(1.79) for first lactation and ln(2.28) for later lactations] between days was reduced significantly (3 to 4 times lower compared with the simple method). Variation in daily harvested milk can be used as a management tool.

Variability in in situ ruminal degradation parameters causes imprecision in estimated ruminal digestibility

T.J. Hackmann, J.D. Sampson, J.N. Spain — 2010-03-01

Abstract: The ruminal digestibility of dietary ingredients is frequently estimated with degradation parameters (e.g., rate and extent of degradation). Mean degradation parameters (e.g., those in a feed library) are often used, but limited data suggest considerable variation around these means, potentially leading to imprecise digestibility estimates. This experiment quantified degradation parameter variation for forage hays and determined the impact of this variation on the precision of ruminal digestibility estimates. Degradation data were those previously published by our laboratory and included degradation rate, λd (h−1), fraction instantly degraded, a (g·g−1), potential extent of degradation, (a + b) (g·g−1), and fraction not instantly degraded that is potentially degradable, b (g·g−1) of alfalfa, grass, and grass-legume hays. Ruminal digestibilities of chemical fractions (dry matter, neutral detergent fiber, acid detergent fiber, hemicellulose, crude protein) were estimated using these data. Ninety-five percent confidence limits of digestibility were determined using propagation of uncertainty with measured standard deviations of degradation parameters. Values for coefficients of variation of degradation parameters were large; averaged across chemical fractions, they were 24.8, 28.6, 20.7, and 12.6% for λd, a, b, and (a + b). Ninety-five percent confidence limits of digestibility were large (80.5% of digestibility means) and often overlapped each other, even when digestibility means differed greatly numerically. Consequently, digestibility values computed with mean degradation parameters may have little biological and practical significance. When uncertainty in all parameters but λd was set to zero (λd alone had uncertainty), 95% confidence limits still encompassed 54.5% of digestibility means. Thus, uncertainty in λd alone caused considerable imprecision in estimated digestibility. These results caution against using mean degradation parameters to estimate digestibility.

Replacement of starch from corn with nonforage fiber from distillers grains and soyhulls in diets of lactating dairy cows1

S.D. Ranathunga, K.F. Kalscheur, A.R. Hippen, D.J. Schingoethe — 2010-03-01

Abstract: Forty Holstein cows were used in a completely randomized design with a 2-wk covariate period followed by a 6-wk experimental period to evaluate incremental substitution of nonforage fiber provided by dried distillers grains with solubles (DDGS) and soyhulls (SH) for starch provided by corn in the diet. Diets provided decreasing concentrations of starch: 29% starch with 0% DDGS; 26% starch with 7% DDGS; 23% starch with 14% DDGS; and 20% starch with 21% DDGS. Diets contained 27% corn silage, 22% alfalfa hay, and 51% concentrate mix and were formulated to be 17% crude protein, 4.7% fat, and 23% neutral detergent fiber from forage. Total neutral detergent fiber increased as DDGS and SH were included in the diet. Soyhulls were included in a linear fashion along with DDGS to replace soybean meal and expeller soybean meal, thereby maintaining a similar crude protein content across diets. Dry matter intake decreased linearly; consequently, feed efficiency tended to increase linearly as starch was replaced by nonforage fiber. There was no effect of diet on milk production or milk fat and protein percentage or yield. Milk fatty acid profiles were similar across diets. Other response variables, including 4% fat-corrected milk, total solids, and milk urea nitrogen, were unaffected by dietary treatments. Ruminal volatile fatty acid concentration did not differ between diets. Concentrations of blood glucose and β-hydroxybutyrate were similar across diets. Results from this research suggest that nonforage fiber from DDGS can partially substitute for starch from corn in dairy cow diets without affecting milk production and milk composition. Economic analysis of the diets showed that feeding DDGS and SH in substitution of corn was cost-effective. Results from this experiment indicate that DDGS and SH can replace corn as an energy source to decrease feed costs.

Control of Escherichia coli O157:H7 in corn silage with or without various inoculants: Efficacy and mode of action

A.F. Pedroso, A.T. Adesogan, O.C.M. Queiroz, S.K. Williams — 2010-03-01

Abstract: This study aimed to evaluate the effectiveness of 3 commercial bacterial inoculants at controlling Escherichia coli O157:H7 in corn silages during ensiling and feedout phases of silage production. A second objective was to determine whether the inoculants exhibited and transferred antibacterial activity against E. coli O157:H7 to the silages. Chopped corn forage was ensiled after treatment with the following: distilled water (control); 5 × 105 cfu/g of E. coli O157:H7 (EC); EC and 1 × 106 cfu/g of Pediococcus pentosaceus and Propionibacterium freudenreichii (EC+BII); EC and 1 × 106 cfu/g of Lactobacillus buchneri (EC+LB); and EC and 1 × 106 cfu/g of L. buchneri and P. pentosaceus (EC+B500). Each treatment was ensiled in triplicate in mini silos for 3, 7, 31, and 82 d and analyzed for pH and E. coli O157:H7 counts. Samples from d 82 were also analyzed for volatile fatty acids, lactate, and aerobic stability. Antibacterial activity of inoculants and silages was determined by the Kirby-Bauer disc diffusion test. The pH of silages from all treatments decreased below 4 within 3 d of ensiling and remained low until d 82. Therefore, E. coli O157:H7 was not detected in silages after any of the ensiling durations. Applying inoculants containing L. buchneri resulted in less lactate, more acetate, and greater aerobic stability compared with the control. Applying EC+BII containing P. freudenreichii did not increase propionate or aerobic stability. Subsamples of d 82 silages were reinoculated with 1 × 105 cfu/g of E. coli O157:H7 either immediately after silo opening on d 82 or after 144h of aerobic exposure (d 88), and E. coli were enumerated 24h later. All silages reinoculated with the pathogen on d 82 had similar, low pH values (<4) and no E. coli were detected 24h later. Control, EC, and EC+BII silages reinoculated with the pathogen after 144h of aerobic exposure had relatively greater pH values (4.71, 5.67, and 6.03, respectively) and E. coli counts (2.87, 6.73, and 6.87 log cfu/g, respectively) 24h later, whereas those treated with L. buchneri had low pH values (<4) and undetectable (EC+B500) or 10-fold lower (1.97, cfu/g; EC+LB) E. coli counts. All pure cultures of commercial bacterial inoculants exhibited antibacterial activity independent of pH against E. coli O157:H7, but the pH-independent activity did not persist in the treated silages, suggesting that E. coli elimination from silages was mediated by pH reduction.

Effect of milk replacer program on digestion of nutrients in dairy calves

T.M. Hill, H.G. Bateman, J.M. Aldrich, R.L. Schlotterbeck — 2010-03-01

Abstract: There are concerns with feeding young dairy calves amounts of milk solids approaching 0.9kg of dry matter (DM) or more because of slumps in average daily gain (ADG) at weaning and low starter intakes. Additionally, programs feeding more than 0.6kg of DM have not been thoroughly tested for success at different weaning ages. Four milk replacer (MR) programs were compared in trial 1. Program A was 0.44kg of DM of a 21% crude protein (CP), 21% fat MR powder fed daily for 42 d. Program B was 0.66kg of DM of a 27% CP, 17% fat MR powder fed daily for 42 d. Program C was 0.66kg of DM of a 27% CP, 17% fat MR powder daily fed for 28 d. Program D was up to 1.09kg of DM of a 29% CP, 21% fat MR daily fed for 49 d. Digestibility estimates were made and blood was sampled for serum constituents on d 53 to 56, and performance was measured for 84 d. Three programs feeding a 27% CP, 17% fat MR powder were compared in trial 2 over 56 d. Calves on program A were fed 0.66kg of DM powder daily and weaned at 28 d. Calves on program B were fed 0.66kg of DM powder daily and weaned at 42 d. Calves on program C were fed up to 1.09kg of DM powder daily and weaned at 42 d. Digestibility estimates were made and blood was sampled for serum constituents d 21 to 24, d 36 to 39, and d 53 to 56. In trial 1, calves fed program A had the least overall ADG. Calves fed program D had the greatest ADG from 0 to 56 d, the least ADG from d 56 to 84, the least digestibility estimates, and the least concentrations of serum amylase. At 84 d, there were no differences in body weights of calves fed programs B, C, and D. In trial 2, calves fed program A had the greatest starter intake and greatest concentrations of serum amylase. Calves fed program C had the least estimates of digestibility from d 53 to 56 and the least serum concentrations of amylase. Calves fed up to 1.09 kg/d of 27 to 29% MR powders and weaned at 42 or 49 d had lower starter intakes, concentrations of serum amylase, and digestion of starter postweaning compared with calves fed conventional 21% CP, 21% fat MR powders fed at 0.44 kg/d. Calves fed 0.66 kg/d of a 27% CP, 17% fat MR powder and weaned at 28 or 42 d of age had no reductions in intake or digestion compared with calves fed conventional MR and gained as much total body weight from 0 to 84 d as calves stepped up to 1.09kg of MR.

Effects of an acute feed restriction at the onset of the seasonal breeding period on reproductive performance and milk production in pasture-grazed dairy cows

C.R. Burke, Y.J. Williams, L. Hofmann, J.K. Kay, C.V.C. Phyn, S. Meier — 2010-03-01

Abstract: Reproduction and milk production responses were compared between dairy cows offered a high (HPA; n=453 in 4 replicates) or low (LPA; n=317 in 3 replicates) pasture allowance for the first 14 d after the planned start of mating (d 0 of experiment) in 2 seasonal, pasture-based dairy herds. Estimated pasture dry matter intake (DMI) between d −1 and 13 were 14.3±2.8 and 8.0±1.7kg of DM/cow per day for HPA and LPA cows, respectively. The LPA cows produced 22% less energy-corrected milk during the 14-d feeding treatment period, and milk yield remained less in LPA cows at d 53 despite all cows receiving pasture allowances to support DMI of 16kg of dry matter/cow per day from d 14 onwards. The 3-wk submission rate (percentage of cows inseminated at least once from d 0 to 20) and the 3- and 6-wk pregnancy rates of LPA cows (88, 45, and 71%, respectively) were lower than those of HPA cows (94, 53, and 78%, respectively), but conception rates to first (50%) or second (47%) service and final pregnancy rates (93%) did not differ between treatments. These results quantify the immediate and subsequent responses in reproductive performance and milk production to a severe restriction in DMI at the onset of a seasonal breeding period in pasture-grazed dairy cows.

Effects of dietary supplementation of rumen-protected conjugated linoleic acid to grazing cows in early lactation

2010-03-01

Abstract: Conjugated linoleic acids (CLA) are potent anticarcinogens in animal and in vitro models as well as inhibitors of fatty acid synthesis in mammary gland, liver, and adipose tissue. Our objective was to evaluate long-term CLA supplementation of lactating dairy cows in tropical pasture on milk production and composition and residual effects posttreatment. Thirty crossbred cows grazing stargrass (Cynodon nlemfuensis Vanderyst var. nlemfüensis) were blocked by parity and received 150 g/d of a dietary fat supplement of either Ca-salts of palm oil fatty acids (control) or a mixture of Ca-salts of CLA (CLA treatment). Supplements of fatty acids were mixed with 4 kg/d of concentrate. Grazing plus supplements were estimated to provide 115% of the estimated metabolizable protein requirements from 28 to 84 d in milk (treatment period). The CLA supplement provided 15 g/d of cis-9,trans-11 and 22g of cis-10,trans-12. Residual effects were evaluated from 85 to 112 d in milk (residual period) when cows were fed an 18% crude protein concentrate without added fat. The CLA treatment increased milk production but reduced milk fat concentration from 2.90 to 2.14% and fat production from 437 to 348 g/d. Milk protein concentration increased by 11.5% (2.79 to 3.11%) and production by 19% (422 to 504 g/d) in the cows fed CLA. The CLA treatment decreased milk energy concentration and increased milk volume, resulting in unchanged energy output. Milk production and protein concentration and production were also greater during the residual period for the CLA-treated cows. The CLA treatment reduced production of fatty acids (FA) of all chain lengths, but the larger effect was on short-chain FA, causing a shift toward a greater content of longer chain FA. The CLA treatment increased total milk CLA content by 30% and content of the trans-10,cis-12 CLA isomer by 88%. The CLA treatment tended to decrease the number of days open, suggesting a possible effect on reproduction. Under tropical grazing conditions, in a nutritionally challenging environment, CLA-treated cows decreased milk fat content and secreted the same amount of milk energy by increasing milk volume and milk protein production.

Estimation of rumen outflow in dairy cows fed grass silage-based diets by use of reticular sampling as an alternative to sampling from the omasal canal1

S.J. Krizsan, S. Ahvenjärvi, H. Volden, G.A. Broderick — 2010-03-01

Abstract: A study was conducted to compare nutrient flows determined by a reticular sampling technique with those made by sampling digesta from the omasal canal. Six lactating dairy cows fitted with ruminal cannulas were used in a design with a 3 × 2 factorial arrangement of treatments and 4 periods. Treatments were 3 grass silages differing mainly in neutral detergent fiber (NDF) concentrations: 412, 530, or 639 g/kg of dry matter, each combined with 1 of 2 levels of concentrate feed. Digesta was collected from the reticulum and the omasal canal to represent a 24-h feeding cycle. Nutrient flow was calculated using the reconstitution system based on 3 markers (Co, Yb, and indigestible NDF) and using 15N as a microbial marker. Large and small particles and the fluid phase were recovered from digesta collected at both sampling sites. Bacterial samples from the reticulum and the omasum were separated into liquid- and particle-associated bacteria. Reticular samples were sieved through a 1-mm sieve before isolation of digesta phases and bacteria. Composition of the large particle phase differed mainly in fiber content of the digesta obtained from the 2 sampling sites. Sampling site did not affect marker concentration in any of the phases with which the markers were primarily associated. The 15N enrichment of bacterial samples did not differ between sampling sites. The reticular and omasal canal sampling techniques gave similar estimates of marker concentrations in reconstituted digesta, estimates of ruminal flow, and ruminal digestibility values for dry matter, organic matter, starch, and N. Sampling site × diet interactions were also not significant. Concentration of NDF was 2.2% higher in reconstituted omasal digesta than in reconstituted reticular digesta. Ruminal NDF digestibility was 2.7% higher when estimated by sampling the reticulum than by sampling the omasal canal. The higher estimate of ruminal NDF digestibility with the reticular sampling technique was due to differences in NDF concentration of reconstituted digesta. This study shows that nutrient and microbial protein outflow from the rumen can be measured using a reticular sampling technique. The reticular sampling technique provides a promising alternative to sampling from the omasal canal because there is less interference with the animal and it does not require advanced sampling equipment.

Effects of spontaneous heating on forage protein fractions and in situ disappearance kinetics of crude protein for alfalfa-orchardgrass hays packaged in large round bales1

W.K. Coblentz, P.C. Hoffman, N.P. Martin — 2010-03-01

Abstract: During 2006 and 2007, forages from 3 individual hay harvests were used to assess the effects of spontaneous heating on concentrations of crude protein (CP), neutral detergent insoluble CP (NDICP), acid detergent insoluble CP (ADICP), and in situ disappearance kinetics of CP and NDICP for large round bales of mixed alfalfa (Medicago sativa L.) and orchardgrass (Dactylis glomerata L.). Over the 3 harvests, 96 large round bales were made at preset bale diameters of 0.9, 1.2, or 1.5m and at moisture concentrations ranging from 9.3 to 46.6%. Internal bale temperatures were monitored daily during an outdoor storage period. The change in concentrations of NDICP (poststorage − prestorage) increased with heating degree days (HDD) >30°C in a relationship best explained with a nonlinear model {Y=24.9 – [22.7 × (e−0.000010 × x × x)]; R2=0.892} that became asymptotic at +24.9 percentage units of CP, thereby indicating that NDICP increases rapidly within bales that heat spontaneously. When maximum internal bale temperature (MAX) was used as the independent variable, the best regression model was quadratic and the coefficient of determination was still relatively high (R2=0.716). The change in concentrations of ADICP (poststorage − prestorage; ΔADICP) also increased with HDD and was best fitted to a nonlinear model {Y=14.9 – [15.7 × (e−0.0000019 × x × x)]} with a very high coefficient of determination (R2=0.934). A similar quartic response was observed for the regression of ΔADICP on MAX (R2=0.975). Increases in ΔADICP as a result of heating (HDD or MAX) were paralleled by concurrent increases in hemicellulose at relatively low increments of heating, but the inverse relationship was observed as hemicelluloses likely became reactive and concentrations decreased in more severely heated hays. Changes in ruminal disappearance rate of CP were best fitted to cubic models for regressions on both HDD (R2=0.939) and MAX (R2=0.876); these changes represented an approximate 50% rate reduction in severely heated hays relative to prestorage controls. Within ranges of heating most commonly encountered under field conditions, changes in rumen-degradable protein decreased in a primarily linear relationship with HDD or MAX. However, the mean change in rumen-degradable protein for the 4 most severely heated hays was only −2.6 percentage units of CP, which represents a minimal reduction from prestorage controls and is far less than the maximum of −7.9 percentage units of CP observed with less-severe heating. Interpretation of these results was complicated by poor recovery of NDICP from our most severely heated hays following machine rinsing of 0-h Dacron bags; theoretically, and by definition, this unrecovered pool of NDICP is assumed to be entirely degradable in the rumen. It remains unclear whether these responses could be corroborated in vivo or by other analytical techniques, or whether the magnitude of HDD or MAX for our most severely heated hays exceeds the reliable limits for estimating RDP via in situ methodology.

Technical note: Common analytical errors yielding inaccurate results during analysis of fatty acids in feed and digesta samples1

T.C. Jenkins — 2010-03-01

Abstract: The basic rules governing the proper fatty acid analysis of feed and digesta samples are sometimes overlooked, leading to potential errors in reporting the fatty acid content or composition of feed and digesta samples. The direct transesterification procedure of Sukhija and Palmquist (1988, J. Agric. Food Chem. 36:1202–1206) has become popular in analyzing fatty acids in feed and digesta samples obtained from animal feeding trials. One shortcoming of the Sukhija and Palmquist transesterification procedure is inaccurate analysis of fatty acids with conjugated double bonds. Digesta and milk samples from ruminant species typically contain a multitude of conjugated linoleic acid (CLA) isomers that easily undergo isomerization and epimerization following prolonged exposure to methanolic HCl. Modifications to the Sukhija and Palmquist procedure are given in this paper that allow successful determination of CLA isomers. Errors in fatty acid analysis also occur from misuse of internal standards; use of an internal standard is recommended in the Sukhija and Palmquist procedure as the preferred method to quantify total fatty acid content. The choice of internal standard may sometimes be important for obtaining accurate results. As an example, applying the direct transesterification procedure to a fat supplement high in saturated fatty acids yielded 613 mg/g of total fatty acids when C17 was used as the internal standard compared with 930 mg/g total fatty acids when C19 was used as the internal standard. Fatty acid content further increased to 952 mg/g when a unique unsaturated fatty acid (C13:1) was used as the internal standard.

Preliminary investigation on reliability of genomic estimated breeding values in the Danish Holstein population

G. Su, B. Guldbrandtsen, V.R. Gregersen, M.S. Lund — 2010-03-01

Abstract: This study investigated the reliability of genomic estimated breeding values (GEBV) in the Danish Holstein population. The data in the analysis included 3,330 bulls with both published conventional EBV and single nucleotide polymorphism (SNP) markers. After data editing, 38,134 SNP markers were available. In the analysis, all SNP were fitted simultaneously as random effects in a Bayesian variable selection model, which allows heterogeneous variances for different SNP markers. The response variables were the official EBV. Direct GEBV were calculated as the sum of individual SNP effects. Initial analyses of 4 index traits were carried out to compare models with different intensities of shrinkage for SNP effects; that is, mixture prior distributions of scaling factors (standard deviation of SNP effects) assuming 5, 10, 20, or 50% of SNP having large effects and the others having very small or no effects, and a single prior distribution common for all SNP. It was found that, in general, the model with a common prior distribution of scaling factors had better predictive ability than any mixture prior models. Therefore, a common prior model was used to estimate SNP effects and breeding values for all 18 index traits. Reliability of GEBV was assessed by squared correlation between GEBV and conventional EBV (r2GEBV, EBV), and expected reliability was obtained from prediction error variance using a 5-fold cross validation. Squared correlations between GEBV and published EBV (without any adjustment) ranged from 0.252 to 0.700, with an average of 0.418. Expected reliabilities ranged from 0.494 to 0.733, with an average of 0.546. Averaged over 18 traits, r2GEBV, EBV was 0.13 higher and expected reliability was 0.26 higher than reliability of conventional parent average. The results indicate that genomic selection can greatly improve the accuracy of preselection for young bulls compared with traditional selection based on parent average information.

The genetic relationship of body weight and early-lactation health disorders in two experimental herds

E. Frigo, C.D. Dechow, O. Pedron, B.G. Cassell — 2010-03-01

Abstract: The objectives of this study were to estimate genetic parameters for body weight (BW) and BW change (BWC) and genetic correlations of BW and BWC with diseases and genomic predicted transmitting abilities (PTA) of productive and conformation traits of Holsteins during the first 120 DIM. Daily BW data were from the Afiweigh cow body weighing system (SAE Afikim, Kibbutz Afikim, Israel), which records BW as a cow exits the milking parlor. Disease categories included metabolic diseases, ketosis, infectious diseases, mastitis, reproductive diseases, and other diseases. Edited data included 68,914 and 11,615 daily BW observations from 441 Pennsylvania State University and 72 Virginia Tech Holstein cows, respectively. Two-trait random regression models were used to estimate relationships between BW, BWC, and diseases at 25, 38, and 58 mo of age at calving. Fixed effects for BW were age at calving nested within lactation group, week of lactation, and herd date; random effects for BW included animal, permanent environment, and error. Fixed effects for disease were herd-year-season of calving and age at calving nested within lactation group; random effects for disease were animal, permanent environment (for mastitis only), and error. Correlations of PTA for BW and BWC with genomic PTA for productive and type traits were also estimated with data from 117 cows. Heritability estimates for daily BW ranged from 0.34 to 0.63. Greater BW and less BWC were favorably correlated with ketosis, metabolic diseases, infectious diseases, and other diseases. The genetic correlation estimate between BW and ketosis was strongest at 60 DIM (−0.51), and genetic correlation estimates at 60 DIM with metabolic diseases (−0.52), infectious diseases (−0.81), and other diseases (−0.48) followed the same trend as ketosis. The genetic correlation estimate between BWC and ketosis was strongest for the change from 5 to 20 DIM (0.70) and was similar for metabolic diseases (0.37), infectious diseases (0.74), and other diseases (0.49). Correlations of BW and BWC with reproductive diseases tended to be in the reverse direction of those reported for ketosis. A larger PTA for BW was significantly correlated with smaller genomic PTA for milk yield, dairy form, rear udder height, and udder cleft. Predicted transmitting ability for BWC was negatively correlated with genomic PTA for protein percentage, strength, and hip width (ranging from −0.26 to −0.13 across lactation) and was positively correlated with dairy form, rear udder height, and udder cleft (ranging from 0.20 to 0.37 across lactation). Selection for reduced BW loss can be implemented with automated body weighing systems and may be successful in decreasing disease incidence in the early stages of lactation.

A model for the genetic evaluation of number of clinical mastitis cases per lactation in Czech Holstein cows

J. Wolf, M. Wolfová, M. Štípková — 2010-03-01

Abstract: Cases of mastitis from 9,550 lactations of 6,242 cows were recorded on 5 farms in the Czech Republic from 1996 to 2008. The number of clinical mastitis (CM) cases per cow adjusted to a lactation length of 305 d was analyzed with 4 linear single-trait animal models and one 3-trait model, which also included lactation mean somatic cell score (SCS) and 305-d milk yield. Factors included in the model of choice were parity, combined effect of herd and a 2-yr calving period, calving season, permanent environmental effect of the cow, and additive genetic effect of the cow. From both the single-trait and multiple-trait models, estimated heritability of number of CM cases was 0.11 (±0.015 for the multiple-trait model). Permanent environmental effects accounted for approximately one-third of the phenotypic variance. Heritability estimates for lactation mean SCS and 305-d milk yield were 0.17±0.019 and 0.25±0.011, respectively, and genetic correlations of these traits with number of CM cases were 0.80±0.059 and 0.34±0.079, respectively. Genetic evaluation of the number of CM cases in Czech Holsteins could be carried out including data from all parities using a 3-trait animal model with SCS and milk yield as additional traits.

Quantitative trait loci mapping of calving and conformation traits on Bos taurus autosome 18 in the German Holstein population

B. Brand, C. Baes, M. Mayer, N. Reinsch, T. Seidenspinner, G. Thaller, Ch. Kühn — 2010-03-01

Abstract: Linkage, linkage disequilibrium, and combined linkage and linkage disequilibrium analyses were performed to map quantitative trait loci (QTL) affecting calving and conformation traits on Bos taurus autosome 18 (BTA18) in the German Holstein population. Six paternal half-sib families consisting of a total of 1,054 animals were genotyped on 28 genetic markers in the telomeric region on BTA18 spanning approximately 30 Mb. Calving traits, body type traits, and udder type traits were investigated. Using univariately estimated breeding values, maternal and direct effects on calving ease and stillbirth were analyzed separately for first- and further-parity calvings. The QTL initially identified by separate linkage and linkage disequilibrium analyses could be confirmed by a combined linkage and linkage disequilibrium analysis for udder composite index, udder depth, fore udder attachment, front teat placement, body depth, rump angle, and direct effects on calving ease and stillbirth. Concurrence of QTL peaks and a similar shape of restricted log-likelihood ratio profiles were observed between udder type traits and for body depth and calving traits, respectively. Association analyses were performed for markers flanking the most likely QTL positions by applying a mixed model including a fixed allele effect of the maternally inherited allele and a random polygenic effect. Results indicated that microsatellite marker DIK4234 (located at 53.3 Mb) is associated with maternal effects on stillbirth, direct effects on calving ease, and body depth. A comparison of effects for maternally inherited DIK4234 alleles indicated a favorable, positive correlation of maternal and direct effects on calving. Additionally, the association of maternally inherited DIK4234 marker alleles with body depth implied that conformation traits might provide the functional background of the QTL for calving traits. For udder type traits, the strong coincidence of QTL peaks and the position of the QTL in a region previously reported to harbor QTL for somatic cell score indicated that effects of QTL for udder type traits might be correlated with effects of QTL for udder health traits on BTA18. Our results suggest that loci in the middle to telomeric region on BTA18 with effect on conformation traits may also contribute to the genetic variance of calving and udder health traits. Further analyses are required to identify the causal mutations affecting conformation and calving traits and to investigate the correlation of effects for loci associated with conformation, calving, and udder health traits.

Relationships between milk yield and somatic cell score in Canadian Holsteins from simultaneous and recursive random regression models

J. Jamrozik, J. Bohmanova, L.R. Schaeffer — 2010-03-01

Abstract: Multiple-trait random regression animal models with simultaneous and recursive links between phenotypes for milk yield and somatic cell score (SCS) on the same test day were fitted to Canadian Holstein data. All models included fixed herd test-day effects and fixed regressions within region–age at calving–season of calving classes, and animal additive genetic and permanent environmental regressions with random coefficients. Regressions were Legendre polynomials of order 4 on a scale from 5 to 305 d in milk (DIM). Bayesian methods via Gibbs sampling were used for the estimation of model parameters. Heterogeneity of structural coefficients was modeled across (the first 3 lactations) and within (4 DIM intervals) lactation. Model comparisons in terms of Bayes factors indicated the superiority of simultaneous models over the standard multiple-trait model and recursive parameterizations. A moderate heterogeneous (both across- and within-lactation) negative effect of SCS on milk yield (from −0.36 for 116 to 265 DIM in lactation 1 to −0.81 for 5 to 45 DIM in lactation 3) and a smaller positive reciprocal effect of SCS on milk yield (from 0.007 for 5 to 45 DIM in lactation 2 to 0.023 for 46 to 115 DIM in lactation 3) were estimated in the most plausible specification. No noticeable differences among models were detected for genetic and environmental variances and genetic parameters for the first 2 regression coefficients. The curves of genetic and permanent environmental variances, heritabilities, and genetic and phenotypic correlations between milk yield and SCS on a daily basis were different for different models. Rankings of bulls and cows for 305-d milk yield, average daily SCS, and milk lactation persistency remained the same among models. No apparent benefits are expected from fitting causal phenotypic relationships between milk yield and SCS on the same test day in the random regression test-day model for genetic evaluation purposes.

Evidence of genetic resistance of cattle to infection with Mycobacterium bovis

2010-03-01

Abstract: Anecdotal evidence points to genetic variation in resistance of cattle to infection with Mycobacterium bovis, the causative agent of bovine tuberculosis (BTB), and published experimental evidence in deer and cattle suggests significant genetic variation in resistance and reactivity to diagnostic tests. However, such genetic variation has not been properly quantified in the United Kingdom dairy cattle population; it is possible that it exists and may be a factor influencing the occurrence of BTB. Using models based on the outcome of the process of diagnosis (ultimate fate models) and on the outcome of a single stage of diagnosis (continuation ratio models, herd test-date models), this study shows that there is heritable variation in individual cow susceptibility to BTB, and that selection for milk yield is unlikely to have contributed to the current epidemic. Results demonstrate that genetics could play an important role in controlling BTB by reducing both the incidence and the severity of herd breakdowns.

Genomic predictions for New Zealand dairy bulls and integration with national genetic evaluation

B.L. Harris, D.L. Johnson — 2010-03-01

Abstract: A method is described for the prediction of breeding values incorporating genomic information. The first stage involves the prediction of genomic breeding values for genotyped individuals. A novel component of this is the estimation of the genomic relationship matrix in the context of a multi-breed population. Because not all ancestors of genotyped animals are genotyped, a selection index procedure is used to blend genomic predictions with traditional ancestral information that is lost between the process of deregression of the national breeding values and subsequent re-estimation using the genomic relationship matrix. Finally, the genomically enhanced predictions are filtered through to nongenotyped descendants using a regression procedure.

Polymorphisms in the bovine lactoferrin promoter are associated with reproductive performance and somatic cell count

F. O’Halloran, D.P. Berry, B. Bahar, D.J. Howard, T. Sweeney, L. Giblin — 2010-03-01

Abstract: Lactoferrin plays an important role in the innate immune system, with well-characterized antibacterial, antiviral, and immune modulatory properties. The objective of this study was to determine the allele and haplotype frequency of polymorphisms at positions −586, −190, and −28 of the bovine lactoferrin promoter in Holstein-Friesians and to quantify their association with performance using phenotypic data on progeny from 848 sires. Associations between genotypes and performance were quantified using weighted mixed models with genotyped individuals included as a random effect, and average expected relationships among individuals accounted for through a numerator relationship matrix. The dependent variables were daughter yield deviation for production traits and deregressed predicted transmitting ability for calving interval and functional survival. The C to T polymorphism at −586, which distorts a putative activating protein 2 (AP-2) binding site, was associated with a shorter calving interval and higher somatic cell score. The G to A polymorphism at −190, located in a putative selective promoter factor 1 (SP-1) binding site, was associated with a longer calving interval and decreased functional survival. A third polymorphism (A to C) at position −28, found within the noncanonical TATA box, had a tendency to associate with functional survival. On the basis of the data we proposed a haplotype combination that was associated with improved reproductive performance in the Holstein-Friesian breed. We hypothesized that the observable phenotypic associations with lactoferrin promoter polymorphisms can potentially be explained by allele-specific differences in constitutive or inducible levels of gene expression. The lack of a pleiotropic effect of the single nucleotide polymorphisms studied on both fertility and milk production traits strengthens the importance of these polymorphisms, or at least the lactoferrin promoter, in selection for improved fertility.

Short communication: Milk protein genetic variation and casein haplotype structure in the Original Pinzgauer cattle

A. Caroli, R. Rizzi, G. Lühken, G. Erhardt — 2010-03-01

Abstract: Milk protein genetic polymorphisms are often used for characterizing domesticated mammalian species and breeds, and for studying associations with economic traits. The aim of this work was to analyze milk protein genetic variation in the Original Pinzgauer, a dual-purpose (dairy and beef) cattle breed of European origin that was influenced in the past by human movements from different regions as well as by crossbreeding with Red Holstein. A total of 485 milk samples from Original Pinzgauer from Austria (n=275) and Germany (n=210) were typed at milk proteins αS1-casein, β-casein, κ-casein, α-lactalbumin, and β-lactoglobulin by isoelectrofocusing to analyze the genetic variation affecting the protein amino acid charge. The Original Pinzgauer breed is characterized by a rather high genetic variation affecting the amino acid charge of milk proteins, with a total of 15 alleles, 12 of which were found at a frequency >0.05. The most polymorphic protein was β-casein with 4 alleles detected. The prevalent alleles were CSN1S1*B, CSN2*A2, CSN1S2*A, CSN3*A, LGB*A, and LAA*B. A relatively high frequency of CSN1S2*B (0.202 in the whole data set) was found, mainly occurring within the C-A2-B-A haplotype (in the order CSN1S1-CSN2-CSN1S2-CSN3), which seems to be peculiar to the Original Pinzgauer, possibly because the survival of an ancestral haplotype or the introgression of Bos indicus.

The carbon footprint of dairy production systems through partial life cycle assessment

C.A. Rotz, F. Montes, D.S. Chianese — 2010-03-01

Abstract: Greenhouse gas (GHG) emissions and their potential effect on the environment has become an important national and international issue. Dairy production, along with all other types of animal agriculture, is a recognized source of GHG emissions, but little information exists on the net emissions from dairy farms. Component models for predicting all important sources and sinks of CH4, N2O, and CO2 from primary and secondary sources in dairy production were integrated in a software tool called the Dairy Greenhouse Gas model, or DairyGHG. This tool calculates the carbon footprint of a dairy production system as the net exchange of all GHG in CO2 equivalent units per unit of energy-corrected milk produced. Primary emission sources include enteric fermentation, manure, cropland used in feed production, and the combustion of fuel in machinery used to produce feed and handle manure. Secondary emissions are those occurring during the production of resources used on the farm, which can include fuel, electricity, machinery, fertilizer, pesticides, plastic, and purchased replacement animals. A long-term C balance is assumed for the production system, which does not account for potential depletion or sequestration of soil carbon. An evaluation of dairy farms of various sizes and production strategies gave carbon footprints of 0.37 to 0.69kg of CO2 equivalent units/kg of energy-corrected milk, depending upon milk production level and the feeding and manure handling strategies used. In a comparison with previous studies, DairyGHG predicted C footprints similar to those reported when similar assumptions were made for feeding strategy, milk production, allocation method between milk and animal coproducts, and sources of CO2 and secondary emissions. DairyGHG provides a relatively simple tool for evaluating management effects on net GHG emissions and the overall carbon footprint of dairy production systems.

Extended lactations in a seasonal-calving pastoral system of production to modulate the effects of reproductive failure

S.T. Butler, L. Shalloo, J.J. Murphy — 2010-03-01

Abstract: This study was conducted to determine whether extending the calving interval (CI) to 24 mo would be an alternative to culling and replacing cows that had failed to become pregnant. Forty-six nonpregnant lactating cows were assembled in November 2004 and assigned to receive either 3kg (low) or 6kg (high) of concentrate supplement and a basal diet of grass silage and maize silage over the winter period (13 wk). Cows returned to pasture in late March and received 1kg of concentrate/d until dry-off (milk yield <5 kg/d). Cumulative milk production was calculated from calving to the end of November 2004 (12-mo CI) and from the start of December 2004 until dry off in 2005 (extended lactation part of 24-mo CI). High winter feeding resulted in greater milk production over the winter confinement (20.0±0.3 vs. 17.8±0.3 kg/d for high and low winter feeding, respectively) and had a carryover effect during the remainder of the 24-mo CI period (5,177 vs. 4,686kg; SEM=173kg). At the end of the study, cows were ranked on cumulative milk solids and separated into 3 groups (R1, R2, and R3). During the 24-mo CI, milk yields were 7,287, 6,267, and 5,273kg (SEM=308kg) in yr 1, and 5,738, 4,836, and 4,266 (SEM=241kg) in yr 2 for R1, R2, and R3, respectively. Eighty-five percent of the cows became pregnant during the breeding season of yr 2, with a conception rate to first service of 52%. An economic analysis of different ranks with a 12-mo CI, a 24-mo CI, and an annualized herd effect, which compared an efficient spring calving system with 30% recycled cows in R1 and 10% recycled cows in R3, was carried out. Farm profit was reduced by 60% and 65% at a milk price of 22.3 euro-cents (c)/L with the corresponding values of 17% and 30% for a milk price of 30 c/L, respectively, when R1 and R3 systems were compared with an efficient spring milk (12-mo CI) production system. Within a spring system where 30% and 10% of R1 and R3 animals were subjected to extended lactations, the profit difference was reduced compared with an efficient spring system, The results indicated that lactations with a 24-mo CI may be a viable alternative to culling nonpregnant cows and be economically more suited to higher producing cows.

Debunking the myth of the hard-to-reach farmer: Effective communication on udder health

J. Jansen, C.D.M. Steuten, R.J. Renes, N. Aarts, T.J.G.M. Lam — 2010-03-01

Abstract: Worldwide, programs to control mastitis are implemented using different strategies to reach farmers. Even though education materials and best practices may be technically optimal, they need to be used to be successful. Thus, effective communication with farmers is essential in order to change their behavior and to improve their farm management. During a Dutch national mastitis control program, a substantial number of farmers seemed to be hard to reach with information on udder health. Consequently, this study was designed to provide insight into the attitude and motivation of such farmers. In the period of October 2007 to July 2008, 24 in-depth, semistructured interviews were conducted with farmers whose veterinarians considered to be difficult to approach with advice on udder health management (8 practices, 3 farmers from each practice). The interviews included questions about the farms and the farmers, their attitude and behavior regarding mastitis, and their information sources and social environment. The results show that so-called hard-to-reach farmers were not always badly informed about udder health and did not always experience problems with mastitis. These ostensibly unreachable farmers were not a homogeneous group, but rather could be divided into 4 categories based on their trust in external information sources regarding mastitis and their orientation toward the outside world: proactivists, do-it-yourselfers, wait-and-see-ers, and reclusive traditionalists. There are ample opportunities to reach hard-to-reach farmers, provided that the communication strategies are tailored to their specific needs. There is especially much to gain in communication with do-it-yourselfers and wait-and-see-ers, but this demands a more proactive role on the part of veterinarians and extension specialists. Different types of farmers need to be approached in different ways and through different channels with information on udder health. Consequently, this study can contribute to the optimization of future programs designed to control and prevent diseases.

A survey of dairy calf management practices in Canada that affect animal welfare

2010-03-01

Abstract: There is growing interest among the public in farm animal welfare and a need for methods to assess animal welfare on farm. A survey on calf rearing practices that might affect dairy calf welfare was performed via a 1-h interview on 115 dairy farms (mean ± SD: herd size=52.5±20.9 cows; milk production=8,697±1,153L) distributed throughout the province of Quebec. Despite frequent recommendations, many dairy producers continue to use management practices that increase the health risks of milk-fed calves. Major risk factors for poor calf welfare identified were 1) no use of calving pen in 51.3% of herds and low level of surveillance of calvings, especially at nighttime (once every 12h), 2) no disinfection of newborn's navel in 36.8% of herds, and delayed identification and, hence, calf monitoring (3 d), 3) 15.6% of farms relied on the dam to provide colostrum and none checked colostrum quality or passive transfer of immunity, 4) dehorning and removal of extra teats proceeded at late ages (6.4 wk and 6.7 mo, respectively) and without adequate pain control, 5) use of traditional restrictive milk feeding and waste milk distributed to unweaned calves without precaution in 48.2% of herds, 6) abrupt weaning performed in 16.5% of herds, and 7) calves housed individually in 87.9% of herds, and most inappropriate housing systems (crate=27.0%, tie-stall=13.9%, attached against a wall=5.7%) remained. This risk factor assessment was the first step in an intervention strategy to improve calf welfare on dairy farms.