Showing papers in "Journal of Dairy Science in 2012"

TL;DR: This work assessed the gain in accuracy of GEBV in Jersey cattle as a result of using a combined Holstein and Jersey reference population, with either 39,745 or 624,213 single nucleotide polymorphism (SNP) markers.

TL;DR: Results show that time of onset and BHBA concentration of first SCK-positive test are important indicators of individual cow performance and are associated with a decrease in milk production for the first 30 DIM.

TL;DR: Results indicate that increased growth rate before weaning results in some form of epigenetic programming that is yet to be understood, but has positive effects on lactation milk yield.

TL;DR: In conclusion, heifer mastitis can affect the profitability of dairy farming because of a potential long-term negative effect on udder health and milk production and an associated culling risk, specifically when major pathogens are involved.

TL;DR: Neither metritis nor SCH influenced the resumption of estrous cyclicity by 38 DIM, but cows with SCH had a reduced pregnancy rate and a longer interval to pregnancy compared with normocalcemic cows.

TL;DR: Bovine milk miRNA was investigated using microarray and quantitative PCR analyses to identify the differences between colostrum and mature milk, and the presence of some mRNA in bovine Milk was confirmed.

TL;DR: The importance of the design of a reference population consisting of cows was shown and optimal designs of the reference population for genomic prediction were suggested and reliabilities of DGV predictions were calculated deterministically using selection index theory.

TL;DR: These results showed considerable variation in lameness and leg injury prevalence as well as facility design and management among freestall farms in North America, suggesting great opportunities for improvement on other farms within the region.

TL;DR: Research must continue to be conducted on AMS to understand the causes and consequences of differences between milking systems as well as the impacts of the different facilities and management systems that surround them on dairy cow behavior, health, and welfare.

TL;DR: The quantitative effects of and interactions among forage PS, peNDF, and diet fermentability with regard to rumen metabolism and prevention of SARA are analyzed, and an overview of the latest achievements in the estimation of dietary fiber adequacy in high-producing dairy cattle is given.

TL;DR: The effects of a grain-based subacute ruminal acidosis (SARA) challenge (GBSC) and an alfalfa-pellet SARA challenge (APSC) on fermentation and endotoxin in the rumen and in the cecum, as well as on endotoxins in peripheral blood, were determined.

TL;DR: The data implicate His as a limiting AA in high-producing dairy cows fed corn silage- and alfalfa haylage-based diets, deficient in MP, and propose that, similar to monogastric species, AA play a role in DMI regulation in dairy cows.

TL;DR: It is concluded that heat stress of the dam during the dry period compromises the fetal growth and immune function of offspring from birth through weaning.

TL;DR: High serum concentrations of NEFA, BHBA, and low concentrations of calcium around parturition were associated with early lactation milk loss, andLow calcium concentration around partURition was associated with impairedEarly lactation reproduction.

TL;DR: Six rumen-fistulated dairy cows were used in 2 trials to validate the technique for the collection of ruminal fluid by an oral stomach tube (OST) and results indicated that the OST should be inserted to reach the central rumen to obtain representative rumen fluid samples.

TL;DR: Responses to fat feeding were highly heterogeneous for all variables studied and heterogeneity was present within responses to individual fat groups, indicating the varied and profound biological effects of fats.

TL;DR: Data indicate that rumination time can be used to estimate within-cow variation in feeding behavior and intake, but daily summaries of rumination behavior are a poor indicator of DMI.

TL;DR: Mid-infrared reflectance spectroscopy is a reliable and cheap method whereby MCP can be improved at the population level; this is because such spectra are already routinely acquired from the milk of cows enrolled in milk recording schemes and exhibit high phenotypic and genetic correlations.

TL;DR: Almost 60% of MC on dairy farms is inadequate, and a large number of calves are at risk of failure of passive transfer or bacterial infections, or both, and the data indicate that regional differences exist in colostrum quality.

TL;DR: Elevated serum NEFA and BHBA concentrations and lower serum calcium concentrations within 1 wk before calving through 2 wk after calving were associated with an increased risk of culling in early lactation, and measuring the concentration of selected metabolites around parturition may help to develop monitoring and intervention strategies to prevent early culling.

TL;DR: Cows with high AFC had 3.34 times greater odds of being pregnant at the end of the breeding season compared with cows with low AFC; the odds of a successful pregnancy at first service were 1.75 times greater in the intermediate compared with the low group.

TL;DR: A comprehensive, quantitative metabolomic analysis of rumen fluid samples from dairy cows fed 4 different diets confirms and greatly extends earlier observations on dietary effects onRumen fluid composition and shows that the use of multiple metabolomic platforms permits a far more detailed understanding of metabolic causes and effects.

TL;DR: The textural characteristics of probiotic yogurts improved depending on the ingredient variety and the fortification with SCaCN decreased texture scores in probiotic yogurt; probably due to the lower water-holding capacity and higher syneresis values in the caseinate-added yogurt sample.

TL;DR: Herd-level milk production was positively associated with overall ADUR, ADUR of systemically administered ceftiofur, cephapirin administered for dry cow therapy, and pirlimycin administered for clinical mastitis treatment, and β-lactams were most commonly used on Canadian dairy farms.

TL;DR: Several herd-level thresholds for the proportion of cows with increased NEFA or BHBA, or decreased calcium in the week before and after calving were associated with higher risk of displaced abomasum, milk loss at the first Dairy Herd Improvement Association test, and decreased pregnancy at first AI.

TL;DR: In this paper, the effect of different forage sources on performance, apparent digestibility, and feeding behavior of Holstein male calves was evaluated in a series of three experiments to evaluate the effects of different sources of forage on performance.

TL;DR: Findings provide strong evidence that this commercially available yeast culture product provides significant improvement in several important milk production outcomes as evaluated in production settings typical for commercial dairies in North America.

TL;DR: Substantial variation in RFI and 250-d body weight was demonstrated and 8 SNP with large effects on RFI were located on chromosome 14 at around 35.7 Mb, which may be associated with the gene NCOA2, which has a role in controlling energy metabolism.

TL;DR: The objective of this study was to estimate the costs of clinical mastitis (CM), having a special focus on the cost variation related to culling decisions, and to decrease the costs, more emphasis should be given to hidden costs.

TL;DR: On-farm monitoring of methane emission rate during milking could provide a low-cost reliable method to estimate daily methane output by individual dairy cows, which could be used to study variation in methane, to identify cows with low emissions, and to test outcomes of mitigation strategies.