Association of Calf Growth and Feed Intake Traits with Mature Cow Milk Yield and Body Weight

Data from six different calf trials were compared to 134,469 daily milk records and 37,403 body weights to determine how heifer growth traits are associated with milk yield and mature cow body weight. Animals were classified into 3 categories (low, intermediate and high) according to their body weight, hip height, growth rate and starter feed intake. Calves that were classified in the intermediate body weight category tended to produce more milk during the first ten weeks of lactation than cows classified as having low or high body weights as calves. Additionally, cows classified in the low hip height group as calves produced less milk during the first ten weeks of lactation when compared to cows classified in the intermediate or high hip height category as calves. Calves classified in either the low growth rate or the low starter feed intake group tended to be lighter as mature cows when compared to the intermediate and high classifications of their respective categories. The results suggest that calf hip height and body weight can be useful predictors of milk yield, while calf growth rate and starter feed intake can impact mature cow body weight

Body Condition Score and Dairy Form as Indicators of Dairy Cattle Disease and Reproductive Performance.

The objectives of this research were to estimate heritabilities and correlations between body condition score (BCS) from various sources, determine the genetic relationship among BCS, dairy form, cow health and reproductive performance and investigate various models to analyze BCS and dairy form. BCS was obtained from herds using PCDART dairy management software and from linear type appraisals by Holstein classifiers. Cow health data was obtained from several herds recording disease treatments. Genetic evaluations for cow health in Denmark were also obtained. Reproductive data and yield data were provided by DRMS and AIPL-USDA. Heritabilities and correlations among traits were estimated with REML using animal and sire models. Random regression and repeatability sire models were compared. Fixed effects for all models included contemporary group effects, age, and days in milk (DIM) when available. Random effects were sire or animal and error. The heritability estimate of BCS from linear type appraisal was 0.22. The genetic correlation estimate between BCS from PCDART records and linear type appraisals was 0.87, between BCS and dairy form was –0.72 and between BCS and strength was 0.69. The genetic correlation estimates from random regression models between DIM 0 in lactation 1 and DIM 305 in lactation 3 were estimated to be 0.77 for BCS and 0.60 for dairy form. Higher BCS and lower dairy form were significantly correlated with lower milk yield, less metabolic disease and fewer days open. The relationship among BCS, dairy form, cow health and reproductive disease remained significant after adjustment for milk yield. The relationship between BCS and cow health and reproductive performance tended to be non-significant after adjustment for dairy form. Supplementing direct genetic evaluations for days open with evaluations for dairy form increased reliability of days open by an average of 0.06 for 19 recently proven bulls. Selection for lower dairy form or higher BCS will slow the deterioration of cow health and reproductive performance that accompanies selection for increased yield

DNA methylation patterns in peripheral blood mononuclear cells from Holstein cattle with variable milk yield

Abstract Background Milk yield for Holstein cows has doubled over five decades due to genetic selection and changes to management, but the molecular mechanisms that facilitated this increase are mostly unknown. Epigenetic modifications to the cattle genome are a plausible molecular mechanism to cause variation in milk yield and our objective was to describe genome-wide DNA methylation patterns in peripheral blood mononuclear cells (PBMC) from mature Holstein dairy cows with variable milk yield. Results Whole genome MeDIP-seq was performed following DNA extraction from PBMC of 6 lactating dairy cows from 4 different herds that varied in milk yield from 13,556 kg to 23,105 kg per 305 day lactation. We describe methylation across the genome and for 13,677 protein coding genes. Repetitive element reads were primarily mapped to satellite (36.4%), SINE (29.1%), and LINE (23.7%) regions and the majority (78.4%) of CpG sites were sequenced at least once. DNA methylation was generally low upstream of genes with the nadir occurring 95 bp prior to the transcription start site (TSS). Methylation was lower in the first exon than in later exons, was highest for introns near the intron-exon junctions, and declined downstream as the distance from the gene increased. We identified 72 differentially methylated regions (DMR) between high milk yield cows and their control, and 252 DMR across herd environments. Conclusions This reference methylome for cattle with extreme variation in milk yield phenotype provides a resource to more fully evaluate relationships between DNA methylation and phenotype in populations subject to selection. The detection of DMR in cows of varying milk yield suggests potential to exploit epigenetic variation in cattle improvement programs

Short communication: Immunoglobulin variation in quarter-milked colostrum

Whereas whole first-milked colostrum IgG1 variation is documented, the IgG1 difference between the quarter mammary glands of dairy animals is unknown. First colostrum was quarter-collected from healthy udders of 8 multiparous dairy cows, all within 3h of parturition. Weight of colostrum produced by individual quarters was determined and a sample of each was frozen for subsequent analysis. Immunoglobulin G1 concentration (mg/mL) was measured by ELISA and total mass (g) was calculated. Standard addition method was used to overcome colostrum matrix effects and validate the standard ELISA measures. Analysis of the data showed that cow and quarter (cow) were significantly different in both concentration and total mass per quarter. Analysis of the mean IgG1 concentration of the front and rear quarters showed that this was not different, but the large variation in individual quarters confounds the analysis. This quarter difference finding indicates that each mammary gland develops a different capacity to accumulate precolostrum IgG1, whereas the circulating hormone concentrations that induce colostrogenesis reach the 4 glands similarly. This finding also shows that the variation in quarter colostrum production is a contributor to the vast variation in first milking colostrum IgG1 content. Finally, the data suggests other factors, such as locally acting autocrine or paracrine, epigenetic, or stochasticity, in gene regulation mechanisms may impinge on colostrogenesis capacity

Association of Calf Growth and Feed Intake Traits with Mature Cow Milk Yield and Body Weight

Data from six different calf trials were compared to 134,469 daily milk records and 37,403 body weights to determine how heifer growth traits are associated with milk yield and mature cow body weight. Animals were classified into 3 categories (low, intermediate and high) according to their body weight, hip height, growth rate and starter feed intake. Calves that were classified in the intermediate body weight category tended to produce more milk during the first ten weeks of lactation than cows classified as having low or high body weights as calves. Additionally, cows classified in the low hip height group as calves produced less milk during the first ten weeks of lactation when compared to cows classified in the intermediate or high hip height category as calves. Calves classified in either the low growth rate or the low starter feed intake group tended to be lighter as mature cows when compared to the intermediate and high classifications of their respective categories. The results suggest that calf hip height and body weight can be useful predictors of milk yield, while calf growth rate and starter feed intake can impact mature cow body weight.</p

Quarter variation and correlations of colostrum albumin, immunoglobulin G1 and G2 in dairy cows.

A high variation in immunoglobulin G1 (IgG1) concentration in first milked quarter colostrum has been reported, but BSA quarter colostrum variation is not known. The occurrence of serum albumin in milk has been attributed to increased blood-milk barrier penetration. Reports of serum albumin binding to the Fc Receptor of the neonate, the receptor thought to be responsible for IgG1 transcytosis, suggested that a correlation with the appearance of IgG1 in colostrum of dairy cows was likely. The objective of the study was to establish the quarter colostrum concentration and mass of immunoglobulins and serum albumin. First colostrum was quarter collected within 4 h of parturition from healthy udders of 31 multiparous dairy cows. Individual quarter colostrum weight was determined and a sample of each was frozen for subsequent analysis. Concentrations of immunoglobulin G1, G2, and BSA were measured by ELISA and total mass of components was calculated. In addition, colostrum was also analysed for L-lactate dehydrogenase activity. Analysis of concentration and mass of BSA, immunoglobulin G1, G2 established that the quarter variations were different by cow, quarter and quarter within cow. Partial correlations corrected for colostrum weight indicated that BSA and IgG2 concentration and mass are closely correlated while that of BSA and IgG1 concentration and mass exhibited no correlation suggesting that BSA and IgG1 may have different transport mechanisms. Interestingly, immunoglobulin G1 and G2 concentration and mass exhibited strong correlations suggesting that also some unknown mechanism of immunoglobulin G2 appearance in colostrum is occurring. Finally, no measured protein exhibited any correlation with the activity of lactate dehydrogenase in colostrum

Copy number variations of the extensively amplified Y-linked genes, HSFY and ZNF280BY, in cattle and their association with male reproductive traits in Holstein bulls

BACKGROUND: Recent transcriptomic analysis of the bovine Y chromosome revealed at least six multi-copy protein coding gene families, including TSPY, HSFY and ZNF280BY, on the male-specific region (MSY). Previous studies indicated that the copy number variations (CNVs) of the human and bovine TSPY were associated with male fertility in men and cattle. However, the relationship between CNVs of the bovine Y-linked HSFY and ZNF280BY gene families and bull fertility has not been investigated. RESULTS: We investigated the copy number (CN) of the bovine HSFY and ZNF280BY in a total of 460 bulls from 15 breeds using a quantitative PCR approach. We observed CNVs for both gene families within and between cattle breeds. The median copy number (MCN) of HSFY among all bulls was 197, ranging from 21 to 308. The MCN of ZNF280BY was 236, varying from 28 to 380. Furthermore, bulls in the Bos taurus (BTA) lineage had a significantly higher MCN (202) of HSFY than bulls in the Bos indicus (BIN) lineage (178), while taurine bulls had a significantly lower MCN (231) of ZNF280BY than indicine bulls (284). In addition, the CN of ZNF280BY was positively correlated to that of HSFY on the BTAY. Association analysis revealed that the CNVs of both HSFY and ZNF280BY were correlated negatively with testis size, while positively with sire conception rate. CONCLUSION: The bovine HSFY and ZNF280BY gene families have extensively expanded on the Y chromosome during evolution. The CN of both gene families varies significantly among individuals and cattle breeds. These variations were associated with testis size and bull fertility in Holstein, suggesting that the CNVs of HSFY and ZNF280BY may serve as valuable makers for male fertility selection in cattle