Project description:Cows were fed a lactation diet at ad libitum intake (n = 6). At 27±3 days in milk, cows were injected with 50 µg of LPS E. coli in one healthy rear mammary quarter. Milk samples were collected just before LPS challenge (LPS-) and 6.5 h after LPS challenge (LPS+) from the same cows. Microarray analysis was performed using customized 8x60K ruminant miRNA microarrays to compare LPS- to LPS+ miRNome. MiRNome comparison between LPS- and LPS+ identified 37 differentially abundant miRNAs (q-value ≤ 0.05)
Project description:Analysis of key genes and gene networks determining milk productivity of the dairy HF cows Transcriptomes were compared of in the mammary glands of the healthy lactating Holstein Friesian cows of the high- (average 11097 kg milk/lactation) and low- (average 6956 kg milk/lactation) milk yield.
Project description:The study explores the genetic basis of high or low antibody (Ab) and cell (DTH)-mediated immune responses in Canadian Holstein cows using microarray hybridization to an in-house immune-endocrine cDNA microarray Keywords: immune response comparison
Project description:In dairy cows, milk production and composition are affected by numerous factors, including diet. Milk is the body fluid with the highest RNA concentration, including numerous microRNA. These microRNA presence in the different milk compartments is still poorly documented and the effect of feed restriction on milk miRNome has not been described yet. The aim of this study was to describe the effects of feed restrictions of different intensitizes on milk compartment miRNome composition. Two feed restriction trials were performed on lactating dairy cows, one of high intensity and one of moderate intensity. 2 896 mature microRNA were identified in milk, including 1 493 that were already known in bovine specie. Among the 1 095 miRNA that were abundant enough to be informative, 10% were exclusive to one milk compartment and the abundance of 155 varied between compartments, revealing a specific miRNome for each milk fraction. Feed restriction affected differently these miRNome, with microRNA in whole milk and milk extracellular vesicles being the most affected and microRNA in fat globules and exfoliated mammary epithelial cells being relatively or completely unaffected. Target prediction of known microRNA that varied under feed restriction reflected modification of some key pathways for lactation related to milk fat and protein metabolisms, cell cycle and stress responses. These findings open up opportunities for future research on the use of milk miRNA as biomarkers of energy status in dairy cows.
Project description:To explore potential functional genes related to milk production traits in cow, we performed total RNA-seq using liver biospy collected from 77 Holstein Friesian cows at postpartum 2 weeks.
Project description:In the livestock industry, feed is the largest expense, driving interest in breeding more feed-efficient animals. Residual feed intake (RFI) is a widely used measure of feed efficiency, accounting for actual feed intake versus expected requirements for maintenance and production. Because feed efficiency is highly polygenic, associated genes may have pleiotropic effects on traits such as immunity, complicating breeding strategies. One way to study pleiotropy is through -OMICs technologies, including transcriptomics, which uses RNA-Sequencing (RNA-Seq) to analyze the transcriptome at specific tissue levels and time points. This study used RNA-Seq to identify differentially expressed (DE) genes between Low RFI (n = 22) and High RFI (n = 17) Holstein cows. A total of 36 genes were DE between groups, enriched in 28 metabolic pathways (FDR < 0.01), most of which were immune-related, including the RIG-I-like receptor signaling pathway. QTL annotation and enrichment analyses were also performed for the DE genes. Within these gene regions, 646 previously annotated QTL were identified, of which 26.7% were related to milk traits. Notably, 10 QTL were associated with feed efficiency, while 4 were linked to host immunity. QTL enrichment further revealed 387 significantly enriched QTL, with the majority of the top associations related to health. In summary, this research identified candidate genes and QTL regions suggesting potential pleiotropic relationships between feed efficiency and immunity in Holstein dairy cows. These findings highlight the need for further investigation to balance productivity and health in genetic improvement programs.