Expression profiles of genes regulating dairy cow fertility: recent findings, ongoing activities and future possibilities

Subfertility has negative effects for dairy farm profitability, animal welfare and sustainability of animal production. Increasing herd sizes and economic pressures restrict the amount of time that farmers can spend on counteractive management Genetic improvement will become increasingly important to restore reproductive performance. Complementary to traditional breeding value estimation procedures, genomic selection based on genome-wide information will become more widely applied. Functional genomics, including transcriptomics (gene expression profiling), produces the information to understand the consequences of selection as it helps to unravel physiological mechanisms underlying female fertility traits. Insight into the latter is needed to develop new effective management strategies to combat subfertility. Here, the importance of functional genomics for dairy cow reproduction so far and in the near future is evaluated. Recent gene profiling studies in the field of dairy cow fertility are reviewed and new data are presented on genes that are expressed in the brains of dairy cows and that are involved in dairy cow oestrus (behaviour). Fast-developing new research areas in the field of functional genomics, such as epigenetics, RNA interference, variable copy numbers and nutrigenomics are discussed including their promising future value for dairy cow fertility

Towards field specific phosphate applications norms with machine learning

Efficient use of animal manure is an important link in the nutrient cycle in agricultural systems. On Dutch dairy farms, most manure is applied on grass and cropland, with maize as main crop. With the aim of balancing P input and output at field level, which is the idea behind the currently used, but rather fixed, ..

Inbreeding depression due to recent and ancient inbreeding in Dutch Holstein–Friesian dairy cattle

International audienceBackground : Inbreeding decreases animal performance (inbreeding depression), but not all inbreeding is expected to be equally harmful. Recent inbreeding is expected to be more harmful than ancient inbreeding, because selection decreases the frequency of deleterious alleles over time. Selection efficiency is increased by inbreeding, a process called purging. Our objective was to investigate effects of recent and ancient inbreeding on yield, fertility and udder health traits in Dutch Holstein–Friesian cows.Methods : In total, 38,792 first-parity cows were included. Pedigree inbreeding ( FPED ) was computed and 75 k geno-type data were used to compute genomic inbreeding, among others based on regions of homozygosity (ROH) in the genome ( FROH).Results : Inbreeding depression was observed, e.g. a 1% increase in FROH was associated with a 36.3 kg (SE = 2.4) decrease in 305-day milk yield, a 0.48 day (SE =0.15) increase in calving interval and a 0.86 unit (SE =0.28) increase in somatic cell score for day 150 through to 400. These effects equalled −0.45, 0.12 and 0.05% of the trait means, respec-tively. When FPED was split into generation-based components, inbreeding on recent generations was more harmful than inbreeding on more distant generations for yield traits. When FPED was split into new and ancestral components, based on whether alleles were identical-by-descent for the first time or not, new inbreeding was more harmful than ancestral inbreeding, especially for yield traits. For example, a 1% increase in new inbreeding was associated with a 2.42 kg (SE =0.41) decrease in 305-day fat yield, compared to a 0.03 kg (SE =0.71) increase for ancestral inbreeding. There were no clear differences between effects of long ROH (recent inbreeding) and short ROH (ancient inbreeding).Conclusions : Inbreeding depression was observed for yield, fertility and udder health traits. For yield traits and based on pedigree, inbreeding on recent generations was more harmful than inbreeding on distant generations and there was evidence of purging. Across all traits, long and short ROH contributed to inbreeding depression. In future work, inbreeding depression and purging should be assessed in more detail at the genomic level, using higher density information and genomic time series