Dairy cattle breeding is undergoing a significant transformation, driven by genomic selection. It enables breeders to analyse an animal’s DNA and select those with desirable traits at a very early stage.
Genomic selection enhances traditional selection methods that rely on phenotypic observations and pedigree records, which require extended time for accurate data collection (such as milk production or body size). Since its widespread implementation in the early 2000s, dairy cattle performance has improved substantially in key metrics like milk production efficiency. The genomic profile of Holstein dairy cattle is particularly well-characterised and widely used in selective breeding programs.
Genomic selection for cattle breeding
Genomic selection is based on the analysis of DNA markers, particularly single nucleotide polymorphisms (SNPs), associated with economically important traits like milk production, disease resistance, and reproductive efficiency. Through genome-wide analysis of these markers, breeders can predict an animal’s performance and breeding value with higher accuracy than traditional methods.
A genome-wide analysis of the SNPs associated with desirable traits, called genotyping, provides detailed insight into an animal’s genetic composition and enables breeders to make more informed decisions in dairy cattle breeding.
Genotyping technology
Genotyping is mainly done with SNP microarrays. This technology enables efficient genotyping by detecting specific SNPs in the DNA extracted from animal tissue samples. Advanced computational algorithms analyse this data to quantify an animal’s genetic potential and generate genomic estimated breeding values (GEBVs). Based on these, animals with the highest GEBVs can be selected early for breeding to ensure the transmission of desirable traits to the next generation.
Genomic selection – Key selection metrics
1. Milk yield and composition (protein/fat content)
Genomic selection has significantly improved the accuracy of predicting milk production traits, i.e. the volume of milk produced (milk yield) and quality of milk produced (fat and protein percentages).
2. Feed Saved
Feed Saved indicates the expected reduction of feed consumed each lactation based on evaluations for Residual Feed Intake and Body Weight Composite; measured in pounds of dry matter intake.
3. Health and disease resistance
Improving health traits not only enhances animal welfare but also reduces costs for veterinarians and medical interventions. One of the main traits to select for is mastitis resistance (infection of the udder) which would reduce costs for dairy farmers. Further resistances against lameness, metabolic disorders, or respiratory diseases are increasingly included in genomic evaluations.
4. Longevity and durability
Genomic selection can identify animals with traits associated with durability, such as strong udders, feet, and legs. After all, cows that remain in the herd longer contribute more to profitability.
5. Fertility and reproductive performance
reproductive traits easier to identify animals with superior reproductive performance, i.e. shorter calving interval (time between successive calvings) and higher conception rates (likelihood of a cow becoming pregnant after insemination).
6. Genetic diversity
The focus on selecting animals with specific traits could inadvertently narrow the gene pool, making cattle more susceptible to diseases or environmental changes. Genomic selection allows breeders to monitor and manage genetic diversity of a herd more effectively, ensuring long-term sustainability and avoiding inbreeding depression.
Genomic selection can also greatly improve the sustainability of dairy farming by improving traits like feed conversion efficiency and disease resistance. Enhanced feed efficiency reduces methane emissions per unit of milk produced, while improved health traits decrease resource usage and medical interventions. These improvements help address environmental concerns while maintaining productive dairy operations.
Genomic selection – Easy access
1. Purchase the test on our website: genfarmeval.com
2. We will send you a Tissue Sampling Unit (TSU) to collect the sample easily and conveniently.
3. Return the sample to our laboratory in Denmark.
4. Log in to the GenFarmEval App to access your results online.
Overall, genomic selection represents a paradigm shift in dairy cattle breeding, offering unprecedented precision and efficiency in genetic improvement. By leveraging tools like SNP microarrays to analyse a wide range of genetic markers, breeders can make data-driven decisions that enhance milk production, improve animal health, and promote sustainability.
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