Genetic technologies offer new opportunities to develop precise management plans that will help a farmer capitalize on the genetic merit of each animal in his or her herd. Being able to make marketing decisions based on the animal’s genetic potential for traits such as milk production, or carcass traits in beef cattle, is possible through genomics. Genomic data, in combination with more traditional evaluation methods, is another tool that producers have which helps identify genetically superior animals early in their lifespan. This information provides a higher level of certainty in estimating the value of an animal’s progeny. Producers that have not registered their animals or are not part of any DHI reporting system would also benefit from genomics as it will help deliver genetic evaluations for animals that would otherwise not have a PTA.
The evaluation of dairy records developed by USDA and breed associations has been the foundation of genetic evaluations. To this you add DHI records and powerful algorithms to generate Predicted Transmitting Abilities (PTAs) which help rank animals on various traits. The number of progeny a specific animal had would help increase its reliability for PTAs; because of this the majority of genetic progress in dairy herds in the US and worldwide has been driven by bull selection. This enabled one bull to be used as the sire of thousands of offspring, helping the industry learn about the impact of sires and their ability to transmit genes to their offspring. On the cow side, the commercial dairy cow typically has only a few offspring and production records throughout her life. With genomics there is an opportunity to progress at a faster rate within the female population.
After years of research, scientists sequenced the bovine genome, which has approximately 3 billion base pairs, identifying which markers impact directly her physical appearance and production performance, genes of greatest importance to the dairy producer. The overall genetic influence on the phenotype is the sum of the effects of different genes dispersed throughout the animal’s DNA. For many of the traits, there are hundreds of genes that are involved and in addition to that environment has a major role to play. Genotyping helps identify which genes an animal has inherited, giving an indication of what might be transmitted to its offspring. The results are reported as Genomic Predicted Transmitting Abilities (GPTAs) and are presented in the same way as traditional genetic evaluations.