Genetics and animal breeding

Farmers have been trying to build healthier, more productive animal herds through selectively breeding animals for thousands of years. This process involves selecting parents with desirable traits, which offspring could inherit. Over time, more animals in the herd will tend to be born with the desired trait(s). Traits are passed from parents to offspring via one or more genes, which contain DNA. Animal geneticists have developed techniques, such as genomic selection, that identify and
isolate genes to pass along desirable traits, such as milk production or disease resistance, and even “good mothering” characteristics can be important, especially with beef cattle. These techniques provide animal breeders with the ability to identify and select animals with desirable genes more efficiently. Examples of modern breeding programs include efforts to improve resistance to specific livestock diseases, and cattle that are polled, which means born without horns. Some farmers breed their animals naturally, while others may choose a process called “artificial insemination” (AI). In this case, semen from the male animal is collected, frozen, and eventually delivered to the female’s reproductive tract to create offspring. AI makes it possible to introduce the best traits available into a herd, even though males with those traits might not live nearby. AI also limits the transmission of disease, and increases safety for the animals and farmers, as mature males of many species can be unpredictable. Farmers can also more accurately predict the date that an animal will give birth, so that they can provide better care for both the mother and offspring at that time.