New technologies help to breed the cow of the future

by Jeff Stuart

y speeding up the selective breeding process and applying the latest reproductive and molecular tools, U of G researchers are enhancing milk productivity and dairy profits.

Animal science professor John Gibson and his colleagues are combining reproductive technologies with genetic markers to give dairy farmers even more control over the quality of their herd.

"For the first time we can look inside the genetic black box," says Gibson. "And what we find in there will lead to a new era of genetic improvement."

Genetic screens have been developed for many deleterious genes that cause very specific and identifiable problems. Genetic screens are limited, however, by the need for specific problematic genes to be identified, a laborious and expensive process. With more than 70,000 genes comprising the genetic makeup of an individual animal, the identities of the vast majority of genes responsible for particular characteristics remain unknown.

So, Gibson and Yves Plante at the University of Saskatoon are undertaking a collaborative research program, using genetic markers. Genetic markers identify a specific region of the genome containing possibly hundreds of genes. The presence of these markers can be matched to any number of desirable traits. Better yet, the identity of the individual genes need not be known. Researchers can just follow the occurrence of the genetic markers over a few generations of a bull's offspring, and correlate the presence of the marker with the many measures of a good dairy cow, like milk quality and quantity. Using this approach, specific genetic markers can be linked with a database of characteristics.

The genetic markers can be detected in very young animals -- even in embryos -- which can then be selected for further testing or breeding. This is where recent advances in reproductive technologies come in. Using in vitro fertilization and embryo transfer, elite cows and bulls can rapidly be produced from selected offspring. There's no need to wait for animals to mature to measure desirable characteristics in adults; the presence of the genetic marker in young animals indicates that the animal will be genetically superior and can pass this superiority onto its progeny.

"These molecular and reproductive tools will help farmers breed the cow of the future, which will be healthier and more productive and give better quality milk," says Gibson.

This research is sponsored by the Ontario Ministry of Agriculture, Food and Rural Affairs, the Cattle Breeding Research Council, the Natural Sciences and Engineering Research Council and the Saskatchewan Research Council.