The roots of dairy genetics

by Polly Stanley

of G researchers mean business -- BIG business -- when it comes to enhancing Ontario dairy genetics.

The university is home to an unparalleled team of geneticists and reproductive biologists who have played an integral role in improving Ontario dairy genetics. Together, they're applying knowledge in a way that's practical and economical. Their success is borne out by Canada's respected position in the global dairy genetics market.

"That's the real value of work in embryo biotechnology," says Dr. Donald Rieger of the Animal Biotechnology Embryo Laboratory (ABEL). "The techniques are making it into the business world and keeping the Canadian dairy industry well situated to respond to changes in genetic requirements."

ABEL is dedicated to making procedures less complicated and more available to Canadian producers. The laboratory was launched by embryologist and reproductive biologist Prof. Keith Betteridge through a major Natural Sciences and Engineering Research Council research chair program. ABEL now consists of 15 personnel under the directi on of Prof. Stanley Leibo.

ABEL researchers are all working towards the same goal -- increasing the intensity and accuracy of genetic selection while decreasing the generation interval of dairy cattle. They're doing this by perfecting a variety of techniques for use in dairy her ds.

Since the 1950s, semen from elite bulls has been used for artificial insemination (AI), a technology that has become the backbone of dairy cattle improvement programs. It has resulted in a dramatic increase in the intensity of the gene pool for dairy b reeding.

"Artificial insemination is now -- and will remain -- the most important breeding technique for genetic improvement," says Rieger.

Multiple ovulation and embryo transfer (MOET) was developed in the 1970s. Like AI, this technology has played a leading role in distributing the genes of the very best animals. MOET involves treating a genetically superior cow with hormones that stimu late her to produce many embryos at a time. The embryos are collected and transferred into a recipient female. This way, a good donor cow can produce 30 to 60 calves a year instead of just one.

In vitro production (IVP) of embryos differs from MOET in that unfertilized oocytes (eggs) -- rather than embryos -- are collected, then fertilized and matured in the lab. This means embryos can be produced from otherwise infertile, yet valuab le cows. In addition, because eggs can be collected from sexually immature heifers, the generation interval can be significantly reduced.

Another research avenue that stems from IVP is embryo manipulation. IVP -- in contrast to MOET -- gives researchers access to embryos before significant cell division has occurred. At this stage, the embryos can be split to produce groups of identical calves, a technique that will have a significant impact on the industry in future.

"These techniques are now at or near the point of practical application," says Rieger. "Fortunately, here in Canada we have the expertise, the infrastructure and a history of willingness to implement new techniques for genetic improvement."