LINDELL BEACH, B.C. – Checking the genetics of living cattle is routine work – test a blood sample or a tuft of hair from a newborn calf for genetic traits and determine its market potential.
But what about cattle owners who select embryo transfer as part of their breeding program?
At Iowa State University’s College of Veterinary Medicine, Dr. Jim West and a team of clinicians, diagnosticians and genetic researchers are trying to figure out how to test for genetic traits at the embryonic stage before the embryo is transplanted into a cow.
Read Also
Land crash warning rejected
A technical analyst believes that Saskatchewan land values could be due for a correction, but land owners and FCC say supply/demand fundamentals drive land prices – not mathematical models
“We are testing embryos that are seven days old after conception,” said West, a clinical medicine professor who has worked in embryo transfer science for 30 years.
“The lab we are working with is the Ames Center for Genetic Technologies Inc. It has the ability to do this testing with just two or three cells.”
The value of this work to ranchers and dairy producers is that an embryo can be tested before transplant for genetic defects, gender, production traits and health conditions.
Armed with this knowledge, a breeder can then decide on the value of the embryo and whether or not to impregnate the cow.
Embryos that are defective or not of the desired gender can be discarded, which saves producers money, time and effort bringing a pregnant cow to term. As the system is refined, West hopes that they will be able to test for other traits such as milk production, beef tenderness and feeding efficiency.
The researchers have been working with fresh embryos, and results are obtained within three hours of biopsy. They are now beginning a trial to freeze biopsied embryos that can be stored for later transfer.
“It’s very cost effective,” West said.
“It will be a really valuable tool for farmers or for owners of elite breeding animals.”
For example, farmers breeding Angus cattle and using the embryo transplant method will be able to test for curly calf syndrome, a genetic defect that produces calves with a bent, twisted spine, limited muscle development and legs that are rigid, contracted or hyper-extended.
The defect was found through standard genetic testing when it was discovered that a popular breeding bull was a carrier.
Using West’s method, genetic testing just days after conception will let a breeder know if the embryo carries the syndrome. If so, it can be discarded, which not only saves money but also weeds the defect out of a herd’s genetic profile.
The process could do the same for bovine leukocyte adhesion deficiency (BLAD), a genetic condition in Holstein calves that produces recurrent pneumonia, stomatitis, enteritis, delayed wound healing, stunted growth and early death.
The U.S. Department of Agriculture says subsequent investigation of pedigrees traced all the affected calves back to a common and popular sire, Osborndale Ivanhoe, which was used for breeding in the 1950s and 1960s. Eliminating embryos carrying the BLAD gene would be valuable to Holstein dairy producers.
While the system will benefit cattle breeders in the U.S. and Canada, tested embryos will not be available for export. West said embryos for export must have an intact membrane to protect against viruses. Penetration to extract a few cells for testing compromises this membrane.
West expects the service will be available to cattle breeders throughout North America. The system may eventually work for other livestock species.
“In sheep, identifying embryos with resistance to scrapie would be a big issue for breeders,” he said.
“We are not working on that yet, but we have had contact from the federal lab on it.”
