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First EPDs for udder and teat conformation in the works

Angus herds studied for desirable traits to improve genetic selection

That first feeding of colostrum invariably charts the course for a calf’s future success and profitability. Knowing that the dam’s udder and teat structure is important to a successful first feeding Kajal Devani, is aiming to improve the genetic selection for improved mammary conformation in Canadian Angus cattle.

Kajal Devani.
photo: File

Devani, who is the Canadian Angus Association’s (CAA) member service team leader, chose this research project while in pursuit of a doctorate in production animal health under the supervision of Dr. Karin Orsel at the University of Calgary faculty of veterinary medicine with support from the University of Alberta.

Her research earned first place in this year’s poster session at the faculty’s beef cattle conference.

To begin, 10 Canadian Angus herds were randomly selected from seedstock producers who volunteered their herds for the project. This formed a representative population of 2,051 active registered Angus cows that provided the discovery genotype samples and phenotypic references.

Teat size and udder suspension were scored according to the Beef Improvement Federation’s scoring guidelines ranging from one to nine for each trait. For udder suspension, a score of one is very pendulous and nine is very tight. For teat size, a score of one is very large, balloon-shaped teats and nine is very small.

Devani and an intern independently scored each trait and the intern’s scores were used as the phenotypic reference. Hers and the intern’s scores were very similar when compared after the scoring, but having parallel scores ensured repeatability and objectivity, she explains.

Devani collected DNA samples from each cow scored and the CAA provided pedigree and performance information for each cow and its calves.

Preliminary results so far show that the sample set was representative of the Canadian Angus population. Of the approximately 60,000 calves registered in 2015, 67 per cent were Black Angus and 33 per cent were Red Angus. Of the 2,051 cows sample and scored, 585 were red, 1,299 were black and 146 were red-black crosses.

The number of calvings for each scored cow ranged from one to 13. The average parity was 3.26 for the red cows, 2.86 for the black cows and 1.72 for the crosses.

Average scores for the red cows were 5.80 for udders and 5.78 for teats. The black cows averaged 6.26 for udders and 6.50 for teats. The crosses averaged 6.87 for udders and 6.57 for teats.

The purpose of this research isn’t to determine which combination of udder and teat size is most desirable. Devani says that decision is up to individual producers and will depend on the goals for their operation and their environment.

“The goal is to give Canadian Angus breeders access to genetic selection tools that can help maintain the most functional, healthy and profitable Angus cow herd possible.

Angus is known as a maternal breed and for structural soundness. This is a way to maintain those qualities and make sure they are a focus for new breeders, she says.

EPDs for Angus cow teat and udder structure will be generated using pedigree, performance and progeny information. The DNA samples have been genotyped by Delta Genomics and part of the project involves looking for SNP markers that describe the phenotypic variation seen in these traits. These markers will help make the resulting EPDs more accurate.

“We know that the two traits (udder and teat conformation) are highly correlated but for now we will have an EPD for each trait. In the long term we hope to have a female sustainability and longevity index that includes both,” Devani says, adding that indexes are handy because producers have one number that represents all the traits included in the index instead of having to work with several EPDs.

Devani’s study is part of a larger pro­ject exploring female longevity because it has such an impact on producer profits. Poor udder and teat conformation alone has negative consequences for profitability, calf nutrition and health, influencing the cow’s susceptibility to mastitis, the use of antibiotics to treat cow and calves, and the demands on a producer’s time treating animals and assisting calves with the first feedings of colostrum.

Improving market access is an overarching goal, she adds, because breeds known for superior genetics are in demand from bull buyers and seedstock producers domestically and internationally.

Although her research is specific to Canadian Angus cattle, other breeds could do similar work to establish genomic tools for these traits. She is aware that both the Red and Black Angus groups and the Hereford association in the U.S. are working toward this goal.

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