Committee Technical Session:
Genetic Predictions
Improving our Genetic Prediction of Female Reproduction
BOZEMAN, Mont. (June 3, 2011) — If you’re not a rancher from “down under,” you might not be familiar with EBVs, and you’ve probably never heard of the reproductive trait “days to calving,” David Johnston, University of New England, New South Wales, Australia, told attendees of the 43rd annual Beef Improvement Federation (BIF) research symposium. Johnston told those attending the Genetic Prediction Committee technical session to think of estimated breeding values, or EBVs to Australian producers, as expected progeny differences, or EPDs.
The days-to-calving trait, however, doesn’t have an American counterpart. “Reproduction is a key profit driver in beef. We should be striving for a 100% calf crop in our production systems,” Johnston said, adding that he prefers the term “reproduction” to “fertility” because it encompasses a wider array of traits.
“Days-to-calving is a simple trait to measure,” he said. “You record the ‘bull-in date,’ or the start of mating, and then you record the date of the birth of each calf. The amount of time that passes between these two dates becomes the days-to-calving figure.” A successful pregnancy within the first cycle followed by a live calf would equate to a calving success number of 1. A cow that did not become pregnant would receive a 0 calving success rating.
Accuracy of data collection on any one cow is not particularly high, Johnston said, so he has focused on herd data collection. “The key is to obtain data on 25 to 50 daughters of a particular bull,” he said. “Then we can begin to make determinations that will help breeders make selections.”
While heritability of the particular trait is relatively low, at about 5%-10%, it could be associated with a high economic value, especially depending on a herd’s current conception rate. “If your current pregnancy rate is 95%, you won’t benefit nearly as much from a proven bull than a herd with a 60% rate of reproduction,” Johnston said.
Johnston has faced obstacles in obtaining useful data. “We currently have only studied natural-selection situations. There are a lot of producers who utilize AI, so I would like to be able to use data from their herds,” he said. Another roadblock related to data collection is the naysayers who don’t want to be the “guinea pigs” for this relatively new concept.
“We need tens of thousands of records, and we are nowhere near this. Purebred breeders want to wait until there is more established genomics research, but breeds will never have genomic predictions if they never get cracking with collecting data,” he said.
Johnston encouraged producers and breed associations to take the plunge, collect the data and begin the process of determining what the days-to-calving traits are in their particular breed or herd.
Johnston concluded with a mild challenge to producers in the form of several questions. “Is reproduction a profit driver in your herd? Is there an opportunity to improve this though genetics? Is it possible to record these traits in your herd?”
To listen to this presentation and to view the PowerPoint that accompanied it, visit the Newsroom at www.BIFconference.com.
BIF’s 43rd Annual Research Symposium and Annual Meeting was hosted June 1-4 on campus at Montana State University, Bozeman, Mont.
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