Solving sire mysteries
By Miranda Reiman
Give or take a week or more, gestation varies enough to make cattlemen wonder: Is this an AI (artificial insemination) calf or a natural service? Multi-sire pastures raise even more questions.
"There are some unique things you can do if you know which bull sired which calf," says Tonya Amen, with Angus Genetics Inc. From bull behavior to replacement heifer selection, the possibilities are both interesting and applicable.
Commercial Angus producers now have that ability. In July, GeneMax, a DNA test to measure gain and grade potential, added a function without adding cost: sire match. If bulls that could have bred a cow have been Pfizer-50K tested, the $17 commercial test can reveal her calf's sire.
Barb Downey, a registered and commercial Angus producer near Wamego, Kan., says knowing complete parentage would give her another layer of information for selection.
"We use performance data, the 205-day weights and the frame sizes. Then we look at history of the dam," she says. "We'll kick out some of the extremes on both ends."
After visual appraisal, they're either sent to the feedyard, developed for retention in the Downey Ranch herd or sold as bred heifers.
"Having a little bit more information for your buyer is always good," she says.
After an aggressive AI season, Downey turns out females with as many as 22 cleanup bulls in the same pasture.
"We are going more and more to rotational grazing," she says. "With my commercial cows, we have one large group and swing them through pastures. That makes managing my grazing better and easier.
"After AI, we wait a couple days before we turn out bulls, but with natural differences in gestation length, there is always a big question as to who is the sire of that calf."
With numerous bulls, Downey says, "There is a wide variety of sires and genotypes and phenotypes in there."
Adding a DNA test could help sort that out.
"Anything I can do to get those cows up in the front of the season--and those are generally your AI calves with more highly accurate, proven genetics--serves me and my customers well in the long run," she says.
GMX adds genetic predictions for performance and carcass measures in the form of a percentile ranking.
"If she's got everything else going for her and you can tell me that she's got stellar grading genetics, then maybe I could use that for a high-end sort," Downey says, looking to future applications.
Widespread AI breeding to a relatively few prominent bloodlines causes a challenge for Patsy Houghton, of Heartland Cattle Co., at McCook, Neb. As her staff makes mating decisions for commercial heifers, knowing the sire could help avoid pitfalls.
"The relatively narrow pool of popular sires used can easily lead to accidental line breeding, and even inbreeding," she says. "In turn, that can result in decreased fertility, longevity, immune response and growth. The DNA technology provides an opportunity to solve this problem."
Not everyone is interested in sire assignment purely from an AI standpoint.
"In multi-sire pasture situations, it's pretty valuable to be able to identify the bulls that are getting the job done for you and those that aren't," Amen says. "That's based not only on quality of calves, but also quantity of calves."
Downey says finding out more about the bulls is as intriguing as the heifer information.
"I do know there are real differences in how well bulls manage themselves in terms of getting cows covered, how aggressively they breed and how smart they are in their breeding behavior," she says.
The sire match function could be added to GMX test results without charging more because it draws on information already in the system.
"The markers we use for GeneMax are a subset of the 54,000 markers that are used on the Pfizer high-density test (50K)," Amen says. "When we have calves that we've tested for that reduced set, and bulls that have been tested for all of them, we then go back and see which markers might have been inherited from which sire."
The test will return results ranging from the "most likely" to "not likely" candidates.
"The one that comes back 'most likely' is probably the sire," Amen says. "If it lists, 'other possible'--those are bulls that meet some of the criteria, but it's still most likely the first one." Bulls with similar pedigrees may show up as "other possible", for example.
Commercial cattlemen can order 50K tests on registered and transferred Angus bulls, or work with their seedstock suppliers to order them as an aid in analyzing subsequent calf crops.
"You can choose to request the sire match feature up front when you order the test, or you can go back and request it after you receive GMX results," she says.
Anyone who has already run a GMX test may request this new layer of information in retrospect if they have the sire information.
"You may like the looks of a set of cattle, but it can pay to know more than that," Amen says. "GMX results are one tool that can help you keep the right candidates in your herd, and guide strategic mating decisions if you discover strengths or weaknesses in the individuals."
GeneMax was introduced in February 2012 by CAB and AGI in cooperation with Pfizer Animal Genetics for use on high-percentage Angus cattle. It is not intended for use on registered animals. For more information visit www.CABpartners.com/genemax.