Heifer-Fertility Research Lays Groundwork for DNA Genetic Test by Heather Smith Thomas for the Red Angus Magazine
Fertility in cattle is the largest driver of profitability in the beef industry – no calf, no income. It’s expensive to develop heifers as replacement females. A heifer that is fertile, settles early in the breeding season and continues to raise a calf every year for a long life of productivity is profitable. A non-profitable heifer does not breed, breeds late or comes in open after her first calf. Her spot in the herd must then be replaced by another heifer that takes two years to develop. Producers utilize multiple ways to select heifers but determining future fertility has been elusive. Dr. Jared Decker, associate professor at the University of Missouri, is starting a research project to look at genetics of fertility and heifer puberty with a grant from USDA National Institute of Food and Agriculture. He is currently recruiting 2,500 Red Angus and 2,500 Hereford heifers for his research, and producers who participate will get free genomic-enhanced EPDs for their females. Fertility Indicator Traits The beef industry needs informative indicator traits for heifer fertility prediction, similar to calving ease and carcass traits. “Currently we don’t have any predictions of heifer puberty, and with the heifer pregnancy predictions that we do have, we don’t give any credit to the heifers that calve early in the breeding season,” Decker said. “We have indicator traits like birthweight for calving ease, and ultrasound data for carcass traits,” continued Decker. “Perhaps we can use reproductive tract scores, pelvic measurements and fetal age from ultrasound pregnancy diagnosis as indicator traits to more accurately predict heifer preg40 Red Angus Magazine ■ October 2020
One to two months before breeding, a veterinarian will examine each heifer, collect pelvic measurement and assign a reproductive tract score based on her puberty status.
nancy. Reproductive tract scores and pelvic measurements can also be used to predict the onset of puberty.” Settling a heifer early allows her more time to recover after calving, with more chance to rebreed. Jordan Thomas, University of Missouri state beef reproduction specialist, is also involved with this research. He said heifers that become pregnant in the first 21 days will stay in the herd over a year longer, on average, and wean more pounds of calf during their productive life span. “This is partly because she weans that additional calf and because she breeds early each year. Her calf is older and heavier at weaning,” explained Thomas. “With this research, we’re trying to develop precise ways of identifying heifers based on their genetic merits for reproductive traits. If I want heifers pregnant as early as possible in their
first breeding, they must reach puberty before the start of that breeding season. I could use protocols to help them, but even those protocols function best when most of the group has already attained puberty. We also need heifers with the fertility potential to conceive with as few of services as possible, so they become pregnant as early as possible,” he said. Current methods of trying to make genetic progress in reproductive performance are limited. “The heifer pregnancy EPD is calculated as a yes or no: did she become pregnant after she was exposed? That’s better than nothing, but not as good as we think we can do. We’re now collecting pre-breeding and pregnancy information on a large group of heifers to retrospectively determine which heifers are reaching puberty at younger ages, and which are conceiving early in the breeding season.