John Maday, Managing Editor, Drovers CattleNetwork | Updated: 06/19/2014
Genetic improvement is great, but changes in management can significantly improve profitability with existing genetics in cow-calf herds. That was one message from University of Nebraska animal scientist Rick Funston, PhD, to the genetics-oriented crowd during the opening day of the 2014 Beef Improvement Federation conference this week in Lincoln, Nebraska.
Funston’s presentation focused on decreasing costs through improved heifer development strategies. He led off by stressing that the U.S. beef industry needs to build cow inventories to support our infrastructure, and economic signals support expansion decisions for many producers. Ranchers face a challenge though, in building their cow herds with cost-effective heifer selection and development.
A tight calving season offers numerous benefits, and research has shown that replacement heifers born early in the calving season tend to conceive early compared with those born later, Funston says. And that advantage continues through the productive life of the female. In fact, a heifer born early in the calving season will produce about 400 more pounds of weaned-calf weight over its life cycle than a late-born heifer.
Once replacement heifers are selected, nutrition becomes critical in ensuring good pregnancy rates, particularly first-service conception rates. Research at Nebraska and elsewhere has shown that heifers can be developed effectively in a low-input grazing system, targeting a breeding weight of 50 to 55 percent mature weight. Funston and his team have compared development systems using corn stubble verses drylot feeding during the winter, with heifers from both groups going to grass pastures at spring green-up. The drylot heifers gain considerably more during the winter, but the low-input corn-stubble heifers put on compensatory gain on spring grass and out-gain the drylot heifers during that stage – by one pound per day on the same pasture in one trial. That late weight gain results in better first-service conception in the low-input groups compared with those on a system that provides more steady weight gain through development.
In the Nebraska research herds, the team uses prostaglandin to synchronize estrus in females prior to natural-service breeding. Funston says synchronization allowed reducing the breeding season from 60 days to 40 without any reduction in pregnancy rates.
Funston says low-input heifer-development systems, in which heifers are managed more like stocker cattle, could help identify heifers that conceive early as those best adapted to the ranch environment and most likely to remain in the breeding herd. Open heifers in these systems retain high value as feeder cattle due to their relatively light weight at breeding.
A key point, Funston says, is that heifers need to be gaining weight at breeding time for optimum pregnancy rates. Heifers bred in late spring or early summer generally fit that description, but in herds where heifers are bred later in the summer, when forage quality is declining, pregnancy rates can decline without supplementation.
Funston also reminds producers and researchers of the upcoming Applied Reproductive Strategies in Beef Cattle conference, scheduled for October 8 and 9 in Stillwater, Oklahoma.