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Working Ranch April/May 2016

conception rates as much as 15% to 20%. Selecting heifers most likely to become pregnant in that fi rst estrous can provide benefi ts for the lifetime of the animal.” Ultrasound for use in beef production management decisions has been available since the mid 1980’s and allows for real-time visualization of heifers’ internal structures that are otherwise diffi cult to evaluate. Use of the technology in making reproductive management decisions increases the likelihood of reproductive success and pregnancy diagnosis. “Ultrasound may not be an option for some producers,” Cushman adds. “It’s one of many tools that aids in heifer selection. I encourage producers to use as many of the tools as possible to identify fertile heifers and improve pregnancy rates.” REFINING RESULTS Compared to the dairy industry, beef producers have good pregnancy rates. Dairy rates with single service are around 30% and beef between 50% and 70% to a single service. Heifers tend to have lower conception rates than cows, but using research fi ndings to increase pregnancy rates even slightly can signifi - cantly improve profi t. “A current study is showing that in some states, 50% of heifers are producing just 3 calves in their lifetime,” Cushman says. “If producers managing those heifers aren’t losing money, they’re at least leaving a lot of money on the table without realizing it. Just to pay for themselves, heifers should produce between 3 and 5 calves without any open seasons.” Perry recommends that, whenever possible, producers should retain more heifers than they actually need. The practice allows them to evaluate heifers at weaning and select the cream of the crop; those that exhibit the highest degree of performance stay in the herd permanently. “If you need 20, maybe you keep back 40,” Perry suggests. “That adds selection pressure to your herd genetics, improving genetics each year. For the heifers that didn’t make the cut, there’s usually a good market for them.” BEYOND SELECTION In more recent research, Cushman is fi nding genetic markers that may prove to be associated with reproductive tract development and/or early calving as well as animal longevity. Future confi rmation of the genetic marker relationship with those traits could give beef producers additional tools for accurate heifer selection. Ideally, heifers remain in the herd from 8 to 12 years. Once high-quality heifers are identifi ed, developing them appropriately is as important as selecting them. “You don’t feed a heifer in the same way as a steer,” Perry explains. “You want heifers with a body score of 5.5 to 6. If they’re too fat they won’t cycle correctly or perform as well and they’re harder to breed. Underdeveloped heifers won’t reach puberty at the correct age and won’t develop correctly, so there’s a fi ne line to walk with heifer development.” Perry recommends that heifers attain 65% of their expected mature weight by the beginning of breeding season. In addition, he suggests heifers shouldn’t receive any growth-promoting implants prior to breeding season. Placing heifers in a feedlot or confi ned feeding situation allows for intensive management of nutrient intake and growth, which positively infl uences heifer effi ciency and performance. The signifi cance of appropriate nutrient intake prior to breeding season is found in research data that demonstrates that heifers that produce a calf at 24 months of age tend to achieve maximum lifetime productivity. PENCIL IT OUT Cushman stresses the importance of recording heifer data in order to thoroughly evaluate performance and ensure return-on-investment. “Economic studies show that the average heifer needs to produce between 3 and 5 calves without any open season in order to pay for herself,” Cushman reiterates. “Looking closely at performance data over a span of time is the only sure way to accurately assess heifer performance.” 108 I WORKING RANCH I APRIL / MAY 2016


Working Ranch April/May 2016
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