By Becky Mills
Progressive Farmer Contributing Editor
If you've priced replacement heifers lately, or even just added up all the costs of raising your own, you are probably feeling a renewed appreciation for those older, productive cows in the herd.
"Next to fertility, longevity is the most important thing," said Jimmy Collins, Opelika, Ala., producer. He estimates it currently costs him between $1,250 to $1,700 to develop a heifer. So the longer they last is like money in the bank.
Rick Funston, University of Nebraska reproductive physiologist, said one challenge in raising heifers is that for two years they're not productive. But there are things producers can do during those two years to help tip the scales toward longevity and better reproduction.
Funston starts by selecting heifers born the first part of calving season. "It sets them up for the rest of their productive life and impacts their ability to breed back. The longer their postpartum interval, the longer they have to breed back. Plus, it impacts the weaning weights of their calves," he explained.
Steve Hancock, manager of Creek Plantation, said they won't keep a heifer born after December 23. He said their calving season starts November 20, so that's about a 30-day window.
The Martin, S.C., cattleman explained: "The heifers born first are older, and as a result more likely to breed earlier and stay in the program as three-year-olds. And, heifers out of cows that were quick to breed tend to breed quick themselves."
Funston added, "Heifers don't necessarily need more inputs, but they need to always be increasing their gain. From development to rebreeding with their second calf, ideally they are always moving up and never going backwards."
The researcher wants heifers to experience compensatory gain while they're breeding, which is how Hancock times his heifer program. From weaning the first part of September through fall, the heifers graze bermudagrass. As it goes dormant, he adds high-quality bermudagrass hay. Other than minerals, that's all they get until the ryegrass is ready to graze, which coincides with breeding season starting February 15.
His 250-plus replacement heifers usually have pregnancy rates of 95% to 96% over a 90-day season.
Alabama's Jimmy Collins and his son, Jim, develop around 200 homebred heifers a year, both to keep in their own herd and to sell as replacements. They keep costs down and nutrition up with several byproduct feeds. Calves learn to eat alongside their dams, so when they are weaned it's an easy transition.
Jim said, "That avoids a feed recognition problem. They get used to the smell and taste of feedstuffs."
Jimmy echoed Funston's philosophy about continual gain. He said from the day a heifer is weaned until she is rebreeding with her second calf, she should be on an increasing plane of nutrition.
The Collins' heifers also have conception rates similar to Hancock's, but over a 60-day breeding season.
LOWER BREEDING TARGET WEIGHTS
The longstanding rule heifers should be at 65% of their projected mature weight when they are bred is outdated, said Funston.
He explained most of the research recommending that target took place between the 1960s and the 1980s. The genetic makeup of the U.S. cow herd has changed significantly since then.
For starters, Funston said heifers now routinely calve as two-year-olds. This means heifers have indirectly been selected for an earlier age of puberty and a lower percentage of mature weight.
Also through selection, the average yearling EPD (Expected Progeny Difference) scrotal circumference of bulls has increased significantly since the 1980s. This moderately correlates to age of puberty in a bull's heifers, resulting in heifers reaching puberty sooner. So while mature cow weights have increased, the weight heifers reach puberty has not. As a result, heifers reach puberty at lower percentages of their expected mature weights.
Funston targets breeding when heifers reach 50% to 57% of their mature weight. "They can still get acceptable pregnancy rates of 80% to 95% on a 45- to 60-day breeding season," he said.
However, he went on to stress that their lower input phase needs to be followed by an increasing plane of nutrition at and after breeding.
"Going backward can affect pregnancy rates," Funston said. "We try to design our heifer development programs so they get gains of 1 to 1.5 pounds a day in the feedlot, then continue that gain or better on pasture."
He recommended breeding more heifers than you need for replacements, then selling the open ones on the feeder market.
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