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- The beef industry has long encouraged purebred sires in crossbreeding, but the use of crossbred and composite bulls is catching on.
“Crossbred sires simplify crossbreeding. After you’ve settled on an optimal proportion for your herd, you can keep it that way by using crossbred bulls,” Wade Shafer, American Simmental Association (ASA) director of performance programs says.
Tap Into Complementarity
“Another important benefit, independent of heterosis, is the complementarity that hybrids bring. You don’t have to deal with the big swings in cow size or biological type that occur when using purebred bulls of one breed and then another,” Whittier says.
“There are many different breeds being used in creating composites, but the ones most discussed include SimAngus (Simmental-Angus), Balancer (Gelbvieh-Angus) and LimFlex (Limousin-Angus). Any of those three continental breeds appear to be fairly complementary with Angus, which explains their acceptance,” Whittier says.
This is a very powerful tool. “Using crossbred seedstock allows commercial producers to fully utilize complementarity while maintaining consistency,” Shafer says. Staying within one breed severely limits selection of sires to complement your herd.
“Complementarity is most thoroughly exploited by crossing diverse biological types, but using purebred bulls in a rotational crossbreeding system creates large variations in breed proportion within the herd – and lack of uniformity. To counteract this, a producer may select breeds of similar biological type. This approach delivers consistency, but does not leverage the power of complementarity. With use of crossbred sires, you can maintain a constant breed proportion, and uniformity will be maintained in spite of utilizing diverse breeds,” Shafer explains.
Hybrid bulls have higher-than-average fertility and longevity. “Those traits appear to be a natural result of heterosis,” Whittier says. He’s referring to a summary of research on crossbred sires that appeared in the Journal of Animal Science in 1987.
“Kentucky researchers reviewed nine published reports that dealt with productivity of crossbred bulls, focusing primarily on reproductive traits of yearling crossbred and straightbred bulls. The researchers looked at semen traits and fertility, and found increased survivability of sperm in crossbred bulls, which might have an influence on overall pregnancy rate,” he says.
Crossbred bulls compared to parent breeds showed advantages in semen quality, age at puberty, scrotal circumference and pregnancy rates, he says. Hybrid bulls also reached puberty at an earlier age, had improvements in scrotal circumference, improved sperm concentration, and increased pregnancy and weaning rates in the cows they bred.
Another interesting fact is that average date of calves born when sired by crossbred bulls was 8-10 days earlier than calves sired by purebred bulls, indicating earlier conception. The payoff is that calves born earlier have more time to grow before weaning, and cows that calve earlier have more chance to rebreed on schedule earlier in the season.
Improved sperm traits are also an advantage of hybrid bulls. “Greater concentration of sperm cells and improved initial motility should enhance collection, extension and freezing from hybrid sires for artificial insemination. These traits would also improve the ability of young hybrid bulls to successfully pass a breeding soundness exam prior to being offered as yearling sires,” Whittier says. He adds that these results are now being seen, as more hybrid and composite bulls are used for artificial insemination.
Producers who have used hybrid bulls feel one advantage over purebreds is that the hybrid bull has a tendency to stay structurally and reproductively sound longer, with fewer breakdowns. This depends partly on the individual bull, of course. “There hasn’t been much research on this, but we know crossbred cows stay in the herd longer, and we feel the crossbred bulls would, too,” says Matt Spangler, a University of Nebraska assistant professor in beef cattle quantitative genetics.