Temperament and Reproduction
Dam’s temperament affects reproductive performance.
by Kasey Brown, senior associate editor
DES MOINES, Iowa (Sept. 8, 2016) — “We don’t need to raise puppy dogs, but we do need to select for temperament in the cow herd,” said Reinaldo Cooke. Temperament is a heritable trait at 0.50, so it affects the calf. The associate professor and beef cattle specialist at Oregon State University spoke to attendees of the 2016 Applied Reproductive Strategies in Beef Cattle symposium in Des Moines, Iowa, Sept. 7-8.
He noted several ways, both objective and subjective, to score temperament, including chute scores and exit velocity. He averages those scores to create a temperament score, ranging from docile to aggressive, designated by 1-5, respectively. Adequate temperament includes those cows that earn a temperament score of three or less, and excitable temperament includes the scores of 4 and 5.
Cooke suggested selecting for temperament by sire selection and culling aggressive females, but granted that some “personality” should remain without impairing safety and productive traits. In cow-calf systems like his in Oregon, one pair goes on about 40 acres and that cow must have enough spark to protect her calf against predators and overcome challenges. Since temperament is heritable, he added that a cow’s calf needs some personality to compete for bunk space at the feedlot. He prefers females with a temperament score of 2-2.5.
Temperament affects reproduction in several ways. He shared data that heifers with higher temperament scores reach puberty later. Higher temperament scores correlate to higher cortisol levels. He shared that cortisol affects luteinizing hormone, so these heifers have a harder time ovulating.
In addition to puberty rates, pregnancy rates improve with lower temperament scores, and so do weaning weights. Cooke reported that cows with adequate temperament scores weaned a calf, on average, 30 pounds (lb.). heavier than cows with excitable temperaments.
While temperament is heritable, acclimation also plays a large role. In a study in which heifers were acclimated to human interaction three times a week for one month, the acclimated heifers reached puberty sooner than the control group of heifers. These acclimated heifers had decreased cortisol concentrations and hastened reproductive development, regardless of breed type. He granted there were no positive effects on cows due to acclimation. Acclimation works best with younger cattle.
Cooke spoke during Thursday’s ARSBC morning session focusing on health and well-being. Visit the Newsroom at www.appliedreprostrategies.com, which features comprehensive coverage of the symposium, to view his PowerPoint, read the proceedings or listen to the presentation. Compiled by the Angus Media editorial team, the site is made possible through sponsorship by the Beef Reproduction Task Force.
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