NORMAN — My family always told me crazy cows led to crazy ranchers. Because of this, we had a zero-tolerance policy for any member of our cow herd that acted silly more than once. When half-ton cows are aggressive or flip out over nothing, people get hurt, and there is just no place for them on the farm.
Now, according to Dr. Glenn Selk with Oklahoma State University, we have another good excuse to cull cows due to bad temperament. Producers who routinely breed cows artificially realize that cows that are unruly and nervous are less likely to conceive to artificial insemination.
Presumably the lowered conception rates were because they have been stressed as they are passed through the facilities and restrained while being synchronized and inseminated. Now it seems that cows with bad dispositions are less likely to conceive when mated naturally with bulls. University of Florida animal scientists recorded disposition scores over two years on 160 Braford and 235 Brahman x British cross cows. They wanted to evaluate the effects of cow temperament and energy status on the probability to become pregnant during a 90-day natural breeding season.
Cows were scored as 1 (calm, no movement) to 5 (violent and continuous struggling while in the chute). A pen score assessment was assigned as 1 (unalarmed and unexcited) to 5 (excited and aggressive toward technician). An exit velocity speed score was measured as the cows exited the working chute as 1 (slowest) and 5 (fastest).
An overall temperament index score was calculated by averaging the chute, pen and exit velocity scores. Blood samples were analyzed for cortisol concentrations.
Increased cow temperament score and elevated plasma cortisol concentrations both were associated with decreased probability of pregnancy, suggesting that excitable temperament and elevated cortisol concentrations are detrimental to reproductive function of cows.
These authors concluded that management strategies that improve cow disposition, enhance their immune status and maintain the cow herd at adequate levels of nutrition are required for optimal reproductive performance.
Heath Herje is an agriculture educator with the Cleveland County Cooperative
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