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How docility impacts conception rates

Producers working heifers and cows through the chute for breeding would benefit from taking chute scores to record and identify disposition issues.

In our seedstock business, we are seeing an increased interest in buyers who select for two common traits — disposition and calving ease.

I think these priorities correlate with the trend that the average age of the rancher is nearing 60 years old. With age comes wisdom, and I always think it’s a good idea to avoid bad temperament and dystocia problems whenever possible.

In addition to seasoned wisdom, I believe many of these older producers may not have the energy and agility to tolerate ornery cows and calving problems like they did in their 20s and 30s.

And while we shouldn’t base our purchasing decisions on single-trait selection, I do believe that docility impacts everything from feed efficiency to pregnancy rates to carcass quality to the well-being of the producer.

A recent article written by Glenn Selk, Oklahoma State University emeritus Extension animal scientist, highlights exactly how cow disposition affects pregnancy rates.

Selk writes, “Now we have another good excuse to cull cows due to bad temperament. Producers that 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 working facilities and restrained while being synchronized and inseminated. Research trials indicate, even in the serenity of a natural breeding pasture, cows with bad dispositions are less likely to conceive when mated with bulls.

“Louisiana State University researchers presented data about the impact of temperament on growth and reproductive performance of beef replacement heifers. They used crossbred heifers that were evaluated for ‘chute score.’ Heifers were scored as 1= calm, no movement to 5= violent and continuous struggling while in the working chute and exit velocity.

“Exit velocity is a measurement of the speed at which the heifer would travel as she exited a working chute. ‘Slow’ heifers (presumably more docile) were heavier at breeding time and tended to have a higher body condition score. Pregnancy rate did not significantly differ between slow, medium, and fast heifers when all crossbreds were considered,” Selk says.

“However, it was interesting to note that pregnant Brahman-Hereford F1 cross heifers tended to have lower exit velocities (at both weaning and at the end of the breeding season) than their counterparts that failed to become pregnant. These researchers concluded that some important relationships between growth, reproduction and temperament may exist in beef replacement heifers.

“University of Florida animal scientists recorded disposition scores over two years on 160 Braford and 235 Brahman x British crossbred 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 working chute. Also, a pen score assessment was assigned as 1= unalarmed and unexcited to 5 = very excited and aggressive toward the 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 score, pen score and exit velocity score,” he says.

“Blood samples were analyzed for cortisol concentrations. Cortisol is a hormone released when mammals are stressed or excited. Increased cow temperament score and elevated plasma cortisol concentrations both were associated with decreased probability of pregnancy.

“These results suggest that excitable temperament and the subsequent elevated cortisol concentrations are detrimental to the 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.”

Selk’s article is worth noting as producers prepare to artificially inseminate replacement heifers and cows in the weeks to come.
For myself, this article is timely as we have plans to place CIDRs in our replacement heifers this week as we follow a synchronization protocol for timed artificial insemination.

As each heifer works through the chute, I will be taking notes on her disposition, and I think the aforementioned notes of including a chute score, pen score and exit velocity score will give us a good indication of any culling decisions we need to make. We’ll also be able to note any differences in sires and perhaps correlate any disposition trends to specific genetic lines.

Focusing on disposition pays, no matter what your operation’s goals are. Working with mean, spooky or ornery animals is dangerous, costly and limiting. Pay attention to this trait and reap the rewards.

The opinions of Amanda Radke are not necessarily those of or Farm Progress.

TAGS: Farm Life
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