Behaviour temperament scoring in replacement heifers

Different scoring systems have included chute, gait, exit and flight speed

Due to consumers’ perpetual concerns regarding animal welfare, producers are displaying a renewed interest in the study of temperament behaviour in beef cattle. Producers are also searching for legitimate technology and data to keep them on the cutting edge in their operational and financial decisions. They face more and more studies out of universities and colleges, with results that may or may not be relevant to their personal operations.

These numerous studies have been largely theory with only small amounts trickling down to ground level of ranches and feedlot treatment barns. Expected progeny differences for docility have been widely used in purebred cattle operations specifically referring to potential herd sires and breeding stock. But their use has not greatly affected the rest of the livestock industry. However, the data is growing, encouraging producers to look again at these numbers, especially when it comes to selecting replacement heifers.

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The behavioural response of cattle to restraint and handling is an indication of temperament, according to researchers H.M. Burrow and N.J. Corbet. Variation in this trait has allowed the beef cattle industry to develop measurement techniques to associate temperament with various measures of cattle productivity.

Researchers have tested different scoring systems including chute, gait, exit and flight speed in recent years. Chute scoring is a numbered system grading an animal on the amount of struggling or aggression they portray in a chute. Usually a score of one means calm behaviour, while a four indicates violent struggling and extremely aggressive behaviour. The exit speed scores points based on the speed or gait of the animal as it leaves the chute, while flight speed measures the actual velocity of the animal at a designated distance from the chute exit.

Noted animal behavioural scientist Temple Grandin hypothesized that exit or flight speed tests are mainly a measure of fear. She proposed that they are more reliable than chute scores as fewer variables are involved. Chute scores can be greatly affected by using a squeeze and are subject to the variations in force used to subdue an animal.

In 2012, Grandin and M.D. Vetters documented just under 1,200 yearling steers using exit and flight speed scoring systems. They then moved 357 of those steers to a 140-day research feedlot trial where they were weighed and scored with both systems at 35-day intervals. They concluded that exit speed and flight speed systems were reliable indicators of temperament, along with having a direct connection to average daily gain.

R.D. Randle of Texas A&M University and J.F. Baker from the University of Georgia used two radar detectors placed six feet in front of a squeeze chute to gather exit speeds. They deduced that calves with higher exit speed scores had lower weight gains than calves with lower scores. They also agreed with previous studies that heifers generally scored higher in exit speeds, thereby confirming the need to note available data when selecting replacement heifers.

“Being a ‘good mother’ can be an important trait in a cow for protecting her calf, (but) being too aggressive can have negative consequences,” wrote Elaine Grings in a South Dakota State University (SDSU) fact sheet. “Excitable cattle tend to have high levels of the stress hormone cortisol in their blood, which can affect health, reproduction and growth in your cattle.”

Grings was an SDSU production specialist and is now a livestock research advisor for the U.S. Agency for International Development. In the fact sheet, she described an Oregon trial on reproduction effects of over 400 range cows using both a chute and exit speed scoring system. One group of cows was bred by artificial insemination and then cleaned up with bull service, while the other group was only bred by natural service. Approximately 25 per cent of the cows were scored as aggressive and finished with a pregnancy rate of 89 per cent. The adequate-temperament cows delivered a 95 per cent pregnancy rate.

In 2012, a combined study between Montana State University and Idaho State University attempted to compare chute and exit speed scores with physiological responses of body temperature, metabolites and hormones since exit speeds can be expensive and difficult to use. Researchers tested blood and saliva samples for cortisol and glucose and recorded body temperatures in a search for a biomarker which could improve objective temperament classifications.

They concluded that “in combination with exit velocity, simple objective chute-side measures of body temperature and plasma lactate using a simple digital thermometer and a hand-held meter (Lactate Pro meter), respectively, can potentially increase accuracy of temperament identification.” Their chute, exit and physiological testing data also indicated that heifers were more excitable than steers. They further stated, “Plasma lactate and rectal temperature have the potential to become strong objective measures to augment exit velocity in predicting an animal’s temperament.”

Numerous studies show cattle with excitable temperaments have a lower rate of gain and decreased growth rates resulting from high levels of stress hormones. They also display negatively affected carcass characteristics from stores of energy and protein. In addition, these higher-scored animals show more bruising and register more dark cutters.

It is accepted that both genetics and experience affect behaviour temperament but there is still much to be learned. In the yearling steer study mentioned above, Grandin asks whether temperament is fearfulness and behaviour based on experience. Why do flighty, excitable animals with moderate temperament influenced by their home ranch experience suddenly become highly agitated when they enter a novel environment such as an auction ring? It is impossible to complete all research studies handling individuals of a test group in exactly the same environment and conditions, thereby making all results suspect to a varying degree.

Still, there is substantial research and data to confirm usefulness in these scoring systems. Their potential and possibilities should not be dismissed when choosing replacement heifers.

Bruce Derksen worked in the livestock industry and specifically as a feedlot pen rider for over 30 years in Western Canada. He now lives in Lacombe, Alta. He writes about present-day feedlot and ranching practices, drawing on his numerous experiences in the industry.

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