Stockmen know that wild, temperamental cattle present a danger to handlers, facilities and other cattle. They’ve also learned that cattle behavior can play a role in performance, health and carcass value, making selection for calmer cattle a worthwhile effort. At the Beef Improvement Federation conference this spring, Texas A&M University animal scientist Ron Randel, PhD, outlined methods for objectively measuring temperament in cattle and applying that information to genetic decisions. Although handling and environmental factors also influence cattle behavior, temperament is a moderately heritable trait. Several breed associations have developed EPDs for temperament, and genomics companies have identified genetic markers associated with temperament. For cow-calf producers, measuring temperament can be a useful tool in selecting replacement heifers, helping them avoid the most aggressive heifers that could pass that trait to future generations. Researchers have developed several methods for evaluating temperament. Randel notes that each method has some limitations, as temperament is a complex mixture of behaviors. Each, however, can be useful for meaningful measurements.
Docility score — The BIF guidelines include a method called a docility score or chute score. This involves catching each animal, ideally at about weaning weight, in a squeeze chute but without applying the squeeze. The 1-to-6 scoring system awards a score of 1 to animals that are docile, gentle and unexcited in the chute and a 6 to animals that become extremely aggressive when confined. Randel says this method has advantages in that it is easy to use in routine handling, and research shows the scores are correlated with other measures of temperament. The scores are not, however, correlated with cortisol levels in the blood, which indicate stress.
Pen score — Another method, also listed in the BIF guidelines, is a pen score. This involves placing a group of about five calves, also at about weaning weight, in a small pen, approximately 24 feet x 24 feet. Two observers approach the pen and rank calves on a 1-to-5 scale, with 1 indicating very calm and not excited by humans and 5 indicating very aggressive, excited and dangerous behavior. This method does require some additional handling, but the scores are positively correlated with cortisol levels and other measures of temperament.
Exit velocity — A third method is to measure exit velocity or flight speed as cattle exit the chute. This typically involves electronic triggers to record the time it takes each animal to travel a 6-foot distance upon leaving the chute. This method provides an objective measurement that is correlated with cortisol levels and other measures of temperament and can be used with calves as early as 3 weeks of age. The disadvantage is that it requires extra equipment and is not as convenient as chute scores or pen scores for commercial producers.
For more information on selecting and developing replacement heifers, visit MoreCowsNow.com.