Temperament and Stress Effect
Beef Cattle Performance
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Douglas Landblom
DREC Beef Cattle and Integrated Systems Specialist
Dickinson Research Extension Center
Office: 701-456-1109; Mobil: 701-690-8245
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Managing temperament in beef cattle is an important issue that needs continuous surveillance and monitoring, because of the negative effects on reproduction, health, feed intake, average daily gain, growth, and carcass quality. The negative expression of stress in cattle is the behavior response to fear brought on by human handling. Cattle that become excitable have their well being upset and are not able to cope with human handling, which is classified as “stress”. An animals’ adaptation to stress is controlled by glucocorticoid hormones synthesized in the zona fasciculata tissues of the adrenal cortex and cortisol is the predominant hormone associated with stress (Murray, et al. 2000). Comparing calm cattle to excitable cattle, research has shown that excitable animals have elevated levels of cortisol in circulating blood.
Stress and Body Weight Gain
Steers and heifers that are more excitable have greater levels of circulating plasma cortisol. Cattle that are more temperamental react negatively to external stimuli in the feedlot by spending less time eating. Reduced time eating leads to reduce feed dry matter intake and metabolic repartitioning consumes energy that would normally be involved in tissue accretion. Thus, excitable steers and heifers under feedlot conditions have reduced average daily gain and gain to feed efficiency (Cooke, 2014).
Stress and Meat Quality
Excitable temperament also has a negative effect on carcass weight and meat quality. Carcass weight can be reduced and a greater number of dark cutters have been reported. Measurements of cattle with elevated levels of cortisol have muscle tissue that is less tender and have a greater tendency for muscle bruising.
Reproduction and Stress
Unlike animals reared in environments where there is continual contact with humans, cattle reared extensively under range conditions or those that experience minimal exposure to human handling easily become more excitable when handled for calving, branding, weaning, and shipping. Brandao and Cooke (2021) classified cows for production and reproduction based on excitability scores ranging from 1 to 5 (chute and exit velocity) as adequate temperament (≤ 3) or excitable (≥ 3). Excitable cows had reduced pregnancy, calving, and weaning rates, and reduced pounds of calf weaned per cow exposed. In a separate investigation, Cooke and co-workers (2019) evaluated growth, plasma cortisol concentration, and pubertal attainment in beef heifers and reported that puberty attainment and weight at puberty were reduced among excitable heifers. Efforts to evaluate acclimation to handling compared to no-acclimation revealed that heifers acclimated to human handling attained puberty at an earlier age. Acclimating heifers at an early age to human handling is paramount to producing heifers that will subsequently become easy handling stock cows. Acclimating heifers to human handling requires cattlemen to be in and amongst heifers frequently for feeding supplements, walking through them often, and handling for weaning weight measurement, BANGS vaccination, shipping and other operations on a specific ranch. Routine handling allows the cattleman an opportunity to identify less calm individuals that should to be marketed as feeder cattle and not retained for replacements.
Docility in beef cattle is a moderately heritable trait equaling 0.37. This is the bull buying season. In addition to the myriad of production traits listed in bull sale catalogs to consider, cattlemen that need to infuse greater docility into their cow herds are encouraged to review reference sire EPD values for docility, accuracy, and the percentile rank within the breed of interest. For example, reference sire A has a docility value of +21, an accuracy of 0.69, and ranks in the top 30% of the breed whereas reference sire B has a docility value of +24, accuracy of 0.51, and ranks in the top 20% of the breed. Comparing these two reference sires to reference sire C that has a docility value of +17, accuracy of 0.50, and does not rank in the top 35% of the breed, bulls from reference sires A and B would be a better choice to make genetic docility improvement assuming all other EPD traits are similar for sires A, B, and C.
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