385 Awardee Talk: Impacts of temperament on productive and reproductive responses of Bos taurus and B. indicus females

Abstract

Abstract Temperament is defined as the fear-related behavioral responses of cattle when exposed to human handling. Our group evaluates cattle temperament using: 1) chute score: 1 to 5 scale that increases according to excitable behavior during chute restraining, 2) exit velocity: speed of an animal exiting the squeeze chute, 3) exit score: dividing cattle according to exit velocity into quintiles using a 1 to 5 scale (1 = slowest quintile; 5 = fastest quintile), and 4) temperament score: average of chute and exit scores. Subsequently, cattle are assigned a temperament type; adequate temperament (ADQ; temperament score ≤ 3) or excitable temperament (EXC; temperament score > 3). Our group associated these evaluation criteria with reproductive responses of Bos taurus and B. indicus-influenced females. Cattle classified as EXC had greater (P ≤ 0.04) plasma cortisol vs. ADQ during handling, independent of breed type or parity. Both B. taurus and B. indicus cows classified as EXC had reduced (P ≤ 0.09) annual pregnancy rates vs. ADQ cohorts, resulting in decreased calving rate, weaning rate, and kg of calf weaned/cow exposed to breeding. Bos indicus heifers classified as EXC as yearlings had less (P < 0.01) growth rate and delayed puberty attainment by 15 months of age compared with ADQ heifers. Bos taurus heifers that reached puberty by 12 months of age had less (P ≤ 0.05) temperament score and plasma cortisol concentrations at weaning compared with heifers that did not reach puberty. Acclimating B. indicus-influenced and B. taurus heifers to human handling after weaning improved (P ≤ 0.02) temperament and hastened puberty attainment. Hence, temperament impacts productive and reproductive responses of beef females independent of breed type and parity. Strategies to improve herd temperament are imperative for optimal production efficiency of cow-calf operations based on B. taurus and B. indicus-influenced cattle.