Influence of Modified 2-point Temperament Score on AI Pregnancy in Beef Heifers

Temperament is described as the reacting characteristics of cattle when exposed to human handling. Excitable temperament has been alleged to have detrimental effects on both production and reproduction parameters. The objective of this study was to evaluate the effect of temperament, determined by chute exit and gait, on artificial insemination (AI) pregnancy rates in beef heifers following fixed time A.I. The hypothesis was excitable temperament will lower AI pregnancy rates. Angus cross beef heifers (N=947) at eight locations were the subjects in this study. At the initiation of synchronization (Day 0), all heifers received a body condition score (BCS; 1=emaciated; 9=obese), and temperament score (0=calm; slow exit and walk); (1= excitable; fast exit or jump or trot or run). Heifers were synchronized with 5-day CO-Synch+ controlled internal drug release (CIDR) protocol. Blood samples were collected at both the instigation of synchronization and the time of AI for cortisol measurement. [...]