The relationship between measures of reproductive soundness, behavior, and hair testosterone concentrations during performance testing of bulls

Cattle temperament strongly impacts handlers’ safety, and testosterone is associated with cattle docility. Measuring hair testosterone may provide a non-invasive way to evaluate hormone concentrations. This study aimed to analyze chronic hair testosterone concentrations as a method of assessing relationships between endocrine, production, behavioral, and reproductive traits in bulls. Bulls (n=30) were separated into 3 pens for 84 days. Hair, serum, and data were collected at 28-day intervals. Dataloggers on each bull tracked total steps taken, total lying time, number of lying bouts, and lying bout duration from d 0-28 and d 56-84. Reproductive evaluation and carcass ultrasound took place on d 85. Correlation analyses were performed in SAS 9.3. Hair testosterone positively correlated with serum testosterone on d 0 (r=0.50, P