Effects of repeated electroejaculation on bull behavior and serum cortisol concentrations

Abstract Text:

Negative perceptions surrounding the use of electroejaculation for semen collection of bulls have led to animal welfare concerns. Therefore, objectives of this experiment were to determine impacts of repeated electroejaculation of bulls on behavior and serum cortisol concentrations. Angus×Simmental crossbred bulls (n = 23; average initial BW = 796 ± 160 kg) were electroejaculated once a wk for 10 wk. Bulls were blocked into 2 barns, each with their own handling equipment. Bulls were assigned temperament scores during loading, chute restraint, and electroejaculation (1 to 5 scale; 1 = most ideal, 5 = least ideal); and chute exit (1 to 3 scale; 1 = most ideal, 3 = least ideal). Vocalization scores (1 to 5 scale; 1 = no vocalization, 5 = more than 10 vocalizations) were assigned before, during, and after electroejaculation. Blood was collected from the tail vein following electroejaculation to measure cortisol concentrations. Handlers and bull order were consistent each wk. Behavioral data were analyzed with the GENMOD procedures of SAS with repeated measures. Cortisol concentrations were analyzed with the CORR procedures of SAS. Bulls became easier (P < 0.01) to load into the chute over time, initial score was 1.6 and final score was 1.1. Furthermore, bulls became less (P < 0.01) agitated while restrained in the chute over time, initial score 1.4 and final score 1.1. Vocalization scores before, during, and after electroejaculation did not differ (P ≥ 0.62) over time. Bull behavior during electroejaculation procedure and when exiting the chute after the procedure did not differ (P ≥ 0.49) over time. Serum concentrations of cortisol were not correlated (P = 0.12) to week. Behavior scores and serum cortisol concentrations either did not change or improved over time, suggesting repeated electroejaculation can be used to collet semen on bulls with no adverse effects on temperament or stress. Data collected from this study further implies animal welfare concerns surrounding electroejaculation procedure for semen collection are unfounded.

Keywords: behavior, bulls, electroejaculation