Cattle Review

Studies suggest that high cortisol resulting from lameness-associated pain decreases testosterone and disrupts spermatogenesis leading to decreased fertility. The objective of a study by Boakari et al (2022) (Theriogenology10.1016/j.theriogenology.2022.03.034) was to investigate the effect of lameness on cortisol and testosterone concentrations and breeding soundness examination of beef bulls. Bulls, 2 years of age or older, that presented for lameness, foot trim, and/or breeding soundness examination were enrolled. Blood samples were collected for cortisol and testosterone evaluation. A complete breeding soundness examination (BSE) was performed on all bulls. Subsequently, a complete lameness examination was performed, and limb/foot lesions recorded. A blinded evaluator used a lameness score of 1–5 to classify each bull as lame (>1) or not-lame (1). A total of 60 bulls were enrolled (34 with a satisfactory BSE and 26 with an unsatisfactory BSE result). Cortisol and testosterone were not different between the unsatisfactory and satisfactory group. The odds of a satisfactory BSE result were 4.40 times higher in not-lame bulls when compared with lame bulls. The authors conclude therefore that lameness is associated with an unsatisfactory BSE result in beef breeding bulls.