Libido test scores, body conformation and testicular traits in Boer and Kiko goat bucks

摘要

Independent of whether natural mating or artificial insemination is used for breeding, libido (sex drive) is evidently crucial to reproductive competence in all male meat animal species. Breeding goat bucks vary in their levels of libido; therefore, there is a need for the development of a predictive standardized test for estimating sex drive. The objective of this study was to evaluate libido (sex drive) and examine its relationship to body conformation (body condition scores-BCS, chest girth-CG, height at withers-HTW, body length-BL, body weight-BTW) and testicular traits (scrotal circumference-SC and testicular consistency-TC) in two breeds of goat bucks. Eight sexually mature Boer and Kiko bucks (four from each breed) were trained to mount and service a teaser buck. Results show that reaction time in seconds did not differ significantly (P>0.05) between breeds (65.1 ± 11.1 vs. 49.2 ± 7.1 seconds for Boer and Kiko bucks, respectively. Mounting enthusiasm (total mounts), although not significantly (P>0.05) different between the two breeds, appeared to be more evident in Kiko bucks. Mean values for body conformation and testicular traits were 4.25 ± 0.47 vs. 3.43 ± 0.21 (BCS), 51.2 ± 7.1 vs. 45.1 ± 3.6 kg (BTW), 64.1 ± 3.0 vs.65.1 ± 2.2 cm (HTW), 62. 8 ± 5.7 vs. 60.9 ± 3.2 cm (BL), 27.3 ± 3.3 vs.22.8 ± 1.03 (SC) and 4.25 ± 0.25 vs. 3.75 ± 0.23 (TC) for Boer or Kiko bucks, respectively. A highly significant correlation coefficients were established between scrotal circumference and reaction time (r = 0.555, P 0.05) correlated to any body conformation traits (RT vs. BWT, r = 0.048; RT vs. BCS). This study has demonstrated for the first time a relationship between scrotal circumference (testicular size) and libido in male meat animal specie.