ISSN: 0041-3216 (Online), 0041-3216 (Print)
Volume 69 Number 3
Gonadal and extragonadal sperm reserves in two breeds of mature zebu (Bos indicus) bulls in Ethiopia
Gonadal and extragonadal sperm reserves were determined in testicular and epididymal tissues obtained from 14 Small Highland Abyssinian Zebu (SHAZ) and from 15 Borana bulls slaughtered at the Debre Zeit abattoir. Bulls were mature and over six years of age. Mean (± SEM) body weight was 242.1 ± 3.8 and 278.1 ± 2.6 kg for SHAZ and Borana bulls, respectively. Mean scrotal circumference (SC) measurements were 27.9 ± 0.9, 30.7 ± 0.8 cm for SHAZ and Borana bulls, respectively. Both body weight and SC differed significantly (P < 0.05) between the two breeds. Paired testes and epididymal weights averaged 268.1 ± 23.0, 306.0 ± 27.2 g and 32.0 ± 2.0 and 33.9 ± 2.2 g for SHAZ and Borana bulls, respectively; the differences were not significant. Daily sperm production (DSP) did not differ between SHAZ (2.89 × 109) and Borana (3.67 × 109) bulls. Although extragonadal sperm reserves (ESR) did not differ significantly between the two breeds, corpus sperm reserves were significantly (P < 0.05) higher in Borana than in SHAZ bulls. Cauda epididymis contributed 58 and 51 % of the total epididymal sperm reserves. It was concluded that Borana bulls tended to have better reproductive potential than SHAZ bulls in Ethiopia.
Keywords: Zebu; Bulls; Sperm reserves; Breed