Semen characteristics of local breeder cocks in the Sahel region of Nigeria

Semen characteristics of local cocks (60.9 ± 10.6 weeks old) in the Sahel region of Nigeria were recorded from May to September 1998. Mean values (± SD) were: semen volume 0.28 ± 0.14 ml, sperm concentration 2.26 ± 1.08 x 109 sperm/ml, total sperm count 0.64 ± 0.44 x 109 sperm/ejaculate, percentage of live spermatozoa 86.6 ± 8.4%, individual motility 73.9 ± 0.2%, pH 7.4 ± 0.2, and abnormal spermatozoa 11.6 ± 8.5%. Sperm concentration, total sperm count and semen volume were positively correlated (r = 0.25, 0.24 and 0.16, respectively) to the individual motility of the spermatozoa. The percentage of abnormal spermatozoa tended to decrease as the number of either motile or live spermatozoa increased (r = -0.42, r = -0.30). Significant (p < 0.05) variations in semen characteristics were observed between the cocks within the rainy season. Sperm concentration increased from May and peaked in August. The frequency distribution of the semen volume was bimodal with values of 0.13 and 0.38 ml. There was a positive correlation between the semen volume and the total sperm count, which suggested that the sperm output of the local cocks might be improved through selection for higher semen volume (0.38 ml).