Abstract:
The semen quality during the low (May-July) and the peak (September-November) breeding seasons in 18 Nili-Ravi buffalo bulls varying in age from 3 to 15 years was studied. Ejaculatory volume was higher (P < 0.05) in adult (3.03 ± 0.13 ml) and old (2.86 ± 0.13 ml) than young (2.51 ± 0.11 ml) bulls and during the low (3.44 ± 0.11 ml) than the peak (2.57 ± 0.90 ml) breeding season. Mass activity of semen collected from bulls of 3 age groups differed significantly and was higher (P < 0 .05) in the peak (2 .27 ± 0.09) than the low ( 1.49 ± 0.08) breeding season. Sperm concentration did not differ among bulls of three age groups and between the two seasons. Total sperms per ejaculate were higher (P<0.05) in semen collected from audit (3.49 ± 0.22 billions) and old (3.11 ± 0.23 billions) than young bulls (2.77 ± 0.18 billions) and in the low (3 . 38 ± 0.11 billions) than the peak (2.87 ± 0.17 billions) breeding season. Higher (P < 0.05) percentage of motile spermatozoa was seen in ejaculates collected from young (60.69 ± 0.77) and adult (62.50 ± 0.78) than old (58.16 ± 0.76) bulls and during the peak (62.35 ± 0.66) than the low (58.56 ± 0.59) breeding season. Percentage of dead spermatozoa was higher (P<0.05) in semen collected from old (14.57 ± 0.74) than young ( 13.96 ± 0.98) and adult (12.04 ± 0.67) bulls and in the low ( 14.30 ± 0.57) than the peak (12.74 ± 0.75) breeding season.
Ejaculates collected from old bulls (14.29 ± 1.03%) had higher (P < 0.05) number of abnormal spermatozoa than those from young 13.02 ± 0.85%) and adult (12.22 ± 0.58%) bulls and in the low (13. 74 ± 0.61%) than the peak (11. 94 ± 1.61%) breeding season.
