A Comparative Study of Fresh and FrozenThawed Semen Quality in Relation to Fertility of Black Bengal Goats

Semen from six adult male Black Bengal goats (Capra hircus) was collected to compare the fresh and frozen-thawed semen quality and investigate its relationship with the fertility. Each collected samples was divided into two parts: One part of semen was used as fresh and another part was filled into 0.50 ml straws, sealed, cooled (5 ?C) and equilibrated for freezing. In both cases, semen was diluted with commercial Triladyl diluent (a Tris based diluter). The motility and morphology of fresh and frozen-thawed semen was subjectively evaluated by one operator. It was revealed that motility and sperm abnormality of the frozen semen differed significantly (P < 0.05), but differed insignificantly in fresh semen between males. Besides these, fresh and frozen-thawed sperm motilities also differed significantly (P < 0.01) between males which varied from 70.83±1.54 to 74.23±1.59% and 44.17±2.39 to 52.31±1.08%, respectively. A significantly (P < 0.01) higher sperm abnormalities was observed in frozen-thawed semen (11.18±0.42 to 16.55±0.09%) than that of fresh semen (8.82±0.24 to 9.71±0.52%). Cervical inseminations were performed with fresh and frozen-thawed semen in 997 and 1004 female goats, respectively, both at Nucleus Breeding Flock (NBF) and four project areas. Fresh semen showed significantly (P < 0.01) higher kidding rates (59.8%) than that with frozen-thawed semen (43.9%). The motilities of fresh and frozen-thawed semen were positively corre-lated (0.526 and 0.987; P < 0.01), whereas the proportion of morphologically abnormal spermatozoa was negatively correlated (-0.530 and -0.776) with fertility of Black Bengal goats. Males with a higher motility and lower proportion of abnormal spermatozoa provided better fertility.