Seasonal Variation in Scrotal Circumference and Semen Characteristics of Black Bedouin and Black Bedouin-Damascus Crossbred Bucks

다국어 초록 (Multilingual Abstract)

The objective of this study was to evaluate monthly variation in semen characteristics in Black Bedouin and Black Bedouin${\times}$Damascus crossbred bucks. Twenty one Black Bedouin Goat bucks (BG) and 20 $F_1$ Black Bedouin${\times}$Damascus crossbred goat bucks (CB) were used in the study. Animals were 2 to 5 years old at the beginning of the study. Body weight (BW), body condition score (BCS), scrotal circumference (SC) and semen samples were evaluated monthly for all bucks. Body weight, BCS and SC differed according to month of collection (p<0.0001). Body weight and BCS were greater in the spring and summer months while SC reached their highest values during the autumn months. No differences were detected between breeds with respect to semen characteristics with the exception of ejaculate volume (p<0.05) and ejaculate appearance (p=0.053) which were greater in CB than in BG bucks. With the exception of ejaculate appearance, all semen characteristics were influenced by month of collection (p<0.05). Semen concentration and motility were better during the late summer and autumn months than during the spring. The percentage of abnormal spermatozoa declined from its greatest values in the spring to its lowest values in the autumn. Results of the present study show no effects of goat breed on most of the studied parameters. In general, most semen quality parameters were better in both breeds during the autumn than the spring months. Minimal variation in semen quality was observed between the summer and autumn months indicating the ability to use bucks for semen collection and for natural breeding during both of these seasons.