Study on effect of hair coat color on various reproductive attributes of Cholistani service bulls

The objective of the present study was to assess the possible effect of hair coat color on various orchidometric, seminal and andrological attributes of black-coated and brown-coated Cholistani service bulls. Adult Cholistani bulls (n= 8) were grouped as black-spotted (n= 4) and brown-spotted (n=4). Semen collection was performed once weekly (2 ejaculates/collection) using artificial vagina (AV) throughout the study period (October-May). Semen samples were evaluated for various physical attributes. Body weight and orchidometric attributes of the bulls were attained using calipers. Blood sampling was performed twice weekly and serum testosterone level was deduced through automated analyzer. The scrotal circumference, Scrotal Skin Fold Thickness and Paired Testicular Volume were significantly higher (P<0.05) in black-spotted Cholistani bulls as compared to brown-spotted bulls. Similarly, the ejaculatory volume (5.8±0.1 mL) and individual sperm motility (63.3±1.4%) were significantly higher (P<0.05) in black-spotted bulls. Percentage of live spermatozoa, and spermatozoa with normal morphology and acrosome was also higher in black-spotted bulls though statistically non-significant (P>0.05). Amongst post-thaw seminal attributes, percentage of live spermatozoa, and spermatozoa with normal morphology and acrosome were significantly higher (P<0.05) in black-spotted bulls. Similarly, serum testosterone level in black-spotted Cholistani bulls (6.9±0.3 ng/mL) was significantly higher (P<0.05) compared to brown-spotted bulls (5.4±0.3 ng/mL). The black-spotted Cholistani service bulls showed substantially better orchidometric and seminal attributes allied with higher serum level of testosterone.