Study on semen quality in relation to scrotal surface temperature gradient, testicular covering thickness and scrotal circumference in Murrah bulls

Abstract

Present study was carried out to evaluate the effect of scrotal surface temperature gradient, testicular covering thickness and scrotal circumference on semen quality in Murrah bulls. Murrah buffalo bulls (n = 18), were selected from Artificial Breeding Research Centre, ICAR-National Dairy Research Institute, Karnal, Haryana, for the present study. Testicular parameters viz. scrotal surface temperature (SST), scrotal circumference (SC) and testicular covering thickness (TCT) of individual bulls were measured. Temperature of scrotum (Proximal Pole Temperature, Mid Pole Temperature, Distal Pole Temperature, Right Epididymis and Left Epididymis) was measured three times a day per week during peak winter season. Semen quality attributes viz., volume, mass motility, non-eosinophilic sperm and sperm abnormalities of each ejaculate were evaluated. The TCT and SC were measured by using ultrasonography and measuring tape, respectively. The bulls were divided into three groups on the basis of scrotal surface temperature Gradient (SSTG) (Group I- ≤ 4 oC, Group II- 4.1- 6.8 oC and Group III- ≥6.9 oC) and into two Groups on the basis of TCT (Group I- 4.53-5.28 and Group II- 5.36-7.36 mm) and SC (Group I- 28-31 and Group II- 32-35 cm). Mass activity and non-eosinophilic sperm count was improved significantly (P<0.05) and head, midpiece, tail and total abnormalities were reduced significantly (P<0.05) with increase in SSTG. The significant (P<0.05) effect of TTC on sperm abnormalities was observed. Ejaculate volume and non-eosinophilic sperm count increased significantly (P<0.05) with increase in SC. In conclusion scrotal surface temperature gradient, thickness of testicular coverings and scrotal circumference significantly affected semen quality in Murrah buffalo bulls.