Influence of non-genetic factors on semen characteristics of Malabari bucks

Abstract

A study was designed to analyse the effect of non-genetic factors on semen quality traits of Malabari bucks maintained at Frozen Semen Bank, Madras Veterinary College, Chennai, Tamil Nadu. Data on 675 ejaculates collected from four Malabari bucks spread over six years were used. The overall least-squares means for semen volume, sperm concentration, mass activity, initial sperm motility, pre-freeze motility, post-thaw motility and number of frozen semen doses per ejaculate were 0.81±0.01 ml, 3144±17.24 million per ml, 4.80±0.02, 79.60±0.00%, 76.31±0.00%, 35.16±0.00% and 27.16±0.59 doses, respectively. The bucks had significant influences (P<0.01) on all the traits. Season had highly significant influence on semen volume, sperm concentration, initial sperm motility, post-thaw motility, number of doses per ejaculate (P<0.01) and pre-freeze motility (P<0.05). Winter season was found to have the highest semen volume, post-thaw motility and number of doses per ejaculate, whereas initial sperm motility was highest in summer and sperm concentration and pre-freeze motility in south-west monsoon. The effect of ejaculate number was significant on post-thaw motility (P<0.01), sperm concentration and pre-freeze motility (P<0.05). Among ejaculates, significantly higher sperm concentration, pre-freeze and post-thaw motility were observed in second ejaculates. The semen samples obtained during winter season and in second ejaculate were superior in seminal characters and more suitable for cryopreservation.