TYROSINE PHOSPHORYLATION OF SPERM PROTEINS

Crossbred dairy cattle provide 27% of the total milk produced in the nation, which points out the importance of crossbreeding programme in India. Both male and female animal contributes equally to this condition but, male infertility is of major concern as a single bull is used to inseminate several thousands of cows. Further, in crossbred bulls, the incidence of poor semen quality and susceptibility of spermatozoa to cryodamages are very high. Recent evidence indicates that protein tyrosine phosphorylation (PTP) also occurs during cryopreservation and is associated with cryo-capacitation, a phenomena detrimental to sperm fertilizing potential. Simultaneous assessment of sperm functional attributes and PTP has helped in understanding the relationship of PTP with other important sperm functional characteristics thus the fertilizing potential. The present study confirms that proportion of post-thaw motile spermatozoa was significantly higher in above-average bulls, although every bull used in the experiment qualified the minimum requirement of 50% and above.