The artificial use of germ cells of genetcally superior bucks can enhance
the growth potential of goat population to meet the shortage of mutton meat in Pakistan for daily slaughtering, sacrificial events, skin, hair and goat milk too.
Beneficial use of superior germ cells can be made only when there is extension of life of germ cells for long periods, maintenance of motility of spermatozoa and increase in number of doses of ejaculate, for which an extender of choice has to be developed. Semen characteristics of forty ejaculates of bucks were evaluated. Pooled samples of ejaculates having motility estimates of at least 60% were used for evaluation. After washing of seminal plasma with physiological normal saline (20% ringer solution) and centrifugation at l000xg for 10 minutes to remove the sperm toxic factor Lecithinase-A. Pooled semen samples were extended in Tris yolk fructose citric acid (TYFCA), milk yolk (MY) and egg yolk citrate (EYC) extenders. Samples were extended using one
step extension at a ratio of 1:60 in such a way that each milliliter of semen contained 30x106 progressively motile spermatozoa. Finally extended semen samples were placed at 5°C and 37°C for evaluation of motility percentage after every 24 hours interval and livability (hours) and absolute index of livability o spermatozoa, respectively. Mean±S.E. values of ejaculates of bucks for volume, pH, mass motility, individual motility percentage, sperm cell concentration, live and dead percentage, sperm abnormalities was recorded and post-extension motility percentage at 5oC, livability (hours) and absolute index of livability of of' spermatozoa of pooled semen at 37°C was recorded. Significant differences were observed (P<0.01) in post extension motility percentage at 5°C, at all intervals except at 120 hours interval where deference vas non-significant (P>0.05) between milk yolk and egg yolk citrate extenders. Post extension motility percentage at 5°C was highest in TYFCA than MY and EYC e\tenders. Post extension livability (hours) at 37°C was significantly different among three extenders at a level of probability (P<0.05) but non-significantly different among three extenders at a level of' probability (P>0.01). Absolute index of' livability at 37°C shows significant differences (P<0.01) for all extenders under statistical analysis. Livability (hours) and absolute index of' livability was higher in TYFCA than MY and EYC extenders. Based on these results and effect of extenders on semen characteristics of Beetal Buck, Tris- Yolk-Fructose-Citric Acid was developed as an extender of choice for short term preservation of' semen of' Beetal Buck.