The Fertility Of Ewes Inseminated With Diluted Ram Semen Either In Tris Or In Semi-Skimmed Milk

Preliminary tests showed that the motility and live percentages of ram ,spermatozoa were significantly (P0.05) lower for semen samples were diluted in citrate buffer than semen samples in either tris buffer or semi-skimmed cow milk. This study was carried out to compare the applicability of two type of diluents, either tris or milk, for liquid storage of ram semen under Iranian fann conditions. Semen was collected from three fat - tailed breed of Moghani rams by the use of an artifical vagina in Animal science Research Institute, Karaj, Iran. After visual appraisal of collected ram semen, suitable samples were pooled and divided into two portions. Each portion was diluted randomly with one volume of either tris buffer or sterilised and homogenised semi-skimmed cow milk at 30 QC and cooled to 5 QC for further assessment and use. Fourty Moghani ewes were syncronised by daily intramuscular injection oj 10 mg progesterone for 12 days. Ewes on oestrus were marked by teaser and inseminated cervicaZly 54 hours after the last progesterone injection using 0.20 ml semen containing 200*106 spermatOzoa through EGO-cervical approach. The non-return rates for ewes were recorded when they had not return to oestrus and been marked by the rams within 34 days of artifical insemination. Means (SEM) of progress linear motility percentages of spermatozoa in tris or milk diluent at 0,4,8 and 12 hours of incubation were 83.7(0.3) and 82.7(0.3); 65 and 65.7(0.9); 50 and 51; 36.7(0.7) and 33.7(0.7) respectively. Differences between two diluents were not signficant (P":'0.05). Percentages of non-return rates and lambing of inseminated ewes were 80(16/20) and 65(13/20) when semen was diluted in tris; 75(15/20) and 55(11/20) when semen diluted in semi-skimmed milk. Chi-squre analysis showed that the effect of two types of diluents on the lambing rates of inseminated ewes was not significant (P0.05). In conclusion, artifical insemination is applicable in Irainian sheep farming and also semi-skimmed cow milk can be used instead of tris for ram semen liquid storage.