Grymak K. Biotechnological methods of improving the quality of a deconserved sperm of ram-sires and the fertility of ewes

Studies on the ukrainian carpathian mountain breed (UCMB), breed precos and genotype ? suffolk x ? precos found that ram-sires are able to produce sperm throughout the whole year under optimal feeding, care and maintenance conditions. It was also discovered that the period of seasonal activity and ram-sires breed significantly influences the sperm productivity and the deconserved sperm parameters. During the breeding season (August-October) compared with the non-breeding season (April-June), quantitative and qualitative indicators of freshly collected and thawed sperm were higher by 6,6 24,2 %, while the sperm fertility after the first insemination - by 3,7 4,7 %. The analysis of the sperm productivity indicators of the ram-sires under study found that those of UCMB sires were significantly higher during both periods. The advisability of adding 5 ?m reduced glutathione and 15 mg/ml bovine serum albumin to lactose-yolk-tris-citrate-glycerine extender is scientifically proved. This contributed to the increase in the activity of sperm after equilibration by 10,6 % (p0,01), after thawing by 11,0 % (p0,001), the sperm resistance to freezing by 6,0 %, acrosome preservation by 9,5 %, the sperm survival rate by 23,9 % (p?0,05), the absolute survival indicator by 21,8 % (p?0,05), kinetic parameters (VCL, VAP, VSL) by 14,3 %, 12,5 and 15,4 % (p?0,05 0,001) respectively, insemination of ewes from the first insemination - by 11,9 %, from all inseminations - by 3,7 %. Key words: ram-sires, ewes, sperm, cryoconservation, extender, sexual hunting, hormonal agents, stimulation, reproductive organs, insemination.