Abstract
Arctic and northern latitudes are rarely used in animal husbandry, meanwhile, wild species of animals that are best adapted to the harsh climate successfully live in these territories. The aim of the study was to obtain new breeding forms in sheep using assisted reproductive technologies. Domestic sheep of the Buryat Coarsewool and sperm from 4 Siberian bighorn sheep of the Yakut population (Ovis nivicola lydekkeri) were used. Methods of postmortal removal of viable semen from epididymal aspirate and also the composition of a newly created extender for freezing epididymal semen have been developed. Thirteen sheep were inseminated using laparotomy. Sheep in estrus were identified by a test ram. The viability of the semen is influenced by the time interval from the moment of death to the removal of the semen from the epididymal aspirate. The temperature of the environment in which the testicles were kept before the semen removal also affects the final quality of the sperm. Thus, the highest viability of epididymal semen was observed at t = + 4°C when removed within 2 hours after the ram` death. As a result of research, the optimal composition of the extender was developed from test solutions of different compositions. The viability of spermatozoa for the extender was 25–30% higher than in others. Since the fertilizing properties of epididymal semen are lower than that of ejaculated semen, we used the intratubal insemination method. As a result, 8 hybrid F1 offsprings (1/2 domestic sheep x 1/2 wild bighorn sheep) were obtained, which can be kept year-round in winter pastures in the conditions of extremely low temperatures.
Disease and secondary sexual traits: effects of pneumonia on horn size of bighorn sheep