Biological indicators of hybrids sperm derived from crossing of domestic sheep with Yakutian snow sheep

Abstract

Interspecies hybrids show benefits in breeding but frequently suffer from reduced fertility. The aim of the study was to determine the fertility of male ovchubuks hybrids with assessment of biological parameters of sperm. Two male ovchubucks of the first generation were studied. Both animals were at the age of 1.5 years, live weight were 65 and 69 kg. Evaluation of the ejaculate reproductive ability of the hybrids was performed by studying of its reproductive characteristics. Characteristics such as ejaculate volume, sperm count, fast and progressive motility and average mobility rate were measured in fresh undiluted sperm. Sperm quality was examined using a Sperm Fertility Analyser SFA-500-2. 4 samples of ejaculate were taken from male hybrids, 1 time per day for 4 days. The volume of ejaculate was 1.8 to 2 ml, which is lower than the standards for stud rams. This is may be due to the young age of objects that have not yet reached physiological maturity. Sperm count in animal No. 2 amounted to 428 million per ml, what is slightly higher than animal's No. 1 sperm count. However, animal No. 2 has only 16.5% of spermatozoa with fast motility, while in animal No. 1 about 40% of spermatozoa are highly motile. In addition, in animal No. 1 progressive motility is observed in 61% of spermatozoa, which is 22% higher than in animal No. 2. The average speed of sperm motility is also higher in hybrid No. 1. These results can be explained by the fact that male No. 2 had pneumonia at the age of 6-7 months, which may have affected his reproductive efficiency. In general, despite the slight difference, the sperm of both male hybrids is qualitative, what is indicating their fertility. Hybrid males were mated with domestic sheep to produce second generation offspring. As a result, 94 sheep were inseminated. 60 (63.8%) hybrids of the second generation were obtained, which indicates fertility of the first generation hybrids. The results obtained on the assessment of sperm allow us to conclude that ovchubuks hybrids are capable of producing quality offspring.