Comparative analysis of the Romanov breed rams-producers' cryopreserved and freshly obtained sperm indicators

A systematic analysis of native and cryopreserved sperm obtained from breeders of the Romanov breed was carried out. The experiment was conducted on the basis of the Federal State Budgetary Institution "VGNKI" in 2020–2021. A total of 20 semen samples from 10 breeder rams were analyzed. The paper studies such parameters of identification of morphofunctional abnormalities of sperm of rams-producers, such as: mobility (normokinesis, hypokinesis), abnormal acrosome, pathological and abnormal forms of spermatozoa, DNA fragmentation index. The collection of genetic material was carried out in accordance with the requirements of regulatory documents. In a comparative analysis in terms of sperm motility, a deviation from the norm was found only in cryopreserved sperm, PPD = 13.2 %. When assessing morphology in cryopreserved semen in 7 sperm samples, more than 20 % of abnormal spermatozoa were detected. It was found that cryopreserved sperm contains 9 sperm samples with fragmented nuclear and mitochondrial DNA of spermatozoa. A decrease in the number of spermatozoa (oligospermia), a decrease in their general and translational mobility (asthenospermia), the appearance of a large number of spermatozoa with various abnormal forms (teratozoospermia) were revealed. The simultaneous presence of combined disorders (oligoasthenospermia, oligoastenoteratozoospermia) was quite often observed. Survey data on the methodology of veterinary and sanitary control of sheep semen do not give us an extended interpretation of the data under study. The Romanovsky staining method with eosin, azure-eosin, specified in the regulatory document, makes it difficult to conduct studies to identify damaged acrosomes and pathological forms of sperm. The proposed staining method using the "Diff-Quick" test kit makes it possible to speed up the staining time and get results more quickly. The acridine orange staining technique will reveal fragmented nuclear and mitochondrial DNA.