Studying the biological completeness of sperm in semen with bacterial contamination

The aim of the study is to investigate the relationship between bacterial contamination of bull semen and the biological value of spermatozoa, as well as reproductive performance. The object of the study was Holstein bulls (n = 17). The material for the study was frozen-thawed semen of bulls in the amount of 61 samples. Microbiological studies of sperm doses were carried out using standard nutrient media in accordance with GOST 32222-2013. The total number of microorganisms was calculated by the number of grown colony-forming units (CFU/ml) in 1 cm3, with subsequent determination of their morphological properties. Sperm motility and morphology were determined using the Argus CASA program. The state of DNA in spermatozoa was studied by the acridine orange test (AO test) using a fluorescence microscope. The study revealed a high positive correlation (r = +0.940**) between the number of microorganisms in sperm and pathology in individual sperm segments. Analysis of variance confirmed a statistically significant effect of the number of microorganisms on sperm morphology F = 123.2 (p=0.000). The correlation relationship between the fragmentation index and the content of microorganisms has a high value (r = +0.965**). Sperm motility negatively correlates (r = -0.768**) with the number of microorganisms (CFU/ml). In the presence of Mycoplasma spp in the samples, the number of cows with fruitful insemination was 35.5 % due to reduced motility, morphology and high fragmentation of sperm DNA (58 %). Sperm motility in samples containing Mycoplasma spp averages 24.5 %, while in samples without these microorganisms it is 48.9 %. Thus, it can be assumed that the presence of Mycoplasma spp in samples and high bacterial contamination rates lead to to lower reproductive performance in bulls.