Microbiological tests of fresh bull semen collected at breeding establishment

Bacterial and fungal contamination of the semen collected in production environment largely depends on the sanitary conditions of its collection as well as on the bacteria carrier state in breeding bulls. Since antimicrobials contained in the diluent used during semen product cryopreservation do not allow an objective assessment of semen contamination, a microbiological testing of fresh undiluted bull semen was carried out at the AO «Krasnoyarskagroplem» breeding establishment to identify the contamination source. The isolated opportunistic microorganism cultures were tested for their susceptibility to antibiotics for the purpose of effective treatment of bacteria carriers. The experiment was performed at the Department for Epizootiology, Microbiology, Parasitology and Veterinary and Sanitary Expertise of the Institute of Applied Biotechnology and Veterinary Medicine of the FSBEI HE «Krasnoyarsk State Agrarian University» and at the Veterinary Laboratory of the AO «Krasnoyarskagroplem» in 2017 and 2018. Semen was collected in accordance with GOST 32222-2013 and tested for veterinary and sanitary parameters according to GOST 32198-2013. Isolated microorganism cultures were tested for their susceptibility to antibiotics with disc-diffusion method according to the Methodical Guidelines 4.2.1890-04 «Testing of microorganisms for their susceptibility to antimicrobials» using discs containing eight antimicrobials. Analysis of microbiological test results showed that semen was rejected for sanitary reasons at the breeding establishment due to isolation of the following opportunistic microorganisms: Pseudomonas aeruginosa (6.4% samples) and Proteus vulgaris (8.5% sample) in 2017 and Pseudomonas aeruginosa (2.4% samples) in 2018. Other test parameters (total microbial count, coliform count) were within admissible limits. № anaerobes and pathogenic fungi were detected. Four Pseudomonas aeruginosa isolates and three Proteus vulgaris isolates recovered during the test have demonstrated susceptibility to ciprofloxacin that can be used for etiotropic treatment of bulls identified as bacteria carriers

Bovine leukosis control measures

Bovine leukosis is one of the most common infectious diseases of farm animals, causing significant economic damage due to a decrease in production of livestock products, premature culling and slaughter of cows and servicing bulls. The disease needs special attention and control on behalf of the on-farm veterinarians and zootechnicians. The article briefly describes epizootic situation on bovine leukosis in the Russian Federation in 2004–2020. It also includes a report on the disease situation in “Sibirskaya Niva” LLC (the Irkutsk Oblast) for 2015–2021 and assesses effectiveness of health support and disease prevention measures taken on the farm. The paper gives a brief description of the agricultural establishment: its zoosanitary status as well as zootechnical, veterinary, therapeutic and preventive measures (disinsection, deratization, vaccination). Based on the data obtained, we found the ultimate cause of bovine leukosis on the farm: presumably, these were crossbred animals brought into the farm. In order to eradicate the disease, “Sibirskaya Niva” LLC has developed a plan on health support and disease prevention, which includes veterinary, zootechnical and economic measures. Thus, due to the actions taken from 2015 to 2019, the number of infected cows and heifers reduced by 6.42 and 2.78 times, correspondingly. At the same time, the overall number of infected animals decreased by 9.9%. Task-oriented measures taken by the state veterinary services made it possible to steadily reduce the number of infected animals by 2020. The comprehensive approach embracing the farm peculiarities has proven to be effective to quickly eliminate bovine leukosis, as the above-mentioned agricultural establishment exemplified it