The specific features of subcutaneous gadflies development in cattle in Northern Kazakhstan

Subcutaneous gadflies cause significant damage to cattle breeding, which consists in milk and meat productivity losses, raw hides spoilage and decrease in animal resistance. Reduction in livestock hypodermatosis in Kazakhstan does not imply the complete elimination of this disease. Considering high fertility of female gadflies and the fact that restoring the number of these insects to the initial level (EI>50%), is fast, and takes 3 to 5 years, the need for further anti-gadflies measures and increasing their effectiveness is obvious. It is particularly relevant in modern conditions of climate change and reduction in the number of these parasites in their habitats, as these factors determine the time of different phases and stages of parasites development. The study of subcutaneous gadflies ecology in cattle was carried out in 2016-18 in the North Kazakhstan region, which borders with the Tyumen region in the north and with the Omsk region in the East of the Russian Federation. As a result of the researches it has been established that the subcutaneous gadflies species composition in cattle in this district is represented by two species: Hypoderma bovis and Hypoderma lineatum, while the total number of parasites is dominated by Hypoderma bovis specimens and amount to 97.4%, while Hypoderma lineatum specimens represent 2.6%. Despite the systematic treatment of animals on the farms of the district, the number of these harmful insects continues to threaten prosperous farms in the neighboring regions of Kazakhstan and the Russian Federation. So, the extensiveness of invasion in the surveyed cows on average is 8.2%, with invasion intensity of 1.6 larvae per animal. In young cattle these indices are 18.6% and 3.7 larvae per animal, respectively. Under the influence of long- term elimination measures and climate change, which led to a decrease in the number of subcutaneous gadflies, phenological dates of passing different phases in the cycle of development by these parasites have been shifted to a later date by 10 days on average. In this regard, the optimal period of early cattle chemotherapy against hypodermatosis is from mid-September to mid-November. Spring inspection and decontamination of young cattle should be done in late April, and the same procedures in cows should be carried out 10 days later, respectively.