Effect of agro-climatic conditions on the incidence of brucellosis of reindeer in the arctic regions of Yakutia

Abstract

The spread of brucellosis in reindeer depending on agroclimatic conditions of their housing was studied. The experiment was conducted in Momsky, Nizhnekolymsky and Eveno-Bytantaysky districts of Yakutia in 2012–2019. It was shown that the annual air temperature for the studied period in all districts was higher than the norm by 1.1 ... 1.9 °С due to its more significant increase in the cold period (by 1.5 ... 2.8 °С) compared to the warm period (by 0.5 ... 0.6 °С). The highest temperature increase was registered in April (by 2.8 ... 4.4 °C) and November (by 2.2 ... 4.1 °C), in spring-summer period - in May (by 0.9 ... 1.7 °C), in July it was 0.2 ... 1.0 °С below the norm. The annual precipitation on the territory of the Eveno-Bytantaysky district changed slightly, and on the territory of the Momsky and Nizhnekolymsky districts increased by 40 and 70 mm, respectively. The incidence of brucellosis of reindeer, depending on the place (area) where reindeer are kept and weather conditions, ranged from 0 to 3.86% (coefficient of variation of 131%), fewer sick animals were in the Nizhnekolymsky district (0.20%), more – in Eveno-Bytantaysky (1.15%). There was a negative correlation (r = –0,19...–0,42) between the incidence of brucellosis in reindeer and the temperature during the cold months and the annual temperature, with the temperature of the spring-summer months - medium positive (r = 0,30...0,53) with a reliable level in July. In general, temperature had a greater effect on morbidity (r2 = 0.115) than precipitation (r2 = 0.092), but a significant inverse relationship (r = –0.48; r2 = 0.23) was found between annual precipitation sum and animal morbidity. In all months there was also a negative correlation between these indicators (r = –0.13...–0.41), except for April and August (r = 0.10 and 0.11, respectively). In winter months, this dependence was more significant (r = –0.30...–0.40) than in summer (r = –0.13...–0.27).