Resistance of Kalmyk cattle breed to high ambient temperatures of the highlands of the North Caucasus

Abstract

The purpose of the research is to establish indicators of heat resistance and study the growth of Kalmyk cattle youth in different natural, climatic, organizational and technological conditions in the highlands of the Kabardino-Balkarian Republic. The investigations were carried out in LLC «Dargan» (Chereksky district, in village Gerpegezh) and LLC «Malka» (Zolsky district, in village Malka) of the Kabardino-Balkarian Republic of the Kalmyk breed bulls during the period of grazing (from 7 to 12 months). The highest values of the heat resistance index and tolerance coefficient were recorded at the beginning of the grazing period in species of both farms, when the ambient temperature during the day was within comfortable limits for the species as a whole. Subsequently, the heat resistance indicators were decreased by the middle of the analyzed period of detention, which is explained by the temperature stress for the body of the experimental animals. However, temperature conditions and resistance were restored to their original values for them by the end of the experiment. Inter-farm divergences in growth intensity in age period of 7-9 months were 31 g (P<0.95), 9-12 months - 65 g (P<0.999) and for the entire period - 52 g (P<0.99). The largest absolute increase in live weight over the analyzed period was distinguished by bulls from LLC «Malka», which were under other conditions, recorded the lowest feed costs per 1 kg of live weight gain. Thus, the differences in the cost of energy feed units in comparison with individuals from «Dargan» LLC were 0.18, digestible protein was 11 g.