Оценка клинического состояния и способности к терморегуляции бычков чёрно-пёстрой и симментальской пород и их двухтрёхпородных помесей

The research-productive experiment purposed to study the productive and biological peculiarities of Black-Spotted and Simmental bull-calves and their doubleand triple-cross hybrids has been carried out in the APC (agricultural productive cooperative) and collective farm «Oktyabr», Orenburg region. Bull-calves of 6-months age were kept on feedlots under covered yard system. Deep irremovable litter was provided for animals’ rest and barrow was made in the range-grazing yard. The clinical state of animals and their thermo-regulative abilities were studied. The data obtained indicate that the clinical parameters of bull-calves were greatly dependent on the season and day time: the rise of body temperature, breathing and pulse rate in summer and increase of the above indices in the day time. The optimal indices of the animals’ general physiological condition were observed in Simmental bull-calves, the double-cross hybrids were second after them and the triple-cross hybrids occupied an intermediate position. The pure-bred Simmental bull-calves showed the least coefficient level of adaptability and they were distinguished by the maximum level of tolerance. In spite of the fact that double-cross and triple-cross hybrids were inferior by adaptation plasticity to Simmentals of the same age they are recommended to be bred under the conditions of the sharp continental climate.