¹Animal Research Center, National Research and Innovation Agency, Bogor 16911, Indonesia

*Email: peni.wahyu.prihandini@brin.go.id

Physiological conditions is one factors that can affect growth of cattle. The study aimed to determine the physiological responses of several beef cattle breeds that are reared in Beef Cattle Research Station (BCRI), Grati District, Pasuruan Regency, East Java Indonesia, was carried out by measure temperature, humidity, Temperature Humidity Index (THI), rectal temperature, respiration frequency, Head Tolerance Coefficient (HTC) and heart rate of 159 cows consisting of Ongole crossbred (PO), Madura, Bali, Jabres, Galekan, Rambon, Belgian Blue x PO crossbred, PO x Bali (POBA) crossbred which were observed during 4 months in individual cages. Data were analyzed descriptively. The temperature and humidity of the cage during the observation ranged from 25-34.12°C and 54.88-84.27%, respectively. The average of rectal temperature, respiration frequency, and heart rate were 37.76-39.30ºC; 20-54 times/minute; and 65-92 times/minute. The average of THI and HTC were 74.92-84.97 and 1.81-3.34. It was concluded that several breeds of beef cattle in BCRI has mild to severe heat stress, high heat tolerance, respiration rate, and heart rate but this condition does not cause production problem.