Physiological responses of the Holstein Friesian dairy cows raised under tropical conditions in Indonesia

Abstract

This study aimed to evaluate the physiological responses of the Holstein Friesian (HF) dairy cows raised under tropical conditions in Indonesia. Twenty-one dry-pregnant cows, approximately 7-8 months of pregnancy, 1-3 of lactation, 500-600 kg of body weight and 3-5 of body condition score were used for that purpose. The cows were fed twice daily in the form of total mixed ration (TMR) and given add libitum amounts of drinking water. Ambient temperature, relative humidity and temperature humidity index (THI) were recorded. Physiological responses i.e. rectal temperature (RT), pulse rate (PR) and respiration rate (RR) and heat tolerance coefficient (HTC) were also recorded. Descriptive statistics such as mean and standard deviation were performed using SPSS software. The results showed that both ambient temperature and THI reached their maximum (26.5±1.520C and 77.1±2.21, respectively) at 01:00 PM and minimum (22.6±0.510C and 71.8±0.90, respectively) at 3:00 AM. Contrarily, the relative humidity was highest (88.9±1.56%) at 03:00 AM and lowest (78.8±2.49) at 01:00 AM. The physiological responses (RT, PR and RR) and HTC increased in line with the increasing ambient temperature and THI. In conclusion, all of the HF cows are exposed to mild stress due to increasing ambient temperature and relative humidity.