THERMAL CONDITIONED IN RESTING AREA OF FREESTALL FACILITIES AND ITS CONSEQUENCES ON PRODUCTIVE AND PHYSIOLOGICAL RESPONSES IN DAIRY COWS

Abstract

This work aimed to evaluate the efficiency of thermal conditioned in resting area offreestall facilities and its consequences on productive and physiological responses in dairy cows.Experimental period was 28 consecutive days of November 2003. Third dairy multiple cows withmean milk production of 20 kg.day-1. Treatments were: non-fan (NF), fan (F) and fan + misting (FM)in direction to animal bedding. Dry bulb temperature (DBT), air relative humidity (RH) and blackglobe temperature (BGT) inside and outside of facilities were measured every 15 minutes through aperiod of 24 hours. Milking was realized at 1, 9 and 17 hours and registering daily production.Animals were fed twice a day (10 and 15 hours) and amounts of offered and rejected feed were dailyregistered. Physiological data, as respiratory frequency (RF), rectal temperature (RT) and skintemperature (ST), were taken at 9, 11, 13, 15 and 17h. The RH was higher in NF (61.8%) and FM(61.8%) treatments than in F (60.3%). The facilities (F) where it was used had higher BGT (27.4C)in relation to NF (27.1C). Also, THI was higher in F (75.0) than in NF (74.5) and FM (74.3)treatments. In relation to physiological parameters, lactating cows of V0 treatment had lower rectaltemperature at 11, 13 and 17h. Respiratory frequencies and skin temperature were within normalvariation in all treatments. Higher feed intakes were observed in animals of NF (20.5 kg DM.day-1)and F (21.3 kg DM.day-1) treatments, but it did not increase milk productions.