Effect of Temperature and Humidity on Heat Stress Responses in Vietnamese Yellow Cattle

http://www.fao.org/docrep/013/i1860e/i1860e.pdf

SUSTAINABLE IMPROVEMENT OF ANIMAL PRODUCTION AND HEALTH

Edited by N.E. Odongo, M. Garcia & G.J. Viljoen
Animal Production and Health Subprogramme
Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture,
Department of Nuclear Sciences and Applications,
International Atomic Agency, Vienna, Austria

Food and Agriculture Organization of the United Nations
Rome, 2010

Effect of Temperature and Humidity on Heat Stress Responses in Vietnamese Yellow Cattle
V.T.K. Thanh  & W. Shichang 

ABSTRACT
Four female cattle (local Yellow breed), eight months of age, were  fed a diet of 50% urea-treated and 50% untreated rice straw  ad libitum, with free access to water. The levels of ambient temperature/ relative humidity (RH) were random combinations of 25, 29, 35 and  39°C and 70, 80 and 90% RH, achieved in an experimental chamber  fitted with air conditioners, heaters and ultrasonic humidifiers. The treatments were based on the natural conditions which frequently  occur in an indoor animal house in Central Vietnam in summer. Feed  intake decreased linearly while water intake increased with increasing ambient temperature. Heart rate increased in direct proportion to the air temperature but was not affected by RH levels. Body temperature only increased when the chamber temperature reached  39°C and RH was 90%, while respiration rate increased when the ambient temperate exceeded 35°C. Measurements of HSP70 (heat
shock protein, a biochemical stress indicator) from leukocytes using  PCR showed that HSP70 was evident when RH reached 90% with an  ambient temperature of 25°C, or with an RH of 70% and an ambient
temperature of 39°C.
Key words: Yellow cattle, heat stress, physiology indexes, HSP70.