STUDIES OF RECTAL TEMPERATURE, RESPIRATORY RATES AND HEAT TOLERANCE IN CATTLE IN THE HUMID TROPICS

The rectal temperature and respiratory rates of German Brown, Friesian, German Brown/Friesian crosses, N'Dama and German Brown/N'Dama (BN) crosses were studied with a view to establishing baseline data for cattle in the humid tropical environment of Nigeria. Mean morning (38·62°C) and late afternoon (39·19°C) rectal temperatures for the various breeds were found to differ significantly (P<0·01). However, general breed differences as well as differences between heifers, milking cows, bulls and calves were not significant. Respiratory rates (counts/min) were also significantly higher (P<0·01) in the afternoon than in the morning and appeared related to changes in atmospheric temperature and relative humidity. Breed differences in respiratory rates were also significant, being within the range 17 to 34 in N'Dama, 24 to 43 in BNs and 29 to 51 in the German Brown and Friesian. Heat tolerance indices were very high (89 to 91) for all the breeds studied but showed that the Friesian and German Brown were less heat tolerant than the BNs, and the N'Dama and White Fulani. The results indicate the need to consider diurnal changes in rectal temperature and respiratory rates in the use of these parameters for clinical diagnostic purposes. © 1979, British Society of Animal Science. All rights reserved.