SOME FACTORS AFFECTING HEAT REGULATION MECHANISM OF JERSEY CATTLE AND BUFFALOES

Abstract

The present study was carried out on Buffaloes and Jersey cows under the prevailling environmental conditions of Assiut Governorate in Upper Egypt.

A total number of 152 pure Jersey and 92 water buffaloes were subjected to some series of field studies under certain conditions during winter and summer seasons from 1991-1992.

This study consists of three parts:

1 - Effect of seasonal and diurnal variations on some bodily reactions. 2 - Series of some field treatments of a limited time during summer season. 3 - Skin thickness and hair coat characteristics.

Results obtained could be summerized in the following:

1 - Species, seasons and day times had a significant effect (P<0.01 & P<O.OS) on RT, RR and ST. The lowest values were observed at 8 a.m. followed by 8 p.m. while the highest ones were obtained at 2 p.m. 2 - Comparing readings at 2 p.m. and 8 p.m. in summer, buffaloes can get rid of surplus heat more rapidly at the evening than did Jersey cows; indicating that the superiority of buffaloes to regulate their RT only in shade or at the evening. 3 - Values of PR was not affected by species or day times while season of the year had a significant effect (P<0.01) on such trait. It was significantly (P<0.01)