The present work aims to investigate adaptation of local Wahati sheep ( Farafra) and Wahati goats in the breeders' flocks, to summer heat stress of desert oasis in the New Valley , Egypt. The study involved , 9 flocks from ; El Dakhla, EL Kharga and El Farafra oasis . Total animals covered were 113 mature Wahati ewes and 100 mature Wahati does. Animals were exposed to summer heat stress (SHS) under solar radiation, from 12 pm to 2 pm in July 2018 and 2019. THI during exposure , averaged 101.8 and 103.8, respectively; indicating that animals were under severe heat stress.
Exposing the animals to summer heat stress, significantly increased their physiological body parameters. Rectal temperature (RT) increased by 1.00 C; where skin temperature (ST) increased by 9.5 and 9.00 C, in only two species, respectively. These can be attributed to high intensity of solar radiation under desert oasis conditions. The major changes with SHS were in the respiratory rate (RR) as the main mechanism practiced by desert sheep and goats to get rid of the extra heat load through respiration. Accelerating RR, was not sufficient to cope with the severe heat stress load, so animals practiced deep breathing (increase gas volume); which was more recognizable in sheep than in goats. Species variation in response to heat stress can be attributed, for a great extent, to differences in their body size and coat. The smaller the animal size, the lesser changes in their physiological body parameters with heat stress.