Twelve adult females of each of Abou-Delik sheep and Saladi goats raised at
Hederba Research Station (in the extreme south of the eastern desert of Egypt ). were
divided into three equal groups (each 4 sheep: 4 goats). The first group was standing
outdoors just inside wire-fenced pen and watered once every day as control. The
second group was enforced to walk 12 km from 09.00 hr. to 15.00 hr. and watered daily.
The third group walked the same distance. at the same time, and watered once every
48 hours for consecutive two cycles (each 2 days). After the end of the treatments,
animals were left for recovery in their pens for extra two days. This study aimed at
studying the adaptive physiological mechanisms that enabled such animals to
withstand the walking stress and water deprivation during grazing under hot desert
conditions. In this respect. blood samples were collected from all animals to determine
some hematological parameters (hematocrit, hemoglobin concentration, red blood cells
and white blood c ells counts in addition to hemoglobin indices ( mean corpuscular
volume. mean cell hemoglobin and mean cell hemoglobin concentration). Some blood
biochemical measures in terms of plasma proteins, glucose, urea, creatinine, lactate
dehydrogenase and transaminase enzymes (aspartate and alanine
aminotransaminase ) were also determined. Results revealed that hematocrit % , hemoglobin concentration, red blood cells
and white blood cells counts were markedly elevated (P values in both sheep and goat groups suffering either single or combined stress. On the
other hand. results of hemoglobin indices revealed a marked reduction in mean
corpuscular volume, elevation of mean cell hemoglobin and mean cell hemoglobin
concentration coincided with higher elevation in red blood cells count, hematocrit value
and hemoglobin concentrations in both sheep and goat groups either under single or
combined stress. Muscular activity seemed to accompany with glycogenolysis in the
liver cells as indicated by prolonged elevation in glucose concentration and enzymes
activity following exercise and rest periods. Following exercise. blood urea and
creatinine concentration was markedly elevated either due to single or combined stress
in both sheep and goat groups. Plasma enzymes activity as well as lactate
dehydrogenase increased (P<0.01) in both sheep and goat groups due to single or
combined stress. During the rest period. most of these parameters recovered nearly
their pre-exercise values. It could be concluded that walking for long distances between
grazing areas and water holes is an great problem facing animal flocks in desert areas.
The lower metabolic rate reported for walking animals as well as hemo-biochemical
changes seemed to be the target physiological mechanisms particularly when suffering
combined stresses under desert conditions.