DIURNAL CLIMATIC PRESSURE ON HAEMATOLOGY AND BLOOD BIOCHEMISTRY OF WEST AFRICAN DWARF SHEEP

Abstract

Twelve 2.5-year-old West African Dward (WAD) sheep consisting of eight (8) ewes and four (4) rams with mean body weight 19.4kg were used to study the effects of diurnal (morning and afternoon) climatic variations on the haematological and biochemical responses in WAD sheep. The animals were randomly assigned to two treatment groups with three replicates for each treatment. Blood samples ((80ml) were collected from each of the three replicates twice per day at 9am and 3pm for 12 weeks. A significantly (p<0.05) higher diurnal relative humidity (57.805) and wind velocity (3.03km/hr) were recorded in the morning hours, with a significantly (p<0.05) higher ambient air temperature (32.360C) and radiation intensity (0.87kcal) noticed during the afternoon period. Most of the climatic factors were positively (p<0.05) correlated with ambient air temperature, except the relative humidity 9RH) which had a negative relationship (r—o.25) with the air temperature. Most of important haematological and biochemical parameters were fairly distributed throughout the diurnal periods, except blood glucose, which was significantly (p<0.05) increased with increased diurnal radiation intensity and relative humidity. Ambient air temperature exhibited positive correlations with red blood cells (r=0.41), packed cell volume (r=0.50 vs 0.20) and negative correlations with white blood cells (r=-11), plasma protein (r=-0.50) and blood glucose (r=-0.61). on the contrary, RH had positive (p<0.05) correlations with plasma protein (r=0.97), blood glucose (r=0.50), blood coagulation time (r=0.26) and specific gravity fo plasma/whole blood (r=0.36 vs 0.280. red blood cell, haemoglogin, glucose and specific gravity of plasma/whole blood showed positive relationship (p<0.05) with wind velocity and radiation intensity, except packed cell volume and white blood cells which had negative correlations with radiation intensity 9r=-0.91 and 0.40). The results of this study suggested that WAD sheep have the inherent ability to tolerate vagaries of diurnal tropical climatic conditions through prompt corrective adjustments of their body haematology and blood biochemistry.



Keywords: Diurnal climate, haematological and biochemical responses West African Dward Sheep, humid tropical climate.


[Niger Agric. J. 34 (2003): 103-109]