Carbonic anhydrase and acid base balance in relation to thermal stress in buffaloes (Bubalus bubalis).

The blood samples from fifteen normal lactating buffaloes were taken from December 15th 1978 to 31st August, 1979. Depending upon the climatic conditions, the whole period of study was divided into four seasons. The mean values of carbonic anhydrase (moles CO2/l/sec×10−5) were 3.08±0.26, 4.94±0.44, 5.23±0.35, 6.44±0.32 in pregnant and 4.87±0.27, 4.53±0.41, 4.74±0.45, 6.36±0.40 in non-pregnant animals during winter, spring, hot and dry and hot and humid seasons. Mean values of pO2 (mm Hg) were 31.26±1.41, 31.92±0.61, 35.90±0.59, 33.80 ±0.67 in pregnant and 31.89±0.44, 31.53±0.54, 35.52±0.69, 31.65±0.95 in non-pregnant buffaloes during winter, spring, hot and dry and hot and humid periods, respectively. There were highly significant (P< 0.01) differences between seasons with respect to pO2, pCO2, actual HCO3 and heamoglobin. However, PCV changed significantly (P<0.01) with the physiological status of the animal. Different correlation of biochemical parameters with climatic elements were discussed. Thus, the shifts in the levels of carbonic anhydrase, HCO3 and heamoglobin may prove to be a better tool/index for thermal stress in buffaloes.