Published online by Cambridge University Press: 27 March 2009
Two breeds of zebu viz. Hariana and Sahiwal were examined for the possible existence of red cell K+ polymorphism. All the animals examined appeared to be LK type. However, red cell K+ concentration varied rather widely between 7 and 50 m-equiv/1. Within the major LK type three distinct subtypes, tentatively designated as low low (LLK), medium low (MLK) and high low (HLK) were observed. The mean red cell K+ concentration in the various subtypes in the same order were 12·5, 19·5 and 38·0 m-equiv/1 respectively. LLK animals were significantly more frequent in the Sahiwal than in the Hariana breed. The possible genetic basis of the occurrence of these subtypes within the major LK type is discussed.
LLK animals had significantly higher pcv, Hb and RBC, than MLK animals. The WBC and plasma protein values were also higher, though not significantly, in the former group. In addition, animals of the LLK subtype showed consistently lower rectal temperature at comparable levels of respiratory effort under conditions of thermal stress than MLK animals.