EFFECT OF CLIMATIC VARIABLES ON AVERAGE DAILY MILK-PRODUCTION IN CROSSBRED CATTLE

The effect of climate variables on average daily milk production (milk yield/cow/day) was examined in crossbreds of Hariana with Holstein-Fr iesian, Brown Swiss and Jersey. The correlations of average daily milk yield with wet bulb temperature and relative humidity were negative a nd significant whereas with temperature, the correlation though negati ve was nonsignificant. The correlations of meteorological indices with average daily milk yield were in general negative and nonsignificant. The regression coefficients of average daily milk yield on temperatur e and all the indices were negative and nonsignificant while that on r elative humidity was negative and significant. The regression of avera ge daily milk yield on temperature and humidity taken together was, ho wever, negative and significant (-3.397+/-0.887). Temperature and humi dity together explained 62.75% of variation in milk yieid/cow/day whic h was higher than that explained either by temperature or humidity alo ne and the indices indicating that temperature and humidity combinatio n in absolute values should be taken instead of constructing meteorolo gical indices for explaining variation in milk yield/cow/day.