Milk yield is a repeatable character. The genetic contribution towards milk production during different lactation's of an individual remain same and therefore the differences in production levels from one lactation to other are due to the various environmental changes including nutrition and climate along with the physiological changes. The physiological changes may be observed in many forms viz. body growth, and functional efficiency of udder etc. The attainment of higher body weight at early age(i.e. at first calving) seems to play a vital role in building the efficient production life of dairy cows. Therefore production from different cows may change due to change in body weight, age at first calving and calving intervals. A major objective for cattle breeding is to enhance milk production for higher economic return.The present study was conducted on Jersey x Sahiwal crossbrede with following aspect.To estimate average milk production and profit during first five lactation. To predict optimum body weight at first calving for maximum herd life milk production or profit. This book is valuable for Livestock Production and Management research workers, scholars and dairy managers.