ESTIMATION OF OPTIMUM FIRST DRY PERIOD IN KARAN FRIES CATTLE

Study for estimation of optimum first dry period was conducted on 571 Karan Fries Cattle (Crossing Tharparkar and Sahiwal cows with American Holstein Friesian Sires) at National Dairy Research Institute, Karnal, Haryana. The data were corrected for non-genetic factors by using least squares analysis. The genetic and phenotypic parameters were estimated using standard statistical methods. The overall least squares mean for first dry period estimated as 64.47 ± 1.46 days. The relationship between first dry period and second lactation production traits were studied by using polynomial regression analysis and class interval method. Six classes of first dry period was used. Optimum first dry period was identified on the basis of higher second lactation milk production and numbers of animals in various classes as 51-70 days. However, to determine optimum level maximum profit to be taken into account.