GENETIC AND NONGENETIC FACTORS AFFECTING BODY WEIGHT IN NILI RAVI BUFFALOES

Live body weight of Nili Ravi buffaloes was studied to investigate the effect of certain environmental sources of variation such as herd, lactation number, lactation stage, season of recording and age of buffaloe at the time of recording alongwith appraisal of genetic parameters of body weight including heritabilities, genetic correlation and phenotypic correlation of body weight with mik yield. Five milking herds belonging to Nili Ravi buffaloe breed in Punjab were utilized in this study. Data recorded during 2010 to 2012 included 839 observations. Estimation of genetic parameters were carried out by Best Linear Unbiased Prediction (BLUP) procedure through ASREML set of coputer program. Least square mean for body weight was found as 523.13 +/- 81.63 with a coefficient of variation of 15.60%. Herd, stage of lactation, lactation number, recording season and buffalo's age at the time of recording significantly affected live body weight. Univariate analysis of body weight indicated that heritability estimate for body weight was 0.33 +/- 0.07. Phenotypic correlations of body weight with milk yield in 305 days and milk yield on day of recording were found as 0.071 +/- 0.034 and 0.090 +/- 0.053 while genetic correlations were found as 0.16 +/- 0.00 and 0.20 +/- 0.00, respectively. High heritability and positive genetic correlation of body weight with milk yield suggested that body weight should be included in selection program for improved milk yield in Nili Ravi buffaloes.