CORRECTION FACTORS ADJUSTING SIX MONTH WEIGHT FOR AGE OF DAM AT LAMBING IN SHEEP

Data on 751 lambs pertaining to synthetic population developed by inter se mating of half
bred of Corriedale and Russian Merino rams with Nali ewes were used to developed Additive Correction Factors (ACF) and Multiplicative Correction Factors (MCF) for age of dam at lambing. The mathematical model for least squares analysis for deriving correction factors for age of dam at
lambing also included the fixed effects of year, season of lambing, sex of lamb and Dam’s weight at lambing as covariate. On the basis of CV both ACF and MCF were equally effective. However, the comparison of age correction factors on the basis of means squares among age group, ACF was found to be more effective. The phenotypic correlation between ages at lambing with corrected body weight increased over the uncorrected values. It showed that both the methods were equally effective.