Abstract
Pedigree and performance records (N=3197) of 1322 Nili-Ravi buffaloes maintained at the Livestock Experiment Station, Bahadumagar, Okara, Pakistan during the period 1954 to 1998 were utilized for the estimation of heritability of various production and reproduction traits. The heritability values were estimated by using restricted maximum likelihood procedure fitting an individual animal model. The derivative-free restricted maximum likelihood set of computer programmes was used in this analysis. The heritability estimates were computed as 0.01±0.02 for 305-day lactation milk yield(first record), 0.10±0.01 for 305-day lactation milk yield (all records), 0.001±0.0 I for total lactation milk yield (first record), 0.07±0.06 for total lactation milk yield (all records), 0.06±0.05 for lactation length (first record), O.lI±0.06 for lactation length (all records) 0.07±0.14 for dry period (all records), 0.003±0.01 for age at first calving, 0.06±0.03 for service period(all records), 0.06±0.03 for gestation period (all records) and 0.04±0.05 for calving interval (all records). The low estimates of heritability for all of the production and reproduction traits suggested that most of the observed variation in these traits was due to environmental conditions or non-additive genetic effects. They also indicated low correlation between genotype and phenotype of individual buffaloes and hence much more attention should be paid to the performance of collateral relatives and the progeny in selection programmes. The prospects of improvement of these traits from selection appeared to be poor. The improvement in these traits may be sought by the provision of better environmental conditions i.e. better feeding, better management etc.
