Buffalo milk yield records were obtained from monthly milk recorded by the Animal Breeding Organization of Iran from 1992 to 2009 in 33 herds raised in the Khuzestan province. Variance components, heritability and repeatability were estimated for milk yield, fat yield, fat percentage, protein yield and protein percentage traits. These estimates were carried out through single trait animal model using DFREML program. Herd-year-season considered as fixed effect in the model. For milk production traits, age at calving fitted as a covariate. The additive genetic and permanent environmental effects were also included in the model. The mean and standard deviation for milk yield, fat yield, fat percentage, protein yield and protein percentage were 2285.08±762.47 (kg), 144.35±54.86 (kg), 6.25±0.90 (%), 97.30±26.73 (kg) and 4.19±0.27 (%), respectively. The heritability and standard errors of milk yield, fat yield, fat percentage, protein yield and protein percentage were 0.093±0.08, 0.054±0.06, 0.043±0.05, 0.093±0.16 and zero, respectively. These estimates for repeatability were 0.272, 0.132, 0.043, 0.674 and 0.0002, for milk yield, fat yield, fat percentage, protein yield, protein percentage, respectively. Lower values of genetic parameter estimates require more data and reliable pedigree records.

Key words: Animal model, Buffalo, Heritability, Iran, Repeatability