Normal lactations (n=2353) of buffaloes from four institutional herds and four field data collection centers involved in a progeny testing progranune in Pakistan were used for the development of correction factors for lactation length. adjusted to 305 days, by simultaneously accounting for age at calving. A single trait animal model was employed and regressions were estimated for first and later parity groups. Estimated milk yield increased linearly with increase in lactation length. coefficients being different with inclusion or exclusion of records for a certain lactation length. More precise recording of lactation information and changes in the methodology of lactation length adjustment are emphasized for future milk yield predictions and evaluation of animals. ~ •. "J •• " ". Key words: milk yield, lactation length. buffaloes
