animals, depend on both genetic and non-geneticfactors. Genetic improvement may be done byselection. The non-genetic factors such asmanagement, amount and quality of feed, season etc.also influence milk yield and lactation length, and needto be assessed in a production set up. Analysis of fiveyear data of Nili-Ravi buffaloes maintained at dairyfarm in the home tract of the breed has shown thatfactors affecting milk yield in buffaloes are almostsimilar to those of cattle including: year, season, herd,parity, days in milk, days open, age and sire [3].The objective of the present study was to evaluatethe effects of year, season and parity on total lactationmilk yield, 305 day milk yield and fat percentage inMurrah buffaloes.