Most of the Sahiwal cattle (80%) do not produce milk for a standard duration of 305 days (Dahlin, 1998). Shorter lactations are either deleted from the data set or are used irrespective of duration (considering them the genetic potential of the animal) or can be adjusted. Contradictory views are available in the literature as to which lactation should be declared short. Assumption that yield from a shorter lactation should be considered as the genetic potential of the cow (Syrsted, 1993) is difficult to justify especially when reasons for a lactation to be short are rarely recorded; genetic control of lactation length is weak and because statistical procedures can be developed which can yield very precise adjustments even if the animal dried (Norman et al., 1985) or if information on the reason of drying was not clear/recorded. Limited resources further necessitate that every recorded lactation, short or long, should be best utilized. Present study was planned to see how best lactation length could be adjusted so that shorter lactations could be utilized without sacrificing genetic variation.
Proceedings of the World Congress on Genetics Applied to Livestock Production, Volume 2002. Session 1, , 1.56, 2002
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