Statistical Weighting for Age of Advanced Registry Cows

ANY study of milk production that is made from a statistical standpoint must necessarily be complicated, for the reason that advancing age in a cow up to the time she is mature enables her to produce more milk and butter fat. A further difficulty lies in the fact that after maturity the effect of age on production has not been determined with any degree of certainty. Whether or not the increase in capacity is directly in proportion to the advance in age; at what age is the maximum of production reached; what relation is there between age and per cent. of fat in milk, and at what age is a cow past the power of full productiveness, are all questions that need investigation in a broad way. Necessarily, the various breed associations must have made some comprehensive investigations to enable them to fix standards for milk and fat production, and since the only extensive authenticated records that we have are records of these associations, this study was . made for the purpose of determining if their records were consistent with their standards, and if these standards could be used as a basis for weighting cows of different ages.