A note on the properties of the cumulative difference method for sire evaluation

Several of the various dairy sire evaluation methods now in use account for the genetic level of contemporary herdmates. In the cumulative difference method of Bar-Anan and Sacks the contemporary comparison estimate is first calculated and then adjusted by taking into account the genetic level of the contemporaries. These estimates depend on the genetic level of the herdmates. A modification of the procedure in which account is taken of the herdmates' genotype before regressing for small numbers would remedy this deficiency without increasing computing costs.