Abstract

This paper presents equations that can be used to quantify the differences in value to a commercial farmer among rams available for purchase from a single ram breeder. The same approach can be taken for a group of breeders for which across-flock genetic evaluation results are available. Separate equations are presented in detail for buyers of both dual-purpose and terminal sire rams. A working version of the terminal sire equation incorporates the difference in the terminal sire index value between two rams, the number of years, and the number of ewes per year, to which the ram is to be mated and the tailing percentage in the commercial flock as variables. A working version of the dual-purpose sire equation incorporates the same variables as the terminal sire equation, but with the percentage of the ram`s daughters to be kept as replacement ewes also added.

A, Meikle, and PR Amer

Proceedings of the New Zealand Society of Animal Production, Volume 63, Queenstown, 187-189, 2003