By Greg Palen
The numbers game in dairy genetic selection began when the AI industry switched to frozen, storable semen in the 1960s, thus providing a true choice of sires. This was the beginning of the genetic horse race for the best sires, and the long battle to define the word “best.”
Fads came and went. Genetic ranking shifted from pounds of butterfat to pounds of milk (and later protein). Universities partnered with feed companies to figure out how much grain a dairy cow would eat without getting sick, then studied “type” to determine traits most responsive to making milk in volume at younger ages. Breed type classification became a tool for bull evaluation. Ultimately, we accepted the idea of ranking bulls on a composite of milk yield and type traits. PD for each trait gave way to Net Merit, TPI and other data formulas that we could treat as a “single trait selection” process. Continue reading “The grass cow: Don’t fall for promises of breeding shortcuts”