Cows with daughters were 309 pounds superior to unselected cows. This resulted in 15 pounds genetic trend due to female selection. Non-AI sire selection resulted in 17 pounds of milk and 0.25 pound of fat genetic trend per year. AI sire selection produced a genetic trend of 53 to 130 pounds of milk and 1.31 pounds of fat per year. Actual results are very poor compared to theoretical results.
Results are very optimistic compared to actual.
Assume the dairyman has a 100-cow herd. Table 1 contains the superiority of AI over non-AI for combinations of year on the program, AI genetic trends, and breeding costs per cow per year. The non-AI genetic trend is assumed to be 32 pounds per year. Costs per cow are zero. Results indicate years on a program and the magnitude of genetic trend in the AI population are very important in the economy of a program.