Optimizing breeding decisions for Finnish dairy herds

The purpose of this study was to determine the effect of reproductive perfo rmance on profitability and optimal breeding decisions for Finnish dairy he rds. We used a dynamic programming model to optimize dairy cow insemination and It placement decisions. This optimization model maximizes the expected net revenues from a given cow and her replacements over a decision horizon . Input values and prices reflecting the situation in 1998 in Finland were used in the study. Reproductive performance was reflected in the model by overall pregnancy ra te, which was a function of heat detection and conception rate. Seasonality was included in conception rate. The base run had a pregnancy rate of 0.49 (both heat detection and conception rate of 0.7). Different scenarios were modeled by changing levels of conception rate, heat detection, and seasona lity in Fertility. Reproductive performance had a considerable impact on profitability of a he rd; good heat detection and conception rates provided an opportunity for ma nagement control. When heat detection rate decreased from 0.7 to 0.5, and e verything else was held constant, net revenues decreased approximately 2.6% , If the conception rate also decreased to 0.5 (resulting in a pregnancy ra te of 0.25), net revenues were approximately 5% lower than with a pregnancy rate of 0.49. With lower fertility, replacement percentage was higher and the financial losses were mainly from higher replacement costs. Under Finnish conditions, it is not optimal to start breeding cows calving in spring and early summer immediately after the voluntary waiting period. Instead, it is preferable to allow the calving interval to lengthen for the se cows so that their next calving is in the fall. However, cows calving in the fall should be bred immediately alter the voluntary waiting period. Ac ross all scenarios, optimal solutions predicted most calvings should occur in Fall and the most profitable time to bring a replacement heifer into a h erd was in the fall. It was economically justifiable to keep breeding high producing cows longer than low producing cows.