An Economic Comparison of Four Culling Decision Rules for Reproductive Failure in United States Dairy Herds Using DairyORACLE

Abstract

Farmers must frequently decide when to stop breeding cows if cows fail to conceive. Four culling decision rules were defined and economically evaluated using a stochastic simulation model (DairyORACLE), which models the management of a dairy herd. Two rules are based on a fixed cutoff point for service and two varied according to production and reproductive status of individual cows. Decision analysis techniques were used. For maximum profit the reproductive culling policy should not be too restrictive. Income over variable costs per cow decreased if maximum allowable number of days for breeding was reduced from 250 to 165 d, despite the positive effect on calving interval of the herd. The advantage of a shorter calving interval was outweighed by the negative effects of increasing culling, especially in herds with poor reproductive performance. In these herds the most profitable strategy was a flexible culling criterion based on production and reproductive status of the cow. With better reproduction, it was worthwhile to continue breeding all cows until 250 days after calving, provided that the lowest producing cows were not bred but were culled for low production irrespective of reproduction.