Net partial cashflow of dairy cows with different voluntary waiting periods until first insemination

Based on modeling studies, a 1-yr calving interval is generally considered optimal from an economic point of view. Recently some dairy farmers are deliberately extending the voluntary waiting period for insemination (VWP) to extend the calving interval. Reasons to extend the VWP are to reduce the frequency of transitions such as dry-off and calving to improve health, to reduce labor related to these transitions, and to reduce the number of surplus calves. This study aimed to evaluate yearly net partial cashflow in a randomized controlled trial for individual cows with a VWP of 50, 125, or 200 d. The net partial cashflow included revenues and costs for milk yield, calves born, number of inseminations, concentrate supply, roughage supply, disease treatments, discarded milk due to disease treatments, culling, and labor (for calving cows, inseminations, and disease treatments). Holstein-Friesian dairy cows (n = 153) within one herd were blocked for parity, calving season, and 305-d milk yield, randomly assigned within the blocks to one of 3 VWP (50 d, 125 d, or 200 d; VWP50, VWP125, or VWP200), and monitored from wk 6 postpartum until 6 wk after the next calving. Revenues and costs were calculated per individual cow, and expressed per cow per year. Primiparous and multiparous cows were evaluated separately. Revenues from milk and costs for roughage and concentrate contributed most to the yearly net partial cashflow. For primiparous cows, the VWP did not affect yearly revenues from milk.