Economic consequences of postponed first insemination of cows in a dairy cattle herd

The purpose was to analyse the economic consequences of postponed first insemination of cows in dairy herds with different reproduction management, and to analyse the sensitivity of the results to a further decrease in beef prices, using a model simulating production and health in a dairy cattle herd. Three different period-to-first-insemination scenarios were analysed. Period to first insemination was defined as days post partum for initiating insemination at observed heat. The three scenarios consisted of a short period to first insemination (70 days for primiparous and 35 days for older cows), a 70 days postponed first insemination of primiparous cows and a scenario with 70 days postponed first insemination for all cows. At a 70 days postponed first insemination for primiparous cows a decrease in annual herd profit of 1% were found. A 70 days postponed first insemination for all cows led to a decrease in annual herd profit by 3% at good reproductive efficiency and 4% at poor reproductive efficiency. The herd profit was calculated as the profit to cover labour costs and fixed costs. Postponed inseminations might reduce labour per cow-year. The reduction in labour per cow-year need to be 3.2 h at good reproductive efficiency and 4.3 h at poor reproductive efficiency to counterbalance the reduction in herd profit by postponing first insemination for all cows by 70 days. In a situation with a 50% decrease in beef prices in a herd constrained by a milk quota (optimising profit per kg milk) herd profit was increased by 0.8% at good reproductive efficiency and 0.3% at poor reproductive efficiency by postponing first insemination for all cows by 70 days.