Influences of Culling Types on Optimum Replacement Rates and Profitability of Dairy Herd

An integer linear programming model was developed to establish the optimal replacement strategy for a commercial dairy herd. Monthly revenues and costs for cows were computed based on factors such as milk production, calf and carcass values, feed expenses, replacement heifer costs, insemination charges, and veterinary expenses. The model characterized cows using five parity numbers, two decision options (retain or replace), a 5-year planning horizon, and ten cow categories. It accounted for variations in milk yield, milk prices, calf and carcass values, feed costs, and replacement expenses. The parameters and prices used were tailored to reflect the Holstein-Friesian population in a commercial dairy herd in Egypt. The optimal annual replacement rate was determined to be approximately 30%, with an average productive life of 3.33 years. The maximum annual net revenue, expressed as a yearly annuity over the 5-year planning horizon, was estimated at 1,055 LE per cow. Sensitivity analyses were conducted to assess the impact of variations in average milk yield and the prices of milk, calves, carcasses, feed, and replacement heifers on the optimal replacement decisions. Profitability declined as the replacement rate increased from 10 to 50%. Productive life, replacement rate, and annual net present value were most influenced by changes in average milk yield and the prices of milk, feed, and replacement heifers. In contrast, variations in calf and carcass prices had relatively minor effects on the optimal replacement policy.