Evaluating net income from different durations of breeding seasons in beef production using a deterministic simulation model

Abstract

A deterministic computer simulation model was used to evaluate the economic efficiency of reproductive management decisions in beef production: length of breeding season (45, 70 or 120 days) and whether to initiate breeding of heifers 3 weeks earlier than the mature cows. Four conception rates at first service (an indicator of reproductive efficiency) were also simulated (50%, 60%, 70%, 80%) with each length of breeding season. The economic model organizes and summarizes herd performance data, feed requirements and prices to calculate the net income for one year of production. A description of the economic model and a discussion of how net income is influenced by length of breeding season and conception rate at first service are included. The optimum length of breeding season was found to depend upon conception rate at first service. In cows, length of the breeding season has little influence on net income when conception rates at first service were higher (70%, 80%), but a longer breeding season (120 days) increased net income when conception rates at first service were low (50%, 60%). Initiating breeding of yearling heifers 3 weeks before the cows generated greater net incomes when conception rates at first service were low (50%, 60%), but only slight differences in net income were evident with higher conception rates at first service (70%, 80%).