A Stochastic Model to Compare Breeding System Costs for Synchronization of Estrus and Artificial Insemination to Natural Service

Abstract

A stochastic model was used to compare costs of natural-service breeding with several synchronization of estrus and AI systems and to identify important factors in determining the differences in expected economic returns between systems. Three herd sizes, 3 cow-to-bull ratios, and 7 systems for synchronization of estrus were examined. Stochastic variables in the model included bull purchase price, percent calf crop, calf price, AI conception rate, cull bull value, cull bull weight, genetic value premium of AI-sired calf, heat detection rate, season pregnancy rate, semen cost, and synchronized calf weight advantage. The AI systems were more cost effective at lower cow-to-bull ratios. Compared with natural service, heat detection and cleanup fixed-time AI synchronization systems were economically preferred 33% of the time, 41% for strict fixed-time AI, and 49% for heat detection only systems. Heat detection only systems in large herds using low cow-to-bull ratios demonstrated a net economic advantage relative to natural service 85% of the time. Genetic value premiums and semen cost were consistently included in the top 3 factors that determined expected economic differences between natural service and AI systems across herd sizes and cow-to-bull ratios. Variability in bull purchase price was the most important factor when the cow-to-bull ratio was low. Estrus synchronization and AI were economically advantageous compared with natural service when a sufficient genetic value premium could be obtained from AI-sired calves.