Cost comparison of natural service sires and artificial insemination for dairy cattle reproductive management.

Despite the widespread popularity of artificial insemination, many dairymen still prefer the use of natural service sires due to a variety of reasons, including a common perception that it is easier to manage and less expensive than AI. Little has been done to estimate the explicit and implicit costs, including the probable loss of genetic progress associated with the use of natural service sires in dairy herds. A partial budget approach was used to stochastically model the expected costs and returns of reproductive management options in large, western, Holstein dairies. Option one was natural service sires managed using currently recommended approaches including breeding soundness evaluations, bull vaccination, and a rotational breeding system. Option two was an AI system using a modified Presync-Ovsynch timed AI program in conjunction with estrus detection and inseminations performed by a commercial route breeder. Stochastic variables in the model included the cost of the lactating ration and purchased bulls, as well as the value received for milk, market bulls, and net merit gains. All other variables were treated deterministically. Under the model's assumptions, the use of natural service sires averaged approximately US dollar 10 more in cost per cow per year as compared to an AI program. Sixty percent of the time, AI was less expensive than using bulls. However, there was wide variation in expected differences in cost between the two systems with net merit estimates having the largest impact, followed by prices received for milk sold and market bulls.