From Beef Magazine:
Few beef producers would disagree that the genetic potential available for use in their herds via artificial insemination (AI) is greater than that of most natural service sires. The advantage of using AI stems from the improvement in the predictability of the bulls; their EPDs are simply more accurate and reliable.
However, less than 10% of the beef cows in the U.S. are artificially inseminated each year (NAHMS, 2008). Many reasons exist for the low rate of implementation of estrus synchronization and AI (ESAI) into beef cow-calf operations. One factor that limits the use of ESAI in commercial cow-calf herds is the hassle factor. It is simply too much effort to gather the herd and work them 2-3 times in a 10-day period. However, the major reason, in my opinion, is that most producers cannot capture the added value of their AI-sired calves and the enterprise is not profitable.
Beef Magazine article here: http://tinyurl.com/4pntnrd