Significant changes have occurred in the beef cattle industry in the past few decades. Many of these changes have occurred because cattlemen have applied information provided by animal scientists. Some of these changes are crossbreeding, selection, meeting nutrient requirements of cattle in various stages of production, use of feed additives,’ use of implants, use of non-protein nitrogen, artificial insemination, oestrus synchronization, and management systems for improving reproduction in heifers and cows. Although these changes have been substantial, many practices have been adopted only partially or by a limited number of ranchers. Therefore, a wide gap exists between available knowledge and the application of that knowledge. To help the cattleman make decisions, animal scientists need to develop models able to predict the economic value of adopting various techniques. The cattleman can then decide when and if the technique should be used in his operation. However, the problem of how to use the technique in different situations still remains and must be the concern of thoughtful animal scientists.