U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska


Date of this Version


Document Type



Published in Beef Research Program Progress Report (1988) No. 3: 55-56


Utilization of the intact male by the beef industry has been the focus of much research in recent years. Advantages of bulls compared to steers in production efficiency, performance, and carcass leanness have been well documented. Disadvantages include aggressive behavior, darker postmortem muscle color, lower USDA quality grades, and, often, less tender meat. The superior production performance of bulls has not been utilized by the meat and livestock industries partly because of these disadvantages.

Postmortem muscle color is associated with energy content of the diet, antemortem muscle glycogen content, postmortem muscle pH decline, and ultimate pH, all of which are affected by the degree and amount of physiological stress induced before slaughter.

Electrical stimulation of prerigor carcasses has resulted in improved tenderness and marbling scores, enhanced lean colors, and increased rate of pH and glycogen decline. Thus, the objectives of this study were to determine the effects of diet and electrical stimulation on postmortem glycogen depletion, muscle color, and sensory properties of bull longissimus dorsi muscle.