November - December 2000
Due to the low price of raw soybeans, farmers are considering feeding whole soybeans to beef cattle and other farm animals. Contrary to some producers' belief, the protein in raw soybeans appears to be utilized as efficiently as the protein in solvent soybean meal. No nutritional advantage for cooking, roasting, or extruding soybeans has been shown when fed to beef cattle. The high fat content gives whole soybeans a higher energy value than corn. However, this high fat content does limit the amount of whole soybeans that can be used to advantage in beef cattle rations. Also, the fat in ground raw soybeans will become rancid after a few days of storage in hot weather. Cooking or other high heat treatment of soybeans will inactivate enzymes that cause the fat to become rancid, allowing potentially longer storage time.
The bottom line when feeding whole soybeans to cattle can be summarized as follows:
Soybeans Enhance Conception Rate
Feeding whole soybeans to ruminants seems to protect a portion of the fat from degradation in the rumen. Recent trials by Zumbrunnen and others at the University of Missouri indicate that whole soybeans can be an economical way (at least based on today's prices) for delivering a level of unsaturated fatty acids necessary to increase early conception rates in beef cows. In these studies beef cows fed rations containing whole soybeans (3.5 pounds per head per day for 50 days prior to breeding) had more calves than cows fed traditional supplements (an equal ration containing corn gluten feed and soybean meal). First service conception for the cows fed the whole soybean supplementation showed a 15% improvement in conception rate compared to the traditionally supplemented cows. In a similar study conducted at the MU Thompson Research Farm, the results were even more dramatic with over a 20% advantage to the whole soybean supplemented cows. Interestingly, work done at the USDA Research Center in Miles City, Montana, found that calf survivability was improved when cows were fed high fat diets prior to calving. However, in the Missouri study no difference in survivability between treatments was recorded.
Studies from Missouri, Texas, Montana, and New Mexico have all demonstrated that fat supplementation (at appropriate levels) in the gestation diet of first calf heifers could have a positive effect on the subsequent reproductive rate and calf weaning weight.