Submitted to: Journal of Sheep Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 1, 1993
Publication Date: N/A
Interpretive Summary: The Southern Great Plains produces wheat in amounts that are occasionally surplus to human needs and can be used in animal diets. In feedlots, animals comsume a high energy diet that promotes a rapid rate of growth and adds enough fat to the carcass to make it a quality product for the consumer. Typically, corn or sorghum is the grain source used in feedlot diets, but at times wheat is cheap enough to be economically competitive with these grains. However, wheat is a rapidly digested grain which can cause gastrointestinal disturbances and lower animal performance. The following experiment examined the possibility of feeding wheat with other grains to modulate the negative impact of wheat on lamb performance. When wheat was fed with corn lambs consumed less feed and as a result gained less weight, but the amount of feed required for a unit of gain was not different from the all corn diet. When wheat was fed with sorghum gain feed intake was not affected, but when wheat comprised more than 20% of th diet daily gain was decreased. It appears that wheat can be fed with corn at any proportions, but must not exceed 20% of the diet if sorghum is used.
Technical Abstract: Two experiments were conducted to determine dry matter intake, ADG and feed efficiency of lambs fed diets containing wheat grain in combination with corn (Exp. 1) or grain sorghum (Exp. 2). In Exp. 1, feeder lambs (N=143) were randomly assigned to one of three diets for the 166-d finishing period. The grain source for each diet was either 100% corn (C), 50% corn and 50% wheat (CW) or 100% wheat (W). As the proportion of wheat in the diet increased daily dry matter intake and ADG decreased. The efficiency at which the dry matter was converted to gain averaged 5.76 kg DM/kg of gain and was not affected by treatment. In the second experiment, 115 ewe lambs and 339 wether lambs were randomly assigned to one of four diets in a randomized complete block design. The dietary treatments were 100% sorghum (100S), 80% sorghum and 20% wheat (80S), 60% sorghum and 40% wheat (60S) and 40% sorghum and 60% wheat (40S) diets. As the amount of wheat in the diet increased from 0 to 60%, ADG decreased (P<.05) from 223 to 204 g. Dr matter intake was similar across all treatments, but feed efficiency was poorer for the diets containing more than 20% wheat as compared to the 100S diet. From these two experiments it appears that feeding wheat with corn is more efficient than feeding wheat with sorghum.