Fermented Ammoniated Condensed Whey as a Crude Protein Source for Feedlot Cattle

Abstract

Four feeding trials were conducted to evaluate fermented ammoniated condensed whey (FACW) as a crude protein (CP) supplement for finishing cattle fed corn silage or corn-corn silage diets. In the first trial, when 40% corn:60% corn silage diets contained 0, 3.5, 7.0 and 14.0% FACW (dry matter basis), daily dry matter intakes by yearling Hereford steers (290 kg) were 7.16, 8.23, 8.90 and 8.52 kg/head (P>.10), respectively. In trial 2, the addition of soybean meal, FACW or urea as a CP supplements for corn silage or 40% corn:60% corn silage diets increased rates of gain (P<.01) by Charolais × Hereford calves (260 kg) over those obtained with similar diets not supplemented with a CP source. Feed efficiency was improved by an average of 34 and 12%, respectively, in comparison to that of unsupplemented steers, when corn silage and corn-corn silage diets were supplemented with CP. Trial 3 involved 96 yearling Hereford steers (338 kg) fed 60% corn: 40% corn silage diets. There were six protein supplement treatments (no supplement, 2.45% FACW, 4.85% FACW, 7.05% FACW, 1% urea and 6.58% soybean meal) and two sources of S (sodium sulfate and calcium sulfate). S source had no effect on feedlot performance or carcass traits. Pooled daily gains with the protein treatments were 1.17, 1.29, 1.33, 1.37, 1.29 and 1.42 kg/head (P<.01), respectively. Feed efficiencies tended to be greater for FACW and soybean meal-supplemented steers than for urea-supplemented or control steers. No differences in carcass traits were observed among steers fed different protein supplements. In trial 4, 48 yearling Hereford steers (299 kg) were fed three levels of FACW (0, 2.8 and 5.6% of dry matter) and two sources of corn (high wax or regular yellow dent) in 60% corn: 40% corn silage finishing diets. Source of corn did not influence feedlot performance or carcass traits. When data were pooled, the level of FACW did not affect (P>.05) daily gains, but carcass fat thickness and yield grade were greater (P<.05) for steers supplemented with FACW. The results of these trials suggest that FACW is comparable to soybean meal as a CP source for cattle fed corn silage or corn-corn silage finishing diets.