Feeding Value of Corn Silage Containing Added Urea and Dried Whey

Abstract

Corn silages containing either .5% urea plus 1% dried whey or .5% urea were compared in a lactation trial utilizing nine cows per treatment, in a feeding trial with ten 4 to 8 mo old heifers per treatment, and in a digestion trial with four 150kg Holstein steers per treatment. Cows received the silage ad libitum as the sole source of roughage and a 19% crude protein grain ration at 1 kg/2.5kg milk produced during the 10 wk lactation trial. Cows fed urea-whey silage produced more milk (31.6 to 29.3 kg/day) and were more persistent (−1.4 to −3.3 kg/day from pre-treatment production) than cows fed urea silage. No differences were found in percent milk fat, protein, or nonfat solids. Ruminal propionate and total volatile fatty acids were higher from cows fed urea-whey silage (39.8 to 30.4μM/ml and 124.2 to 111.8μM/ml). Weight gains and feed intake of heifers fed urea-whey or urea silages for a 16 wk growth trial were .90 and .84 kg/day, and 5.7 and 5.3kg dry matter/day. Digestion coefficients with steers were: dry matter, 65.9 and 64.2; nitrogen, 56.6 and 48.6; and digestible energy, 2.49 and 2.43 McalAg dry matter for urea-whey and urea corn silage. The lactation, growth, and digestion trials all indicated that adding dried whey to urea-treated corn silage improved the silage's feeding value.