Cane molasses and cottonseed meal supplementation of ammoniated tropical grass hay for yearling cattle.

Laboratory, digestion, and growth studies were used to evaluate liquid cane molasses (MOL) and(or) cottonseed meal (CSM) supplementation of ammoniated (4% of the forage DM) stargrass (Cynodon nlemfuensis Vanderyst var. nlemfuensis) hay. Ammoniation increased (P < .01) total N concentration (1.0 to 1.4% vs 1.7 to 2.8%) and in vitro digestion of OM, NDF, and ADF and decreased (P < .01) NDF concentration of stargrass hay. Two digestion (4 x 4 Latin square, 250-kg steers) and two growth (230-kg Brahman crossbred steers, seven to eight steers per pasture, three to four pastures per treatment, October through February) trials evaluated MOL and(or) CSM supplementation of ammoniated hay. Supplementation with CSM alone did not influence (P > .05) apparent digestibilities of OM or NDF, whereas supplementation with MOL either alone or with CSM increased (P < .05) apparent OM digestibility, but decreased (P < .05) apparent NDF digestibility. In the growth trials, hay intake was not affected (P > .05) by supplementation with CSM alone and was decreased (P < .05) by supplementation with MOL either alone or with CSM; however, total feed intake was increased (P < .05) by MOL supplementation. Cattle fed only ammoniated hay gained approximately .20 kg/d. In both trials, daily gain and gain/feed were improved (P < .05) by CSM (.39 to .47 kg; .062 to .071) or MOL (.34 to .35 kg; .047 to .048) supplementation. Improvements (P < .05) in daily gain (.54 to .76 kg) and gain/feed (.077 to .083) by supplementation with MOL plus CSM were additive to responses from supplementation with MOL or CSM individually.(ABSTRACT TRUNCATED AT 250 WORDS)