Abstract
AN F2 population of maize, segregating for brown midrib-3 mutant (bm3) and with non mutant “normal” plants, and a commercial hybrid (CH) were ensiled without ears to determine voluntary intake and digestibility when fed to lambs. Lignin percentages for the three silages were 4.5, 6.8 and 6.9 for bm3, normal and CH. Lambs fed the bm3 silage ration had a 29% greater (P<.01) voluntary consumption than lambs fed normal silage. When rations were fed ad libitum, apparent digestibility of dry matter (P<.10), cellulose (P<.05), hemicellulose (P<.01) and energy (P<.01) were greater for bmg than for normal or CH. Feeding lambs at 90% of ad libitum intake resulted in similar differences. The bm3 silage had a faster in vitro rate of digestion of dry matter, cell walls, cellulose and hemicellulose. These results indicate that the decreased lignin content of the bm3 genotype probably accounts for the faster ruminal rate of digestion in vitro and the greater apparent digestibility in vivo. The 29% greater voluntary intake of the bm3 silage was probably a result of faster rate of ruminal digestion due to a lower lignification of cellulose and hemicellulose. Copyright © 1972. American Society of Animal Science . Copyright 1972 by American Society of Animal Science.