Abstract
Pure stands of three small grain crops (triticale, wheat and rye) and two mixtures composed of a small grain (triticale and rye), ryegrass and crimson clover were grazed by light-weight (172 kg initial weight), growing beef calves. Certain characteristics of these forages were compared with each other and with animal performance. Forage characteristics included dry matter (DM), organic matter (OM), in intro organic matter digestion (IVOMD), neutral detergent fiber (NDF) and crude protein (CP). Simple correlation coefficients and multiple regression analyses were computed between average daily gain (ADG) and forage characteristics for three segments (28 to 147 days, 28 to 84 days and 84 to 147 days) of the experimental period. During the first 84 days on trial, the data indicated that, under conditions of unrestricted intake of high quality forage by calves of the type used in this investigation, animal potential rather than forage quality was the limiting factor influencing ADG. From 84 days to the end of the trial, highly significant positive correlations (r = .68 and r = .61) existed between ADG and IVOMD and CP, respectively. However, the highly significant correlation (r = .80) between IVOMD and CP indicated that IVOMD was associated with 64% of the variability in CP or vice versa. The partial regression coefficient for IVOMD was highly significant and indicated that IVOMD was the most valuable measure for predicting animal performance after 84 days on experiment. Consequently, forage quality, as measured by IVOMD (73% and lower), rather than animal potential became the limiting factor influencing ADG. Copyright © 1975. American Society of Animal Science . Copyright 1975 by American Society of Animal Science.