Feeding value of peas for backgrounding beef heifers

Chen, J.-Q., Okine, E. K., Price, M. A. and Khorasani, G. R. 2003. Feeding value of peas for backgrounding beef heifers. Can. J. Anim. Sci. 83: 779-786. Four diets in which peas progressively replaced barley [0% (OP), 30% (30P), 50% (50P), and 100% peas (IOOP)] and one in which canola meal (CM) replaced 10% of the barley, were fed to 90 beef heifers (initial weight 215.8 ± 13.8 kg). The heifers achieved average daily gains (ADGs) of 0.72, 0.80, 0.79, 0.83, and 0.76 kg d^-1 on the five diets, respectively, with the difference between the OP group and the IOOP group being significant (P = 0.028). The total feed costs of gain were $0.786, 0.779, 0.799, 0.860, and 0.817 kg^-1 for the five groups, respectively, with the cost of gain being significantly greater (P < 0.05) for the IOOP group than for the OP, 30P or 50P groups. The latter three were not significantly different from each other. Three rumen-cannulated steers (575 +- 56.3 kg) were used to estimate the degradability of the dry matter (DM) and N in the barley straw (BS), CM, barley grain (BG) and peas used in the feeding trial. The rumen undegradable protein (RUP) levels supplied by the five diets were 17.5, 19.0, 19.9, 21.5, and 22.5%, respectively, and all of them met the requirements of these cattle. The RUP content of peas ground through a I-mm screen was lower than that of peas ground through 2- or 4-mm screens (P < 0.01), which were themselves not significantly different from each other (P = 0.67). The low RUP content of peas was not a limiting factor for growth in backgrounding cattle.