Effects of Pasture Inclusion of Mimosa on Growth by Sheep and Goats Co-Grazing Grass/Forb Pastures

摘要

Animut, G., Goetsch, A.L., Aiken, G.E., Puchala, R., Detweiler, G., Krehbiel, C.R., Merkel, R.C., Sahlu, T. and Dawson, L.J. 2007. Effects of pasture inclusion of mimosa on growth by sheep and goats co-grazing grass/forb pastures. J. Appl. Anim. Res., 31: 1?￠????10. Effects of mimosa alley-cropped in grass/forb pastures on growth performance of co-grazing sheep and goat wethers were determined. Eighteen sheep (Katahdin) and eighteen goats (?￠???￥75% Boer blood), with BW of 22???±0.3 and 21???±0.2 kg, respectively, and age of 4 to 5 months were used. Wethers grazed 0.4-ha pastures of grasses andforbs for 16 weeks. Three pastures with alley-cropped mimosa (W) and three without (WO) were divided into four paddocks for 2-week rotational grazing. Based on mimosa leaf mass at the beginning of grazing periods and animal days, daily consumption of mimosa leaf DM averaged 47 g per animal, although mimosa leaf harvest was complete long before the end of the grazing periods. Mimosa leaf samples averaged 2.81, 37.8, and 85.9% N, NDF and in vitro true DM digestibility (IVDMD), respectively. Forage mass (grass and forbs) was similar between treatments before (2928 and 2695 kg/ha) and after grazing (1507 and 1452 kg/ha) for WO and W, respectively. Pre-grazed forage concentrations of N (1.25 and 1.24%), NDF (64.5 and 63.8%) and IVDMD (52.9 and 56.2%) for WO and W, respectively, were similar between treatments, as was also true post- grazing. ADG was numerically greater (P=0.17) for W vs. WO (70 vs. 51 g/d; SE=7.7). In summary, alley-cropped mimosa increased nutritive value of the forage available for consumption. Nonetheless, mimosa had limited effect on growth performance of co-grazing sheep and goats perhaps because of decreasing mimosa leaf availability as 2-week grazing periods advanced or overall relatively low intake of mimosa leaf.