Field pea (Pisum sativum) inclusion in corn-based lamb finishing diets

Two hundred crossbred lambs were used to determine energy value and optimum inclusion level of field pea (Pisum sativum) in corn-based diets. In experiment one (Exp. 1), 100 crossbred lambs (33.9+/-1.3 kg initial BW) were blocked by weight and sex (two blocks of ewe lambs per treatment; three blocks of ram lambs per treatment) and fed for 89 days. In experiment two (Exp. 2), 100 crossbred ram lambs (39.1+/-0.2 kg initial BW) were blocked by weight (five pens per treatment) and fed for 63 days. Treatments for each experiment were similar; field pea replaced corn at 0, 150, 300, or 450 g/kg of the diet (DM basis). Diets contained 750 g/kg corn and/or field pea, 100 g/kg alfalfa hay, 50 g/kg concentrated separator byproduct (CSB), 60 g/kg soybean meal (SBM), and 40 g/kg supplement. In Exp. 2, a fifth treatment was added to evaluate if field pea can replace corn and SBM in high-grain diets (450−SBM); this diet consisted of 450 g/kg field pea, 350 g/kg corn, 100 g/kg alfalfa, 50 g/kg CSB, and 50 g/kg supplement. Diets contained 28 mg/kg lasalocid and a minimum 149.6 g/kg CP, 7.6 g/kg Ca, 4.4 g/kg P, and 12.2 g/kg K. Only carcass data from ram lambs were recorded. Data for each experiment were analyzed separately with GLM procedure of SAS and linear, quadratic, and cubic effects of field pea were determined. In Exp. 1, a cubic (P=0.02) response for DMI occurred, greater intake of 150 g/kg than 300 g/kg diet. No other performance measurements were affected by treatment. In Exp. 2, lambs fed 450−SBM tended to be more efficient (P=0.10) than lambs fed 450+SBM. Carcass characteristics were not affected by treatment (P>0.10). Based on lamb performance (Exp. 1) there was a tendency for a linear (P=0.10) increase in dietary net energy. In Exp. 2, no difference in dietary net energy occurred with increasing level of field pea. Dietary net energy was greater for 450−SBM compared with 450+SBM. Average calculated NEm and NEg for field pea were 2.75 and 2.02 Mcal/kg, which was 14% greater than corn. Field pea is a suitable replacement for corn in lamb finishing diets and is at least equal in energy density to corn.