Effects of field pea supplementation on digestibility and rumen volatile fatty acid concentrations of beef-cattle diets containing high and low quality forages

Field peas (Pisum sativum) are increasingly available with limited data on the effects on forage digestibility. Two experiments were conducted to determine the effects of field pea supplementation in forage-based diets on total-tract digestibility and RUP digestibility in growing beef cattle. In Exp. 1, 5 ruminally fistulated steers (202 kg) were used in a 2 × 3 factorial. The first factor was high quality forage (50% alfalfa, 50% sorghum silage) or low quality forage (50% bromegrass hay, 50% wheat straw). The second factor was supplement type: a nonsupplemented control (CON), dry-rolled corn (DRC), or ground field peas (FP), supplemented at 0.43% of BW. Each diet was fed for 14 d. There were no interactions between forage quality and supplement type for digestibility estimates (P ≥ 0.25). Intake and digestibility of OM were greater with high quality forage (4.96 kg/d and 64.2%, respectively) than with low quality forage (3.60 kg/d and 50.1%, respectively; P < 0.01). The FP supplement increased DMI and OM digestibility (6.14 ± 0.512 kg/d and 61.6 ± 1.94%, respectively) over DRC (5.33 kg/d and 56.1%, respectively) or CON (4.80 kg/d and 53.8%, respectively; P ≤ 0.03); DRC and CON did not differ in intake or OM digestibility. In Exp. 2, the RUP digestibility of field peas was evaluated using a mobile bag technique. The RUP content of FP was 32.6 ± 4.39% and 35.2 ± 4.39% with a postruminal digestibility of 97.4 and 98.9 ± 1.17% for yr 1 and 2, respectively, for FP grown in 2 growing seasons. Field peas are an acceptable supplement in forage diets.