Feeding value of field pea as a protein source in forage-based diets fed to beef cattle.

Three studies were conducted to evaluate the feasibility of field peas as a protein source in diets for beef cattle. In the first study, 4 cultivars of field pea were incubated in situ to determine rate and extent of CP disappearance. Results indicate that field pea cultivars vary in CP content (22.6, 26.1, 22.6, and 19.4%, DM basis for Profi, Arvika, Carneval, and Trapper, respectively). Soluble protein fraction ranged from 34.9% for Trapper to 54.9% for Profi. Degradable CP fraction was greater (P = 0.01) for Trapper compared with the other cultivars, and no differences (P ≥ 0.25) were observed among Profi, Arvika, and Carneval. Rate of CP degradation differed (P ≤ 0.03) for all cultivars, with Profi being the greatest and Trapper the smallest (10.8, 10.0, 8.1, and 6.3 ± 1.4%/h for Profi, Carneval, Arvika, and Trapper, respectively). Estimated RDP was not different (P = 0.21) for all 4 cultivars. In the second study, 30 crossbred beef steers (301 ± 15 kg) were individually fed and used to evaluate effects of field pea processing (whole, rolled, or ground) on steer performance. Diets contained 40% field pea grain. Growing steers consuming whole field pea had greater ADG (P = 0.08) than those consuming processed field pea (1.69, 1.52, and 1.63 ± 0.05 kg/d, for whole, rolled, and ground, respectively). However, DMI (kg/d and as % of BW) and G:F were not different (P ≥ 0.24). In the third study, 35 individually fed gestating beef cows (694 ± 17 kg) were used to evaluate the use of field pea as a protein supplement for medium quality grass hay (9.3% CP). Treatments consisted of whole field peas at 1) 0 g (CON), 2) 680 g (FP680), 3) 1,360 g (FP1360), and 4) 2,040 g (FP2040), and 5) 1,360 g of 74% barley and 26% canola meal (BCM). Total intake (forage + supplement) of gestating beef cows increased with increasing field pea level (linear, P = 0.01; supplemented vs. nonsupplemented, P = 0.01). In summary, protein quantity and rate of ruminal protein degradation vary across sources of field peas used in this study. Additionally, because of source variability, nutrient analysis and animal requirements should be considered when field pea is incorporated into beef cattle diets. Processing field pea does not improve performance of growing steers. Supplementation of field pea to gestating cows consuming medium-quality grass hay increased total DMI. Overall, our data indicate field pea can be used in a wide variety of beef cattle diets.