Growth Performance of Weaned Pigs Fed Raw, Cold-Pelleted, Steam-Pelleted, or Extruded Field Pea

Field pea can be an alternative starch and protein source for swine. However, pigs fed raw field pea immediately after weaning have reduced G:F. Whether heat processing can increase nutritive value of field pea for weaned pigs remains unclear. To explore, field pea ingredient was ground (Hammer mill; 10/64” screen), or processed using cold-pelleting, steam-pelleting, or extrusion, and then re-ground (Hammer mill; 8/64” screen). Field pea was cold-pelleted at 70-75ºC (Model PM 1230, Buskirk Engineering, Ossian, IN), steam-pelleted at 80-85ºC (Model 1116-4, 70 hp; California Pellet Mill, Crawfordsville, IN), or extruded at 115° C (Model X115, Wenger, Sabetha, KS). Diets contained 40% raw, cold-pelleted, steam-pelleted, or extruded field pea replacing 30% soybean meal (SBM) and 10% wheat grain, and were formulated to provide 2.4 Mcal NE/kg and 1.2% standardized ileal digestible Lys and other AA were balanced for ideal ratio. A total of 236 pigs (initial BW: 10.0 ± 0.85 kg; weaned at 20 d) were housed in 60 pens in 4 nursery rooms. The study was a randomized complete block design with 5 pens per block. In total, there were 12 pens per diet with 4 pigs per pen. Each pen was fed 1 of 5 diets starting 2 wk post-weaning for 3 wk. Data was analyzed with the MIXED model of SAS with diet and week as fixed effects, block as random effect, and pen as the experimental unit. Overall (d 0–21), the ADFI was greater (P < 0.05) for pigs fed diets containing raw, cold-pelleted, or extruded field pea diets (869, 878, and 878 g/d, respectively) than pigs fed the SBM diet (807 g/d). The ADG did not differ (P > 0.05) between pigs fed the SBM diet or pigs fed field pea diets. Consequently, G:F was lower (P < 0.05) for pigs fed diets containing raw, cold-pelleted, or extruded field pea (0.61, 0.61, and 0.62, respectively) than for pigs fed SBM diet (0.67). Final BW of pigs fed raw, cold-pelleted, steam-pelleted or extruded field pea, or SBM diets were 21.3, 21.2, 21.4, 21.5, and 21.5 kg, respectively, and were not affected (P > 0.05) by feeding field pea and/or processing. In conclusion, weaned pigs fed raw field pea 2 wk post-weaning can maintain growth but not G:F. The reduced G:F in weaned pigs could not be ameliorated by processing the field pea using cold-pelleting, steam-pelleting, or extrusion.