Vern Anderson and Jon Schoonmaker
One hundred twenty-seven crossbred heifers (avg. wt. 799.9 ±
11.4 lbs.) were allotted by weight to one of three pea-supplemented diets (4
pens per treatment, 10 or 11 head per pen) to determine the optimum level of
pea processing to maximize cattle performance. The corn-based diets contained
ground, dry-rolled or whole peas as a protein source. Diets were formulated to
contain 13.5% CP with 56.5 Mcal/cwt NEg in the finishing diet. Diets were corn-based and contained
whole, dry-rolled, or ground peas as a protein source. During the first 28-day
period, the diet contained 22% grass-hay, after which cattle were transitioned
to a 15% grass-hay diet, fed until slaughter. The 22 and 15% grass-hay diets
were formulated to contain 13.5% CP and 52.5 and 56.5 Mcal/cwt
NEg, respectively. Cattle were slaughtered at Tyson
Particle size of ground, rolled, and whole peas was 701, 3100, and 9250 microns, respectively. Dry matter intake was greatest (P<.05) for the rolled-pea treatment (22.81 lbs. per hd/day) for the entire feeding period compared to ground (21.21 lbs.) and whole (21.33 lbs.). Intake exhibited a quadratic response (P<.05) to processing treatment during each of the feeding periods with reduced intake for the ground- and whole-pea treatments. Average daily gains were greatest (P<.01) for the rolled- pea treatment for the entire feeding period (3.39 lbs./hd/day) compared to ground (3.12 lbs.) and whole (2.96 lbs.). Statistical differences in gain were greater during period 1 (P<.01) and period 2 (P<.06) than period 3 (P<.15). Feed efficiency expressed as feed per gain or gain per feed was not different during any of the feeding periods or overall (P>.16). Carcass data followed the pattern of rate of gain and final weight with predictable numerical differences observed. Hot carcass weight (P<.13) and yield grade (P<.10) showed the greatest response to treatment with higher values for the rolled-pea treatment.
Heifers consumed more (P<.05) of the dry-rolled pea diet and gained faster (P<.01) than rations with ground or whole peas. No differences in feed efficiency or carcass traits were observed (P>.10). Field peas can be successfully included in feedlot rations with the greatest intake and gain from dry-rolled peas.