Effects of corn processing and dietary fiber source on feedlot performance, visceral organ weight, diet digestibility, and nitrogen metabolism in lambs

In Exp. 1, early-weaned Targhee and Polypay crossbred lambs (60 ewes and 66 rams; initial BW 24 +/- 1.0 kg) were used in a 2 x 3 factorial experiment to determine the effects of corn processing (whole shelled corn [WSC] or gr ound and pelleted corn [GC]) in combination with supplemental fiber (none [ control]; soybean hulls, SBH [highly digestible]; or peanut hulls, PH [high ly indigestible]) on DMI, ADG, feed efficiency, and visceral organ weight. For the total trial, WSC resulted in a 4% increase (P < .01) in ADG vs GC, and supplemental fiber resulted in increased (P < .01) DMI and ADG vs the c ontrol diet. Experiment 2 was conducted using 12 Targhee and Polypay crossb red wether lambs (initial BW 25 +/- 7 kg) to determine the effects of corn processing and fiber source in high-concentrate diets on diet digestibility and N retention using the same diets as in Exp. 1. Lambs fed WSC had great er (P < .001) apparent N digestion, true N digestion, and N retention(P < . 01) than those fed GC. The apparent digestibilities of DM, OM, and NDF were greater (P < .001) for WSC than for GC diets. Peanut hulls resulted in dec reased (P < .01) DM, OM, and NDF apparent digestibilities compared with the control and SBH diets. Starch digestion was not affected (P > .10) by diet . Whole corn resulted in improved DM, OM, NDF, and N digestibility compared with GC. Overall, both the SBH and PH diets resulted in greater DMI and AD G than the control diet, which lacked supplemental fiber.