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Effect of corn residue harvest method and monensin inclusion on performance of growing cattle
An 89-d growing study utilizing 60 crossbred steers (initial BW= 309 ± 27 kg) was conducted to evaluate the impact of alternative corn residue harvesting methods on cattle performance. Steers were individually fed in a Calan gate system and were limit fed a common diet of 50% alfalfa and 50% wet corn gluten feed at 2% of BW for 5 d followed by 3 d weights at the beginning and end of the experiment. Steers were implanted on d 1 with Ralgro. Steers were blocked by initial BW into 10 blocks and were assigned randomly to 1 of 6 treatments within block. Diets consisted of 1 of 4 forages: sorghum silage, corn stalks, husklage, or ensiled husklage. Stalks were harvested by raking and baling after grain harvest. The husklage was collected and baled directly behind the combine and contained 27% leaf, 17% husk, 14% upper stem, and 42% cob. Two additional ensiled husklage diets were fed either, with or without monensin on a 3 week rotation. All diets included 3% SoyPass and 30% wet corn gluten feed. Feed refusals were collected and weighed weekly. Steers fed sorghum silage had the greatest DMI at 9.55 kg/d and greatest ADG at 1.48 kg (P < 0.01) compared to other forages. Steers fed husklage had greater ADG, DMI, and an improved G:F ratio compared to cornstalks (P < 0.01). Steers fed cornstalks had the lowest DMI, ADG, and G:F ratio (P < 0.01). Ensiling husklage resulted in an increase in DMI and ADG (P < 0.05) but did not change G:F ratio (P = 0.13) compared to husklage that was not ensiled. Steers consuming husklage and ensiled husklage refused 5-8% of their daily feed offering vs. 2% for the cornstalks. Steers receiving monensin for 89 d had the greatest ADG (P < 0.01), while there was no difference between no monensin and rotating monensin. Steers not fed monensin had the lowest DMI (6.79 kg) with steers fed monensin having the greatest (7.70 kg; P = 0.04) and steers rotating monensin being intermediate (7.05 kg). No effect of monensin inclusion on G:F was observed (P > 0.12). Changing the harvest method of the corn residue may improve forage quality compared to conventional stalks.
Keywords: Corn residue, growing cattle, harvest method