The Effect of Harvest Method and Ammoniation of Corn Residue on Growing Calf Performance

Corn residue is a valuable feed resource for cattle, and both harvesting technologies and chemical treatment can influence the feeding value of baled residue. Utilizing 120 crossbred steers (319 ± 22 kg), a randomized complete block design study with a 3 x 2 factorial treatment structure was conducted with the objective of assessing animal intake, gain, and feed efficiency when fed diets containing corn residue harvested using three different methods, with or without ammoniation. Animals were individually fed one of six diets for 84 d via Calan gates. Diets contained 65% baled corn residue which was either untreated or ammoniated, and harvested one of three ways: conventionally harvested rake-and-bale method (CONV), harvested using the New Holland Cornrower™ with two rows of stem chopped into the windrow with tailings (2ROW), or harvested using the EZ-Bale system (EZB) with a disengaged combine spreader and all tailings added to the windrow. Randomly selected bales of each harvest method were chemically treated with anhydrous ammonia at 3.7% of DM for 60 d in late fall (CONVAM, 2RAM, EZBAM). The remaining diet ingredients consisted of 30% wet distillers grains and 5% supplement which contained trace minerals, limestone, monensin and Soypass. No interactions (P = 0.40) between harvest method and chemical treatment were observed. Corn residue harvested as 2ROW resulted in increased (P <0.01) ADG (1.06 kg/d) compared to CONV (0.96 kg/d) and EZB (0.99 kg/d), which did not differ (P = 0.27). Harvest method also significantly (P < 0.01) affected total diet intake, with 2ROW treatments eating 1.96% BW compared to 1.73% BW and 1.72% BW for CONV and EZB, which did not differ (P = 0.82). Ammoniation increased ADG from 0.75 kg/d to 1.26 kg/d over non-ammoniated residue regardless of harvest method (P < 0.01). Feed efficiency was not affected by harvest method (P = 0.61), but ammoniation increased (P < 0.01) G:F from 0.1582 to 0.1793 over non-ammoniated residue. Although alternative harvest technologies can improve animal performance by changing the proportion of less digestible plant parts (stem and cob) to more digestible plant parts (leaf and husk), chemical treatment of corn residue with anhydrous ammonia has a considerably greater impact on ADG and feed efficiency of growing cattle.