PSXIV-36 Effect of corn variety and amylase enzyme on cattle performance and carcass characteristics

Four hundred and thirty-three Angus and Angus cross-bred steers (Body Weight 344 ± 13.3 kg) were utilized in this experiment to compare different varieties of grain corn and α-amylase enzyme on feedlot cattle performance and carcass characteristics. Steers were blocked by body weight and breed and randomly assigned to treatments. Treatments consisted of: 1) Commercial commodity corn (CON); 2) Experimental test corn (TEST;), 3) 50:50 blend of CON and TEST corn sources (BLEND), and 4) CON with 5g of α-amylase enzyme added/hd/d (AMZ; Amaize®, Alltech). Steers were slaughtered after 138 days on feed. Feedlot performance, net energy recovery, hot carcass weight, dressing percentage, subcutaneous adipose tissue depth, longissimus muscle area, marbling score, and calculated yield grade data were analyzed as a randomized complete block design using PROC MIXED of SAS. Dietary treatment had no effect (P > 0.20) on BW, average daily gain, feed efficiency, or net energy recoveries. There was a tendency for daily dry matter intake (DMI) to be influenced by treatment: d 0 – d 90 (P < 0.09), d 91 – slaughter (P = 0.11), and d 0 – slaughter (P < 0.08). Dry matter intake was consistently greater for steers receiving the AMZ treatment when compared to all other treatments. Daily DMI for the TEST treatment was consistently lower than DMI for all other treatments. Hot carcass weight (P = 0.56), dressing percentage (P = 0.10), 12th subcutaneous fat depth (P = 0.88), longissimus muscle area (P = 0.84), yield grade (P = 0.91), marbling score (P = 0.76), quality grade (P = 0.67), and the distribution of USDA yield and quality grades (P > 0.74) were similar across treatments. These results indicate the value of the TEST corn as an energy source in feedlot cattle diets is similar to the value of COM corn an energy source.