title: Protein sources for finishing calves as affected by management system.
abstract: Two beef production systems were evaluated in conjunction with an evaluation of escape protein sources for finishing calves. Two hundred forty crossbred steers and 80 crossbred heifer calves (BW = 267 +/- 2 kg) were split into two groups: 1) control, finished (207 d) after a 3-wk feedlot adjustment period and 2) grazing cornstalks for 74 d after a 3-wk feedlot adjustment period, then finished (164 d). Finishing treatments were sources and proportions of supplemental CP: 1) urea 100%; 2) soybean meal (SBM) 100%; 3) blood meal (BM) 50%, urea 50%; 4) feather meal (FTH) 50%, urea 50%; 5) SBM 50%, FTH 25%, urea 25%; 6) SBM 25%, FTH 38%, urea 37%; 7) FTH 25%, BM 25%, urea 50%, and 8) FTH 38%, BM 13%, urea 50%. Treatments 1 to 8 were fed in dry-rolled corn (DRC)-based diets. Treatments 9 and 10 were supplement Treatments 1 and 7 fed in diets based on high-moisture corn. Calves finished after a 74-d period of grazing cornstalks consumed more feed (P < .01) and gained faster (P < .01) but were less efficient (P < .05) than calves finished directly after weaning. Although not statistically different, calves finished after grazing cornstalks and supplemented with natural protein in the feedlot were 7% more efficient than calves supplemented with urea alone. Efficiency of calves finished directly after weaning was similar for calves supplemented with natural protein or urea alone. Supplementing SBM/FTH/urea or BM/FTH/urea improved feed efficiency compared with supplementing FTH/urea alone. These data suggest that allowing calves to graze cornstalks before finishing is a possible management option, but this system may require more metabolizable protein in the finishing diet to maximize feed efficiency if the calves are expressing compensatory growth.
authors: Department of Animal Science, University of Nebraska, Lincoln 68583-0908.
authors: M H
authors: MH
authors: Sindt
authors: R A
authors: RA
authors: Stock
authors: T J
authors: TJ
authors: Klopfenstein
authors: B A
authors: BA
authors: Vieselmeyer
mesh_terms: D000821:Animal Feed; D000822:Animal Husbandry; D000818:Animals; D002417:Cattle / Q000254:growth & development*; D004044:Dietary Proteins / Q000008:administration & dosage*; D004435:Eating; D005260:Female; D005527:Food, Fortified; D008297:Male; D011897:Random Allocation; D014886:Weaning; D015430:Weight Gain; D003313:Zea mays
chemical_list: D004044:Dietary Proteins