Intake, digestibility, performance, and nitrogen metabolism of feedlot-finished young bulls (Bos indicus) fed diets containing peanut cake

摘要

This aim of this study was to evaluate the use of peanut cake as a dietary substitute for soybean meal and to determine the effects on intake, apparent digestibility, performance, and N metabolism in feed-lot-finished young bulls. Thirty-two young Nellore bulls with an average initial BW of 390 +/- 43.5 kg were distributed in a completely randomized design and individually housed in stalls. The young bulls were fed Tifton 85 hay and 4 concentrate mixes containing 0, 33, 66, or 100% peanut cake replacing soybean meal. The diets were formulated to be isonitrogenous, containing 150 g/kg CP, and isocaloric (65% TDN), to have a 40: 60 forage: concentrate ratio, and were provided as a total mixed ration. The experiment lasted 90 d and data were collected every 28 d. Blood and urine samples were taken during the last 6 d. Intakes of DM (P = 0.005), OM (P = 0.006), CP (P = 0.002), NDF (P = 0.022), nonfiber carbohydrates (P = 0.002), and TDN (P = 0.018) linearly decreased as the dietary inclusion of peanut cake in the diet was increased. Conversely, intake and ether extract digestibility linearly increased (P 0.035). The average daily weight gain decreased (P = 0.015) as the peanut cake levels were increased. Plasma urea N decreased (linearly; P = 0.005). Peanut cake may not be used to replace soybean meal in the diet of young feedlot-finished Nellore bulls.