Concentrate Supplementation Frequency Effects on Early-weaned Beef Calves Grazing Annual Ryegrass

Abstract

The objective of this study was to evaluate the concentrate supplementation frequency effects on forage characteristics and performance of early-weaned beef calves grazing annual ryegrass (Lolium multiflorum). The experiments were conducted in Ona, FL from February to April (Exp. 1) and June (Exp. 2) 2019 and 2020. In Exp. 1, thirty-two early-weaned calves (82±12 d of age) were allocated to 8 annual ryegrass pastures (4 calves/pasture) and supplemented with 1% BW. Treatments were 2 concentrate supplementation frequencies, daily (DAILY) or three times per week (3X; Monday, Wednesday, and Friday) distributed in a randomized complete block design with 4 replicates. Calves receiving the 3X treatment had the daily supplement level multiplied by 7 d and divided by 3 feeding days. Pastures (experimental units; 0.4 ha/pasture) were grazed with a continuous and fixed stocking rate. There was no difference in herbage mass (P = 0.85; mean = 3050 kg/ha), herbage allowance (P = 0.91; mean = 3.0 kg DM/kg BW), CP (P = 0.88; mean = 17.5%), and in vitro digestible organic matter (P = 0.82; mean = 74%). In addition, there was no difference in ADG (P = 0.60, mean = 0.65 kg/d), plasma urea nitrogen (P = 0.88; mean = 10 mg/dL), and glucose (P = 0.45; mean = 72 mg/dL). In Exp. 2, twenty early-weaned calves from Exp. 1 were maintained in the same treatment and placed in a drylot with individual stall for forage DM intake, total DM intake, and in vivo digestibility measurements. Treatments were the same described in Exp. 1 distributed in a randomized complete block design with 10 replicates. Calves receiving the DAILY treatment had greater forage DM intake (P = 0.02; 1.8 vs. 1.6% BW), total DM intake (P < 0.01; 2.7 vs. 2.5% BW), and in vivo digestibility (P < 0.01; 87 vs. 85%) than 3X. Feeding three times per week may be a feasible management practice to decrease the cost of labor related to feeding early-weaned beef calves.