Effect of Supplemenation Method on Supplement Intake and Performance of Steers Grazing Dormant Tallgrass Prairie.
Abstract
The objective of this experiment was to determine the effect of supplementation method (hand-fed vs. ad-libitum access) on supplement intake and performance of beef steers grazing dormant native tallgrass prairie. The experiment was conducted for 56 d in late winter in central Oklahoma. Angus x Hereford steers (n = 40; BW = 242.6 ± 3.6 kg) were randomly assigned to one of three supplementation methods; either control (CON; no supplement; n = 8), hand-fed (HF; n = 16), or self-fed (SF; n = 16). Both the HF and SF treatments received a supplement consisting of 80% soybean meal and 20% soybean hulls (TDN = 76.6 %, CP = 43.9 %; DM basis). Sixteen steers were assigned to the HF, where 4 steers received either 0.39, 0.78, 1.17, or 1.56 kg per day, fed 3 days per week in individual stanchions. Sixteen steers were assigned to the SF group and received supplement via the SmartFeed system (C-Lock Inc., Rapid City, South Dakota). The SmartFeed is a portable, self-contained system designed to measure individual feed intake. The SF group had ad libitum access to supplement, to which NaCl was added to achieve mean intake of approximately 1.0 kg/d. The overall mean intake of supplement in SF ranged from 0 to 1.21 kg per steer per day. The CV for the SF animal on mean intake was 50.8% and animal on day-to-day intake was 96.7%. The mean NaCl that was present in the SF supplement was 40.5% and NaCl intake averaged 0.39 kg/d. Steers were weighed weekly and ADG and supplement efficiency was regressed on supplement intake, supplementation method, and the interaction. No significant difference between treatment group was detected for ADG (P = 0.24) or supplement efficiency (P = 0.30) regressions. Aggregated CV of weekly intake with animal significantly (P ? 0.01) decreased residual ADG and residual supplement efficiency. Steers grazing dormant tallgrass prairie with minimal change in weekly supplement intakes had a slightly greater ADG and supplement efficiency. Directly managing supplementation may be more efficient than traditional, self-fed approaches that rely on NaCl as a limiter.
Collections
- OSU Theses [15752]