PSVII-18 - Feeding Behavior of Beef Steers Consuming Finishing Diets with an Added Nutritional Packet in a Calf-fed System

Abstract: The effects of a nutritional packet containing a direct-fed microbial combined with vitamins/electrolytes offered at the beginning and end of the finishing phase to beef steers in a calf-fed system on feeding behavior were evaluated. Angus crossbred steer-calves (n = 18; BW = 234 ± 4 kg) were assigned to a randomized complete block design (block = body weight; steer = experimental unit) and stratified into two treatments: a) control (no packet, finely-ground corn carrier only); and b) 30 g of DM/animal-daily of a nutritional packet [live-yeast (Saccharomyces cerevisiae; 8.7 Log CFU/g), vitamin C (5.4 g/kg of ascorbic acid), vitamin B1 (13.33 g/kg of thiamine hydrochloride), and electrolytes of NaCl (80 g/kg) and KCl (80 g/kg)]. Animals were individually offered [electronic feed-bunks (Smart-Feed/C-Lock Inc.)] a steam-flaked corn-based finishing diet ad libitum once daily for 233 d, while treatments were offered during the first (phase-1) and last 60 d (phase-2) on feed only. Feeding behavior activities were assessed in min/d by using CowManager^TM ear tag sensors. Data were analyzed using the GLIMMIX procedure of SAS. There was no treatment × phase interactions (P ≥ 0.15), except that steers receiving the nutritional packet tended (P = 0.10) to spend more time (6 vs. 9 min/kg) eating digestible DM during phase-2 only. Regardless of phase, steers consuming the nutritional packet spent more time (P = 0.04) eating per kg of hemicellulose. Regardless of treatment, a decreased rumination (P ≤ 0.03) and chewing (P ≤ 0.01) activity-variables were observed for the phase-2 compared to phase-1. Steers receiving the nutritional packet exhibited superior time spent on eating activities, especially during the final 60 d before slaughter, and fiber seems to be the major driver inducing such effect. Towards the end of the finishing phase, cattle reduced rumination and chewing compared to the arrival phase.