PSXV-23 - Effects of a nutritional packet composed of live yeast, vitamins, and electrolytes on the feeding behavior of intensively managed beef steers

The effect of a nutritional-packet was evaluated on time spent ruminating, eating, and chewing (ruminating + eating) by intensively managed beef steers consuming a finishing diet during the final 65 d of feeding prior to slaughter. Furthermore, the influence of behavior on CH₄ production was determined. Twenty-four Angus-crossbreed steers were distributed into pens with SmartFeed (C-Lock) technology in which they were treated with: control or nutritional-packet [0.29% DM basis; live yeast (8.7 Log CFU/g); Vitamin C (5.4 g/kg); Vitamin B1 (13.33 g/kg); NaCl (80 g/kg); KCl (80 g/kg)]. An ear tag containing multiple accelerometers (CowManager) was placed on steers, and such device continuously recorded rumination and eating time (min/day). Enteric CH₄ emissions were measured for 15 d using the SF₆ tracer technique. Feeding behavior data were analyzed as a randomized complete block design using the MIXED procedure of SAS. The model included the fixed effect of treatment and the random effect of block. Steer was considered experimental unit. The GLM procedure of SAS was used for regressing behavior and CH₄ production data. There were no differences between treatments for time (within 24 h) spent ruminating, eating, or chewing (P ³ 0.197). When nutrient intake was taken into account, no differences (P ³ 0.139) were observed between treatments for time spent ruminating, eating, and chewing per kg of dry matter, organic matter, neutral detergent fiber intake, and acid detergent fiber intakes. The production of CH₄ was not affected by time spent ruminating (0.93 g/min; R² = 0.0003; P = 0.935), eating (3.34 g/min; R² = 0.03; P = 0.409), or chewing (0.69 g/min; R² = 0.006; P = 0.728). The feeding behavior of intensively managed beef steers during the final 65-d of feeding was not driven by the nutritional-packet supplied, neither was CH₄ production associated with feeding behavior variables measured.