349 Effects of Adding a Yeast Blend to Diets with High Levels of Dried Distillers Grains on Feeding Behavior, Intake, and Performance of Beef Cattle Fattened in Feedlot

Abstract

Abstract Feeding ruminants with a blend of autolyzed yeast grown on sugarcane molasses and live yeast allows nutritionists to explore synergistic effects on digestion and performance (Angulo et al.,2021; Zapata et al., 2021). However, the feeding behavior and the challenges faced in large pen feedlot operations differ from the behavior and challenges faced by animals studied in small groups or metabolic cages. Therefore, we aimed to study the feeding behavior and performance of beef cattle fed in groups in large pens, mimicking the feedlot operations of leading producers and exports of meat in the world. The trial lasted 112 days and was conducted in Nutripura’s research center in the midwest of Brazil. Six hundred five non-castrated males (Nelore and F1 Nelore-Angus), 405 kg (± 35), distributed in 20 pens, were divided into two treatments: 1) Control, a diet with no yeast additives; 2) Yeast Blend (YB), a diet with a blend of autolyzed yeast and live yeast, SymbioYeast, 7g/anima/day (ICC, São Paulo, Brazil). Both diets contained monesin (28 mg/kg DM). The data were analyzed in the software SAS following the model Yijk= μ+Ti + Fj + Bk +еijk (μ = general mean; T = treatment effect; F = Breed effect; B = backgrounding phase effect; e = error). Initial body weight was used as a covariable to analyze final body weight and average daily gain (ADG). Dry matter intake increased (P < 0,05) when animals were supplemented with YB (10,99kg vs. 11,12kg). Final body weight and hot carcass weight tended (0.1 > P ≥ 0.05) to increase when YB was added to the diet. (598 kg vs. 602 kg, 343 kg vs. 345 kg). The ADG was unaffected (P = 0.1069, control 1.735 kg, and YB 1.768 kg). Increasing DMI is a well now property of some yeast derivatives (Torres et al., 2022). This may be related to changes in digestion (Torres et al., 2022) and the diet’s palatability. The palatability of yeast products is claimed on organoleptic and flavor characteristics (Tao et al., 2023). Drone photos taken every 15 minutes suggested that YB altered how animals interact with feed. Feed was delivered between 0700 h and -0930 h and 1300 h and 1530 h. After delivery, a greater percentage of the visit of the animals to the feed bunkers in YB groups. This behavior was even more evident in the morning feed delivery (Figure 1). In summary, YB increased intake and performance. It also changed the interest of animals in visiting feed bunk.