PSXIII-13 - Feeding carbohydrases to grazing beef cattle under different nutritional strategies on dry season: feeding behavior

The aim with this trial was to evaluate two nutritional plans with the addition of dosages of carbohydrases enzyme blend on feeding behavior of grazing Nellore bulls in rainy season. One hundred and two contemporary Nellore steers (BW = 294.10 ± 3.35 kg) were equally distributed in six paddocks (17 steers/paddock) following a completely randomized design in a 2x3 factorial arrangement, being the factors two nutritional plans: mineral-proteic supplementation (Fosbovi^® Proteico 35; PS) offered at 0,1% BW or mineral-protein-energetic supplementation (Fosbovi® Proteico-Energético 25; PES) offered at 0.3% BW); and three levels of enzymatic carbohydrases blend (0, 4,75 or 9,50 g/animal/day). The enzymatic blend was mainly composed by beta-glucanase and xylanase enzymes (Ronozyme^® VP and Ronozyme^® WX); Both enzymes and supplemented were provided by DSM Nutritional Products Brasil S.A. Feeding behavior data were collected daily and individually by an automatic scale/feeder system installed in the paddocks. Data were analyzed using PROC MIXED of SAS. Animals fed PES presented greater number of visits to the feed bunks (19.73 vs. 10.12 visits/day; P < 0.0001), to the water fountains (2.95 vs. 2.32 visits/day; P < 0.0001) and greater water intake (22.43 vs. 17.73 L/day; P < 0.0001) in comparison with animals fed PS treatments. Also, animals receiving PES spent more time taking supplement (1.332 vs. 545 seconds/visit; P < 0.0001) and water (203 vs. 153 seconds/visit; P < 0.0001) then PS animals did. No linear and quadratic effects were observed for feeding behavior when including carbohydrases enzymes to PES or PS supplement. PSE nutritional plan positively influence feeding behavior of Nellore bulls in dry season, increasing cattle feed bunk access and water intake in a daily basis.