Terminação de bovinos alimentados com grão de milho e/ou aveia branca, sem volumoso

Abstract

The objective was identify the maximum productive efficiency of feedlot finished steers submitted to diets in which corn grain is replaced by white oat grain without the use of roughage. Forty-five non-castrated, Charolais x Nellore cross steers, with initial age of 18 ± 0.22 months and initial weight of 259.4 ± 31.67 were used. The experimental design was completely randomized. The cattle were randomly distributed according to the level of replacement of corn grain by white oat grain, as follows: 0; 25; 50; 75 and 100%. The diets were composed of 85% grain and 15% mineral-protein-vitamin nucleus. Feeding intake presented quadratic behavior due to the replacement of corn grain by white oat grain. Low dry matter intake in these diets resulted in consumption of neutral detergent fiber, crude protein and total digestible nutrients. Cattle in the period of adaptation to the experimental diet presented an evolution in body weight gain, indicating adequate food management. During the experimental period, average daily gain presented a quadratic response to the inclusion of white oat, with a maximum point of 47%. Biological efficiency, measured by different forms, had a quadratic behavior with maximum efficiency when 20 to 40% of white oat were added, instead of corn. Rumination time presented a quadratic behavior with the inclusion of corn replacement by white oat, with the maximum point adjusted to a diet of 54% white oat grain. Minimum rumination efficiency points of DM and NDF were set at 52.7 and 48.36% of white oat grain, respectively. Finishing feedlot beef cattle in diets without the use of roughage is a viable alternative to be used, and the association of the grains showed better conditions for the steers to present excellent productive responses. The replacement of the corn grain by white oat grain in the proportion of 40 to 60% of substitutions were the intervals in which the steers presented better productive, biological performances and better feeding behavior.