Adjustment of physically effective fiber sources in diets for beef cattle

Abstract

In view of the increasing trend of using high-concentrate diets for feedlot cattle, more studies are necessary for the quantification of physical effectiveness value of fiber as a parameter for minimum inclusions of forage or for the substitution of fiber sources in total mixed ration. Thus, these studies aim to avoid lack of response in animal performance, minimizing metabolic problems and consequently increasing profit. On the other hand, different protocols are used to measure the physical effectiveness of a feed which may create a considerable difference in effectiveness value for the same feed. Therefore, it becomes desirable to analyze this physical effectiveness value of forage and by-product utilizing biological methods, since variation in the effectiveness value of the same ingredient may cause different inclusions in the ration. Thus, the objective of this study is: to determine the physical effectiveness of the forages and by-products such as the fresh sugarcane, sugarcane bagasse, soybean hulls and high oil cottonseed meal compared to corn silage, utilized as a standard ingredient; to compare this physical effectiveness value utilizing biological and laboratorial methods; furthermore to determine the effect of different fiber sources on the overall nutrient digestion in feedlot cattle diets. (AU)