Evaluation of turnip forage residue extracted from biodiesel production as supplement for grazing beef cattle

Abstract

Two experiments were performed to evaluate the use of the turnip forage residue extracted from biodiesel production as alternative protein source for grazing zebu cattle. At the first experiment, the performance of Nellore zebu cattle was evaluated on grazing grass. Twenty four animals were distributed in three treatments and allocated on six paddocks, with four animals each and two repetitions. Treatments consisted of supplements with two levels of turnip forage residue (7.5 and 15.0% dry matter) and without turnip forage (control). Pasture availability and quality were also evaluated. At the second trial, degradability of the residue turnip forage was measured in six rumen fistulated zebu cattle fed basal diet composed by grass coast-cross hay and concentrate (35% CP) with 15% of turnip forage. No difference was observed among the treatments for the animal performance, but the steers fed 7.5% of turnip forage residue showed the highest daily gain weight (0.575 kg DGW). The turnip forage residue showed high and fast ruminal effective degradability of the dry matter (83.8%), crude protein (88.9%) and neutral detergent fiber (52.1%). In conclusion, the turnip forage residue can be used as protein source in supplement diet for cattle, shifting the conventional protein sources up to 15% in supplement with 35% of total crude protein.