EFFECTS OF CONCENTRATE LEVELS AND OIL SUPPLEMENTATION IN DIETS ON RUMEN CHARACTERISTICS AND PERFORMANCE OF CATTLE - N. T. Ngu; N. T. H. Nhan; N. V. Hon; L. T. Danh; Duong Minh Vien; Luu Huynh Anh; Nguyen Hong Xuan (Journal of Animal and Plant Sciences, 2019)