Two experiments were implemented aiming to find out the appropriate neutral detergent fiber (NDF)
levels in the crossbred beef cattle diets for improving the growth rate and roughage utilization. In the first experiment,
four male Charolais crossbred cattle (Charolais x Zebu crossbred) with 17.6±1.49 months of age and 255±30.1 kg live
weight (mean±SD) were used in a 4x4 Latin square design. Four treatments were 47, 51, 55, and 59% NDF in diets
(DM basis) corresponding to NDF47, NDF51, NDF55 and NDF59 treatments. In the second experiment, a total of
30 crossbred beef cattle were assigned into three groups (Charolais, Black Angus and Wagyu) which each consisted of
ten animals (5 males and 5 females). The experiment consisted of a 7 days adaptation period when crossbred cattle were
introduced to the pens and experimental diets (from the result of experiment 1), followed by a 90-day experimental
period. Results of the first experiment demonstrated that enhancing NDF percentage in the diets of the cattle from
47 to 59%, the dry matter and organic matter digestibility were gradually reduced (Psignificant differences between the NDF47 và NDF55 treatment (P>0.05). Before and 3 h after feeding the rumen
pH values, N-NH3 and total volatile fatty acids concentration of cattle were no differences and good for the rumen
activities. In this research content, the NDF55 treatment revealed an expectation for the applied studies. Results of the
second experiment indicated that with the NDF 55% in the diets, the Charolais crossbred cattle showed a superior
trend on feed intake, daily weight gain and feed conversion ratio compared to the Black Angus and Wagyu crossbred
ones. Therefore, the recommendation of this study was that the dietary NDF level of 55% could be appropriate for the
crossbred beef cattle.
Keywords | Neutral detergent fiber, Beef production, Digestion, Growth performance, Ruminants