Table of Contents
ISRN Veterinary Science
Volume 2013 (2013), Article ID 532528, 8 pages
Research Article

Ruminal Degradability and Summative Models Evaluation for Total Digestible Nutrients Prediction of Some Forages and Byproducts in Goats

1Departament of Animal Nutrition and Forages, Decanato de Ciencias Veterinarias, Universidad Centroccidental Lisandro Alvarado, Tarabana 3001, Venezuela
2Universidad del Zulia, Maracaibo 4005, Venezuela

Received 28 February 2013; Accepted 28 March 2013

Academic Editors: L. Badinga and R. Gamble

Copyright © 2013 Oswaldo Rosendo et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


In in vitro true dry matter degradability (IVTDMD), in situ dry matter degradability, and neutral detergent fiber degradability, both in vitro (IVNDFD) and in situ (ISNDFD) techniques were used with crossbred goats to determine dry matter and neutral detergent fiber (NDF) ruminal degradability in eight forages and four industrial byproducts. Total digestible nutrients (TDN) content obtained with five different summative models (summative equations) were studied to compare the precision of estimates. All these models included digestible fractions of crude protein, ether extract, and nonfiber carbohydrates that were calculated from chemical composition, but digestible NDF (dNDF) was obtained from IVNDFD (IVdNDF), ISNDFD (ISdNDF), or by using the Surface Law approach. On the basis of the coefficient of determination () of the simple lineal regression of predicted TDN (-axes) and observed IVTDMD (-axes), the precision of models was tested. The predicted TDN by the National Research Council model exclusively based on chemical composition only explains up to 41% of observed IVTDMD values, whereas the model based on IVdNDF had a high precision (96%) to predict TDN from forage and byproducts fiber when used in goats.