Internal Indicators of Digestibility in Diets Containing Ammoniated Hay from Leaves of the Babassu Palm in the Maintenance of Goats

Abstract

The efficiency of the indigestible Dry Matter (DMi), indigestible Neutral Detergent Fibre (NDFi), indigestible Acid Detergent Fibre (ADFi) and Indigestible Lignin (LIGi) internal indicators was evaluated as a replacement for the method of total faecal collection in estimating faecal dry matter excretion and Dry Matter (DM) digestibility in diets containing hay from leaves of the babassu palm ammoniated with 4% urea in the maintenance of goats. Total diets, which included 70% hay from Guinea grass or ammoniated hay from leaves of the babassu palm were used. Twenty male goats in metabolic cages, were fed the above diets, with water and a mineral mixture at will. Mixed-model statistical analysis was adopted, with treatments consisting of the diets and the methods for evaluating faecal DM excretion and apparent DM digestibility. The diets were tested by linear regression and t-test to compare the mean values for faecal DM excretion and DM digestibility by total collection and internal indicators. The source of fibre in diets with a high proportion of bulk had an influence (P<0.05) on the estimation of faecal DM excretion and DM digestibility. The DMi NDFi, ADFi and LIGi indicators were recovered efficiently from the faeces and were effective in estimating faecal DM excretion by goats fed 33% hay from leaves of the babassu palm ammoniated with 4% urea as a replacement for Guinea-grass hay. The DMi, NDFi and ADFi indicators are accurate in estimating faecal DM excretion and DM digestibility in goat diets containing fibrous ammoniated hay from leaves of the babassu palm.