Use of markers for estimation of feed digestibility in cattle

Abstract

The objective of this work was to evaluate external and internal markers in studies of partial and total digestibility in cattle. Chromic oxide (Cr₂O₃) was used as external marker and acid-insoluble ash (AIA) and indigestible neutral detergent fibre (INDF) as internal markers. The animals were fed a diet 13.7% crude protein (CP), with 50% concentrate and 50% forage. Four Holstein steers with 320 kg average body weight implanted with ruminal and duodenal cannulas, and three cows with ruminal cannula for INDF determination were used. The experiment was carried to study duodenal and faecal dry matter (DM) and organic matter (OM) flows estimated by markers. To compare markers, the averages for DM and OM flow were estimated using the trust interval, and the coefficient of variation of average estimation. Under the conditions of the present work it was concluded that chromic oxide presented higher precision than AIA and INDF for estimation of DM and OM flows.