Two experiments were conducted to evaluate the number of days required for total fecal collection and the viability of using the indigestible dry matter (iDM), indigestible neutral detergent fiber (iNDF), and indigestible acid detergent fiber (iADF) internal markers to determine the fecal excretion of dry matter (FEDM) and digestibility in nutritional trials with small ruminants. Eight sheep in the first experiment and eight goats in the second experiment were distributed into two 4 × 4 Latin square designs. There were no significant differences between days of total fecal collection for FEDM; digestibility of dry matter (DM), organic matter (OM), crude protein (CP), ether extract (EE), neutral detergent fiber corrected for ash and protein (NDFap), and non-fibrous carbohydrates corrected for ash and protein (NFCap); and total digestible nutrients (TDN) in both species. The results suggest that only 1 day of total collection is sufficient to obtain the FEDM and the digestibility of the nutritional components in sheep and goats. The markers are efficient in determining fecal production and digestibility in these animal species.
Keywords: In situ; Internal markers; iNDF.