Effects of sampling time on internal markers concentration and fecal recovery in dairy cows

•Fecal recovery was variable throughout the day and dependent on internal maker used.•Indigestible DM, NDF, and ADF had partial fecal recovery.•Fat supplementation affected fecal output and digestibility estimation using different markers.•The lowest concentration of markers occurred one hour after the morning feeding.•The highest concentration of marker was observed between 15:00 and 24:00 h.