Individual FA concentrations were calculated by taking the specific FA area as a percentage of the total FAs and were reported as g/100g FA methyl
esters. Apparent nutrient digestibility was measured during the last week in each period using acid-insoluble ash (AIA) as an internal marker (McGeoughetal.,2010). The fecalsamples (approximately 250 g wet weight ) were collected from the rectum of cows twice daily for 5 day sbeginning on day 16. The fecal samples were composited across sampling times per each cow,dried at 60 C in a forced air oven for
72 h, ground to pass a 1-mm screen and stored for chemical analyses. Chemical composition of the fecal samples was determined according to the procedures mentioned previously (Mc Geoughetal.,2010).