The effect of different neutral detergent fiber (NDF) levels in the diet on the Ile de France x Texel lambs ingestive behavior was evaluated. Twenty lambs distributed in a fully randomized experimental design were used, in a total of four treatments and five repetitions, fed ad libitum with 25%, 31%, 37% and 43% NDF diets. A ration in a complete mixing in sorghum silage (AG 2005 E) and concentrate mixing of soybean meal, fragmented corn grains and mineral mixing was used. The diets were isoproteic (17% crude protein) and were given twice a day, at 8 AM and 4 PM. The ingestive behavior was determined by observation, during 24 hours with 5 minutes intervals, to determine the time spent in feeding, rumination and idleness. The increase of the fiber level in the feed did not effect (P>0.05) on the time spent in feeding, rumination, idleness and total chewing time. The rumination and feeding efficiency increased linearly (P<0.05), as the dietary NDF levels increased. The feedlot sheeps have predominantly diurnal habit of feeding and nocturnal of rumination
feeding; idleness; sheep; rumination
