Productive performance and ingestive behaviour of feedlot finished Santa Ines lambs on diets containing differing fibre levels.

The aim of this study was to determine the ideal level of neutral detergent fibre (NDF) that maximises productive performance and to evaluate the ingestive behaviour of feedlot Santa Inês lambs. Diets consisted of Tifton 85 grass hay (Cynodon sp.), with particle size from 1 to 2 cm, and concentrate, and the treatments were represented by different NDF levels (20, 32, 44, 56 and 68% NDF dry matter). There was a quadratic effect (P < 0.05) for the intake of dry matter, organic matter and crude protein, with maximum intake estimated at 27, 26 and 27% NDF. There was a quadratic effect (P < 0.05) for digestibility of crude protein and NDF, with the lowest digestibility estimated at 40 and 37% NDF. There was a quadratic effect (P < 0.05) for weight gain, average daily gain and feed efficiency, with maximum gains estimated at 27, 29 and 30% NDF. There was an effect (P < 0.05) of NDF levels on variables of ingestive behaviour periods/day of feeding, rumination and idle. For the feedlot Santa Inês lambs fed diets based on Tifton 85 grass hay, we recommend 27 - 30% neutral detergent fibre. [ABSTRACT FROM AUTHOR]