PSXII-37 Effect of diets with different levels of fiber in neutral detergent for finishing of lambs in drylot conditions.

摘要

The objective of this research was to evaluate the dry matter intake, feed conversion and feed efficiency of confined sheep fed diets at different levels of neutral detergent fiber. The experiment was out at the Sheep Research in facilities of the Federal University of Rio Grande do Norte - Natal / RN, Brazil. Twenty four lambs of the Dorper genotype, not castrated, weaned and confined in the second month of life (16.8 ± 3.53 kg) were used during a period of 70 days. The experimental diets were isoproteic (15% crude protein) and composed of concentrate and tifton 85 hay (Cynodon dactylon), differing in relation to the neutral detergent fiber content (21, 30, 39 and 48%) calculated by different relations roughages: concentrated, with ad libitum offer. The leftovers were weighed daily, feed consumption calculated and the adjustment of the offer so as to allow 10% leftovers. The experimental design was completely randomized, with four treatments and six replicates. The animals fed levels of 30 and 39% of NDF had higher values for dry matter intake (g /day, metabolic weight, live weight), while the 48% level of NDF had less consumption, possible due to ruminal repletion due to high fiber. The same was seen with the conversion data and feed efficiency, better results were found with diets containing lower fiber. The animals fed with 48% of fiber had averages for conversion and feed efficiency of 7.37 and 14.23, respectively. However, the treatment with 21%of NDF the averages were 3,71% and 27,5%, respectively, this result is explained by the high energetic density of diet due to high quantity concentrate. It is concluded that the 21% NDF level is more recommended because it promotes better performance for finishing in drylot conditions lambs.