AMMONIA TREATMENT FOR SUGAR-CANE HARVEST RESIDUES .1. DIGESTIBILITY AND CRUDE PROTEIN-CONTENT

Three experiments to evaluate the effect of ammonia treatment to sugar cane harvest residues on digestibility and crude protein content were carried out. Four grade Holstein heifers of 250 kg average LW were us ed to evaluate through an analysis of regression the effect of the dur ation of the ammonia treatment (0, 4, 7, 10 and 14 days) on dry matter digestibility. Four plastic bags with 5 g of sample in each animal we re used in each treatment. Crude protein content of the residues in ea ch period was calculated. Four heifers (2 grade Holsteins and 2 Zebu) of 220 kg average LW were used in the second experiment to evaluate th e effect of ammonia on organic matter digestibility, structural carboh ydrates and N disappearance from fibrous material in the rumen. Four p lastic bags with 5 g of untreated and treated residues were introduced in the rumen . In the third experiment 8 Holstein bulls of 400 kg ave rage LW were used in a completely randomized design with 2 treatments (untreated and treated) to evaluate the effect of ammonia on dry matte r digestibility of leaves and sugar cane. Three plastic bags with 5 g of the fractions of various animals were employed. The ammonia treatme nt significantly increased (P<0.001) dry matter digestibility of leave s and sheaths and a significant quadratic (P < 0.001) relationship was obtained between dry matter digestibility and duration of the residue treatment. The values of crude protein (N x 6.25) were three times hi gher from the 10th day onwards increasing organic matter digestibility and hemicellulose in 14 percentage units and cellulose in 10 units. 9 0% of the total N increasing with the treatment, disappeared from the fibrous material during rumen digestion. The results indicate the favo urable results attained when sugar cane harvest residues are treated w ith ammonia.