Resumen

BERTIPAGLIA, Liandra Maria Abaker; DE LUCA, Silvio; MELO, Gabriel Maurício Peruca de  y  REIS, Ricardo Andrade. Evaluation of urease sources in the ammoniation of Brachiaria brizantha hays with two moisture levels. R. Bras. Zootec. [online]. 2005, vol.34, n.2, pp. 378-386. ISSN 1806-9290.  http://dx.doi.org/10.1590/S1516-35982005000200004.

The urea ammoniation (5.0% dry matter) effects in Brachiaria brizanta hay baled with two moisture contents (15 or 30% moisture), and three urease source (Brachiaria decumbens hay, elephantgrass (Pennisetum purpureum), leucena (Leucaena leucocephala)) was evaluated. The crude protein (CP), soluble nitrogen fraction (A), borate phosphate true protein fractions (B1 and B2), potentially degradable protein fraction (B3), acid detergent insoluble protein (C) were analyzed. The NDF, ADF, cellulose, hemicellulose and lignin contents and in vitro dry matter digestibility (IVDMD) were analyzed. The experiment was conducted according to a completely randomized block design with 10 treatments (two control, 15 and 30% moisture, without urea and urease; two controls, 15 and 30% moisture, with urea and urease; six combinations of urease source and moisture levels), with three replicates. Ammoniation increased CP, and A fractions of the hays baled with different moisture contents associated to urease source; however urea application did not affect the B1, and B2 values. The B3 and C values decreased due to the urea application. The ammoniation of the high moisture hay (30%), associated or not to urease source reduced NDF. External urease source did not affect the cell wall contents of the brachiaria hay, compared to the urea treatment without external urease. Ammoniation with urea had a unconsistent effect on the ADF, and cellulose contents of the hay. The treatment did not affect the lignin content of the hay. The urea application with 15 or 30% moisture increased soluble nitrogen of Brachiaria brizantha hay and decreased the unavailable nitrogen to the ruminant.

Palabras llave : Brachiaria decumbens; chemical treatment; elephantgrass; leucena.