Supplementation and treatment on the nutritive value of barley straw. Digestibility

A herd of castrated male goats of the Murciano-Granadina breed was used to determine the effect of supplementation with lemon by-products (0, 100, 200, 300 g DM/animal/day) on the digestibility of untreated straw supplemented with NPN, urea-treated straw and urea + NaOH-treated straw. DM and OM digestibilities of the rations increased (P < 0.001) with supplementation or with the straw treatment with a significant interaction between both factors. DM, CP and CF digestibilities of the untreated straw increased (P < 0.05) at high supplementation levels. In general, the supplementation with lemon by-products did not affect the digestibility of the treated straws, but at high supplementation levels there was a slight negative effect (P < 0.05) on the DOM of the urea + NaOH treated straw (supplementation level x type of straw, P < 0.01). These results indicate that both the alkali treatment and the supplementation with a the lemon by-product improved the digestibility of the barley straw. The association of both methods, treatment and supplementation, does not affect the digestive use of the urea-treated straw and slightly worsens the use of urea + NaOH treated straw.