Degradabilidade do capim-elefante (Pennisetum purpureum, Schum.) e da cana-de-açúcar (Saccharum officinarum, L.) mais uréia no rúmen de vacas mestiças Holandês x Zebu em lactaçäo / Rumen degradability of elephantgrass (Pennisetum purpureum, Schum.) and sugarcane (Saccharum officinarum, L.) plus urea in crossbred lactating cows

ABSTRACT

Elephantgrass shows a high stocking rate only during the rainy season. Forage production is drastically reduced in the dry season. One of the alternatives to minimize this problem is the supplementation with sugarcane plus urea. In this trial the main goal was to estimate the dry matter intake (DMI) of elephantgrass, chopped sugarcane plus 1 per cent urea and their degradability in three lactating (11.6kg/milk/day) rumen fistulated crossbred cows (472kg/L.W.) grazing elephantgrass during the dry season. The cows had access during three consecutive night to the paddocks grazed every 30 days in a stocking rate, of 4.5 cows/hectare. Between the two milking times, cows received chopped sugarcane plus 1 per cent urea. The DMI was on average 1.01 per cent/L.W. for the elephantgrass and 0.88 per cent/L.W. for the sugarcane plus 1 per cent urea. Total DMI, taking into account both roughage and concentrate (2kg/cow/day) was 2.25 per cent/L.W. The effective rumen degradability (ED), considering the rate of passage in the rumen of 5 per cent/hour was 44.46 per cent for elephantgrass and 41.94 per cent for sugarcane plus 1 per cent urea, DM. The elephantgrass ED crude protein was 48.58 per cent and its neutral detergent fiber 33.82 per cent. During the dry season lactating crossbred cows grazing elephantgrass have to receive a roughage supplement and concentrate to produce around to 12kg of milk per day