Intake, digestibility, milk production and economic analysis of diets with different forages Consumo, digestibilidade, produ o de leite e análise econ mica de dietas com diferentes volumosos

The purpose was to evaluate intake and nutrients digestibility, milk production and economic viability of diets with different forages (sugar cane, sorghum silage, sunflower silage or Tanzania-grass pasture) of crossbred cows Holstein x Gir. Eight cows with approximately 180 days of lactation were used in two Latin squares 4 x 4 (4 animals, 4 diets, 4 periods). In relation to dry matter intake, it was lower for the diet with sunflower silage; neutral detergent fiber intake was lower for the diets with sugarcane and sunflower silage; non-fiber carbohydrates intake was highest for diet with sugarcane, intermediate for sunflower silage and lowest for sorghum silage and Tanzania grass pasture. Total digestible nutrients intake was highest for diets with sugarcane or Tanzania grass pasture. Weight gain was higher for cows fed with sugarcane or sorghum silage, and there was loss of weight and of body condition score for diets with sunflower silage or Tanzania grass pasture. Milk production was similar among experimental diets. Sunflower silage diet presented low digestibility of neutral detergent fiber, but it did not differ from sugarcane. Amongst the evaluated diets, the sugarcane one had the highest cost and the Tanzania grass grazing, the lowest one. Net income from milk was quantitatively lowest for sugarcane diet and crescent, following the order, for diets based on sunflower silage, sorghum silage and Tanzania grass grazing. Objetivou-se avaliar consumo, digestibilidade dos nutrientes, produ o de leite e viabilidade econ mica das dietas com diferentes volumosos (cana de a úcar, silagem de sorgo, silagem de girassol ou pasto de capim - tanzania) com vacas sangue Holandês x Gir. Foram utilizadas oito vacas com aproximadamente 180 dias de lacta o em dois quadrados latinos 4 x 4 (4 animais, 4 dietas, 4 períodos). Em rela o ao consumo da matéria seca, este foi inferior para a dieta com silagem de girassol; da fibra em detergente neutro, foi inferior para as dietas com cana e silagem de girassol; dos carboidratos n o fibrosos, foi maior para a dieta com cana, intermediário na silagem de girassol e inferior na silagem de sorgo e pasto de capim-tanzania. O consumo de NDT foi maior nas dietas com cana ou com pasto de capim-tanzania. O ganho de peso foi superior para as vacas alimentadas com cana ou silagem de sorgo, e para dietas com silagem de girassol ou capim-tanzania houve perda de peso e do escore corporal. A produ o de leite foi igual entre as dietas experimentais. A dieta à base de silagem de girassol apresentou baixa digestibilidade da FDN, mas n