The present work was conducted to evaluate the effects of citrus pulp and corn in when partially replacing corn silage in lactating dairy cattle rations. Four Holstein volatile fatty acids production, cows with ruminal cannula were used for five periods and five experimental rations in an Incomplete Latin Square experimental design. Ruminal fluid samples were collected at 0, 2, 4, 6, 8 and 24 hours after feeding, to determine volatile fatty acids. The production of acetic acid was higher (p<0,05) in diets containing citrus pulp than in those with corn included. The inclusion of corn, associated with citrus pulp, increased propionic acid production (p<0,05). Butyric acid production was higher (p<0,05) in a ration with 23% citrus pulp than rations with 12% citrus pulp or 23% corn. Lower acetate/propionate ratios (p<0,05) were observed, when corn was included in the diet, isolated or associated with citrus pulp. The total volatile fatty acids was not significant (p>0,05). Under these experimental conditions, the results suggested that citrus pulp could replace the roughage resulting in desirable changes in the ruminal conditions. The effects of corn in ruminal fermentation pattern were typical of a concentrated feed. The association of corn with citrus pulp is an alternative option to minimize effects.
animal feeding; citrus pulp; volatile fatty acids; rumen