Assis et al., 2004. Rev. Bras. Zootec., 33 (1): 251-257

Twelve milking cows, purebred and crossbred Holstein, with average weight of 550 kg, were allotted to three Latin Squares 4 x 4. The experimental period lasted 18 days, seven days for the adaptation to the diets and eleven days for data collection.Feeding was supplied to met the requirements of non pregnant cows, producing 20 kg of milk with 4.5% fat. The objective of this research was to evaluate the effects of replacement (0, 33, 67, 100%) of corn meal by pelleted citrus pulp in the concentrate in total mixed rations,observing the parameters digestibility of the nutrients, and ruminal pH and ammonia concentration during two periods of collection of sample of feces (2 and 5 days). The digestibility of the nutrients were not affected by the collection period, as well as there were not differences in the digestibility for the increasing levels of citrus pulp. No significant differences were observed for pH and ammonia concentration of the rumen for the different treatments. The citrus pulp can substitute up to 100% of the corn in complete diets for cows producing 20 kg of milk in average, without effect on the ruminal parameters (pH and ammonia concentration)