Moreira et al., 2009. Ciência Anim. Bras., 10 (1): 184-194

A high percentage of Brazilian beef cattle is reared on forage based diets, often using high density systems. This contributes to the development of diseases like hepatogenous photosensitivity whose aetiology is under constant debate. This study was conducted to evaluate the amount of spores of Pithomyces chartarum fungus, the saponin amount in grasses and the performance of cattle fed with Brachiaria or Andropogon grass. 50 Nelore bulls were divided into two groups of 25 animals and each group was fed with one of the two types of grasses (Brachiaria or Andropogon). It was observed that animals fed with Andropogon grass had better performance especially during the dry season than the other group. The dressing percentage were significantly different (p<0.05) between Andropogon-fed animals (54.9%) and Brachiaria fed animals (53.13%). Brachiaria grass had higher saponin concentrations (0.03 to 1.09%) than Andropogon grass (0.02% to 0.17%). Both types of grass presented ~0 to 50 000 spores/g P. chartarum. It is concluded that both types of grasses have P. chartarum spores and have protodyosin saponins. Better animal performance is observed in animals fed with Andropogon grass.