The physically effective neutral detergent fiber content alone has not been able to explain the appearance of diarrhea in ruminants fed diets with large volumes of spineless cactus, so the proliferation of enterobacteria in spineless cactus may be associated with cases of diarrhea in sheep. In the in vitro test, used two varieties of spineless cactus, both of which were chopped to particles of 4 and 2 cm2. For the in vivo test, 15 lambs were allocated to three treatment groups, namely, spineless cactus crushed and immediately supplied to the animals; spineless cactus crushed 8 h before supply; and silage of spineless cactus. The variables evaluated were dry matter intake, weight gain, fecal score, hemogram, and fecal colony count. In the in vitro test, higher Enterobacteriaceae and lactic acid bacteria counts were found both at 12 h and 24 h when the spineless cactus was crushed to 2 cm2 in both varieties. The sheep fed the spineless cactus crushed 8 h prior to supply showed the highest Enterobacteriaceae count in the feces (8.48 CFU/g), compared to animals fed silage of spineless cactus (4.95 CFU/g). It can thus be concluded that the management of spineless cactus influences the development of total and fecal coliforms, especially when it is chopped to 2 cm2 and exposed to the environment for periods longer than 7 h, and that the bacterial population can be controlled by administering the spineless cactus in the form of silage.
Keywords: Diarrhea; Escherichia coli; Mill; Opuntia ficus-indica; Ruminants.