Dietary exogenous and endogenous abrasives and tooth wear in African buffalo

The potential contribution of exogenous dust and grit and endogenous plant silica to tooth wear of the African buffalo in Kruger National Park was examined. Endogenous silica as percent dry matter on basalt soils (6.58%) was significantly higher than on granite soils (4.41%), and significantly higher in dry season grasses (6.64%) than in wet season grasses (4.41%). Exogenous grit on granite grasses (0.43%) had significantly higher loads than basalt grasses (0.16%) and wet season loads significantly higher (0.50%) than dry season (0.09%) loads. Grasses on granite soils were significantly tougher (0.266 J m-1) than those on basalt soils (0.215 J m-1). Adult buffalo were estimated to consume 10-28 kg per year of exogenous grit and 300-400 kg per year of endogenous silica. First lower buffalo molars are estimated to wear at an average rate of 1.94 mm per year with no significant difference between wear on the different soil types or between sexes. The high silica intake with no observable differences in tooth wear questions the role of silica in tooth wear. It is proposed that there is an interaction between exogenous and endogenous abrasives and that abrasion must be considered more holistically.