Palatability factors and nutritive values of the food of buffaloes (Syncerus caffer) in Uganda

Summary The food preferences of tame buffaloes grazing different vegetation types were recorded. The effects of fire and rainfall were investigated. By initiating a new growth cycle, fire altered the food habits of large herbivores and also the distribution of small mammals. Seasonal variations in the effect of rainfall on plant growth explains why preferences did not change in proportion to precipitation. The more important grasses were collected and their parts analysed physically and chemically. Their stem to leaf ratio is considered to have influenced the species eaten by coarse grazers such as buffalo. A broad correlation was obtained between buffalo preferences and the percentage green leaf of Hyparrhenia filipendula and Themeda triandra. This correlation was improved when preferences were compared with the number of grams green leaf carbohydrate per 100 g dry grass. There was a negative response to the silica present in dead leaves, but stem fibre appeared to have little effect on preferences. A grazing animal experiences a combination of attractants and repellants, i.e. green leaf carbohydrate and protein less stem fibre and dead leaf silica. Other palatability factors were noted, in particular tannins and oils in grasses of the tribe Andropogoneae. These may act as repellants, possibly only when the grazing animal has alternative vegetation from which to choose. The mineral content of grasses appeared to be adequate and calcium and phosphorus were present in about the required proportions. The observations support the belief that selective grazing enables a herbivore to consume a diet of significantly higher nutritive value than that of the average sward. Browsing and new growth after fire help compensate for the low nutritive value of pasture during the dry season. The nutritive value of the diet is considered to be the proximal factor in the seasonal cycle of reproduction of the buffalo and probably the ultimate factor in the reproduction of certain other ungulates and rodents.