The effect of animal size and adaptation on defoliation, selective defoliation, animal production and veld condition.

Abstract

A conceptual model of the veld-herbivore relationship is presented. Large-sized, largely grazing animals feed relatively unselectively on abundant roughage. The carrying capacity of veld for them is high. They are low producers per animal, but high producers per ha. Per unit of metabolic mass they have a relatively minor effect on veld condition. Browsers and small-sized, largely grazing animals select strongly for concentrated food. The carrying capacity of veld for them is low. They are excellent converters per animal and per unit mass of intake. Their production per ha is low. One-animal-species models have been quantified readily. The complexity of two- or more-species models at present makes them prohibitively expensive and laborious to quantify. Two simplifications, one of which is readily testable, are proposed to circumvent the impasse.

Keywords: animal production; browsers; carrying capacity; defoliation; grazing; intake; metabolic mass; modelling; models; production; selective defoliation; south africa; veld condition