The development of stocking rate models for three veld types in Natal.

Abstract

The overall objective was to develop stocking rate models

for three veld types. namely the Lowveld. the Southern Tall

Grassveld and the Natal Sour Sandveld. in Natal. Sub-objectives

were to determine the 1) residual herbage mass at

the end of the summer, 2) residual herbage mass at the end of

winter and 3) individual animal performance under grazing

conditions, and the effect of stocking rate on these three

variables. Multiple linear regression component models were

successfully developed to meet all three of the sub-objectives

for each of the three veld types.

Results show that veld condition is an extremely important

factor determining animal production from veld, and that

stocking rate on veld in good condition could possibly be

double that on veld in poor condition. Stocking rate did not

have the expected impact on individual animal performance in

the summer. although it did have an important moderating

influence under any particular set of environmental

conditions. Stocking rate did. however. have a marked effect

on herbage production and therefore on herbage availability in

winter and so also on the ability to overwinter cattle without

having to supply additional supplementary feed. Stocking rate

in summer therefore had a major indirect effect on animal

production in the winter. Carryover of residual herbage from

one year to the next is probably not as important in these

veld types as in some other parts of the country.