Interrelationships between veld condition, herbage mass, stocking rate and animal performance in the Tall Grassland of Natal.

Abstract

Grazing trials were established at three sites in the tall grassveld of Natal. The objectives were to determine (a) patterns in herbage mass in relation to veld condition, stocking rate and commencement of spring grazing, and (b) animal performance in relation to herbage availability and stocking rate for the period November 1986 to September 1987. Rainfall exceeded the mean annual rainfall and, for moderate condition veld in particular, was very favourably distributed. Distinct patterns in herbage availability were seen during the season. A condition (VCI), stocking rate (SR) and time that grazing commenced in spring (T) (r = 0, 71; P < 0, 01). HM was positively related to VCI and delayed T and negatively related to SR. Seasonal growth phases in cattle were similar for different sites despite their spatial separation and differences in veld condition. It was essentially only the magnitude of mass loss or gain that varied. No linear relationships existed between SR and average daily initial mass of the animals (IM) (r = 0, 93; P < 0, 01). ADG was positively related to IM and negatively related to SR and HM.

Keywords: adg; animal performance; cattle; condition; grassland; grassveld; grazing; herbage availability; herbage mass; initial animal mass; mean annual rainfall; natal; seasonal growth; south africa; spatial separation; stocking rate; tall grassland; veld condition; veld condition index