Heavily stocked 5-paddock rotational grazing effect on cross-bred Afrikaner steer performance and herbaceous vegetation dynamics in a semi-arid veld of Zimbabwe

Abstract

A ten-year high stocking rate trial, mimicking communal areas was initiated at Matopos Research Station, Zimbabwe. Afrikaner steer crosses grazed continuously or rotationally at a high stocking rate (0.4 LU.ha-1) in two 45 ha areas, with one fenced into five 9 ha camps each for the rotational grazing sites, with 30 animals per site. It was hypothesized that, heavily stocked rotation will not improve herbage biomass, decreaser species abundance, basal cover or animal performance. Biomass, basal cover and decreaser species abundance were not (P > 0.05) significantly different between the grazing systems, save for Themeda triandra, Setaria incrassata and Panicum novemnerve, but were significant (P < 0.05) in terms of annual variation. Mean maximum steer weight gain was higher (P < 0.05) under continuous grazing. It was concluded that, the creation of rigid rotational grazing schemes in communal areas without proper stocking rates will not improve animal performance, herbage production, basal cover, but might have an effect on species abundance. In higher rainfall years, heavy stocking has no adverse effects on performance. Hence, any plans of grazing interventions on livestock management in communal areas, should consider stocking rate and rainfall, with a rapid stock reduction strategy in projected low rainfall years. Key words: Basal cover, communal areas, grazing system, herbage biomass, stocking rate, weight gain.