An analysis of the fundamentals of grazing management systems

Abstract

The resting and grazing components of grazing management cycles as practised in South Africa are evaluated from the points of view of objective and effect. While the desirability of resting for seeding and an increase in vigour is recognized, little is known of the optimum duration and frequency of rests in the various types of grazing. The upper limit of camp numbers per group of animals beyond which an increase in resting benefit is only slight appears to be approximately six. While continuous grazing is generally believed to be detrimental to sward composition because of selective grazing, it seems that this effect is due rather to incorrect stocking rates than continuous grazing per se. Rotational grazing does, however, offer a means of attaining higher stocking rates without detrimental effects. High Utilization Grazing and High Production Grazing are two different methods of applying rotational grazing which have different objectives and different effects. The most suitable method to use in any situation depends on the nature of the sward and the reaction of the component species to defoliation. However, both methods require multi‐camp systems for best results.

UITTREKSEL

Die rus‐ en beweiding‐komponente van weidingstelsels soos dit in Suid‐Afrika toegepas word is ten opsigte van doel en uitwerkinggewaardeer. Alhoewel die wenslikheid van rusperiodes vir saadskiet en die verhoging van groeikrag besef word, is min oor die optimum duur en frekwensie van rus vir die verskillende veld‐ en weidingstipes bekend. Dit blyk dat die maksimum aantal kampe waarbo die rusvoordele baie klein word, ongeveer ses is. Weens die gevolge van selektiewe beweiding word aanhoudende beweiding in die algemeen as nadelig beskou. Dit blyk egter dat selektiewe beweiding eerder veroorsaak word deur foutiewe veelading as deur aanhoudende beweiding as sodanig. Nietemin, deur middel van wisselweiding kan ‘n hoër veelading verkry word sonder enige nadelige gevolge vir die weiveld. Hoë Benutting Beweiding en Hoë Produksie Beweiding is twee metodes van wisselweiding wat verskil in doel en gevolg. Die mees geskikste metode om in ‘n spesifieke geval te gebruik sal bepaal word deur die aard van die weiding en die invloed van ontblaring op die samestellende plantsoorte. Beide metodes vereis nogtans veelvoudige kampstelsels vir bevredigende resultate.