Factors affecting the voluntary feed intake of sheep grazing Pennisetum clandestinum (kikuyu) pastures: observations from forage analysis

Abstract

Sheep were used in two investigations to study factors which could limit voluntary intake of Pennisetum clandestinum (kikuyu) pasture. Possible reasons for the low intakes were found in the high soluble nitrogen and nitrate content of the pasture, its high oxalate content, and its considerable potential for foaming, the latter suggesting the presence of saponins. The high fibre content of the material could also have limited intake in wilted, dry or stemmy kikuyu. The relative importance of these factors appears to change with growth stage, the amount of nitrogen fertilizer applied, stocking rate and moisture supply. The factors which are detrimental to forage quality such as oxalates and nitrates are higher in the young and actively growing material than in older material, while the in vitro production of foam seems unrelated to forage quality and remained high despite changes in other factors which detrimentally affected forage quality.

Keywords: fertilizer; foam; forage; forage quality; grazing; growth; growth stage; intake; irene animal production institute; kikuyu; nitrate; nitrogen fertilizer; oxalate; pasture; pastures; pennisetum clandestinum; production; saponins; sheep; sheep grazing; south africa; stocking rate; ukulinga research station

African Journal of Range & Forage Science, 10(3): pp. 140-144