Effect of nitrogen on the oxalate and calcium content of Kikuyu grass (Pennisetum clandestinum Hochst)

Abstract

The effect of the nitrogen content of Kikuyu grass (Pennisetum clandestinum) on the oxalate and calcium content of leaf and stem material was investigated. The grass contained equal portions of soluble and insoluble oxalate. Leaf material contained more than three times as much total oxalate as stem tissue. A high nitrogen content was associated with a high insoluble oxalate content of the sward. The calcium content of both leaf and stem material was extremely low. Results suggested that approximately 95% of the calcium could be bound as calcium oxalate and would probably not be available to ruminants. The bio‐availability of calcium in the herbage tended to decrease with an increase in nitrogen content of the grass.

Die invloed van die stikstofinhoud van Kikoejoegras (Pennisetum clandestinum) op die oksalaat‐ en kalsium‐inhoud van blaar‐ en stingelmateriaal is ondersoek. Die gras het gelyke dele oplosbare en onoplosbare oksalaat bevat. Blaarmateriaal het meer as drie maal soveel totale oksalaat bevat as die stingelweefsel. ‘n Hoë stikstofinhoud was met ‘n hoë oplosbare oksalaatinhoud van die gras geassosieer. Die kalsiuminhoud van beide die blaar‐ en stingelmateriaal was uitermatc laag. Resultate dui daarop dat ongeveer 95% van die kalsium moontlik as kalsiumoksalaat gebind is en waarskynlik nie vir die herkouer beskikbaar is nie. Die biobeskikbaarheid van kalsium in die wciding was geneig om af te neem, met ‘n toename in die stikstofinhoud van die gras.

Additional index words:

• Calcium availability
• rumen metabolism