Factors affecting the nutritive value of kikuyu grass (Pennisetum clandestinum) - a review.
Kikuyu grass (Pennisetum clandestinum), which occurs naturally on the highland plateau of east and central Africa, has been introduced to many countries, where it forms highly productive pastures. However, in many instances, its growth is restricted by a lack of cold and drought tolerance. The grass reproduces vegetatively and by means of seed. Since kikuyu produces stem material throughout the growing season its nutritive value is highly influenced by stage of regrowth. Kikuyu grows well when heavily fertilized with N, but accumulates nitrogenous compounds far in excess of animal requirements. These substances can have a negative impact on digestion and animal performance. Energy is a major limiting factor for milk production on kikuyu, due to a lack of readily digestible non-structural carbohydrates and a low digestibility of structural components. Kikuyu grass contains oxalic acid, which binds calcium, rendering it largely unavailable to the grazing animal. Kikuyu is deficient in sodium and prone to calcium: phosphate imbalances, and also to potassium: calcium plus magnesium imbalances. The grass produces allelopathic substances which may have a detrimental effect on the persistence of mixed pastures in which kikuyu is a component. Kikuyu poisoning and the correction of nutritional limitations by supplementation, manipulation of growth conditions and ecotype selection are discussed.