A review of tree fodder production and utilization within smallholder agroforestry systems in Kenya

Abstract

Although the biological advantages in terms of animal production and improved soil fertility of the use of herbaceous legumes have been well demonstrated in Kenya and elsewhere, adoption by small-scale farmers has often been disappointing. This has led to increased research into the use of both indigenous and exotic fodder trees. In common with conventional pasture legumes, tree fodders contain high levels of crude protein and minerals and many show high levels of digestibility. They are readily accepted by livestock and presumably because of their deep-root systems, they continue to produce well into the dry season. Antinutritive factors can be a problem, however, and polyphenolics, toxic amino acids, cyanogenic glycosides and alkaloids are found in many tree species. There are abundant niches on small farms where fodder trees can be grown without affecting crop production. Although detailed management recommendations are lacking, guidelines exist with regard to appropriate cutting heights and harvesting frequencies. In the Embu region, it has been estimated that three kg of fresh fodder of Calliandra calothyrsus has the same effect on milk production as one kg of commercial dairy meal. Up to about 500 trees (250 m of hedgerow) will produce enough fodder to supplement one dairy cow for a complete lactation. The tree fodder can either replace the concentrate without loss of yield, or it can complement it to produce more milk. It is being enthusiastically adopted by small-scale farmers, many of whom are starting to produce their own seed. Other tree species are now being studied in order to avoid over-reliance on a single fodder species.