A recent paper in Animal Feed Science and Technology ((C.B. Katongolea et al. (2007) Nutritional characterization of some tropical urban market crop wastes. http://dx.doi.org/10.1016/j.anifeedsci.2007.09.002)) did a number on three different kinds of waste from the markets of Kampala, Uganda. Waste from banana, sweet potatoes and Solanum aethiopicum (African eggplant) were chemically analyzed and fed to sheep and goats. That way, the scientists could measure what the wastes contain and how much of that the animals could make use of. Turns out — surprise — that there are differences among the wastes and differences between wet and dry season wastes. Banana leaves and pseudostems were not all that nutritious, and African eggplant leaves were very watery. But sweet potato leaves were just right: “sufficient to provide the CP (crude protein) and ME (metabolizable energy) required by growing goats under tropical conditions”.
Which is nice to know, but not all that surprising, given that about half the sweet potato crop in China is fed to livestock. Of course, pigs are monogastric, while sheep and goats are ruminants, so it was worth checking.
Will this see the market people of Kampala bundling sweet potato waste for sale? Or maybe the farmers will grow the leafy varieties specifically for animal fodder.