Today, livestock graze in open areas during the day but are sheltered in corrals during the night, except for goats, which are permitted to manage on their own within limits. A similar pattern must have developed by the latter part of the 18th into the 19th century. Nonetheless, the disposal of livestock waste, which became "woman's work," required a systematic way of disposing of it. And, over time, the women worked out a method for doing so. In organic gardening, their solution is called sheet composting or mulching. Over time, the women mixed a variety of other organic matter with the manure (kitchen scraps, harvest residues, and vegetative materials from a living fence or hedgerow) and piled it each day on their garden beds and trees to decompose and become nutritious humus. In the 20th century, livestock among the Fulɓe shifted from large animals to smaller types. Horses, perhaps due to the tsetse fly decreased, while goats, sheep, pigs, and poultry increased, and n'dama cattle remain an integral asset.