CIGR Handbook of Agricultural Engineering, Volume II Animal Production & Aquacultural Engineering, Part I Livestock Housing and Environment, Chapter 7 Draught Animals

Abstract

First paragraph: Two major activities in crop production are land preparation and weed control. For most subsistence and smallholder farmers the energy, or power, needed to prepare the soil for sowing or planting can be a major limitation on how much they can grow. Also, the time required to control the weeds, which compete with the crop for nutrients (and moisture in the drier areas), can be a major constraint on the crop yield. For both land preparation and weeding tasks, the use of draught animal power (DAP) can improve the timeliness of farmers operations by supplementing the farmers own muscle power (and that of their families) by providing the effort needed to pull a plough or cultivator and to complete the task more quickly than would be possible by human labor alone. There is, therefore, a double benefit in that not only is drudgery reduced but improved timeliness of ploughing and weeding leads to better crop yields. It is generally considered that the landholding of a typical smallholder farmer (0.5 to 3.0 ha) would be insufficient for a tractor to be economically feasible or sustainable. The are no ostensible physical differences between draught animals and others of the same species, although certain breeds are more renowned for their draught capabilities. Almost any bovine (including buffalo), equid, or camelid can become a draught animal, provided that it is reasonably healthy and responds to training. In general, the most important criterion is body mass, or live weight. This gives an indication of the amount of muscle on the animal and, thus, its potential to exert a force or, more specifically, a pull that the farmer can utilize through soil-working implements. A basic guide is that an animal can pull about 10% to 15% of its weight for aworking period of around 4 h. This is a useful starting point for drawing up the basic specification for a draught animalbased cultivation system, although there is some variation among species, breeds and working conditions. For example, bovines would be nearer to the 10% end of the range, while equids and camelids would be at the higher end. When putting animals to work together, good harnessing systems are essential to avoid unnecessary wastage of animals efforts and energy, and to reduce injuries, which further impair work output. There are basically four types of harness (Fig. 7.1): the head, or neck, yoke (lashed to the animals horns); the withers, or shoulder, yoke (better suited to Bos indicus as it rests against the hump as well as the shoulders); the collar harness; and the breast-band harness. Generally, collar-type harnesses are the most suitable for all species but they tend to be the most expensive. Yokes are simple and relatively cheap but are not recommended for equids. Harnessing animals together increases the draught capability and work output, but losses are incurred. The addition of each extra animal brings about a loss of around 5% to 10% of the combined individual capabilities. Thus, harnessing together more than 10 to 12 animals would be counterproductive unless the harnessing system is first-class. Several guides on the design and use of harnessing and hitching systems have been published, to which the reader is referred for further information (see References).