Feedlots are the epitome of intensive handling of commercial cattle. Each individual component of a feedlot facility must be well thought-out and designed. Last month we started a new section, namely commercial cattle handling and how to choose an adequate site. This month we start discussing the lay-out of some of the most important components. We focus on feeding troughs and shading.
We thank the ARC Institute for Agricultural Engineering in South Africa who made their manual on handling facilities available to the readers of ProAgri Zambia.
Although interior feeding pen systems hold definite benefits, the lower cost associated with an open pen system is usually the conclusive factor and therefore very little interest is shown in other types of housing in Africa. The cattle are kept in limited areas where they receive carefully formulated rations and can be rounded off as fast as possible for slaughter. In some foreign countries, the double line trough lay-out is more prominent because it is a compact and cheaper system. This system, however, causes drainage problems and in Southern Africa a single line feedlot lay-out is used generally. Figure 1 shows such a typical single line trough lay-out.
A moderate incline of between 1% and 6% should keep trough areas dry and will be acceptable to the animals. Such an incline will also drain well, without allowing an excess of solid manure to run off during a flood. A single line trough is therefore placed parallel to the contours so that the pens can drain vertically against contours and in one direction only, away from the troughs.
The sizes of the pens are determined by the number of cattle in a group and the surface of trough space allowed per animal. The accepted practice is to place about 100 to 200 cattle per pen. Depending on the average rainfall in the area, about 8 to 15 m² of pen space is allowed per animal. Pens must be large enough so that a ront-end loader can move comfortably and a truck can turn when the pen is being cleaned. Thus, a minimum width of 20 m is recommended. A disadvantage of a smaller pen is that the material cost per square metre is higher. If more than 5 000 cattle are fed, larger pens can be considered, up to 500 cattle per pen. Although larger pens save on material costs, it makes handling of cattle more difficult.
A minimum trough length of 150 mm per animal is needed if young animals are fed at will. Older animals need a longer trough length. The recommended trough length in adaption pens is 300 mm and these are also shallower. Figure 2 shows a typical feeding trough lay-out. A feeding trough inner width of 600 mm is ideal for the maximum basin measurement, as it also allows young animals to eat everywhere. The bottom must preferably be rounded so that animals can easily eat it clean and it will also prevent feed from remaining in corners and rotting. If the feed is divided into two or three feedings per day and control is exercised over the quantities supplied, troughs will be eaten clean each time. The bottom of the trough must preferably be 150 mm above the standing level of the animal with the feeding sidewall 400 mm from the standing level, while the roadside wall must be 600 mm high from the animal’s standing level. This is high enough for prevention of feed wastage and low enough to ensure mechanical feed supply. The sloped sides help to always bring the feed as close as possible to the animals.
A problem found at feeding troughs is that cattle climb into or fall into troughs. This can however be prevented in different ways. Figures 3 and 4 show a typical solution. The upper cable is fixed, while the lower cable can move in a steel frame. When cattle feed, they press the cable forward in the frame and the cable usually remains in position. When an animal, especially a young one, falls into a trough, it is easy to take it out, by simply pushing the cable back and upwards. Another possibility is to use a pipe instead of a cable. The pipe is welded in the foremost position of the cable and the frame is replaced by a single horizontal pipe as shown in Figure 4.
Troughs may be built of bricks and plastered, or can be cast with concrete. A concrete slab must preferably be cast on both sides of the trough. The concrete slab in front of the trough prevents trampling and keeps the animals dry so that they can feed in comfort. The slab must be coarse to prevent animals from slipping. The slab is scrubbed clean weekly and must be as wide as the scraper blade, approximately 3 m. The slab on the side of the feeding path only needs to be about one meter wide. This is to prevent the feed wagon from treading out the path and to create a level surface for the feed wagon for even feed action.
It is wise to lay the slab as one strip and building the trough on it. The thickness of the concrete slab varies from 75 to 100 mm and must have a slight drop away from the trough. The feeding trough must have a drop in the longitudinal slope with a drainage opening for rain water or washing water to run off. It is advisable to put up gates at the concrete slab between the different pens, as it will simplify mechanical manure removal. It is also convenient, where a grader is used, to scrape away the manure directly next to the trough. In order to limit the cost of maintenance, heavy duty gates should be used.
There is disagreement on the construction of a roof over the feeding trough. It is expensive to construct, but it protects the feed against rainy weather and provides shade for the cattle. Cattle like to lie in the shade and this sometimes prevents the less dominant cattle from feeding. If heat is really a problem, shade structures can be erected elsewhere in the pen, as shown in Figure 5. Figure 6 shows a typical solution for a roof over a trough. If the roof is erected, the roof supports must be placed in such a way that they will not hamper the mechanical off-loading of feed or manure scraping on the concrete slab.
Next month we shall look at the planning and design of water troughs, fencing and gates.
Published with acknowledgement to the AR Institute for Agricultural Engineering for the use of their Beef Cattle Handling Manual. Visit www.arc.agric.za for more information.