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The choice of a suitable site for your sheep production unit is not only important from the perspective of the sheep unit or the specific needs of the sheep. It is also important that the site complements the entire farm lay-out and considers other operational activities.
We thank the ARC Institute for Agricultural Engineering in South Africa who made their manual on sheep production and facilities available to the readers of ProAgri Zambia.
The following factors influence the choice of a site:
The underlying reason for any development or extension of an operation is to maximise profits. It is therefore necessary that all economic factors regarding each potential site should be determined and considered. The question is whether the provision of housing and handling facilities will increase the eventual income to such an extent that it will be possible to recover the expenditure within a reasonable period.
- Effect on the environment:
In the process of maximising profits, we must not be overwhelmed by selfishness regarding the utilisation of natural resources. In the planning – and specifically in the choice of a site – the effect that the system will have on the environment must be assessed. The choice of a site must be made in such a way that the system will not contribute to pollution. The potential soil erosion that can be brought about by poorly planned storm water furrows and changes in the slope must be taken note of and evaluated. The contribution of each structure to the environment must also be taken into account, therefore the shape of the structure is important. If possible, all features or distinctions which enhance the environment, must be retained. An appealing and well-designed system will contribute to an acceptable working environment.
- Relative position:
Relative position means the placing of the complex relative to the farmyard. A compromise must be made between the comfort of being close to the complex and the discomfort of the noise and odours generated by the complex. The general placing is called zoning. The zoning model divides the farmyard into concentric rings with the farmyard as central point. These concentric rings are known as activity zones. Activities are now placed in one of these zones, depending on the degree of annoyance of the activity. Figure 1 (p 7) shows a division of typical activities in the zones. From the figure, we can deduce that the sheep production unit is placed in the development area and not closer than 90 m from the farmhouse. Noise and odour problems will be avoided if the unit is placed further away from the farmhouse, but supervision would then be more difficult (especially at night).
Easy access to the production unit from the main routes, machinery centre and feed area is an important consideration in the choice of a site. If vehicles must pass close to the farmhouse, it will ensure better security to the sheep complex.
Costs and other implications regarding electricity supply, telephone service and water supply are important.
Correct drainage is important, as run-off water may not be allowed into the natural stream areas. Poor drainage also has disease and other negative implications to be kept in mind. Drainage is mainly influenced by the topography and soil type of the relevant site. Low-lying areas must be avoided as far as possible to guard against problems with a high water table during wet periods. Suitable slopes are typically 4 to 6%, with the direction of the fall away from the farmhouse or other buildings. With steep slopes, attention must be given to the potential soil erosion dangers which may occur. A well thought-out run-off control plan will solve this problem. The soil characteristics of the site determine the infiltration tempo of the soil. Clay soils will not only result in a low infiltration tempo and wet, muddy conditions, but also have weak foundation traits that may limit the type of structure to be used.
Prevailing wind directions in orientation of buildings:
The direction and strength of the local winds must be taken into account in placing the facility relative to the farmhouse. Natural shelter such as trees and a northern slope can also be utilised against cold winter winds. The orientation of a housing system must be such that it provides protection against cold winter winds, but still allows ventilation for the summer months.
The orientation of the building also determines the effectiveness of the ventilation openings provided in the building. Orientation is further important in the utilisation of maximum shade in the summer and good heat gathering in winter, if possible. A housing system is usually placed with a long axis in an east-west direction and a low roof on the northern side.
- Waste handling:
Place the facility away from the natural stream areas – this will not only make the design and construction easier, but such a location provides sufficient space for the erection, maintenance and operation of a practical run-off control system. All run-off from a higher-lying catchment area must be diverted away from the facility by means of a run-off control system. Consider roofing for the open feeding pens and alleys in order to limit the volume of polluted run-off water.
- Existing buildings:
Existing buildings must only be used if they comply with the size, position, condition and adaptability of the entire plan.
- Extension possibilities:
With the choice of a site, the possible future extension of the production system must be kept in mind. Poor planning in this regard has inhibited the extension of an operational branch of a facility many times in the past, causing additional costs in the lay-out of a new unit.
The design norms given in this paragraph must be seen as directives to the maximum and/or minimum proven in practice. It is however not necessary to apply these norms rigidly.
The purpose of the proposed group sizes is for the simplification of the management of a production system.
- Sick animals can be identified easier
- Lambs will not be easily separated from their mothers
- Handling and record keeping is simplified
- Proposed group sizes are shown in Table 1
Feeding and drinking space
Water requirements of sheep
Table 4 shows typical values for water requirements of the different animals in an intensive production system. Provision must be made in the design of the water supply system for reserve storage capacity for at least three days.
Next month we shall look at housing systems.
Published with acknowledgement to the ARC Institute for Agricultural Engineering for the use of their Sheep Facilities Manual. Visit www.arc.agric.za for more information.