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Cows play an extremely important role in most African cultures. The ownership of cattle will often be the deciding factor in a man's social position in the community because the herd may be the only practical way of accumulating wealth. However, of greater importance is the fact that cattle represent a source of high protein food, both milk and meat.
This chapter focuses on housing requirements for cattle kept primarily for milk production. Little or no housing is required for herds maintained only for beef production and special handling and support facilities are discussed separately.
Much of the dairying in East and Southeast Africa occurs at elevations of 1500 metres or more. European breeds have been successfully established under these circumstances. However, European bulls crossed with Zebu cows have produced animals that are more tolerant of high temperatures than the European breeds and significantly better producers than the Zebus. Whether purebreds or crosses, they will not provide a profit to the farmer if they are left to find their own feed and water and are milked irregularly. Experience has shown that cattle respond favorably to good management, feeding and hygiene all of which is possible in a system with suitable housing.
The composition and management of cattle herds vary considerably. At one extreme, nomadic herdsmen graze their entire herd as one unit. The small holder with only a few head may keep his heifer calves for replacements or sell them. The commercial dairy producer typically has about four-fifths of his cows milking and one-fifth waiting to calve, while heifers 10 months to calving age plus calves of various ages will approximately equal the number of milkers. Mature dairy cows are bred annually and are milked for 300 to 330 days after calving.
At a closer examination it will be found that several factors influence the number of animals of various categories found in the dairy herd. In a herd of say, 24 cows, having calving evenly distributed throughout the year and a 12-month calving interval there will be, on an average, two calves born per month. The calves are normally kept in individual pens for two to three months, there is thus a requirement for four to six pens in a herd of 24 cows. However, the need for calf-pens is halved in herds where the bull calves are sold or otherwise removed from the herd at one to three weeks of age. A longer calving interval and high mortality among the calves will decrease the required number of calf-pens, while a concentration of the calving season in the herd will increase the pen requirements. If all calving is concentrated in six months of the year, the requirement of calf-pens will be doubled.
A number of cows in a dairy herd will be culled each year for reasons of low milk yield, infertility, disease, old age, etc. These cows are best replaced with young stock from their own herd, since any animals acquired from outside the farm may bring disease to the herd. Cows are commonly culled after three to five lactations, corresponding to a replacement rate of 20 to 30% per year.
In herds with very intensive production there is a tendency for higher replacement rate, but it can not exceed 40%, if the heifers are obtained exclusively from the herd itself, since only about half of the calves born are female and of these some will die or be culled before first calving due to disease, infertility, etc.
The number of maturing heifers will increase with increasing age of the heifers at first calving, increased replacement percentage and a shorter calving interval. Concentrated calving may slightly increase the number of animals during some periods of the year, and will greatly affect the distribution of animals to the different age groups. The age at first calving of heifers of European breeds is typically 24 to 27 months, while heifers of the slower maturing Zebu cattle often are 36 months or more.
Maturing heifers require little or no housing facilities in the tropics. Knowledge of their exact number and distribution in various age groups during different months is therefore not as important to a building designer as to the manager of the herd.
Heifers should be introduced in the dairy herd at least a couple of months prior to their first calving to learn and become adjusted to the handling routines and feed. In loose housing systems with free stalls (cubicles) or in tiebarns this may slightly increase the need for stalls, but normally the heifer will simply take over the stall used by the culled cow, which it replaces.
In herds where cows are taken to a special calving pen during calving, one such pen per 30 cows is sufficient, since the cow and her calf will spend only a few days there. However, in herds where the calving is concentrated in a short period the requirement can increase to one calving pen per 20 cows. The pen should be at least 3.3m by 3.3m.
General Housing Requirements
As has been pointed out, cattle will be more efficient in the production of milk and in reproduction if they are protected from extreme heat, i.e. temperatures of 25 to 30°C, and particularly from direct sunshine. Thus in tropical and subtropical climates shade becomes an important factor. If cattle are kept in a confined area, it should be free of mud and manure in order to reduce hoof infection to a minimum. Concrete floors or pavements are ideal where the area per cow is limited. However, where ample space is available, an earth yard, properly sloped for good drainage is adequate.
With these needs in mind a shade structure allowing 2.5 to 3m: per animal will give the minimum desirable protection for cattle, whether it be for one animal belonging to a small holder or many animals in a commercial herd. A 3x7m roof will provide adequate shade for up to X cows. The roof should be a minimum of 3m high to allow air movement. If financially feasible, all the area that will be shaded some time during the day should be paved with good quality concrete. The size of this paved area depends on the orientation of the shade structure. If the longitudinal axis is east and west, pan of the floor under the roof will be in shade all day. Extending the floor approximately one third its length on the east and on the west as shown in Figure 10. 3, a paved surface will provide for the shaded area at all times.
If the longitudinal axis is north and south, the paved area must be 3 times the roof area i.e. 1/3 to the east, 1/3 to the west and l/3 underneath. Obviously this means an increase in the cost of paving. In deciding which orientation to build, the following factors need be considered:
Figure 10.3 shows shade patterns at various times and orientations. A gable roof shade is shown in Figure 10.4. The gable roof is more wind resistant than a single pitch roof and allows for a center vent. A woven mat of local materials can be installed between the rafters and the corrugated iron roof to reduce radiation from the steel and lower temperatures just under the roof by 10°C or more.
Figure 10.3 Shadows cast at various times and dates at latitude 10° south.
Figure 10.4 Sunshade with insulated corrugated steel roof:
If space is severely limited and only 4 to 5m² per cow is available, then concrete paving is highly desirable. If up to 40 to 60m² per cow is available, then unpaved yards should be quite satisfactory as long as the feed and shade areas are paved and the yard is graded for good drainage.
If the small holder is unable to afford an improved structure such as a shade or a paved area for feeding, then conditions can be prevented from becoming intolerable by building mounds of earth in the yard with drainage ditches between them as shown in Figure 10.5. From 20 to 30m² per cow will keep the animals out of the worst of the mud. The soil in the mounds can be stabilized by working chopped straw or straw and manure into the surface. A number of trees in the yard will provide sufficient shade.
Figure 10. 5a Yard with fenceline feed trough, paved feed area and earth mound.
Figure 10.5b Dimensions for an earth mound.
In a deep-bedded system, straw, sawdust, shavings or other bedding material is periodically placed in the resting area so that a mixture of bedding and manure builds up in a thick layer. Although this increases the bulk of manure, it may be easier to handle than wet manure alone. This system is most practical when bedding is plentiful and cheap. Table 10.3 gives the space requirements for various ages of animals when there is access to a yard. By designing the building to be partially enclosed on the east and west, the shading characteristics can be improved. In as much as a well drained earth floor is quite adequate, such a building will compare favourably in cost with a shaded area which is paved.
Loose Housing with Free Stalls (Cubicles)
Although simple yard and a shade or yard and bedded shed systems are entirely satisfactory in warm climates, particularly in semi-arid areas, some farmers may prefer a system with somewhat more protection. A loose housing yard and shed with free stalls will satisfy this need. Less bedding will be required and less manure will have to be removed. Free stalls must be of the right size in order to keep the animals clean and to reduce injuries to a minimum. When stalls are too small, injuries to teats will increase and the cows may also tend to lie in other areas that are less clean than the stalls. If the stalls are too large, cows will get dirty from manure dropped in the stall and more labour will be expended in cleaning the shed area. A bar placed across the top of the free stalls will prevent the cow from moving too far forward in the stall for comfortable lying down movements, and it will encourage her to take a step backwards when standing so that manure is dropped outside the stall.
The bar must, however, not interfere with her normal lying and rising movements. Table 10.3 lists recommended dimensions for stalls. The floor of the stall must be of a non-slippery material, such as soil. A good foothold is essential during rising and tying down movements to avoid injury. A 100mm ledge at the back edge of the free stall will prevent any bedding from being pulled out to the alley. The number of stalls should ordinarily correspond with the number of animals housed, except that in large herds (80 or more), only about 90% of the animals need to be accommodated at one time. Figure 10.6 shows two free stall designs.
Young stock may be held in yards with shade or in sheds with either free stalls or deep bedding.
The alley behind the free stalls (cubicles) must be wide enough to allow the cows smooth passage and the following minimum widths apply:
Only in the case of purebred herds where considerable individual attention is given to cows can a tie-stall system be justified in tropical areas. If such a system is chosen, stalls and equipment may be purchased, in which case floor plans and elevations may be available from the equipment supplier. However, if equipment is to be manufactured locally, Table 10.5 provides some typical dimensions.
Table 10.4 Alley Widths in Conjunction with Free Stalls (Cubicles)
|Alley between a row of free stalls and a through (increase to 4.0m if there are more than 60 cows in the group)||2.7 - 3.5m|
|Alley between a row of free stalls and a wall||2.0 - 2.4m|
|Alley between two rows of free stalls||2.4 - 3.0m|
|Alley between a feed trough and a wall||2.7 - 3.5m|
Table 10.3 Area for Bedded Sheds and Dimensions of Free Stalls (Cubicles)
|Animal||Age Months||Weight kg||
Bedded ShedArea per Animal (m²)
|Young stock||1.5 - 3||70 - 100||1.5||1.4||1.2||0.6|
|Young stock||3 - 6||100- 175||2.0||1.8||1.5||0.7|
|Young stock||6 - 12||175 - 250||2.5||2.1||1.8||0.8|
|Young stock||12 - 18||250 - 350||3.0||2.3||1.9||0.9|
|Bred heifers and small milking cows||400 - 500||3.5||2.5||2.1||1. 1|
|Milking cows||500 - 600||4.0||3.0||2.2||1.2|
|Large milking cows||> 600||5.0||3.5||2.3||1.2|
A - Enclosed and fully covered bedded shed
B - Bedded shed in conjunction with exercise yard
Figure 10.6 Free-stall cubicle designs.
Table 10.5 Tie-Stall System Dimensions (metres)
|Cow live weight|
|Stall Section||450 kg||550 kg||650 kg|
|Platform slope||2 - 4%|
|Nose Out System||Nose In System|
|Flat manger feed alley||1.7 - 2.0||1.6 - 2.0|
|Feed Alley (excluding step manger)||1.2 -1.4||1.2 -1.4|
|Service alley width||1.4 - 2.0|
|Manure gutter width||0.4 - 0.7|
|depth||0.25 - 0.35|
1 If cows are allowed to lie with their heads over the through, otherwise add 0.4 - 0.5m to the length.
The tie and feed barrier construction must allow the cow free head movements while lying down as well as standing up, but should prevent her from stepping forward into the feed trough. Most types of yokes restrict the cow's movements too much. A single neck nail, set about 1 m high and 0.2m in over the merger may bruise the cow's neck when she pushes forward to reach the feed. The feed barriers that best meet the requirements are shoulder supports and the comfort stall, shown in Figure 10.7. Note the fixing rods for the cross tie which allows vertical movements of the chain. Stall partitions should be used at least between every second cow to prevent cows from trampling each other's teats and to keep the cow standing straight so that the manure falls in the gutter.(figure 10.7c)
Figure 10.7a Shoulder support system.
Figure 10.7b Comfort stall.
Figure 10.7c Stall Partitions.
A bull pen should have a shaded resting area of 12 to 15m² and a large exercise area of 20 to 30m². The walls of the pen must be strong. Eight horizontal rails of minimum 100mm round timber or 50mm galvanised steel tubes to a total height of 1.5m and fixed to 200mm timber posts not more than 2m apart will be sufficient. The gate must be designed so that the bull cannot lift it off its hinges and there should be at least two exits where the herdsman can escape.
A service stall where the cow can be tethered prior to and during service is usually provided close to the bull pen. The stall can have ramps at the sides to support the bull's front feet.
Calf mortality is often high in tropical countries, but proper management and suitable housing that protects the calf from climatic stress, infections and parasites can reduce this.
Individual pens for calves from birth to 2 to 3 months of age are often built with an elevated slatted floor. This floor, which is best constructed from 37 to 50mm by 75 to 100mm sawn timber boards leaving a 25 to 30mm slat between each board, will ensure that the calf is always dry and clean. The required minimum internal dimensions for an individual calf pen are 1200 by 800mm for a pen where the calf is kept to two weeks of age, 1200 by l000mm where the calf is kept to 6 to 8 weeks of age and 1500 by 1 200mm where the calf is kept from 6 to 14 weeks of age. Three sides of the pens should be tight to prevent contact with other calves and* to prevent draughts. Draughts through the slatted floor may be prevented by covering the floor with litter until the calf is at least one month of age. The front of the pen should be made so that the calf can be fed milk, concentrates and water easily from buckets or a trough fixed to the outside of the pen and so that the calf can be moved out of the pen without lifting. The milk or milk substitute fed to the calf will not provide it with enough liquid and therefore it should be given fresh, clean water daily or preferably have continuous access to water in a drinking nipple. All calves, but especially those which are weaned early, should have access to good quality forage as soon as possible to stimulate rumen development. Forage can be supplied in a rack placed above the side wall of the pen. Figure 10.8 shows a thatched shed with six slatted floor calf pens. This construction with a feed alley will be rather expensive but can be cheaper if calves are fed from outside. Calf pens are recommended where the cows are kept in a semi-zero grazing or zero grazing system.
Another system that works well is the use of individual hutches as shown in Figure 10.9. The hutch must be thoroughly cleanedset up in a new location each time a new calf is housed in it. Plenty of litter is placed directly on the ground inside the hutch. Protection from wind, rain and sun is all the calf requires, but always moving the hutch to clean ground is the key to success.
Housing for the Small Herd
For the small holder who wants to make the very best use of his crop land and to provide his cattle with good housing that will encourage high production, a zero grazing system is recommended.
Figure 10.10 shows perspective, elevation and plan views of a zero grazing unit for 3 cows, 2 heifers and a young calf. Additional stalls can be added up to a total of about 10. After that consideration should be given to two milking places and a larger feed store.
Gum poles may be used instead of the cedar posts and sawn rafters, but any wood in contact with or within 5Ocm of the ground should be well treated with wood preservative. It is desirable to pave the alley, but if that is not possible, the distance between the free stalls (cubicles) and the feed trough should be doubled or tripled.
A concrete pit or sloping slab in which to accumulate manure is essential. If the alley is paved, the pit can also collect urine. In fact, paving the alley not only saves space, but the value of the urine will help to pay for the paving.
The circular manure tank shown in Figure 10.10 has a volume of 10m³. This will be adequate to store the manure produced during one month plus any rainfall collected in the alley. If more stalls are added the capacity of the tank will need to be increased or the interval between the emptyings shortened.
A water tank to collect water from the roof can be very useful unless there is an abundant supply of water nearby.
Housing for the Medium to Large Scale Herds
For the farmer with up to about 30 cows a yard with paved shade and feed area would be suitable. The yard and feeding area may alternatively be combined with an open sided barn designed for deep bedding or equipped with freestalls and where the herd consists of high yielding cows the milking shed may be equipped with a bucket milking machine. Some farmers with up to 30 cows may even consider using an open sided tie-stall shed.
In general a medium or large scale dairy unit may include the following facilities:
1 Resting area for cows: a Paved shade, or b Deep bedding in an open sided barn, or c Free-stalls in an open sided barn
2 Exercise yard (paved or unpaved)
3 Paved feed area:
- a Fence line feed trough (shaded or unshaded), or
- b Self feeding from a silage clamp
4 Milking Centre:
- a Milking shed or parlour, and
- b Collecting yard (part of the exercise yard), and
- c Dairy including milk store, and
- d Motor room
5 Bull pen with a service stall
6 Calving pen(s)
7 Calf accommodation
8 Young stock accommodation (yard with paved shade and feed area)
9 Bulk feed store (hay and silage)
10 Concentrate feed store
11 Veterinary facilities:
- a Diversion pen with Artificial Insemination stalls, and
- b Isolation pen
12 Waste store:
- a Slurry storage, or
- b Separate storage of solids and effluents
13 Office and staff facilities
Figure 10.8 Calf shed.
Each of the parts of the dairy unit may be planned in many different ways to suit the production management system, and the chosen method of feeding. Some require ments and work routines to consider when the layout is planned are as follows:
Figure 10.9 Calf hutch.
Figure 10.10 Zero grazing system for the small holder.
Milking and Milk Handling
Hand Milking vs. Machine Milking
In developed countries, where labour is scarce and expensive, machine milking has become very widespread and it is also practiced on many large commercial dairy farms in the tropics. Milking machines not only reduces labour requirement and eliminates the drudgery of hand milking, but in most cases performs a better quality milking operation than would be done by hand. However, most of the many small dairy farms in developing countries have a surplus of cheap labour and the number of cows milked at each of them is not sufficient to economically justify the installation of a machine. Furthermore, machines require power and are more expensive to purchase then the few pieces of equipment needed for hand milking. In many developing countries there is an irregular supply of spare parts and a lack of skilled mechanics.
Machine Milking gives a good quality and operates with a uniform vacuum of 275 - 350mm of mercury, provides a massaging effect on the teats, and is easily cleaned. The milking machine simulates nursing by the calf. Two vacuum lines lead to the teat cups. A pulsator supplies an intermittent vacuum to one line at the rate of 45 to 60 pulses per minute. The line, connected to the shell of the teat cup, causes the teat inflation (rubber liner) to alternately expand and collapse. This massaging action promotes normal blood circulation in the teat. The second line maintains a continuous vacuum on the teat and carries the milk either to a stainless steel bucket or through a pipeline directly to the milk cooler.
Figure 10.11 Basic sketch of a layout for a medium to large scale dairy unit, showing the relative location of the various parts and a suggestion for extension. (Not drawn to scale).
Bucket Milking Machine as shown figure 10.12 is the simplest and least expensive to install, but the milk must be hand carried to the cooler. This type of system is often chosen for the small and medium size herd and where the cows are milked on a level floor of a stable or milking shed. The labor of carrying the milk to the cooler can be avoided by installing a transfer system. This consists of a 30 litres receiving tank, including a built in filter, mounted on wheels so that it can be moved around the stable. It is connected to the cooler with a plastic hose and the milk is drawn to the cooler by vacuum from the milker pump. The hose is reeled in or out as necessary as the cart is moved around the stable.
Pipeline Milking Plants transports the milk through a pipe direct from the cow's udder to the milk cooler. Figure 10.13 illustrates such a system. Pipeline milking systems are usually installed in milking parlouts where the operator stands below the level of the cows. Although they are expensive, they save backbreaking labour and are usually designed to be cleaned in place, a feature that not only saves labour but helps to ensure good sanitation. They may also be installed in stanchion or tie-stall bates but the extra pipeline needed makes the system even more expensive.
Milk Room and Cooler
Sanitation is the primary consideration in the handling of milk whether it is from one or two cows belonging to a small holder or from a commercial herd supplying milk for the city. In either case an adequate supply of potable water is essential for cleaning the milking equipment immediately after use. Hot water (85°C) mixed with a chemical detergent is required for effective cleaning and cold water is used for rinsing.
Milk should be handled in a separate area that can be easily cleaned and that is free of insects, birds, rodents and dust. The small holder producing milk only for his own household, may be able to process, curdle, or consume his milk within a short time so that cooling is not necessary.
Selling milk to the public requires higher standards of sanitation and more elaborate facilities. Whether the cows are hand or machine milked, a separate milk room adjacent to the milking stalls or milking parlour is needed. This room should be well ventilated and designed with a concrete floor sloped 20mm/m to a drain and with masonry walls having a smooth, water resistant surface that can be easily and thoroughly cleaned.
Figure 10.12 Bucket milking machine.
Figure 10.13 Pipeline milking system.
Table10.6 Minimum Water Requirements for Parlour and Milkroom Washing
|Hot Water, 85°C||Warm Water, 40°C||Cold Water 4 - 10°C|
|Hand milking equipment||10/wash||20/wash|
|Bucket milking equipment||20/wash||40/wash|
|Pipeline milking equipment||30/ wash||60/ wash|
|Cooling of milk in||2 - 3 times the|
|plate type milk cooler||amount of milk|
|Parlour floor wash||1/ m², day||3 - 6/ m², day|
|Milkroom floor wash||l / m², day||1 - 3/ m², day|
|Bulk tank wash||25 - 40/wash||20 - 30/wash||25 - 35/wash|
|Miscellaneous||20- 50/day||30 -100/day|
Milk is strained and cooled in this room in preparation for sale. As soon as the cow has been milked the bacteria in the milk starts to multiply, but cooling of the milk to about 4° C within 2 hours will drastically reduce bacterial growth. However, proper cooling is a very difficult problem for the small scale producer. The only practical solution may be for the individual farmers in an area to bring their milk to a central collection depot for cooling immediately after milking. Figure 10.14.
On dairy farms of sufficient size and where power is available, the milk can be cooled by cold water circulated between an evaporative water cooler and a milk cooler (plate heat exchanger), through which the milk is passed until it is adequately cooled. Where milk is stored and transported in cans, cooling can be accomplished by immersing the full cans in a water-filled refrigerated cooler or by passing cold water through a coil, which is immersed in the can. The large scale dairy farm, having a pipeline milking system, and the milk collection by a road tank van, will require a refrigerated cooler and holding tank.
Figure 10.14 Milk collection centre. The dimensions (A) should vary with the capacity of the cooling and holding tank.
Milking Parlour for the Medium Scale Herd
For the farmer with 10 to 30 cows and a yard with a paved shade and feed area, the milking parlour shown in Figure 10.15 is of suitable design. Two stands will be sufficient where the herd number is 8 to 14, but more stands should be added as indicated when the herd number increases. Hand milking would probably be used for an operation of this size. If machine milking is installed the vacuum pump and the engine, which powers it, can be put in the engine room, which is indicated in outline in the plan view. This is arranged by closing off a portion of the store room with a simple partition.
A milk cooler will be necessary to cool and hold the milk for pick up. This and facilities for washing and storing the milking equipment will be accommodated in the milk room, while concentrates are kept in the store room.
A milk room should face the prevailing wind to ensure good ventilation and to keep it as cool as possible, but any openings should be screened with insect mesh.
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