Cattle normally live in herds, but when giving birth, the cow attempts to find a quiet, sheltered
place away from the disturbance of other cows and humans. The cow needs to be alone with her
calf for some time after birth for the cow-calf bond to be estab
For successful results, the drying zone must reach the surface before the grain in this area
deteriorates. It is therefore normal practice to limit the depth of grain so that the drying front
reaches the top in time.
Although increasing airflow increases
Figure 9.35 A Naturally Ventilated Store.
The method of operating the store is depending on the average temperature on the place. If the
average temperature is above 20C it is necessary to extend the walls on three sides down to the
ground like an apron.
Walls made of bricks, mud or cement will absorb moisture from the ambient air. In areas with
high relative humidity it is therefore necessary to protect the grain by adding a moisture barrier
to the silo walls. It will help considerably to bagwash or plas
Figure 10.2 Characteristic appearance of Zebu and [European type cattle.
Beef Cattle make their best gains at temperatures below 25 C. They can easily tolerate
temperatures below 0 C if they have a good supply of feed.
Pigs require a change in ambient tem
Figure 9.37 Large bulk store.
If the cool store is used for other produce it may be desirable to have some refrigeration in the
packing room so that grading and packaging of perishable produce can be completed under cool
Later in this chapter
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 e
Figure 9.31 Simple roof crop clamp.
Another simple store for short time storage is the covered clamp (Figure 9.32) consisting of a
raised platform on which the potatoes are heaped and then covered with 10cm of grass or straw.
Air is free to
policy is particularly beneficial for disease control, where the animals are bought from outside
the farm and in finishing units for pigs as well as broiler and layer houses.
Disease is transmitted in many ways including direct contact between animals, ai
Reception Pit with an Elevator
A concrete wood or steel-lined pit with an inverted pyramid or V-shaped bottom is built in the
ground, see figure 9.29.
Figure 9.29 Dump Pit with an auger moving the grain to the elevator.
The crop is dumped from a trailer i
Figure 9.4 Tray Drier for natural drying of crops in shallow layers. The tray has meshwire
bottom and a pitched roof of transparent plastic.
Ventilated structures for natural drying
The very small producers may suspend bundles of the crop from trees or po
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 labou
example, if a hot spot develops in a storage bin, it can be easily ventilated again. It may also be
possible to provide some low-volume ventilation in an otherwise pure storage system.
There are however, situations when the storage is considered quite sep
It is advantageous to equip milking parlours with grain feeders which allow each cow to be fed
in ratio to her production. Since cows are more likely to enter the parlour when they expect to be
feds some labour will be saved. Manual distribu
c batch driers
d sack driers
They may also be either high temperature or low temperature systems.
Air Volume Requirements
Whatever the system, artificial drying depends on forced air ventilation with, or without, added
heat. Knowing the amount of moistur
Ambient air passed through the grain at the rate of 6 m/ h to 8 m/h for each tonne in the storage
has proved adequate in practice. Depending on the static pressures involved, this range of
ventilation rates would require from 190 to 560W per to
Figure 9.28 Bags stacked in five respective eight bags layers.
Sources of infestation
a The insects can survive from one season to the next in: Infested residues in the field. The
structure of the store Natural habitats like natural vegetation
b Fresh pro
gases and to supply the animal with fresh air for breathing. A wind velocity of 0.2m/s is
generally regarded as a minimum requirement, but it can be increased to 1.0m/s, when the
temperature is nearing the upper critical, or more when it goes beyond that.
Table 9.3 Capacities of Crib at different Lengths (section length 150cm)
width Volume in m No. of bags wet No. of bags of 90 kg
150cm. No. of
maize on cobs
dry shelled maize
Table 9.6 Grain Handling Equipment
of Fixed or Horizontal or H Capacity
Portable Vertical V
1. can be
Figure 9.39 Small-scale chitting racks.
Buildings for chitting stores can be very simple. They may be built of poles, blocks, bamboo,
reinforcing wire and netting and are constructed so that the sides let in light and ventilation. The
interior is always a
Larger concrete silos are built by using a sliding mould which is moved upwards continuously or
step by step. Reinforcement and concrete are supplied from the top Concrete silos can be made
airtight if openings are properly sealed.
Steel bins r
Figure 10.9 Calf hutch.
Figure 10.10 Zero grazing system for the small holder.
2 Movement of bulk feed from store to feeding area and concentrates from store to milking shed
3 Transfer of milk from milking shed or parlour to dairy and then off
Figure 9.19 Improved traditional hint
Figure 9.19 shows a woven basket made of sticks or split bamboo plastered with mud mixed
with cement. The walls slope towards a covered manhole in the top An outlet is near the bottom.
The bin, which is placed on a ra
The measuring of temperature, relative humidity, static pressure and air flow are discussed in
Chapter 7. However, the special situations found in making these measurements relative to grain
drying and storage will be discussed in more detail.
Figure 10.7b Comfort stall.
Figure 10.7c Stall Partitions.
A bull pen should have a shaded resting area of 12 to 15m and a large exercise area of 20 to
30m. The walls of the pen must be strong. Eight horizontal rails of minimum 100mm round
Onions will keep at higher temperatures than shown in Table 9.9 and this seems practical,
particularly in dry areas. This involves placing cured onions in a slatted-floor store which is
freely ventilated except during damp conditions.
Storage Structures f
Figure 10. 1 Classification of factors influencing livestock production.
When feed is converted by the animal's metabolism for the production of milk, eggs, meat, offspring etc., heat is produced as a by-product. An increased production level and thus fee
Figure 9.1 1 Section showing the principle of a vertical shallow layer batch drier.
The grain passes through these driers in a continuous flow at a controlled rate. The grain is kept
in a thin sheet, approximately 100 to 150mm deep
Figure 9.41 Larger-scale potato chitting store.
Fruit and Vegetables
The majority of fruits and vegetables are highly perishable commodities with a short storage life.
The exceptions, including apples and potatoes can, if well stored, las
Assumed exhaust air at 85% RH and 19.5C
Air volume required to remove 1 kg Water:
From the 1500m Psychrometric chart it is
found that the given air can remove, 0.0143 - 0.0118 = 0.0025 kg H 20/ kg dry air.
The volume of incoming air is 1.03m/ kg dry air.