Before the decision on the designing and lay out of the milking parlours is taken it is necessary to keep in view the milking practice in vogue. 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 than the few pieces of equipment needed for hand milking. On commercial farms where several cows are milked at the time, a milking parlour becomes a feasible investment. Several types of milking parlours are in use in dairy regions throughout the world.
The tandem parlour also allows for individual care of the cows. It is used mostly for smaller commercial herds and in particular for herds with high yielding cows. The parlour capacity in terms of cows milked per hour and labour efficiency can compare to that of a small herringbone parlour. The main drawbacks with this type of parlour are its larger space requirement and more expensive construction when compared to other types of parlours of similar capacity
In walk-through or chute parlours cows enter and leave in batches. They have been used mainly for small herds. Their narrow width can be an advantage where a parlour is to be fitted in an existing building, but it is inferior to other types in most other respects, however, it is cheaper to construct than a tandem parlour.
The herringbone parlour layout results in a compact working area and allows feeders to be fixed to the side walls. Four stands on each side of the pit, is the minimum size of this type for high labour efficiency. The popularity of the herringbone parlour is mainly due to its simplicity and its high capacity measured in numbers of cows milked per man-hour. However, the risk of cows kicking the milker is greater in this type than in parlours where the milker stands alongside the cow.
The cows are normally assembled in a collecting yard (holding area) before milking. This may be a portion of the yard that is temporarily fenced off with chains. The collecting yard should have a minimum size of 1.1 to 2.0 m² per cow. Large horned cows and a low herd number will require the largest space per cow. The area should slope away from the parlour 20 to 100 mm/m. This not only improves drainage but also encourages the cows to face the entrance. The collecting yard should be paved for easy cleaning and to allow for sanitary conditions in the parlour. A roof is desirable for shade and to avoid wet cows entering the parlour in the rainy season.