Principles of Clean and Quality Milk Production

Milk is the lacteal secretion of the mammary glands of animals.

It is obtained generally from the cow or the buffalo during the period following at least 72 hours after calving or until the milk is colostrum-free.

Milk is a white opaque fluid in which fat is present as an emulsion, protein, and some mineral matter in colloidal suspension, and lactose together with some minerals and soluble proteins in true solution.

Clean Milk production

Both pre- and post-secretory management of milk at the farm level should be focussed upon for controlling the quality of milk.

The post-secretory changes in milk are of paramount importance.

Some of the vital factors responsible for good milk production that deserve immediate attention are;

the type of farming,
type of milk,
impact on the environment,
farm waste disposal facilities,
milking practices,
procurement systems,
inconsistent price policy,
and farmers’ education/training programmes.

Milk once secreted becomes the target for transformation by a variety of host organisms at the farm itself.

Hence, proper care must be taken regarding the preservation of milk, protection of milk constituents, protection against high temperatures, and natural calamity.

Strict protocols are to be observed and implemented both in hand and machine milking.

The microbiological quality deserves special attention for stringent export requirements for milk products in the global market.

The custodian of milk should never compromise on quality.

Rural milk collection

In Ghana, milk production is a subsidiary activity of agriculture in contrast with organized dairy in Western countries.

Farmers and landless labourers mostly maintain 1-5 milch animals.

As a result, small quantities of milk are produced in a scattered manner.

Milk procurement models from Western countries, such as bulk cooling, bulk transportation, etc. are not applicable due to this reason, under Ghanaian conditions.

The collection of small amounts of milk scattered over long distances, therefore, poses a formidable challenge in maintaining the quality attributes and keeping costs down.

A systematic approach to rural milk collection suitable for tropical climatic and techno-economic conditions prevailing in Ghana has to be developed based on the indigenous experience gained over the past few decades.

In the first phase, extensive surveys are undertaken in the milk shed areas, where the milk plant is to be established.
The second phase involves “route planning” taking into account the availability of quantities of milk, access to roads for plying vehicles, and distance from the site of the dairy plant. Then zones are identified, representing equal costs of collection and transportation.
In the third phase, planning is done for locating the primary collection centers as well as chilling centers, where, milk can be cooled to 4^oC before transporting to the milk plant.
Milk may be collected from individual procedures either by the contractor or by forming village-level cooperative societies.

At the village level, milk brought by the individual farmers is first tested for quality.

As soon as the milk supply reaches collection centers, it is weighed and a representative sample is drawn for quality grading.

The common tests carried out at the point of milk collection are taste and smell, sediment, fat and SNF contents, and acidity tests.

These quick tests generally form the basis for acceptance or rejection of milk supplied.

In Ghana, it is common to pay the producer based on the quantity of fat, while the minimum standard for SNF is set for accepting milk.

All the milk so collected is generally filled in cans to enable transportation to the chilling center or directly to the milk plant.

Care should be taken to bring the milk for chilling/processing within 3 hours of milking otherwise serious deterioration of milk takes place, which affects the quality of products.

Principles of Milking

Milking is defined as a critical and laborious process that involves hormonal reflexes.

The art of milking is performed within 5-8 minutes.

Normally milking is done twice a day.

The cattle and buffaloes are exclusively maintained for milk production.

However, the primary objective is to produce milk.

The amount of milk produced by the indigenous breeds is very low compared to the amount of milk secreted by the exotic animal which is very high and which is more and above the requirement of a calf.

If the calf is allowed to suckle the complete quantity of milk it leads to digestive disturbances, enteritis, etc., usually milk is fed to calves depending upon the body weight of the calf at the rate of1/10 of the body weight during the first week and 1/15 the body weight during the second week.

Though milking is a laborious process, under present circumstances, innovation has been made to extract the milk from the udder.

They are said to be mechanical milkers or milking machines.

Pulsation and intermittent vacuum and pressure are basic concepts of the milking machines.

The advantages of the milking machines are that a large quantity of milk can be harvested in a shorter duration with the help of unskilled personnel.

The major portion of the work of a dairyman is from milking to disposal of the milk.

Nearly 65% of the time is to be devoted to the management in connection with milking and marketing of milk.

There are three principles used in milking.

Natural Technique (calf suckling)
Manual Technique (hand milking)
Mechanical Technique (machine milking)

Natural Technique:

In this method, the calf can draw the milk from the udder.

To extract the milk the calf presses the teat with the tongue and pallet on the other side.

The tongue encircles the teat and a vacuum is created in the mouth by separating the jaws and retracting the tongue nearly 100- 200 alternating cycles may be observed per minute.

A calf’s suckling is the best method of evacuating the milk with the least damage to the delicate tissue of the mammary gland.

The art of milking is a cycle such as;

Active Phase
Restive Phase

The active phase involved;

Creation of vacuum in the teat canal
Pressure is applied over the teat canal
The base of the teat is occluded with the help of the tip of the tongue with the idea of preventing the backflow of the milk into the gland cistern when the pressure is applied which is followed by a restive phase

The restive phase also involves;

At this stage, 20mm Hg pressure is created at the teat end.

Both active and restive phases are alternated and it has been scientifically proved that the amount of pressure applied over the teat canal by the calf is 535mm Hg pressure whereas in the case of hand milking the pressure is 310mm of Hg.

In the mechanical milking pressure on the teat is in the range of 350 mm-400mm Hg.

In the case of buffalos, 400mm of Hg of pressure is applied but in the case of cattle, it can be restricted to360-380mm of Hg.

It has been proved that the cycling rate during nursing is twice as fast as hand or machine milking.

Thus, the difference along with the increased cycling rate facilitates and explains the removal of milk from the udder at a faster rate by a calf when compared to hand or machine milking

Hand milking:

It is commonly practiced in the harvesting of milk.

The order of milking of various teats also differs.

Teats crosswise left four and right hind or right four and left hind.
Fore quarters teat together
Hind quarters teat together
Teats appearing more distended should be milked first. The milk should only be squeezed and not drawn

STRIP CUP:

It is a device with four circular plates for each quarter which has the quantity of milk normally first few strips of milk are drawn in the respective circles to assess the physiological status of the udder.

If there is any change in colour, consistency appearance, etc., the milk should be drawn at the end to prevent spreading the disease from one quarter to another.

Prevention of Kicking of the cow:

Application of;

Milkman’s rope.
Anti-cow kicker.

Methods of manual milking.

Fisting
Knuckling,
Stripping

Fisting method

In this method, the whole teat is held first with the thumb and the index finger encircling the base of the teat.
The base of the teat is closed by the ring formed by the finger so that the milk that is trapped in the teat canal cannot slip back into the gland cistern.
Simultaneously the teat is squeezed between the hollow of the palm and with the middle, ring, and index finger.
The process is repeated in succession.
It is the best method of hand milking though most of the milkmen follow the knuckling method.

Knuckling method

Many milkers tend to bend their thumb against the teat canal and drag the milk out.
This practice should be avoided as it is injurious to the teat.

Stripping method

This method is followed where the length of the teat is small; it is normally practiced towards the end of milking to evacuate the milk completely.
The last drawn milk is called stripping which is rich in fat content.
The process of stripping should be done in quick succession otherwise the animal will become a stripper where the letting down of milk is delayed.

Types of Hand Milking

In most places, wet milking is practiced.

The milkman moistens the hand with certain types of emollients like castor oil, or few strips of milk, or even saliva.
This should be avoided for the sake of cleanliness.
If wet milking is practiced, the teats will look harsh and there is every possibility of development of cracks.
Both hands can be used for milking in continuous milking.
The maximum flow of milk from the udder is usually referred to as a letting down and it is a highly inherited character, cows possessing a teat with a small orifice are very difficult to milk and there is a leaking teat when the teats are pressed.
Both the narrow orifice and leaky teat animals are to be culled.

Frequency of Milking:

It depends upon the quantity of milk yield. Under normal circumstances, the quantity of milk is less than 10 litters/day–2 times milking is followed when more than 10 litters three times milking is followed.

It has been observed and proved that three times milking improves milking by 10-15%.

The factors that are to be considered during milking.

Avoid excitement of the animal during and before milking. If the animal is excited then there is release of adrenaline and it will cause vasoconstriction.
Prepare and collect all the milking equipment before milking.
The milking operation should be continuous.
As far as possible exact time of milking is to be followed.
Prepare the cow for milking.
Complete the milking within 5-7 minutes.
Use both hands for milking.
Use the correct method and type of milking.
Weaned animals should not be milked with the calves nearby.
Provide a concentrated mixture at the time of milking.
Remove the first few strips for any possible abnormalities of milk.
Group the animals 2 hours before milking.
More than one milkman should milk a cow during the lactation so that any change in the milkman will not affect/cause any problem in milking especially in the letting down process of lactating animals.

Machine Milking:

A calf and the machine do the harvesting of milk in a similar fashion.

The function of the tongue, dental pallet, and jaw movement of the calf is done by the inflation tube, pulsator, and vacuum pump.

Milk removal is largely dependent upon the differential pressure across the teat canal.

The total differential pressure created by the milking machine is approximately 352 mmHg, in the case of cattle and 400 mm Hg in the case of buffaloes.

The pressure facilitates the expulsion of milk from the canal.

Advantages

Easy method of extracting milk.
Does not require any skill.
Keeping the quality of milk is high.
Chances of spreading of disease of the milkman to udder through milk are negligible.
Time consumed is less. One or two animals can be milked simultaneously and a maximum of eight animals can be milked at a time.

Disadvantages

Cost is high
Electricity is essential.

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Principles of Clean and Quality Milk Production