The milk and other dairy products we consume today are produced by dairy animals – mostly cows.

The milk is intended for the calf, but through centuries of domestication and breeding, man has created a cow that produces much more milk than the calf will need. Today’s modern cows give less than 5 percent of the milk to the calf and all the rest is used for human consumption. Originally the small amount of surplus milk was hand-milked from the udder after the calf had been fed. Today the cows are machine-milked two or three times per 24 hours while the calf prefers to suckle several times per day.

The working principle of the milking machine is imitating the calf suckling. The milk is extracted in a rubber liner applied on the teat with a lower pressure (vacuum) than the surrounding atmospheric pressure. In order to avoid damage on the teat, the liner is periodically collapsed to create a massage and relief on the teat exposed to vacuum. This is called pulsation and occurs normally once every second.

The working principle was invented almost a century ago and has over time been refined and improved in today’s milking machines. This machine is very rare in the sense that it is the only machine that works regularly and routinely with and on an animal for production purposes. It is therefore extremely important that it works in a correct way to not harm the animal or the quality of the milk.

System design
For milking on the individual farm, you need to specify a system that best meets the requirements on the particular farm.

• You need to consider how many cows, whether they are tied up or loose and to what extent they are pasture-fed.

• You need to know actual and intended yield levels as well as calving patterns.

• Labor cost, qualifications and availability will decide level of automation.

• Technical matters like existing buildings, access to electric power, water quality and availability and access roads will influence system specifications.

• Finally, financing and operation costs have to be considered.

• In many countries, there also are laws and regulations that have to be considered.

Technically you have to design the vacuum system to handle milk extraction, milk transport and cleaning. It has to operate with a stable level to assure optimal extraction. It has to consider disturbances like kicked-off units or air inlet during putting on the unit. It has to have a capacity to transport the milk without too strong agitation which will harm the milk quality. Finally, it has to have a capacity giving strong turbulence in the cleaning water during the cleaning process.

The pulsation system has to give gentle milking with sufficient capacity to handle high flows of milk without harming teats during low flows. You want the milking to be fast but not harmful. The capacity for milking has to be matched by the cooling capacity to safeguard the milk quality. Automation is mostly seen as a way to save on labor cost, but automation can also be a quality assurance by safeguarding a certain work process.

With all these things to consider it is essential to get qualified assistance in specifying the parlor. Serious equipment suppliers can do that. By getting the parlor specified by one supplier, you know whom to contact when there is a problem.

Installation
To make sure that a correctly specified parlor will work properly it has to be installed by a qualified installer. Installations where you cut corners by using weak fixtures or unspecified parts often result in unhygienic conditions or operational disturbances. If, as an example, the milk line is not installed with a proper slope you will get water standing in the pipe between milkings and a high risk for milk quality problems.

Finally, a good installation is made in a way that facilitates service and also contributes to the good appearance of the parlor. A qualified installer will also train and give instructions to the operators making sure that the parlor will be used in the intended way.

Operation
Milking cows is a highly qualified job that will benefit from a persistent use of correct routines.

• Before starting milking make sure all equipment and tools are at hand and in proper condition. Use clean suitable clothing and wash your hands thoroughly before starting milking.

• Always handle animals with care and in a calm and considerate way. No yelling or beating, if you want them to give you all their milk.

• Clean and massage the cow’s udder. Use dry cleaning if the udder is clean. If it is so dirty that wet cleaning is required, make sure you wipe the teat dry after cleaning. Use disposable cloths for each cow or individual cloths that are cleaned in a washing machine between every milking.

• Premilk by hand in a test cup. Take a few squirts from each teat and check for flocculation or blood.

• In some countries a special predip is used to disinfect the outside of the teat. This will eliminate infections to spread from the outside of the teat to the inside of the same or other teats milked with the same unit.

• Put on the milking unit within one minute after preparation.

• A persistent routine is very important for this action as the cows will develop a letdown reflex that is adjusted to such a routine.

• Monitor the milking and adjust the unit if it starts squeaking or if the cow appears uncomfortable.

• Take off the unit when the milk flow has ceased or is very low. Check that the udder is empty before you remove the unit. Avoid developing habits where all the cows expect you to aftermilk with machine before taking off. If you use automatic take-off units, do some random checks that the cows are properly milked.

• Teat dip the cows within one minute after take-off. This will safeguard disinfection and protection of the teat canal while it still is open.

• Register the observations you do on the individual cows during milking. In some production systems, milking is the only time of the day when you are close to all the individual lactating cows.

• Treated and sick cows shall always be milked separately and after all the healthy cows.

• Cows develop habits. If you establish and maintain a persistent milking routine for every milking, the cows will feel comfortable and respond positively with even production.

Cleaning
The milk from a healthy animal is almost sterile when it leaves the udder. To maintain high-quality milk, it has to be handled in a clean installation. It is therefore necessary to clean the milking parlor thoroughly after each milking.

• Sufficient and good quality water is required to achieve a satisfactory cleaning result.

• Water-heating capacity has to match the requirements from the cleaning procedure.

• Detergents have to be selected to work with the actual water quality and dosed in accordance with the instructions given by the equipment supplier.

• The hand washing procedures shall follow the supplier’s instructions.

• If there is an automatic cleaning unit installed it has to be adjusted to the requirements of the parlor and water quality and operated according to instructions.

• Make sure the cooling tank or cans are equally well cleaned and that you don’t forget any part or connection in the whole milk handling chain.

• Avoid standing water in and on the cleaned equipment after cleaning and before next milking. Allow drying by having good ventilation or air movement.

Cooling
To avoid rapid deterioration of the milk after milking it shall be cooled down to 35 to 39ºF within two hours.

• If you have a cooling tank, it has to have the capacity to cool down the milk within two hours. You also have to make sure the milk is not collected before the milk is cooled down.

• The agitation of the milk in the tank has to be gentle to avoid milk quality deterioration.

• If you can avoid mixing warm milk in with cooled that is an advantage from a quality point of view.

• Clean the tank immediately after the milk has been collected by the truck.

Maintenance
• For a continuous trouble-free operation with high-quality milk regular maintenance and exchange of wear and tear parts is necessary.

• A serious supplier and installer will offer a scheduled parlor service to give the required maintenance.

• Such a service will include dismantling and a complete cleaning of the parlor, exchange of all required wear and tear parts according to established time limits, checking of all essential functions and parameters and a complete test run.

• Such preventive scheduled services will markedly reduce operational breakdowns that by experience always will be more costly in the longer perspective.

• A preventive service works as an assurance and reduces production losses and gives peace of mind.

Result
With a correctly specified, installed, operated and maintained milking parlor you will be rewarded with a volume of milk according to your cows’ present ability and with a quality that meets the highest standards.

The payment for your milk is always related to the volume produced and in most cases also influenced by the quality of the milk measured in some way.

• Milk quality can be measured as fat and protein content and then valued as food for human consumption with a certain content of nutrients.

• Milk quality can be measured as total bacteria content (TBC) which measures the hygienic standard of the milk.

• Milk quality can also be measured as somatic cell content (SCC) which measures the animal health or level of mastitis infections in the udder.

• Milk quality can also be measured as odor (smell) and taste, which is a measurement of palatability.

• Finally, contaminations of antibiotic residues, other impurities and water are seen as serious deteriorations of the milk quality.

References omitted but are available upon request at editor@progressivedairy.com
—Excerpts from 2006 International Dairy Federation, International Dairy Congress proceedings

Anders Fagerberg
DeLaval International
Sweden