On the farm

Did you know that cows don't chew their food - they just crop and swallow until they feel full. An average cow can eat up to 70 kg of grass a day! The cow makes up for not chewing by digesting her food extra slowly and thoroughly, using her four stomachs.

The unchewed grass goes straight into stomach number one until that stomach is full.
		The grass then passes into stomach two where it starts to ferment and forms into balls called the cud. The cow then regurgitates the cud (brings it back up into her mouth) and rechews it. A cow can spend as much as eight hours a day chewing her cud!
Once she has finished chewing her cud she swallows it again and it goes into her third stomach where it is broken up by bacteria.
		The fourth and final stomach digests the thoroughly broken up grass and passes nutrients into the cow's bloodstream and udder where they are used to make milk. A dairy cow produces about eight litres each time she is milked or about 16 litres per day. That's about 80 glasses of milk every day!

Milking

In New Zealand, most cows are milked twice a day - once early in the morning and once in the afternoon. Many years ago, cows were milked by hand, but now, most cows are milked by machine.

The farmer slips rubber-lined, metal teat cups onto the cow's udder where they're held on by suction. The cups are connected to a vacuum pump which mimics the rhythmic on-off pressure of a calf drinking. Pipes carry the milk away from the cups and into a refrigerated vat where the milk stays until collected each day by a tanker from the local dairy factory.

Milking one cow usually takes about 10 minutes. Milking a herd of cows usually takes one hour to 90 minutes. When the cows are finished, the milking yard and machinery must be washed with hot water and special detergent until they're spotless.

Milk tankers

Milk tankers are huge trucks with special refrigerated compartments that keep the milk cool from the farm all the way to the factory. The milk must be kept cool so it remains bacteria free.

Every day more than 500 tankers are on the road collecting the milk from farm vats all over New Zealand. They collect as much as 35 million litres a day!

Each tanker can hold around 27,000 litres of milk in its two compartments. The tankers are always kept very clean to protect the milk from bugs.

To get the milk from the farm to the tanker, the driver joins a loading hose to the farmer's vat and pumps the milk into the insulated holding tank in the truck.

Next, the driver takes two samples from each farm's milk for testing at the factory. These important tests show if the milk is pure, and whether the farmer's shed is hygienic and his herd healthy. The tests also show how much fat and protein the milk contains - these factors determine how much the factory will pay for the milk.

Once the tankers have collected milk from all the farms on their run, they drive to the dairy factory and pump the milk into huge storage silos.

At the Factory

At Anchor, milk is processed very quickly to make sure it stays fresh!

Pasteurisation

No matter what final product the milk will become - butter, milk powder, cheese - it's first pasteurised.

Pasteurisation heats the raw milk to a very high temperature (73°C) for 15 seconds and then cools it rapidly. This heating kills micro-organisms that could cause disease and also lengthens the life of the milk.

Standardisation

The amount of cream in milk changes at different times of the year, and the amount of cream is different for each cow! But since we like milk to taste the same each time we drink it, it needs to be "standardised".

First, the cream is separated from the skim milk using a giant spinner called a separator. The machine spins around very fast which makes the cream and skim milk separate from each other. Some of the cream is used to make butter or fresh cream, and some of the skim milk is kept as well.

The rest of the cream and skim milk can then be recombined in just the right amounts to make whole milk, cheese and yoghurts!

Making fresh milk last longer

In New Zealand, we make a lot of milk so it's easy for people to have fresh milk each day. In fact, milk could be in our refrigerator as quickly as 48 hours after it has come from the cow!

Some other countries don't have as many cows as New Zealand so they need to have milk that lasts a bit longer.

UHT Milk (UHT stands for Ultra Heat Treated) has been heated so that all the bacteria and other germs in it are removed. It is then packed in aseptic packaging so that no new bugs can get in! Using UHT, milk can last up to 12 months.

Another way to make milk last longer is to remove all the water - so you get milk powder. Milk powder is made by putting fresh milk into a huge dryer.

Milk powder is also much lighter than fresh or UHT milk so it's easy to transport all around the world.