From Grass to Milk

Everyone knows that cows produce milk that we like to drink.  But do you know how a cow turns grass and other food into the milk that you drink?

Cows have one stomach with four compartments—just like camels, sheep, goats and giraffes.  These animals are called ruminants.  Of the four compartments—the rumen, reticulum, omasum and abomasum—the rumen is the largest and the reticulum is the smallest.

When a cow begins to graze, it chews the food halfway and swallows it.  This mixes with water in the cow’s first stomach compartment—the rumen.  The rumen has tiny organisms within it that helps the cow’s digestion by turning the food material into protein that the cow’s body can use.

The chewed food and water then moves from the rumen into the second compartment—the reticulum—where it’s formed into small balls called cud.  This also grinds the food material down further and has a wonderful honeycomb lining.

The cow then regurgitates the cud into its mouth where it chews the cud for about one minute.  Cow can chew this cud up to 100 times per minute – to count these, don’t count the chews, count the number of times the cow wiggles her head and ears.  A cudding cow is a comfortable cow!

The cow then swallows the cud, where it travels to the third compartment—the omasum—where it’s compressed so the cow’s body can absorb water and important nutrients from it.  The interior of the omasum is like leaves in a book that compress the cud.

The mixture then moves to the fourth compartment—the abomasum—where it’s digested.  The abomasum is a lot like a human stomach, which is why it’s been given the nickname ‘the true stomach’.  The digested material passes through to the cow’s small intestine, where the cow’s body pulls out more nutrients it needs to stay healthy.



The nutrients from the grass are then turned into milk in the four mammary glands located in the cow’s udder.  The milk drains from a duct in the cow’s teat when the cow is being milked. For every litre of milk produced, more than 400 litres of blood must travel through the udder.  Cows may only have 45 litres of blood in their body, so when you see our cows lying in a field sunning themselves, know that their blood is remarkably active to produce the milk we enjoy! 

The cows are milked in specially designed, herringbone style parlour, electronically-controlled by trained dairy staff. 

The milk is transferred to our storage large tank where it is cooled.  This tank can take two days worth of production.  A milk tanker arrives late at night to take the product to a Muller processing plant, which processes the liquid before it is transferred in packaged, product form to the M&S stores.