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How grass can be made into milk and cheese

On World Milk Day Teagasc Staff; Marion Beecher, Emer Kennedy, Eimear Ferguson and Margie Egan, are together addressing the questions you have about cows. How much does a cow eat and drink in a day? How much milk does a cow produce and what is the milk used for? More questions & more answers here...

In this short video clip Emer Kennedy, Teagasc Researcher answers your questions about cows on World Milk Day

Have you ever wondered why grass is green or how grass grows?

Grass grows by taking up water and nutrients from the soil. The nutrients are the food the plant uses to grow. Grass is green because it contains chlorophyll, which is used to trap energy from the sun to help it grow. This is called photosynthesis.  

Why can cows eat grass but humans cannot?

Unlike humans, cows can eat grass because they are ruminants. This means that cows have one stomach with four compartments. The four compartments are called the rumen, reticulum, omasum and abomasum. The rumen is the largest compartment and can vary in size but holds up to 250 litres. Cows have special microbes that live in their rumen and start the digestive process. In Ireland, grass or grass silage is the main part of a cow’s diet but they like to snack on concentrates.

How much does a cow eat and drink in a day?

The amount of grass a cow eats in a day depends on a number of different things like how old she is, how much milk she produces, whether she is just after calving or a long time after calving and what size she is. Bigger and older cows eat more grass than younger and smaller cows. A cow can eat 18kg dry matter of grass or about 120kg of fresh grass per day. A cow will spend up to eight hours a day eating grass. The amount of water a cow drinks in a day depends on how hot the day is or how much milk she is producing. A cow will typically drink 40-60 litres of water per day.

How much milk does a cow produce and what is the milk used for?

A cow can produce up to 30 litres of milk in a day. From 30 litres of milk, you can make 3 kg of cheese. Milk is important for humans because it contains calcium and vitamin D, which is needed to make healthy and strong bones. Milk contains whey and casein proteins, which are easy for humans to digest and is used in our bodies to grow strong muscles and bones.

Watch video in full below as Teagasc researchers tell us more about how milk is made

Further Information:

Read Teagasc advice on Dairy farming here

Read more on Teagasc Dairy Research here

Read about VistaMilk here