Imagine Delia's food cupboard and most of us would picture a tidy place filled to the brim with fresh ingredients. The same principle applies to dairy farmers, who keep their feed in a dry, tidy place where it stays fresh before it is mixed and fed to the cows.

Most British dairy cows eat grass during the summer and silage (preserved grass or maize) in the winter. This is usually supplemented with cereals and protein feeds with added vitamins and minerals that are kept in stores or feed bins for freshness.

Each dairy cow eats between 25 and 50 kg of feed per day and needs a constant and regular supply of fresh water to drink. A healthy and balanced diet is essential for producing milk, so dairy farmers work with animal nutritionists to create special diet plans for them. Cow nutritionist Tim Davies says: "Getting this part right is important to help our cows be healthy and productive."

Cow nutritionists take into account the age and weight of the cows and how much milk they are likely to produce, to design nutritionally balanced meals. This ration usually includes added protein, vitamins and minerals to make up for any deficiencies in the grass or silage.

Nutritionists also consider what the cows' milk is to be used for. For example, cows producing milk for drinking may be given slightly different diets from those producing milk for making cheese.

In the mood for a 'moovie'? Watch our video about cow nutrition.