A cow is a mammal and is able to produce about 25 litres of milk a day during the lactation period. A Dutch cow gives an average of 7800 kilos of milk each year. One litre of milk weighs 1030 grams. Some cows produce the astonishing quantity of 100,000 litres of milk during their lifetime.
Nowadays, the average dairy cow is slaughtered at the age of 4.5 and replaced by a heifer with an often better genetic potential.
At the moment, the dairy farming sector, in cooperation with the breeding organisations, are trying to breed more durable cows, which reach a higher age. When milk production drops or the cows are no longer fertile, cows are often taken to the slaughterhouse. A cow can reach the age of 20, if not slaughtered.
(Source: Wikipedia)
