Why do cows chew their cud?

Aug 26, 2015 | Local Producers

The sunny Saturday afternoon was perfect for this cow to relax and “chew her cud”.  She enjoyed a head rub while I believe she was looking at the melting snow and dreaming of green grass soon to come.  I, on the other hand, was sloshing through the mud and melting snow and dreaming of green grass, but I am not the cud chewing type.

So, you may wonder…why do cows “chew their cud” and what is “cud” anyway?  Humans, poultry and swine have simple stomachs. The simple stomach is a pouch-like structure containing glands which secrete digestive enzymes.  Simple stomachs are not suitable for processing forage (grass, hay, etc.)

Forage consuming species, such as cattle, goats, and sheep have intestinal differences which enable them to digest large amounts of fiberous material. These forage consuming animals are called ruminants.  The four compartments of the ruminant stomach are the rumen, reticulum, omasum, and abomasum. The rumen is the largest compartment, and it contains billions of bacteria, protozoa, molds, and yeasts. These microorganisms live in a symbiotic manner with the cow, and they are the reason cattle can eat and digest large amounts of roughage. The rumen microorganisms are adaptable enough that cattle can digest a large variety of feeds from grass, hay, and corn to brewer’s grains, corn stalks, and silage.

When cattle ruminate, or “chew their cud”, they are regurgitating a bolus of incompletely chewed feed. In order for the microbes to digest fiber rapidly and efficiently it must be in small pieces, so cattle re-chew their food several times.  When cows “lose their cud” or stop ruminating, it is an indication that they have a digestive upset, and their rumen is not functioning properly.  Therefore, healthy cows chew their cud often for up to 8 hours a day and 30,000-40,000 jaw movements.  So, cow #77 at our farm is showing her healthy digestive system is working properly, as she dreams of green grass and “chews her cud”.