Grasses and other types of forage are consumed by all classes of domestic animals and many classes of wildlife. Grazing animals, however, differ in their grass consumption habits. Dog foods contain some grains (from annual grasses); poultry rations contain some grain to supply vitamins, minerals, and proteins; and swine may consume some forage grasses. But it is horses, goats, sheep, and dairy and beef cattle that may get all their feed from forage. The differences in how much and what is consumed result from the different digestive systems and abilities to handle food containing celluloses and lignins. Cattle and sheep have advantages for utilization of forages over single-stomach animals. It is also important to look at how different animals chew their food and interact with a pasture to really understand how to best utilize the growth and regrowth of grasses. Palatability and digestibility of grasses will be discussed in the animal consumption section, followed by the chewing habits of the main forage livestock, as well as the effects of trampling of grass plants by livestock, and the effects of pasture fouling by urine and manure.
As heavier animals, cows can inflict more damage onto a pasture than lighter animals such as sheep. Wet pastures are less able to bear the weight of the cow and wet pasture is more damaged than if it had been a dry field. While cows feed on the grass on the other side of a fence, they usually trample the area around the fence.
Like cows, horses are heavy animals. They tear up wet pastures easily; grasses are no match for their shoed hooves. Horses are often left outside during the winter causing their pasture to be badly damaged or transformed into mud and muck.
As lighter animals, sheep do not cause as much trampling but they can over-graze and extensively damage pastures.