Eating grass is actually a perfectly normal activity for both dogs and cats, and it is part of a normal healthy diet. Many people are surprised when they see their pets do this, and often assume they are sick, or lacking in some dietary nutrients.
In actual fact, young grass shoots are a potent source of nutrients, rich in vitamins, minerals, trace elements and anti-oxidants â€“ which is the reason wheat grass has become so popular again with health conscious people.
What is quite interesting is the fact that when dogs and cats consume a raw food diet, they become more in tune with their primal instincts, and people often comment that they see their pets eating grass, which they never used to. It is also true, that dogs and cats will eat grass when they are feeling sick (nauseous), but in this situation they are not selective, and in fact, ingest a large volume of the older grass shoots, which is high in lignin and tannins, and will stimulate vomiting. This is also a primal/evolutionary action designed to empty the stomach when required.
There is quite a difference however to the nutritional value of older grass, which becomes much less valuable. Young grass shoots (sprouts) are soft, and the cell walls are still digestible for dogs and cats â€“ if you watch them closely when they eat grass, you can see them â€œmouthingâ€ the grass, to check if the blades of grass have rough edges (older grass develops quite sharp serrated edges, and is indigestible).