Holey Cow!

Bovines have an amazing ability to turn relatively undigestable grass, hay and other roughage into nutrients and energy

- Anna O'Brien, D.V.M.

But they can't claim all the credit; their rumen - the enormous (50-gallon) fermentation vat that breaks down what they eat - houses billions of bacteria, yeast and protozoa. These microbes are the real workhorses of digestion, using unique chemical reactions to turn tough cellulose into volatile fatty acids that the cow uses for energy. Talk about teamwork!

When a cow becomes sick, these precious rumen microbes can get sick, too, and even die. Understandably, this has a negative impact on the cow's digestion. One remedy to help a sick cow get back on track is a ruminal transplant. This is where new, healthy microbes from another cow are given to the sick one. This happens with the help of an animal called a fistulated cow.