I got some salad greens at the farmers' market today. Then I got home and realized I had to wash it all. It's too bad I'm not a goat. These hungry animals can eat just about anything-including all the sand that comes with their usual diet of grass and hay.
But goats never seem bothered by the grit. It's a normal part of their eating patterns, and their teeth aren't worn down too much. A new study tells us why.
Researchers from the University of Zurich examined 28 goats that were fed different pelleted diets of grit and hay. The scientists performed CT scans of the goats' stomachs at the beginning of the experiment and then again six months later. They then dissected the goats and examined their digestive tracts' contents.
There was plenty to see, because goats, like cows, have four stomachs. If dinner is yummy food-grass, hay, leaves-it gets placed in the upper stomachs to be regurgitated and chewed thoroughly. Once the chewed-up food is small enough, it's swallowed, and passes through to the lower stomachs to be immediately digested.
The researchers found that when the food hit the upper stomach, the sand sunk to the bottom of the stomach's liquid. It eventually made its way to the lower stomachs, while only the plants were regurgitated for more chewing.
Since the animals just chewed the grit during their first bite of grass, it only wore down their teeth a little. The scientists concluded that this sorting process essentially washes the grass, cleaning it of grit before the grass is regurgitated.
Sources and Further Reading
- Hatt, J-M., et al. (2019). The rumen washes off abrasives before heavy-duty chewing in ruminants. Mammalian Biology. 97, 104-111.
- Supriya, L. Why dirt-eating goats never need to visit the dentist. Science, June 21, 2019.