Jun 18, 2023 20:00:00

It turns out why ``cow teeth'' that eat sand-covered grass do not wear out

``The teeth of ancient Egyptian mummies are well worn,

probably because the sand mixed with the wheat bread ground in the millstone has scraped the teeth.'' The included sand and pebbles are natural enemies of teeth. However, ruminants such as cattle eat grass together with sand and mud, and then put it back into their mouths and chew it regularly with their teeth. is known. Universities in Germany and Switzerland have found that the dental health of cows is related to special stomach functions.

The Ruminant sorting mechanism protects teeth from abrasives | PNAS
https://doi.org/10.1073/pnas.2212447119

Press release: Healthy teeth thanks to the 'washing machine effect”
https://www.uni-goettingen.de/en/73613.html?id=7088

Grass, which is the food of herbivorous animals, is accompanied by sand and dust, but if the teeth are worn down by fine particles, nothing can be eaten. As a result, many herbivorous animals have developed 'long crown teeth ', which are teeth with long enamel.

by

Ignacio Ferre Pérez

Ruminants, such as cattle, also have long crown teeth, but they have less crown , or part that protrudes from the gum, than the teeth of other herbivores.

To find out why there is such a difference even though they eat the same food, a research team led by professor Jürgen Hummel, a zoologist at the University of Göttingen in Germany, mixed sand with four cows. We fed them grass-fed and collected the food put back into their mouths for rumination and excreted excrement.

Then, when we analyzed the amount of

silica , which is the main component of the sand contained in the sample, we found that the feces contained the same amount of silica as that mixed with the food, whereas the food returned to the mouth contained the same amount of silica. was found to contain almost no silica. Specifically, around 84% of the silica contained in the food eaten was removed during rumination.

From this, the research team of Professor Hummel et al. concluded that `` when cows ruminate, they probably wash away the sand in the rumen , which is called the 'lumen.' Ruminants have multiple stomachs, the largest of which is the rumen, where digestive microbes ferment and break down grasses. The view that the rumen has the function of washing sand and mud is supported by anatomical findings obtained in the past.

The results of this study are important not only for modern cattle, but also for clarifying the history and evolutionary steps of ancient herbivores. This is because teeth are easily preserved as fossils, and teeth are often important clues, especially when restoring the ecology and living environment of early herbivores.

``Our study describes a fundamental but little-studied aspect of food chewing in large herbivores, contributing to our understanding of tooth function and evolution,'' Hummel said. Did.