I understand that paleontologists have discovered a decline in the quality of human bones since the beginning of the agricultural age when migratory people changed from hunter gathers to settled agriculturists with a diet change which included a increased amount of grain. Is this also true for their equine partners? Do you also see a difference in the bone quality of wild horses who have not eaten grain compared with domestic horses eating a diet consisting of a large portion of grain or other concentrates?
Dear Kathy K: There is no decline in bone "quality" if by "quality" you mean "bone density"; bone density is the same, within very tight limits, in all healthy mammals. It would help me in answering your concerns if you could please cite the scientific literature that you're referring to; then we'll both be on the same page as to what is meant by "quality".
There is a well-documented decrease in height and overall size that occured in sheep and goats as cultures transitioned from hunting them to herding their selected descendants. This could not have been due to diet, since early pastoralists grew no grain, and what grain they had, they gathered from what was growing wild. And that grain was intended for human, not animal consumption. There is a difference between pastoralists and agriculturalists, in other words.
The decrease in height/body mass that occurred in sheep and goats is thought to be due to selection -- in other words, people deliberately bred small rams to the smallest ewes for preference. Few people today have any experience with the wild species that are thought to be the ancestors, or related to the ancestors, of domestic sheep and goats; but they are large, strong, and potentially dangerous. Anyone who keeps domestic sheep will tell you the same thing: never turn your back on a ram. Domestic sheep today are much larger than they were in antiquity (though still generally smaller than their wild ancestors). Sheep in Iron Age Britain, for example, matured to a withers height of under two feet; they are tiny little things which were not used for meat or milk, but wool. The same may be said for the cattle, which were much smaller than modern breeds, standing under 3 1/2 ft. in all cases (modern Dexter cattle are a parallel example, thought to have ancient ancestry at least in part).
This height/bodymass diminution is not, however, documented for horses. This is because horses are not used in the same way as sheep or goats or cattle, but instead valued for weightbearing capacity, strength, and hardiness. Horses were domesticated much later than sheep/goats or cattle -- the former about 6 thousand years ago, cattle about 8 thousand, sheep/goats 8 to 10 thousand years ago. By the time horses were domesticated, there were agriculturalist cultures. However, all of those existed south of the Silk Road, whereas the horse was domesticated north of it, and the southerners got their first horses by trading with the northern nomads. They also obtained riding and handling instruction from them, as they had no experience at all with what to them was an entirely new species. The natural predomestication range of horses lies north of the Silk Road (see papers on this subject by going to our main website at http://www.equinestudies.org and click on "knowledge base", then click on "Mammalian Species").
Very conceivably the southerners fed their horses some grain, and also possibly alfalfa, which caused the animals to become bigger and stronger than they would have otherwise done. However the "grain" fed to the animals was not oats, nor was it corn (maize); both of these grains were unknown to them. Neither was it emmer or any other sort of wheat, which was reserved for human consumption. What was fed to animals was barley (barleycorn, or what in Europe is called 'corn' as opposed to 'maize'). The barley was cracked, meaning coarsely ground, with stone mills and fed to the animals after no sifting or only one sifting to remove sandy grit introduced from the millstones. Barley intended for human consumption was sifted two or three times (this is why the flour sack even today has "XXX" on it, meaning "sifted three times").
So you see there is a good deal more to your question than might have appeared. Please send along the sources of your information so that I can read them and comment further. Things have not always been the way they now are, and it is always dangerous when internet "sources" forward ideas based not on knowledge of what really went down in antiquity, but rather on what are really mental pictures of modern practices illegitimately transported backwards in time. -- Dr. Deb