We got on the subject of trace mineral diet deficiencies, and Dad was talking how locally, there is no selenium in the soil. The lack of selenium in the diet can cause problems. It isn't a problem for us now because most produce in the country is grown in California, where there is plenty of selenium in the soil, but cows that obviously eat local grown vegetation must be given supplements or there can be problems with calves and probably other problems as well. It got me thinking, just a bunch of seeds and all the venison I can shoot wouldn't be enough if trade was to be shut down for an extended period. The lack of Selenium could be somewhat of a problem here. Obviously it is possible to live without, because there were people here before there was a transcontinental grocery trade, but adding it a bit of extra lethargy or something could easily be the feather that broke the camel's back if things get real bad. I imagine other areas have other trace mineral deficiencies.