well... regarding breeding miniatures.. I'm just thinking that you are definitely not going to want to breed them to a big simmental or anything full-size. So if you aren't keeping your own bull it might be wise to choose cattle that you can breed to what your neighbours own. There may or may not be miniature bulls in the area. Or better, just keep your own bull.
regarding dwarfism... it happens with all the breeds. In dexters and angus it is the result of a single point mutation. In the past it has been more common than it should be in Dexter populations but any reputable breeder will be on this and managing it..but i would check up on them.
i guess i'm not fussy about miniatures, because whenever you get people really emphasizing one trait in their selective breeding the overall quality of the animals diminish. The old heritage breeds I think of as small but not miniature. They were selected for generations for thriftyness, disposition, ease of calving, milk and meat production. They are good solid cows even if they are small. Lately there has been an effort to make everything even smaller for 'miniatures' and in the rush to select for that character I am afraid that breeders aren't always paying as much attention to the other important characters. Dexters and their like have been small statured and working well for hundreds of years of practical use. Miniature herefords got there pretty darn quickly and it seems mostly to satisfy hobbyists.
at the risk of offending even more people, you really see the effect in horses. Take thoroughbreds. Bred hard to win on the track. Now in the USA the breed tends to have a very short working life span, they break down easily, their feet are really really bad, and their dispositions are far from ideal for a working animal. But they are fast for a few years and they win races. In britain where the breeding has been more conservative, thoroughbreds still have nice feet, it's a world of difference.
so i'm just saying that super tiny cows haven't necessarily came from a breeding program that selects for good overall cows
it really depends on sebastion's space, meat requirements, aesthetics, etc. If you spend time with a good small heritage breed they can be docile and easy to handle even though they are a bit bigger. With proper rotational grazing management, hoof traffic can improve soil texture.
as far as working with them... he said around five cattle and i'm assuming he's only going to butcher one or two a year...i don't think it would hurt to put some of his stock to work a bit to help earn their keep. I get the impression that it's an acreage not a full farm, so I don't think we're talking about twelve our days out in the fields with them...I just though it would be a fun thing to learn, and a
sustainable heirloom technology to keep alive and implement on a
permaculture homestead....a few hours in the garden now and then..
cheers, kari