There are two types of Dorset sheep; Dorset Horn and Polled Dorset, with the Polled gene being dominant and more common in North America. Dorset and Suffolk breeds are two of the most common breeds found in North America, and the Dorset breed is especially popular in Nova Scotia.
I have noticed that it is getting harder and harder to find Horned sheep of anybreed, and I would not like to see the Dorset Horn go the the way of the Wiltshire Horn, which is almost an extinct breed. Thus I am paying particular attention in keeping any of the Dorset Horn progeny born in my flock. There are special husbandry skills required with any horned animal, and horned sheep are no exception . Since all sheep , including ewes, like to butt you and the feed bucket, I discourage this practice whenever I can. My pens have to be nailed especially strong. I learned this after my Ram sent a rough sawn 2 by 6 flying thru the air. I nailed it the first time with 3 inch nails, the second time with 6 inch spikes. Special care must be taken when children are around sheep, due to the sheep's herding and flight instincts.
Having said all of this, I prefer Horned Sheep, as the Rams are much more confident in protecting themselves, and are thus calmer and gentler when unprovoked. His serenity also carries over to the remainder of the flock, however my Border Collie (who just passed way this month at the age of 14) owed at least part of her deafness to a horned ram attack three years ago in PEI. To date I have about 4 horned ewes (some others have small scurs), but it is natural for the ewes to have horns in most Horned breeds.
At present I have 1 registered Purebred Dorset (Horn) Ram and two purebred registered Dorset (polled) Ewes with papers. The remainder of my flock consist of unregistered Suffolk ewes, Dorset ewes and SuffolkXDorset in various proportions. I really enjoy the way that lambs "meat-up" when a Dorset sires a DorsetXSuffolk ewe. The resulting lambs are very fast growers, and are usually much taller than Dorset lambs.
Dorset mothers have a strong mothering instinct, and usually produce large quantities of rich milk. They are also one of the few breeds of sheep that have a longer "open season", and thus with proper stimulation (I prefer natural methods over hormonal methods) , lambs can be ready for market at other times of the year.