The Dorper breed has become a popular breed of sheep because it is a single purpose breed, and that purpose is meat. Once you have switched over to Dorpers, you no longer need worry where your next shearer is coming from, because you don't shear Dorpers. So you are out of the wool business, which has become a losing business for so many.
Some sheep farmers can afford to sell their current flock and buy a flock of Dorpers. Others will have to grow into the Dorper business by grading-up. The Dorper registry allows the registration of the offspring of a Dorper ram and other breeds of ewes, and you can grade-up the offspring til they get to a very high percentage level, at which point they are called 'purebloods'. (The animals that are 100% Dorpers with no outside blood are called 'fullbloods'.)
I got my first White Dorper ram (White Dorpers are managed by the registry as if they were a separate breed from regular, dark-headed Dorpers) a couple of years ago. The farmer I bought from told me that in the first cross with the Dorper/White Dorper, the offspring would still have wool I would have to shear. It would be a couple of generations before I would be able to get the wool out.
This turned out not to be the case, because the sheep I had were fullblood Shetlands. The Shetland is a small breed of sheep from the Shetland islands to the north of Scotland. They are noted for their fine wool, and they come in many colors and markings. But more to the point, they are known to grow their wool in yearly fleeces instead of continuously. In the Shetland islands, traditionally the Shetlands were not sheared, but 'rooed' (plucked). That is, the wool of their old fleece was pulled off by hand, leaving the start of the next year's fleece on the sheep.
I have always preferred to 'roo' my Shetlands rather than shear them. I am so bad at shearing that it's like a circus, with the sheep out of my control. I prefer not to have a sharp cutting instrument in my hand during the circus! So my breeding program has tended to favor the sheep that 'roo' well.
And so, I set my first White Dorper ram to the Shetland ewes. The result has been a small flock of F1 (first cross) ewes, every one of which has fully shed her wool!
Now, in the same year in which my F1s were born, my yearling Shetland ewes also shed their wool. I had decided to give it a try to see how fully they would shed. Many shed completely, others partially. All of these ewes were the daughters of a particular ram, Area 51. Unfortunately, Area 51 had been sold for meat that fall, because he'd had a few sons with problems.
Most of my Shetland ewes who were not related to Area 51 didn't shed nearly as much--- but the F1 ewes that ALL shed were sometimes the daughters of Shetland mothers who didn't shed at all.
The key seems to be that the mothers grew their wool in yearly fleeces which all Shetlands do. This enables their half-Dorper daughters to shed their wool completely.
I believe as a result of my little experiment that the Dorper/Shetland cross has some real possibilities. Shetlands are a hardy breed. Three Shetlands can be fed for the price of two sheep of other breeds. They are also good mothers. And they give the would-be Dorper farmer the results he wants in only one generation of crossbreeding. And while Dorpers are larger than Shetlands, I haven't have any birthing problems as a result of the cross.
For crossbreeding purposes, where you may not care about registry papers, you may be able to pick up decent Shetlands at a fair price from hobby breeders getting out of the hobby. You needn't worry about the color of the ewes--- all bred to my White Dorper ram have had white lambs, regardless of the mother's color.
There are other breeds related to the Shetland that also grow yearly fleeces that might be a good fit for crossbreeding. There is the Romanov, famous for multiple births. A Romanov breeder told me that the breed sheds its wool. Finnsheep, also a multiple birth breed, are also related to the Shetland, though I don't know how sheddy their wool coat is. And the Icelandic sheep are also a relative of the Shetland, though they are less available and may be too expensive for a crossing program.
Dorper/White Dorper sheep are a very practice breed choice and I hope I have interested some of you in the possibilities of Shetland x Dorper crosses to build up your flock.