Has anyone outcrossed breeds (similar breed types) in order to help improve in an area that has been struggling in? I need bone density and width but cannot find it in my breed without sitting on a waitlist for years or paying an arm and a leg.
How many generations of outcrosses do you think it’ll take to bring in the bone density and width but not screw up the intended breed? And yes these will be project buns until I can solidify what I need and clear the lines.
We've used outcrosses in three breeds: Satin (x Californian), Polish (x Mini Satin) and Mini Rex (x Polish), all with very good results. We chose the breeds carefully with regard to similarity of type and size, identification of individual rabbits having the characteristic we were looking for, and availability/affordability in our area.
The first and most important advice I can give you is to try hard to find a breeder of NDs (hopefully successful and/or with long experience) in your area and ask if he/she is interested and willing to help you with this project. If you can talk with the breeder of the animals you currently have, all the better, since he/she will presumably know their strong points and weak points and how they respond to selective breeding.
Outcrossing can work fabulously if the lines mesh well, which is just as true for outcrosses from different genetic lines within a breed. You can get kits with all the good points of each parent, kits with all the undesirable features of each parent, or something in between. It will depend on the availability of good stock and your ability to choose the appropriate animal, but to some degree, it's the luck of the draw.
In the Satins, I was looking to increase size, growth rate and muscle tone. Fortunately, the Cal doe I used passed her outstanding attributes to her kits and so did the excellent Satin buck I used, so the qualities I wanted showed up in the first generation. However, it took 2-3 generations to recapture the recessive Satin coat type. Since the kits I kept had what I wanted right off the bat, that was it, and I hit the ground running and haven't looked back.
For the Polish, we were looking to eliminate a recurrent problem in the Blue-Eyed Whites (BEWs), which was malocclusion. We found a Mini Satin/Polish cross doe that was closer in type to Polish than a standard Mini Satin normally is, and used her with our BEW Polish buck. The first and second generation kits have had no problems with malocclusion except when we used one particular Polish buck. Because BEW is produced by another recessive gene, it took a total of 3 generations to get a show-quality BEW. He's still not quite as good (in type and boldness of eye) as his grandfather, but we're expecting his kits to be outstanding...and with no worries about malocclusion. There is the possibility that somewhere down the line satin genes that might be lurking in the herd and might pop out some satin-coated Polish babies, but we haven't had that happen yet.
With the Mini Rex, we were looking to add a color not found in any mini rex in the state (BEW). This was the most challenging cross because it seems that whenever you cross a rabbit with a normal coat with the recessive rex, you lose significant quality in the rex coat, even after you've recaptured the coat type. We used our BEW Polish buck with two of our best mini rex does. In the second generation we got rex-coated babies, but sure enough their coats are thinner than I'd like to see. Their type is quite good, though, so it will just require patience and line-breeding to build the fur quality back up. This will likely take several more generations, since we're balancing coat quality with retaining that recessive BEW gene, and likely longer than that to produce Best of Breed contenders.
For your Netherland Dwarfs, you would choose a breed close in fur type, body type and/or posture/headset. Unfortunately, the other comparable breeds all have recessive characteristics that might be hard to get rid of, namely fur type (wool in Jersey Woolies or Am. Fuzzy Lops), headset (low in Polish), and/or ear type (lopped in Hollands and Fuzzies). I'd suggest staying within the upright and high-headset breeds, since those are so important in the presentation of NDs, and are reliant on the proper skeletal build. Lionheads sound like a possibility, as do Jersey Woolies if you can find one with excellent bone.
Actually, if I was doing it I'd probably look into Holland Lops. They are bred to have similar head shape, high head mount, upright posture, short ears, good width and massive bone. Of course you don't want a ND to have massive bone, but it shouldn't be hard to find a Holland that wasn't as massive as the Holland standard calls for. That might mean you could purchase one for less than a show-quality Holland. You'll have to deal with the ear carriage and the high, wide crown - the opposite of what you want in a ND - but given what your animals need and looking at the point spread in the SOP, I'd prioritize body type. But since I have not raised NDs, again I'd encourage you to build a relationship with one or more ND breeders.
How many generations it takes will depend on the quality of the stock you start with, how well they mesh with the new animal(s), and how hard you cull. You do have to be prepared to be patient, knowing it might take a few generations to get the characteristics you want, and even longer to set them in your herd so that you get them consistently in every litter. You also need to be prepared to do a
lot of culling - keep only the absolute best from each litter, and if none of them are better than their parents, pass on them all.
