In comparison studies, New Zealand produced the fastest growth and highest butcher weights for the amount of food eaten... but...
Calfornians grew more slowly, achieved a minimally lower butcher weight at the same age, on the same amount of food, BUT, they produced a higher amount of MEAT, by a minimal amount. The dressed weight was about the same, the boned weight was higher.
This was shown over several different methods of comparison, including cross breeding, where anything bred to a Californian also carried those traits in comparison to the other parent. Trials were done using Californian, New Zealand, and Flemish Giants.
We opted for crossbreeds - Flemish/Californian and Flemish/New Zealand crosses. We are working toward a blending of the best traits of all of them.
We find that the NZ crosses carry the NZ traits - rounded body of the NZ instead of mandolin shape of the Flemish, but lacking the high muscular shoulders of the Cal. The size is in between the NZ and Flemish.
The Cal crosses have that distinctive rounded muscular shoulder of the Cal, though less pronounced, instead of the mandolin shape of the Flemish. Size is slightly smaller than the NZ crosses, but may end up having the same result as the studies showed.
Californians, especially mature bucks, show a lot of round muscle on them. NZs tend to just be round but not particularly muscular looking. Both have the classic round bunny shape to the back. Flemish have a mandolin shape - higher in the rump, lower in the shoulders. That means generally they do not carry as much weight in the shoulders by proportion as the NZs and Cals do.
Californians have the best dressed weight to live weight ratio, and the best meat to bone ratio. Statistically, they also have the best food to meat conversion rate.
Now, some things about meat rabbits...
All of these comparisons assume that you are butchering between 9 and 12 weeks of age - that is "fryer" age. This is the point at which you get the most meat for the least food. Keeping up with that means you breed and butcher on a demanding schedule though.
Fryer age rabbits assumes an industry standard of 2 to 2 1/2 lbs dressed weight. Both NZs and Cals were bred for the commercial meat industry, where they wanted a standard dressed weight comparable to your average dressed fryer chicken. So if you go with that kind of standard, you butcher one rabbit, for about 1 1/2 lbs of actual meat.
There is a fair bit of difference in weight between a 9 week rabbit, and a 12 week rabbit also. But then, there's three extra weeks of feed also, and the growth rate usually starts a gradual decline around 9-10 weeks.
If you go a little longer, those ratios can change. At that point you get into "roaster" rabbits. Beyond the fryer stage, rabbit growth rates change by breed - and that variance increases over time. This is why we chose Flemish as a cross. Flemish keep growing at a fairly strong rate until they are about a year and a half old, sometimes longer (well into the "stewing" stage). The older they are, the slower the growth rate, but usually by that time we are getting breeding out of them.
That means that the feed for them will continue to convert to meat, though at a slower rate, if we neglect butchering, or if we butcher unsatisfactory or unneeded breeding stock.
Our NZ and Cal bucks and our Satin/Flemish cross buck, have all pretty much stopped growing, and they are around a year old. So their food just gets consumed, not converted to any additional meat at all, should we decide that we don't need one of them.
Things often interfere with a butchering schedule. We hauled eight bunnies with us that should have been dispatched prior to our move, simply because we could not find the time to do it before we moved, and they were not ready soon enough to plan ahead on that job.
I don't know if there is a conclusion from this - at least, not the SAME conclusion for every person. You really have to just decide what your priorities are, get the facts, and then make a choice based on those priorities.
What is right for us isn't best for everyone.
