Rabbit genetics and breeding to get desired quality?????

[jacobmsnyder1991]

Hey guys I'm new here. I've bred New Zealands for about the past 10 hrs and recently got into standard rex for the fur quality. As many know they are slower growing.
I had an idea and I'm not sure if it's possible or how to go about it... is it possible to breed a rex with something that grows alot faster but will produce rabbits thay will have the rex fur?? So would I use a new Zealand buck and rex doe, then breed the back faster growing does to the new Zealand buck?? Then once i have the faster growing rabbit I breed the babies I like back to a rex buck to get the fur back??
I hope I'm making sense. Would it just be better to find some faster growing standard rex? I'm at like 3lbs at 8 weeks right now. Thanks!

 

[eco2pia]

Hi! welcome to rabbit talk!

I believe the gene for rex fur is recessive. Your first generation would not have rex fur but all kits would carry the gene for rex fur. Subsequent generations could have rex fur if bred back to a rex or rex carrier. Therefore I think your best strategy would actually be to get a solid (meaning "excellent", not a color thing) Rex buck, breed to NZ does, and line breed the fastest growing kits from that litter to the rex buck, or a different rex buck. Your next generation would give you some kits with rex fur and some who only carry rex fur. Again breed to the fastest growing of those...at this point you could swap in fast growing NZ/rex siblings who have rex fur...The point I am making is that if one parent is always rex furred you know the kits will either have or carry rex fur and you would not be in danger of losing that gene altogether in your quest for speedy growth.

All of that said, you will likely have a bit of a longish haul back to the goal of correct showable rex who also happen to be fast growing. But if you are a meat breeder who can afford the space to grow out lots of rabbits, and you can eat your mistakes, it could be a breed improving goal in the long run.

 

[Alaska Satin]

Hey guys I'm new here. I've bred New Zealands for about the past 10 hrs and recently got into standard rex for the fur quality. As many know they are slower growing.
I had an idea and I'm not sure if it's possible or how to go about it... is it possible to breed a rex with something that grows alot faster but will produce rabbits thay will have the rex fur?? So would I use a new Zealand buck and rex doe, then breed the back faster growing does to the new Zealand buck?? Then once i have the faster growing rabbit I breed the babies I like back to a rex buck to get the fur back??
I hope I'm making sense. Would it just be better to find some faster growing standard rex? I'm at like 3lbs at 8 weeks right now. Thanks!

My daughter is trying this right now with a Californian doe and a Rex buck. She's not looking for growth rate improvements, rather better depth and loin width in her Rex, but the principle is the same.

The first thing to realize is that you get what you breed, so yes, it's possible to succeed in what you're proposing. There are a couple of difficulties you will encounter, though, in general, and specific to that rex coat.

In my experience, when you cross a rex with a standard coat, it seems to take a very long time to get back to a good-quality rex coat. To be sure, you can get rex-coated babies in the F3 generation if you breed the F2 crosses back to their pure rex parents, but their coats tend to be thin and poor examples of rex. One of the reasons for this, is that part of what makes a rex coat so astounding is the incredible density (higher numbers of hairs per follicle). This density is linked to the genes for rex coat type, but is not an intergral part of the rex genome, i.e. you can get rex coats without the density.

Another issue is that the genes for rex coat type - there are at least three different versions - are recessive, so you know for sure that all of the F2 NZ x Rex babies (which will have standard commercial coats) carry a copy of that alelle. But if you breed those babies back to a pure NZ, statistically only 50% of the resulting F3 offsping will carry a copy; that means theoretically, all of them, half of them, none of them, or anywhere in between may carry it, and you won't know which they are. So to add NZ growth genetics to Rex, you'll need to keep breeding back to Rex as @eco2pia notes, or do sibling crosses with the F2 bunnies (which is fine, IMHO, since the parents are about as unrelated as you'll get).

Additionally, NZs are a fair bit bigger than Rex, at least according to the ARBA Standard of Perfection: NZs are 9-12 pounds, while Rex are 7.5 -10.5 pounds. If you are not aiming for breeding to the standard, that shouldn't be a problem, although remember that the bigger the adults, the more they eat! Increasing growth rates without increasing adult size would be what I was after, myself!

I like genetic experiments, and as @eco2pia just pointed out, you can eat your failures. A much faster way to get to your goal would be to just find some faster-growing Rex stock. But that's not always possible or financially feasible, and you will likely learn a lot more by doing the experiment yourself.

Let us know what you end up doing!

 

[jacobmsnyder1991]

Thanks guys! So in the f3 crosses I should have what I am looking for? Or just keep breeding back to the rex buck until I do?
Also if I did this with 2 sets and breed the f3 crosses from both sets could I end up with a standard? Or would I always end up with some of them slow growing or NZ fur?

 

[Alaska Satin]

Thanks guys! So in the f3 crosses I should have what I am looking for? Or just keep breeding back to the rex buck until I do?
Also if I did this with 2 sets and breed the f3 crosses from both sets could I end up with a standard? Or would I always end up with some of them slow growing or NZ fur?

It's probably not going to be that simple or quick. Like as not, the fastest-growing F3 bunnies will be the ones that don't get the rex coats... Expect to spend a few generations moving toward your goal, and a few more to get it set in your stock so they produce fast-growing rex-coated kits consistently.

Since the rex coat comes from a recessive gene, once you get rex-coated rabbits and breed them together, you'll get nothing but rex coats. But growth rates are not dependent on a single locus like the rex coat type; growth rate depends on many factors, only some of which are strictly genetic. Growth rate is also affected by numerous behavioral, physiological and health-related characteristics, all of which are mediated by genetics, but there are also other complications and interactions. Growth rates rely on lots of moving parts, so to speak.

I've been selecting for growth rates in my Satins for about 11 years, and while most of my litters are satisfyingly consistent, I still occasionally get bunnies that lag behind. Sometimes it's most of a litter - in which case I do not repeat the pairing - but sometimes it's just the luck of the draw for a particular bunny.

Super-fast growth rates are also an anomaly - not normal - so it takes constant selection to maintain them. If you relax that selection, your rabbits will slide back toward "normal."

 

[RabbitsOfTheCreek]

Is it really worth it to spend so much time and resources just to get them to have faster growth?

 

[Alaska Satin]

Is it really worth it to spend so much time and resources just to get them to have faster growth?

They're meat rabbits, so he's not necessarily spending extra time or resources. The OP's already got the NZ and Rex stock, and he'll be breeding and feeding rabbits no matter what. He said has been raising NZs for over 10 yrs (it actually said 10 hrs, but I'm guessing that's a typo! ). If he raises his Rex for the same amount of time, in 10 more years he can have raised slow-growing bunnies for a decade, or he can slowly but surely improve the Rex growth rates and end up with fast-growing bunnies at the end of the same decade.

Over time, if you choose your brood stock with that in mind, growth rates rates will go up, meaning you can butcher earlier, meaning you feed the grow-outs for less time. If you want to put a bunch of meat in the freezer over the summer (or spring, or whenever it works best where you live), the quicker turn-around time means you'll possibly get six litters rather than three, or nine rather than six, or whatever.

What we haven't discussed, though, is the common assumption that with faster growth rates it'll cost you less to raise the bunnies to butcher weight. That may or may not be true. When I started raising meat rabbits here 15-20 yrs ago, the Satins took about 12 weeks to reach butcher weight. My NZs and Cals were butcher weight at about 8 and 10 wks, respectively. However, the Satins ate less total pellets in 12 weeks than the NZs and Cal ate in 8-10 weeks!

In the intervening years, I have used selective breeding, and one Californian crossed into the Satin line, to push the butcher weight age back to about 9 wks for the Satins. What I don't know, though, is whether, to achieve that faster growth, I've given up the Satins' extreme feed conversion efficiency. I kind of suspect I have...and I kind of don't want to know!

 

[jacobmsnyder1991]

Rabbitsofthecreek, they are both meat rabbits and I have Time so I'm not worried about that. It was just a thought I had. I'm not one to give up because something may be hard or not really worth it.

so when choosing which crosses to keep, do you pick the ones that have the closest combination of mom and dad? Or how do you know which ones to keep?

 

[Alaska Satin]

Rabbitsofthecreek, they are both meat rabbits and I have Time so I'm not worried about that. It was just a thought I had. I'm not one to give up because something may be hard or not really worth it.

so when choosing which crosses to keep, do you pick the ones that have the closest combination of mom and dad? Or how do you know which ones to keep?

If it's growth rate you're after, keep track of bunny weights (at least weekly) and choose the ones with the fastest growth for your next generation breeders. Note that those may not be the very biggest bunnies. Of course you don't want to keep runts (which sometimes have a significant growth spurt once they're weaned), but in general, faster-growing bunnies tend to produce faster-growing offspring.

Since you also want rex coats, you will have to compromise, because most likely at least some of your fastest-growing rabbits will have commercial coats. That's one reason I'd expect to work at this for at least a few generations. To get that coat type, you will probably have to use some of the less-fast growing individuals as well.

 

[jacobmsnyder1991]

Thanks everyone for your help. I'm still not sure which of the kit crosses to keep then? If I just keep the fastest growing ones will they have the rex fur gene or only half of them have it?

 

[Alaska Satin]

Thanks everyone for your help. I'm still not sure which of the kit crosses to keep then? If I just keep the fastest growing ones will they have the rex fur gene or only half of them have it?

If one, or both, of the parents have rex fur, you can be certain every kit will carry it, but they may not have rex fur themselves. So if you breed a NZ x Rex, all of the kits will be normal-coated, but all will carry the needed gene. Pick the fastest-growing of those kits for your next generation.

Now, if you breed two of those kits that carry the gene but have normal fur with each other, you will get:
roughly 25% with rex fur;
roughly 25% with normal fur and no rex gene;
and roughly 59% will have normal fur but will carry the gene for rex.
If the rex-coated bunnies grow as fast or faster than the others, you've got your new breeding stock. But if the normal-coated bunnies grow the fastest, the problem is that you cannot tell by looking which of these new normal-furred bunnies carry the gene for rex and which do not. At that point it's trial-and-error, and you'll have to breed them to find out.

If, instead, you breed one of the normal-furred, rex-carrying bunnies with a NZ, all of the bunnies will again have normal fur, but approximately 50% of them will carry a copy of the rex gene. And again, you won't know which ones they are by looking.

If you breed one of the normal-furred, rex-carrying bunnies with a Rex, about half of the bunnies will be rex coated, and about half of them will be normal-furred but carry the gene for rex (you know they will get at least one copy of the allele since the Rex parent has only rex alleles to give).

 

[eco2pia]

Thanks everyone for your help. I'm still not sure which of the kit crosses to keep then? If I just keep the fastest growing ones will they have the rex fur gene or only half of them have it?

If you breed one of the normal-furred, rex-carrying bunnies with a Rex, about half of the bunnies will be rex coated, and about half of them will be normal-furred but carry the gene for rex (you know they will get at least one copy of the allele since the Rex parent has only rex alleles to give).

Therefore I think your best strategy would actually be to get a solid (meaning "excellent", not a color thing) Rex buck, breed to NZ does, and line breed the fastest growing kits from that litter to the rex buck, or a different rex buck. Your next generation would give you some kits with rex fur and some who only carry rex fur. Again breed to the fastest growing of those...at this point you could swap in fast growing NZ/rex siblings who have rex fur...The point I am making is that if one parent is always rex furred you know the kits will either have or carry rex fur and you would not be in danger of losing that gene altogether in your quest for speedy growth.

So, This is what I am getting at in my first post--because you can't SEE where the rex gene goes, but you CAN weigh kits, to keep it simple you should always breed to one rex coated parent.

Then you are guaranteed that all the kits in the litter will have the rex gene, and you should keep the kits who grow the fastest out of each litter. If some of the fast growers have rex fur you have your next rex furred parent, but you need to always have at least one parent be rex furred.

Eventually you will have a parent of each sex who is both rex furred and a fast grower, and repeat that a few times and you have a new herd of rex furred fast growing rabbits, and you can start breeding them to each other and focusing on just speed of growth...