Time for an experiment

[3mina]

Many of us have heard/read about the sibling breeding study that pops up every time the subject of line/inbreeding comes up.
Since I'm hopeless at finding anything on the 'net and I never remember to bookmark, I've decided I want to recreate the experiment so I have actual experience to draw on rather than just hearsay.

So in the interests of science, I'm planning on two litters from two pairs. This gives me four rabbits to work with and more information to record but won't max out my space with this experiment. There's a few other traits I want to see if I can intensify at the same time but for this experiment I'm not going to worry about colour after choosing the initial pairs.

Now for the less fun part, I am having a little difficulty coming up with points I should be recording.
I have some of the obvious ones like growth rate, litter sizes, weights at various ages, sex, genetic anomalies/defects. What else should I be looking at? What information would you want from an experiment like this?

 

[jeannie]

Doing a sibling experiment here as well.
BEW lionheads... started with the doe (a BEW), who does not have the manes I want.
Bred her with my my great maned blue buck.

Two of the above pairing offspring: one has fabulous manes and face (the doe in my avatar), and the sibling buck who is a black VM with great manes, but the face is more "pinched" than I want.

I am hoping for great manes, but also am really interested in the "face" "head" composition. The offspring will be bred back to my BEW doe, or BEW buck ~~ depending on the sex of the best offspring of the sibling pairing.

Really, I am almost ready to give up on the large maned BEW program, but "giving up" is against my very nature ~~ so I will probably keep trying

 

[3mina]

I'm mostly interested in how many generations I can continue to breed littermate siblings before it becomes problematic.

Actually, that brings up a question. What constitutes a problem worth terminating the experiment?

 

[Zass]

What colors are you planning on using?
I've read that crossing dilutes generation after generation can harm the color and color of toenails. That doesn't seem to hold true for americans though...so...I wonder...

 

[MamaSheepdog]

I have some of the obvious ones like growth rate, litter sizes, weights at various ages, sex, genetic anomalies/defects. What else should I be looking at?

I think that about covers it.

I've read that crossing dilutes generation after generation can harm the color and color of toenails.

I think I would avoid using dilutes for this reason only because if you can show the offspring, all the better!

What constitutes a problem worth terminating the experiment?

From what I have read, one of the first signs of "too much" inbreeding is reduced litter sizes. But I personally would stop if there were a large number of kits that had a fatal genetic abnormality.

 

[3mina]

I hadn't decided on which colours to use other than using my castor 'super' doe, the one who gave me 27 kits in two litters.
The colours I have are black, black otter, chocolate otter, blue otter, opal, black/orange tri, red, broken black otter, and SOP lynx. Everybunny, except the castor, opal, and lynx have very saturated colour. The lynx throws very deep colour though. The red and black are does from him out of a black otter.

I was thinking of terminating the experiment when I get nonviable litters, defined as DOAs, multiple missed litters/difficulty breeding, greatly reduced litter size (one reason I want to use the castor doe), genetic abnormalities. I'm thinking that if I can get these girls bred early enough in the spring I might be able to get two generations per year outdoors.

 

[akane]

Reduced litter size isn't a good determining factor for my ND. :lol: I have a brother/sister pair that I bred the sister out to a buck I no longer have and now have the brother with all her doe offspring in colony. Her buckling, an unrelated buck, and an unrelated doe are all I'm working with beyond that. I cut everything else from my herd. Mainly for personality issues. This is it for the next infinite generations until I feel I've reached my limit for fixing something like I have a potential for most of my rabbits to be cow hocked. Keeping the short ears and improving the hindquarters are going to be the main problems while working the colors.

 

[3mina]

Litter size definitely isn't a factor there but I figure with the Rex I can use it

Next question, which selection method should I use for the next generation? If this experiment was being done in a real lab the selection would be random-just pick two and done. Should I use my usual criteria or should it be random?

 

[Zass]

Litter size definitely isn't a factor there but I figure with the Rex I can use it

Next question, which selection method should I use for the next generation? If this experiment was being done in a real lab the selection would be random-just pick two and done. Should I use my usual criteria or should it be random?

I think you just stumbled upon something VERY interesting.

Rabbit breeders have to cull carefully just to maintain overall HEALTH.

If we all started with a meat type like new zealand, and proceeded to select our brood stock completely at random(including runts and kits that were small/sickly), I suspect we WOULD lose litter size, growth rates and maybe even the good immune systems that we all actively cull towards over the course of many generations, without inbreeding even being a factor..

 

[akane]

It depends what your experiment aims to prove. If you want to know how many random generations until you start to lose good traits then pick randomly. If you want to know how quickly a group of good rabbits can turn in to horrible rabbits pick the worst. If you want to prove what many have been saying that you can inbreed as long as you want provided you cull strongly then always pick the best to the point of rebreeding a pair until you get a better offspring than the parents to keep. I would probably go healthiest, best litters (a combo of size and ability to raise that number), and meat produced at a given age. I would not actually choose based on conformation except as it applies to meat ratios at butchering age. Unless we are not doing meat rabbits. If you are picking show rabbits you need to mostly reverse that. Closer to type first, health second, litter raising 3rd. Of course mine are neither. ND aren't for meat and I don't show so mine go health, personality, color, type, litters... If a trait starts to look weaker even if it's farther down in importance you may want to prioritize it for a generation to bring it back.

 

[Zass]

Thanks for going into that further for me Akane!!
It's exactly what I was trying to say.
We are always selecting for and culling for certain things, and if you remove that selecting from the equation during inbreeding, what you would mostly find out would be what would happen to the lines if you stopped being picky about what you breed.

In order to maintain a non-skewed result, you should use the same selection method that use use with your other rabbits.

 

[alforddm]

I think it would be interesting to see if how long you can keep inbreeding, while selecting for the best, before fertility begins to decline. One of the first indicators of two much inbreeding in other animals, such as dogs and horses, is a decline in overall fertility. So I would suspect you will eventually start to see does that don't "take" or bucks who don't "get the job done" as one of the first signs along with possibly reduced litter size and higher kit mortality.

Scientists have been studying the animals that live in the Chernobyl disaster area. What they have found is that mice populations are healthy, even the ones that are right next to the reactors. The reason is that while mortality is higher than in normal populations, the young with problems tend to be weeded out of the population early so generally only the fittest are reproducing, possibly even self selecting for radiation tolerance. If I'm remember correctly the rate of physical problems was in the range of 6%. This would be totally unacceptable in a human population but it does illustrate how animals can thrive under adverse conditions. In this case the "hard culling" taking place is the result of the radiation.

Please keep us posted on how this goes. Really fascinating stuff.

 

[MamaSheepdog]

What they have found is that mice populations are healthy, even the ones that are right next to the reactors. The reason is that while mortality is higher than in normal populations, the young with problems tend to be weeded out of the population early so generally only the fittest are reproducing, possibly even self selecting for radiation tolerance. If I'm remember correctly the rate of physical problems was in the range of 6%.

Wow! That is pretty amazing, isn't it?

Something to be said for multiparous critters, eh? Much easier to maintain a stable breeding population than in animals that have only one or two infants at a time or those that have a longer gestation.

 

[alforddm]

That information was taken from the PBS Nature episode "Radioactive Wolves". It was a really fascinating episode. They just barely touched on the Mice though. Here's a link to the episode if anyone wants to watch it. http://www.pbs.org/wnet/nature/radioact ... sode/7190/

And now back to our regular programming since I've sidetracked this thread enough, sorry 3mina.

 

[akane]

So I would suspect you will eventually start to see does that don't "take" or bucks who don't "get the job done" as one of the first signs along with possibly reduced litter size and higher kit mortality.

Mine already have all that. :lol: Ugh Kuwa why can't you get the does bred. Nice buck, great ears and head, small size, came from a good breeder, and I left him on and off in summer and half of fall with a doe and no litter. Put doe with a different breed buck and in about 1 min she's bred 3 times and has a liter. :wall: He finally got a doe bred and she lost the 2 kits. At least he's not sterile. After attempt 5 I finally got Choroi to breed someone and we'll know around the 10th if anything came of it. Hezaa just failed to produce a litter. Average litter sizes are 2. I think ND in many areas are a perfect example of what happens when you don't select for breeding characteristics. I don't think it's due to inbreeding at all though. It doesn't show on the pedigrees that way. All the problems people are worried about seeing in inbreeding are happening just from lack of selecting for those characteristics in any breeding no matter how close or not.

 

[Dood]

:yeahthat: :mrgreen:

My HIGHLY inbred first trio of 4 generation pedigreed AmChins were everything you'd want in a production meat rabbit - and after worrying about them being too inbred and desiring to improve their looks for the show table I bought in an unrelated pair with DISASTEROUS results - so I continue to inbreed my original trio who are ALL father-daughter, mother-son, full andhalf siblings, first and second cousins for 7 generations now and their production is still stellar

 

[alforddm]

Just out of curiosity Dood what was disastrous about the outcross?

 

[Dood]

Bad attitudes
- cage possessive when not pregnant and dangerous with a litter to protect
- Does were murderous to other rabbits and their own kits after 4 weeks old
-overly aggressive/?eager? bucks who drew blood on does during mounting

Poor fertility
- does didnt have litters 31 days after breeding with 2-3 coverings
- small litter sizes of under 8

Poor milk production
- not enough to feed 8 kits well

I only have one rabbit left of that bloodline - a doe who is 1/4 and she is 2nd on my list for replacing due to a litter of 7 last time and not getting pregnant as scheduled this time

 

[JenerationX]

That information was taken from the PBS Nature episode "Radioactive Wolves". It was a really fascinating episode. They just barely touched on the Mice though. Here's a link to the episode if anyone wants to watch it. http://www.pbs.org/wnet/nature/radioact ... sode/7190/

And now back to our regular programming since I've sidetracked this thread enough, sorry 3mina.

I watched that a while ago.. it was interesting to say the least. They also did an episode on the coywolf.

 

[Zass]

That information was taken from the PBS Nature episode "Radioactive Wolves". It was a really fascinating episode. They just barely touched on the Mice though. Here's a link to the episode if anyone wants to watch it. http://www.pbs.org/wnet/nature/radioact ... sode/7190/

And now back to our regular programming since I've sidetracked this thread enough, sorry 3mina.

I watched that a while ago.. it was interesting to say the least. They also did an episode on the coywolf.

Thread hijack again.

http://en.wikipedia.org/wiki/Eastern_co ... ar.%22.jpg

I didn't really believe in coywolves, until I spent a few years involved with the taxidermy community. It's a fun thing for trappers to compare skulls, carcases and skinned heads from eastern and western yotes. I'm convinced.