Inbreeding Depression

[pamnock]

Yesterday, Lissa and I were discussinginbreeding depression and she wanted me to post more info. Ihad mentioned to her that purebred animals often lack the vigor andlongevity of their heinz 57 counterparts, which may come as a surpriseto some people who believe that purebreds live longer healthier lives.

In a nutshell, show breeders select stock that possess certain traits(let's choose short ears for an example). Linebreeding andinbreedingcan produce superior show animalsconsistentlythat possess the desired traits.Unfortunately, this creates weaknesses in other areas (suchas production and disease resistance). This is a concern notonly in breeding rabbits, but other animals and even humans as well.(Closed populations of people -- Amish, for example -- are more likelyto suffer from congenital defects due to the smaller/condensed genepool.

From Rabbit Production: "It should be mentioned, however, that even inthe best lines of inbred stock, individuals man show less vigor interms of health-and reproductive-related performance than non-inbredindividuals. This is referred to as inbreedingdepression.

Inbreeding depression is more common in rare breeds where breedingstock is very limited. It is a common practice to use arabbit of another breed to add vigor back into the rare inbred line.

This information would certainly cause consideration for adopting amixed breed rabbitover apurebred line-bredindividual as a family pet.

Show breeders will often produce two separate lines that can then becrossed, adding hybrid diversity to the 3rd line.Hybrids are common in commercial meat production as it increasesproduction and disease resistance.

A friend of ours won a steer class with a hybrid -- I was surprisedthat a hybrid would be competitive in such classes, but she explainedthat the hybrid steer are often superior animals.

On the other hand, I had read years ago of a strain of rabbitsspecifically bred for superior disease resistance.Unfortunately, this strain also carried a genetic pre-disposition forself mutilation.

For those interested in further reading:

"Evidence now is accumulating rapidly that reduced geneticdiversity in the small (Pygmy Rabbit) captive population is acontributing factor - a phenomenon called inbreeding depression."

http://www.campusecology.wsu.edu/page_044.htm

Selective Breeding

http://en.wikipedia.org/wiki/Selective_breeding

Inbreeding Depression

http://en.wikipedia.org/wiki/Inbreeding_depression

Pros & Cons of Inbreeding (about dogs, but relates to all species)

http://www.dogbreedinfo.com/inbreeding.htm

Breeding for disease resistance (about pigs, but relates to all species)

http://nationalhogfarmer.com/mag/farming_breeding_better_disease/index.html



Pam

 

[Lissa]

Thank you Pam! This subject is sointeresting. So many people when they adopt"purebred" animals they expect the best. Makes me think twiceabout adopting from a breeder again.

 

[pamnock]

I agree that certainly a mixed breed from arescue is worth much consideration. I do urge caution ofpurchasing mixed breeds from backyard breeders who may not have properdisease management skills and may use sick animals within their herdsfor breeding and also sell those unhealthy animals to pet stores.

For those looking to purchase a rabbit for their child who isconsidering joining 4-H and showing their rabbit, I do recommend apedigreed purebred.

Pam

 

[pamnock]

Sudden Death Syndrome in clones . . .

http://www.lifesite.net/ldn/2003/aug/03082804.html

 

[m.e.]

Ah yes, good ole' Hybrid Vigor.

You'll hear about it in dog circles, how the "mutts" and mixed-breeddogs will rarely display any of the genetic weakness and illnesses oftheir pureblooded counterparts [not a guarantee, of course: a GSD-mixcan still be prone to hip dysplasia]

But it's so often a fact, that animal rescues are quick to capitalizeon it Especially where so many people are convinced purebreds arethe "superior" animals. It's not so black-and-white.

 

:great: I was goingto post a thread similar tothis one asking just this sametopic Thank You Lissa and Pam , I didnthave the word ability to get itset up . Im glad it is postedand the links are going to providevaluable information . I for onewill be pouring overthe links . Onecan never have too much information , even when it is a bitoverwhelming , it always manages to clicktogether eventually.

 

[doodle]

Interesting, I was just reading about this onthe website of a vet/genecistwho breeds Labradoodles. While a few high-end breeders aretrying to develop it into a multigeneration breed and claim to have the'real' Labradoodles, this vet breeds only first generation crossesbecause of hybrid vigor.

She also breeds for medium size and features because of the healthproblems that tend to come with extremes (such as giant size, toy size,large head, long ears, or other extremes in conformation).She explains how it's important to choose two breeds that do not sharethe same genetic problems and that complement one another intemperament. Most 'backyard' breeders don't consider thesefactors.

It's interesting and definitely something to consider when looking fora good family pet, whether it's a dog or a rabbit.

 

[Nicky Snow]

Very interesting subject. Thanks Pam!

Growing up we had 2 "mutt" dogs. They both lived very long (16/14years), and were exceptionally smart. My dad explained, or tried, thatinbreeding/purebreeds can have more health risks etc...

 

[bluebird]

I watched a show on animal planet about dogbreeds.Bichon frises are known to have severe allergies and are oftengiven to rescues for this reason.the vet bills are huge.It pays toresearch before buying.bluebird