[Jacob-list] breeding

[Chovhani]

I'm way too new to the Jacob game to offer any comments on this, BUT I have
experience breeding rabbits for many, many generations (they can give birth
at 5 months of age, so you see how easy that is!) and what is interesting is
"throwback" genes. These are recessive genes that hide for a number of
generations, and pop up at random. For example we have recently had a litter
of 7 in which one was Angora. I own all the ancestors on both sides for 6
generations. The last Angora gene introduced to this strain was 6
generations ago, when I was desperate because a good buck had just died and
all I had spare was a half-Angora pet of my daughter's. This kit at face
value is 100% purebred Angora, ear tufts and everything. Inbreeding in
rabbits is a common practice but still needs to be done with care as several
undesirable traits are genetic, such as poor fur covering on hocks
(resulting in sore feet in wire cages). This can throwback after several
generations too, and I'm at a stage now where I can be picky enough that a
doe with poor hock fur is culled, despite everything else being A1. With my
sheep the best I could do was buy an unrelated Ram but experts tell me that
all Jacobs in Ontario are related down the line, so who know what my
coeffiient is!

Melanie, the one with the "surprise" Fall lamb!


----- Original Message -----
From: <Jacobflock at aol.com>
To: <sugarhil at northland.lib.mi.us>; <wireworks at globaldialog.com>;
<jacob-list at jacobsheep.com>
Sent: Friday, October 06, 2000 4:46 PM
Subject: Re: [Jacob-list] breeding


Marcia is right on with inbreeding...the best and the "wurst".

We have noticed that there is a higher incidence of structural and genetic
problems as inbreeding coefficients increase.  For example:
(1) we bought a pretty yearling ewe about three years ago, coefficient was
about 25% (we idn't check the pedigree closely!).  Barren after three years.
(2) loose ram produced Twinkle Toes, coefficient 22%.  No hoof walls, xray
showed missing digits in feet.
(3) in general we have observed coefficients over 15% tend to result in
"shorter, smaller" Jacobs; offspring also tend to be small

An inbred ram should help to "fix" traits but it takes many generations to
"fix" a trait and see true repeatability; homozygous at virtually all
alleles.

Others that have actual experiences such as these might shed some light on
successful inbreeding for several generations.  One "good" inbreeding does
not stand on its own.  Breeding two with high coefficients with a lower
cofficient offspring would be preferred to increasing inbreeding.  "A
Conservation Breeding Handbook" may be helpful.   Fred Horak

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