[Jacob-list] Generations, Genetic Diversity, and Culling Pressures

[Lynette Frick]

Hi Zach,

The importance of generations is in the theory behind them. The more
generations you have registered the higher the chances that that animal is
truly a pure Jacob. Its somewhat like a guarantee from the registry that
that animal is pure, at least to the number of generations that they have
record of. The higher the letter, the more chances that that animal will
produce true to type. Even if you aren't seeing pictures of grandparents,
ggrandparents, etc. you know that those animals where inspected, deemed
pure, and met the minimum requirements for registration. That's the
importance behind the letters.

I wouldn't suggest buying unregistered stock, or FF stock, unless you
absolutely know the person that you are purchasing from, the history of
their flock, and are confident in your own abilities to pick out crossbreds,
even a generation or two into it. Also, you must realize that just because a
sheep is FF stock doesn't mean that you are being guaranteed genetic
diversity, it just means that somebody didn't keep up with their
registrations. For example, I purchased all my first sheep from Mr. Anderson
also. If I hadn't registered or kept records, and just used the Hillside
genetics that I started with, then what I would have where a bunch of
unregistered pure bred Jacob sheep with extremely concentrated Hillside
genetics, and no way to tell you who they are.

I'm going to agree with the others on the list in saying that knowing lines/
flocks is much more important in my book than the letter of registration.
And the best way to keep your sheep genetics healthy is to do serious
homework into the background of any animal you are interested in adding to
your breeding program, registered or not. Genetic diversity comes in the
form of finding a sheep with genetics most distant from your own sheep. Take
note, that if all the names 5 generations back are the same, you're still
looking at genetics that are very close to what you already have. This is
where it comes in handy to have a program like Tenset technologies "Breeders
Assistant", so that you can see what the Inbreeding coefficient would be if
you where to hypothetically mate two particular animals.
As for your other question, about the progressing of generations in relation
to the commercialization of the breed, I would have to say that the two
items are completely unrelated. Will it lead to a more uniform, or
"standardized" jacob, probably not, as there is enough wiggle room in the
breed standard to allow each shepherd to select what he likes, and each
shepherd is different. Also keep in mind that not  all sheep that are
unregistered are kept running wild, so one can't say that there is any
guarantee that you are getting more "primitive" sheep that have been under
less artificial selection than sheep that are registered.

What you need to look at are the selection pressures of the shepherd in
particular you would be potentially purchasing sheep from, and how much
infasis they put on them. Is the shepherd strictly breeding for beautiful
sheep with great markings, and lovely soft fleeces, and if so what do they
do with their weaker sheep? That hard to come by ewe who meets their
demanding requirements for a particular look, but maybe she gets scours
every once in a while, or they have to pull her lambs every year. Is she
still in their breeding program? (Worse yet, is the the mother
of herdsires?) If you want beautiful sheep at all costs, what you will
eventually end up with are miniature spotted Suffolks. They look great, die
for no reason, and tend to have a hard time counting(lambs). This is where
production records come in handy, and they along with pictures should be
your guide to your purchases.
Look for sheep that are produced in a system similar to your own, and that
have production records behind them. For example I have a small property, so
my sheep are kept in a dry lot for part of the time, and MIG grazed the
other part. What this means is that my ewes have to be able to hold up to
parasite pressures better than a sheep that is MIG grazed on 100 acres, or a
range ewe that doesn't see a particular property again until next year. If I
have a sheep that is weak to parasites they generally show it fast, look
rough and get diarrhea. I could do like my friends with their show sheep and
treat them 500 times, or I can keep my records, treat it once or twice, and
if the problem persists, put her in the freezer. Beautifully conformed, near
perfect sheep $250 or not, she doesn't belong if she is not thrifty.

 Health should be every shepherds overall goal, and selecting for such over
and beyond all our other selection goals is our only way to keep the Jacob
Breed of sheep from falling prey to the same fates as other farm flock
breeds. (I hesitate to call them commercial, as true commercial range sheep
get less care, and are more hardy than even some of our Jacobs could ever
hope for) Its ok, and of coarse even extremely necessary to select for
visible traits, but we must keep in mind that the pressures put on the Jacob
Breed in its development meant that the weakest, least adapted sheep died,
and that if we want hardy true to type Jacobs we have to put feelings behind
us and make sure to include hardyness in our culling and selection
decisions.

Just my two sense, hope it helps!

Lynette Frick
IDEAL FARM
Jacob Sheep
www.idealjacobsheep.com
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