[Blackbelly] A Walking Dichotomy?

[Barb Lee]

I have been thinking about these feeding issues, about lamb performance 
and growth, about our position in the market in relation to other hair 
breeds, and about the natural impulse to "improve" my flock. Another 
thought occurred to me.
This deals specifically with the "American Blackbelly," the strain of 
sheep that is registered by the BBSAI, and any sheep that is qualified 
to register under the breed standards.  I am being fairly specific, 
because the breed standards eliminate a number of variables.  However, 
the idea applies to just about any of the Barbado/Corsican type strains 
of sheep.  This is TOTALLY speculation.

The American Blackbelly is registered under a set of criteria that 
except for horns, are virtually identical to the Barbados Blackbelly. 
The color pattern is set and highly predictable...it breeds true in 
generation after generation with no variation except a rare outcrop of 
white.  Legend has it that the magnificent horns are the result of 
crossing...and back crossing and back crossing and back crossing on 
Mouflon, with perhaps a splash of rambouillet or some such in there as 
well.

The dichotomy arises with the marriage of a polyestrous breed known for 
high prolificacy, to a breed which through generations of natural 
selection, produces a single lamb, seasonally.

Visually, the AB is a walking replica of the BB only with horns...but 
what is going on internally?  Has she also inherited the twinning gene, 
but the singles machinery?  Some flocks have highly successful twinners. 
Some are mostly seasonal singles.  I know that the production of 
singles/multiples varies and can be a fairly fixed characteristic within 
individual flocks.  These single lamb'ers usually do a fantastic job of 
raising a big strapping lamb with "average" inputs of feed.

My limited experience is that the ewes who do produce multiples may or 
may not do so with ease, in terms of lamb vigor and size, plus gain, 
which is related to milking.  Some of the twinners are just fantastic! 
Why is it that with two ewes, under identical management and identical 
feed, bred to the same ram, one will consistently have big, thriving 
twins, and one's twins always require intervention to survive? This is a 
big reason for my concern about gut capacity and feed...now I wonder if 
we have married two opposing reproducing biological systems and don't 
always get the internal mechanics in the "crossbred" animal that are 
present in the original blackbelly stock - which seem to be noted for 
their prolificacy and follow-on rearing abilities.

I know I provide a good environment for my sheep and I know I have a lot 
to learn.  But I have also wondered if some of my "issues" stem from a 
general "breeding fitness" which may be associated with the heavy 
infusion of Mouflon reproductive traits  interfering with my insistence 
on multiple births.

It's an important concept.  The quest for trophy horns probably wasn't 
concerned much with reproductive efficiency.  Think about it - we got 
the Mouflon horns.  We got the Blackbelly coat pattern.  Looking at the 
outside, we see characteristics of both breeds.  In ANY type of 
crossbreeding program you may get the best of one parent and the worst 
of the other.  For instance if you breed a draft horse to a race horse, 
you may get a huge body on flimsy legs, or you may get a huge head on a 
flimsy body.  If you are lucky, you get a superb balance...but that 
individual will not reproduce itself with certainty. We may pick up a 
twinning gene in the cross we are working with, but we do not 
necessarily inherit the plumbing.  It's just thought provoking for folks 
who are trying to identify routes to improved performance in their 
flocks.  I know with my sheep, I have committed to optimizing nutrition 
at all stages (substituting book-learnin' for the experience I lack) and 
any ewes that don't get their twins up and going without having to run a 
hose down their throats for the first day or two, are going to be out of 
here.  No more free ride.

Regards,
Barb Lee 


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