Blue Book Article 2
How One Breeder Limits Inbreeding - by Angus Rouse
In a
closed flock where the total number of breeding ewes is
relatively small, it is important that some planning is used in breeding
strategies to limit in-breeding. The breed in North America goes back to a small
number of imported animals, which gives a further reason for care in preserving
lines and families. The system we use at Homebank Farm may be of interest to
breeders.
We run five breeding groups (A-E). This is a minimum number for this system. We
originally made up each group by putting all related ewes together. With 50 ewes
this gave us around 10 ewes per group. We allocated an unrelated
ram to each group and he breeds those ewes each year.
When ewe lambs are kept for replacements, they move to the group two back (i.e.,
from C to A, D to B, etc.). Replacement ram lambs go one group forward (i.e.,
from A to B, from B to C, etc.). Ewe lambs must go back two groups because their
sires will have come from the group one back.
Against the geneticists' advice of changing generations often, we try to use our
sires for five or six years, and by doing so, a closed flock can limit
inbreeding for many years. We also try to replace rams for all groups the same
year.
We have found that by running a closed flock, except for importations from the
U.K. with long quarantine periods, we can maintain excellent health in our
animals.
If anyone has questions or comments, please feel free to contact me.
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