to Genetic Improvement
the Ideal Ewe
Therapy for A.I.
Shepherd Instructions and Requirments for AIing
SELECTING THE IDEAL
EWE TO ARTIFICIALLY INSEMINATE
Martin R. Dally
Super Sire, Ltd.
Any ewe used in an AI program should
have excellent breed characteristics and be structurally
sound. Only ewes with above average production records should
be considered for AI. Normally, only the top 30% of your
ewe flock would be considered. Producers who are enrolled
in NSIP have an advantage in selecting the genetically superior
ewes in their flock.
the ideal ewe has lambed at least one time and successfully
reared all lambs born. It is also important that she conceived
during the first 18 days of the breeding season, which indicates
that she is highly fertile. Ewes with a history of lambing
late should not be considered for an AI program because
this is an indicator of low ewe fertility.
Ewe prolificacy is extremely important
to the profitability of any sheep enterprise. Therefore,
it should not be overlooked when selecting ewes for an AI
program. When mature ewes are being considered for AI, the
ewe's lifetime lambs born and percent lambs weaned should
be considered. If mature ewes have any daughters in the
flock, their lambing records should also be taken into consideration.
Remember - the object of any breeding program is not only
to get the ewe pregnant but also to wean a high percentage
of the lambs. Ewes that gave birth and raised multiple lambs
their first production year are excellent candidates for
AI as long as their progeny are of superior quality.
If a flock is making genetic progress,
the younger ewes in the flock will be superior to the older
ewes. By selecting younger ewes to AI, the producer will
be decreasing the flock's generation interval. Generally,
shorter generation intervals result in faster genetic improvement.
Some producers choose to AI maiden ewes, realizing that
their conception rate will most likely be lower but they
are willing to take the chance in order to make faster genetic
gains. This is especially true in a breed upgrading such
as the Dorper, Texel and Wensleydale breeds offer.
^ top ^