Agriculture Reference
In-Depth Information
makes a strong yarn that takes dye well. The average fl eece weighs between
2 and 4.5 pounds (0.9 and 2 kg) with a staple from 3 to 6 inches (7.6 to
15.2 cm).
Bluefaced Leicester ewes are good mothers, and have a 250 percent lamb-
ing rate. Lambs grow quickly and mature early. They are quite hardy and
exhibit natural resistance to scrapie.
Booroola Merino
All Merino sheep hail from centuries-old Spanish sheep that were renowned
for the quality of their fl eece during the Middle Ages, and Merinos are still
considered primarily wool sheep today. The Booroola Merino is a strain that
started with a single prolifi c ewe at the Booroola Merino farm in Australia
during the 1960s.
Booroolas are noted for being prolifi c and for their high-quality, fi ne wool
that has a long staple. They have a high lambing rate because of a single gene
(the FecB gene), which affects ovulation; ovulation in other prolifi c sheep is
controlled by a large number of genes. The Booroola strain is also capable of
breeding out of season.
J. Sloan, a Canadian breeder of Booroolas, notes, “Booroola rams may be
crossed on most medium-sized, maternal breeds with a history of excellent
milk production.” There are few Booroola breeders in North America, and no
breed association exists at this time.
THE FecB GENE AND FERTILITY
The unique FecB gene (referred to as the F gene in some sources
and the B gene in others) is epistatic, or dominant over other
genes, so it enhances ovulation rates and the fertility of lambs
born to ewes that are a crossbreed of a Booroola ram and other
breeds of ewes. Purebred Booroola ewes average almost 300
percent lamb crops (or three lambs per ewe), and crossbred ewes
average 120 percent more lambs than they would without the
Booroola crossed in. Although lambing percentages can increase
with Booroola crossbreeding, some of the undesirable traits that
are often associated with other prolifi c breeds may not increase.
But bear in mind that increased lambing rates don't guarantee an
increase in the total lamb weight at weaning per ewe.
