Jacob sheep were originally called Piebald, Spotted or Spanish sheep, but were eventually named for the Old Testament figure Jacob, in whose life spotted sheep played a significant role. The Jacobs found here in the United States came from flocks in Britain in the early 1900s. They were originally attractions at zoos and parks and were not sufficient in numbers to be considered an agricultural breed. Their numbers remained small until the late 1960s, when the Jacob Sheep Society was founded in Britain.
The Jacob sheep are a colorful breed known for the fineness of their black and white wool. They are slight of build, with ewes weighing 100 to 120 pounds and rams weighing 140 to 180 pounds. The Jacob is well known for sporting four or more horns. At least 40% have multiple horns and make a remarkable sight in the pasture.
Recent research has shown that certain Jacob sheep carry genetic anomalies similar to the autosomal recessive genetic disorder called Tay-Sachs disease in humans. This rare disorder negatively affects the nerve cells of the brain, ultimately causing death, and is most often seen in infants. Since the brain of an affected Jacob sheep mimics the problems seen in children with Tay-Sachs, the sheep may serve as a scientific research model, allowing scientists to develop a treatment or cure for this disease.