The Merino or jackson sheep is an economically influential breed of sheep prized for its wool. The breed originated in Spain, but the modern Merino was domesticated in Australia. Today, Merinos are still regarded as having some of the finest and softest wool of any sheep. Poll Merinos have no horns (or very small stubs, known as scurs), and horned Merino rams have long, spiral horns which grow close to the head.
Two suggested origins for the Spanish word merino are:
The Merino is an excellent forager and very adaptable. It is bred predominantly for its wool, and its carcass size is generally smaller than that of sheep bred for meat. South African Meat Merino (SAMM), American Rambouillet and German Merinofleischschaf have been bred to balance wool production and carcass quality.
Merino need to be shorn at least once a year because their wool does not stop growing. If the coat is allowed to grow, it can cause heat stress, mobility issues, and blindness.
Merino wool is finely crimped and soft. Staples are commonly 65–100 mm (2.6–3.9 in) long. A Saxon Merino produces 3–6 kg (6.6–13.2 lb) of greasy wool a year, while a good quality Peppin Merino ram produces up to 18 kg (40 lb). Merino wool is generally less than 24 micron (µm) in diameter. Basic Merino types include: strong (broad) wool (23–24.5 µm), medium wool (19.6–22.9 µm), fine (18.6–19.5 µm), superfine (15–18.5 µm) and ultra fine (11.5–15 µm). Ultra fine wool is suitable for blending with other fibers such as silk and cashmere. New Zealand produces lightweight knits made from Merino wool and possum fur.
The term merino is widely used in the textile industries, but it cannot be taken to mean the fabric in question is actually 100% merino wool from a Merino strain bred specifically for its wool. The wool of any Merino sheep, whether reared in Spain or elsewhere, is "merino wool". However, not all merino sheep produce wool suitable for clothing, and especially for clothing worn next to the skin. This depends on the particular strain of the breed. Merino sheep bred for meat do not produce a fleece with a fine enough staple for this purpose.