He was the vocalist for Ewe and the Merinos. He was the first person to start breeding with Merinos in South Africa. Both these problems are more severe in breeds with heavy wool growth such as Merinos. He took up the Carleton run near Oxford, Canterbury and won prizes for his merinos. Saxony lifted the export ban on living Merinos after the Napoleonic wars. Polled Merinos are now found in the various strains of Merinos. A single gene with three possible alleles controls horn inheritance in Australian Merinos. Walker started 1800 cross-bred sheep, 64 merinos, 312 head of cattle and 15 horses. Macarthur pioneered the introduction of Saxon Merinos with importation from the Electoral flock in 1812. The district is also a renowned sheep producing area, particularly medium-woolled merinos. As a result, there is the branch of merinos called Rambouillet sheep. New strains of Merinos that do not require mulesing are being promoted in South Australia. Frequent crutching of Merinos reduces the incidence of flystrike, but not as much as mulesing. The first Merinos date back to the 12th century. In New Zealand the Merinos are usually in the high country of the South Island.