The idea behind this project came from a feed study executed two years during the lambing season. Both years wool loss was experienced. Low temperature in combination with shearing was believed to cause the wool loss the first year, while protein deficiency was believed to be the cause the second year. In the literature many causes of wool loss are described; mechanical wear, Telogen effluvium, bacterial dermatitis, external parasites, wool break, scrapie, genetic causes and nutritional deficiencies are some examples. The aim of this thesis was to study causes for wool loss and how common wool loss is in Swedish sheep herds.

The most common form of hair loss in young and old people is androgenic alopecia. Hereditary hair loss affects both men and women. Hereditary hair loss in some women begins at the age of 30, but as a rule hair loss begins in post-menopausal women. In women the hair thins out in an oval portion of the front part of the scalp. In men, hair loss can start as early as at the age of 20.