There are varieties of factors which can affect wool (macro and micro elements of wool) in sheep directly or indirectly. Genetic and environmental factors are major factors influencing wool quality and quantity. There are some bacterial, viral, fungal and espically parasitic diseases which also affect the wool. Other factors are exogenous chemicals, hormones, weather and photo period. In the present study, existing knowledge on the factors affecting wool were reviewed but there are gaps to conduct research on fundamental aspects of wool growth, which could have relevance to other areas of biology.Keywords: Wool quality, staple length, ultra high-sulphur proteins, fleec
