Abstract: Hair follicle that is the skin appendage with complicated formation and construction can control the hair growth, and have the characteristic with self-renewal and periodicity growth. The cyclical variation of hair follicle depends on the interaction between follicular epithelial cells with epidermis MES cell, and the anagen begins with hair shaft’ growth from the hair follicle, and the catagen is drove by apoptosis, and hair follicle goes into the telogen. The process is affected by the interaction among a series of signaling molecule, including actuating signal, hair follicle growth maintaining signal, hair follicle growth restraining signal and so on. The primary hair follicle and secondary follicle of cashmere goat appear cyclical variation after born, and the secondary follicle appear seasonal cyclical variation more obviously, because of photoperiod, while the primary hair follicle varies inconspicuous. The cashmere is ramification from secondary follicle, so the yield and quality can be affected by secondary follicle growth. Accordingly, the research about cyclical variation law of hair follicle and molecular regulation mechanism not only can reveal growth law of hair follicle, but also guide the cashmere goat breeding.

Key words: cashmere goat; hair follicles; cyclical variation; regulation