Chinchilla lanigera intensive breeding programmes are affected by an abnormal repetitive behaviour called ‘fur-chewing’, yet the aetiology is still unknown and little scientific work has been published on this condition. Recent studies have supported the idea that fur-chewing is a stress-related behaviour. In the present study, we used a questionnaire survey in order to: 1) describe general aspects on the epidemiology of fur-chewing in Argentinian farms, and 2) identify which management and/or environmental factors within the breeding facilities may be influencing the occurrence of fur-chewing. The survey consisted of 28 questions focused on farm characteristics, environmental variables and husbandry routines, and was distributed to Argentinian chinchilla farmers. All quantitative variables were tested in a multiple logistic regression model. The mean incidence of fur-chewing was 4.32 ± 0.37% (n = 107 farms). Variables negatively related to fur-chewing were the breeder experience in the activity, the total volume of the facility, and the number of wood shaving changes per week. Positive relationships were found for space index, number of rooms in the facility and presence of different rooms for fur production and reproduction. Other tendencies suggested that farms with the presence of external sound disturbance nearby had higher incidence levels. Also, we detected a tendency towards lower numbers of affected animals with an increment in the provision of dusting baths per week. Finally, results suggested a female prevalence in the development of the behaviour.

The effect of melatonin treatment on fur maturation period and hair follicle cycle in 4-month-old male and female chinchillas, kept under conditions of natural photoperiod, was studied. The animals were treated with continuous-release implants of melatonin (18 mg, group M, no. = 56), while no treatment was given to the control (group C, no. = 69). The effect on hair follicle activity cycle under conditions of normal hair growth (no. = 8) and after defleecing (no. = 8) and on number of hair fibres per follicle bundle (no. = 27) were measured by taking skin samples for histological examination once a month. The age at fur priming was reduced by 31 days (P < 0001) in the melatonin-treated chinchillas. When moulting began during the short-day period, the fur reached maturity 13 days (P < 005) sooner than when the moult began during the long-day period. Melatonin administration proved to be effective in these two periods. Melatonin treatment led to hair follicle activity decreasing at a faster rate, and the differences between treated and control groups from day 60 were significant (P < 005). The primary and secondary hair follicles reached the telogen phase 30 days earlier. Due to melatonin administration more fibres per follicle bundle were observed on the matured pelt (P < 005). At 4 months of age, following the removal of hair by defleecing, the growth of the first adult hair was studied without the presence of young-age hairs. No influence of defleecing as opposed to normal hair development on age at fur maturation or on the number of fibres per hair follicle bundle was observed. Within groups M and C the number of fibres per hair follicle bundle proved to be independent of age at first fur priming. No substantial differences between the groups were observed with respect to either body weight or pelt length at the time of pelting. According to these results, melatonin administration is effective in shortening the coat maturation period in growing chinchillas and causing corresponding changes in the hair follicle cycle.