Factors influencing alopecia and hair cortisol in rhesus macaques (Macaca mulatta)

Abstract

Background Alopecia can occur in captive nonhuman primates, but its etiology is poorly understood. The purpose of this study was to assess alopecia and hair cortisol in rhesus monkeys and to identify potential risk factors. Methods Subjects were 117 rhesus monkeys at two National Primate Research Centers. Photographs and hair samples were obtained during routine physicals. Photographs were analyzed using Image J software to calculate hair loss, and hair samples were assayed for cortisol. Results Age, days singly housed, and their interactions contributed to the alopecia model for both facilities. Sex and location changes contributed to the hair cortisol model for Facility 1; sedations contributed for Facility 2. Alopecia and hair cortisol were associated at Facility 1. Conclusions Captive management practices can affect alopecia and hair cortisol. However, there are facility differences in the relationship between alopecia and hair cortisol and in the effect of intrinsic variables and management procedures.

Alopecia in rhesus macaques (Macaca mulatta): Association with pregnancy and chronic stress

“…In contrast, there was no association between hair loss and hair cortisol in any of the female groups; hair loss appeared to be independent of hair cortisol. Although some studies have reported a relationship between hair loss and hair cortisol in macaque monkeys, this has not been the case in all studies or at all facilities and may be due, in part, to the severity of alopecia at a given facility.33 Upon further evaluation of the photographs in the present study, only four animals exhibited what would be considered severe alopecia (>50% of the body affected). Because the association between hair loss and stress is not consistent across facilities, alopecia may not be a reliable indicator of welfare.…”

“…A comparison of three non‐human primate research facilities yielded different findings. Although a significant relationship was detected between hair loss and hair cortisol across the entire sample, this effect was driven by one facility which had a large number of monkeys with more extreme forms of hair loss …”

“…Patterns of missing hair can vary from small discrete patches to diffuse hair loss covering most of the body. Although often presented as a welfare issue in non‐human primates, alopecia is a complex condition that can occur in response to a number of diverse variables including age, sex, seasonal changes, nutritional deficits, pregnancy, stress, hormonal changes, genetic factors, temperament, infection, parasites, and hair‐pulling …”

Fatty acid supplements improve hair coat condition in rhesus macaques

“…Alopecia, a common condition in captive non‐human primates, can affect as much as 50% or more of the hair coat . There are many possible causes of hair loss, including seasonality, age, hormonal imbalances, and friction .…”

Hair plucking, stress, and urinary cortisol among captive bonobos (Pan paniscus)

“…To date, few studies have directly focused on this particular behavior. Hair plucking has been most studied in laboratory‐housed Rhesus macaques ( Macaca mulatta ) (e.g., Reinhardt et al, ; Lutz et al, ). The behavior is both social and self‐directed and suggested to be stress‐induced.…”