Physiological response of wild guanacos to capture for live shearing

Abstract

Context The use of wild guanacos (Lama guanicoe) through live capture and shearing may contribute to their conservation by providing an economic alternative to rural inhabitants. However, none of the biological impacts of this activity, including the physiological ones, have been addressed. Aims The aim of this work was to characterise the acute response of guanacos to stress after capture and shearing in terms of serum cortisol levels, heart rate, and body temperature. Methods The study was performed during 2006 and 2007 in La Payunia Reserve in western Argentina. In order to determine serum cortisol concentration, 128 blood samples were obtained and the unextracted sera were analysed by radioimmunoanalyses (RIA). Sex, age category, heart rate, body temperature and total restraint time (TRT) were also registered for each animal captured. Key results Serum cortisol levels were higher in guanacos captured and sheared during 2007 than in 2006, and male cortisol levels were consistently lower than female levels. No significant differences were observed in cortisol levels of the different age categories. A positive correlation was observed between TRT and serum cortisol concentration. The analyses of cortisol levels in relation to TRT showed differences between males and females. With handling periods longer than 80 minutes, females showed a delayed stabilisation in cortisol response when compared with males. Heart rate and body temperature showed no differences between year, sex or age categories. Conclusions The present results show that the stress response to capture and shearing in wild guanacos increased significantly with handling time. We recommend avoiding capture of large numbers of animals and keeping roundup duration short to reduce TRT. Implications This work provides new information that can improve guanaco welfare during handling and shearing and may have implications for the conservation of the species.

Behavioural and physiological stress responses to handling in wild guanacos

“…Then, the shorn individual was moved to the sector for veterinary procedures. General physical condition, sex, age (yearlings, juveniles and adults by development of dentition), pregnancy status by Doppler, heart and respiratory rate, rectal temperature, and morphologic measures were determined; blood samples and faeces were collected (Carmanchahi et al 2011). At this stage of handling, the guanacos were identified with a blue collar for males and a red one for females.…”

“…The corral trap consisted of two arms forming a "V" shape (Carmanchahi et al 2011), with a distal opening 1500 m wide. These arms were made of black net, usually used as anti-hail protection and consisting of 2 cm knotless nylon mesh netting, 2 m high and 2000 m long north arm and 3000 m long south arm.…”

“…Cortisol concentration (ng/ml) in the serum fraction was determined by using Immunotech cortisol Radioimmunoassay kit 1 M 1841 (Carmanchahi et al 2011). Sensitivity of the assay was 3.62 ng/ml (the lowest concentration detectable).…”

“…Similarly, guanacos that were captured and sheared have had high serum cortisol levels, heart rate and body temperatures (Carmanchahi et al 2011). Elk (Cervus elaphus), and pampa deer (Ozotoceros bezoarticus bezoarticus) from areas with frequent human-induced disturbances exhibited high glucocorticoid concentrations (Garcia Pereira et al 2006;Millspaugh et al 2001).…”

“…Stressful processes in wild animals are classified as: natural processes like climate, social stress, interspecific interactions (Boonstra 2004;Caro 1998;Creel 2001); and human-associated processes, like cattle grazing, energy extraction, hunting, tourism (Baltic et al 2005;Millspaugh et al 2001) and animal capture and handling (Carmanchahi et al 2011). These processes affect behaviour of wild animals (i.e.…”