Comparison of Comprehensive Health Score in North American Housed Giraffe and Free-ranging Giraffe from South Africa

Authors

• Haley Beer, University of Nebraska-LincolnFollow

First Advisor

Lisa K. Karr

Committee Members

Brett White, Trent Schrader

Date of this Version

4-2020

Document Type

Thesis

Citation

A thesis presented to the faculty of the Graduate College at the University of Nebraska in partial fulfillment of requirements for the degree of Master of Science

Major: Animal Science

Under the supervision of Professor Lisa K. Karr

Lincoln, Nebraska, April 2020

Comments

Copyright 2020, Haley Beer. Used by permission

Abstract

Stress is evident in many animal species and has been correlated to disease prevalence. During stressful events, allostasis is initiated by physiologic systems to maintain or reestablish homeostasis to protect an organism’s viability. Over time, the acclimation to frequent stress causes systematic dysregulation, leading to the phenomena of increased allostatic load. Allostatic load has been assessed in animal species via serum through selection of representative, multi-system biomarker indices. Perception and number of stress events may impact dysregulation severity, yielding allostatic load as a predictive tool. However, the allostatic load methodology poses application limitations to individuals without historical data and those lacking a conscious recognition of stress. Comprehensive health score may be more encompassing of populations, as it targets biomarkers dysregulated by life events associated with pathology, despite an unknown level of cognition or history. Serum samples were obtained from zoo-housed (n = 18) and free-ranging (n = 11) giraffe to predict subclinical risk of morbidity and mortality caused by chronic stress. Free-ranging giraffe were younger (m = 7.9 years) on average and had lower cholesterol (p = 0.016) and fructosamine (p = 0.039) levels when compared to captive giraffe (m = 12.8 years). Additionally, free-ranging giraffe had higher cortisol (p = 0.007) levels and NEFA (p = 0.004) status, while DHEA-S (p = 0.548) was found at relatively similar concentrations between the populations. Although suitable composites rely heavily on specific species and environmental factors, comprehensive health score provides a foundation for a more applicable tool in conservation research through comparison of biomarkers across populations.

Advisor: Lisa K. Karr