Research Article - Artificial Insemination
RESEARCH ARTICLE - Faecal glucocorticoid metabolites and body temperature in Australian merino ewes (Ovis aries) during summer artificial insemination (AI) program
Edward Narayan 1,2*, Gregory Sawyer1, Simone Parisella2 1
School of Science and Health, Western Sydney University, Locked Bag 1797, Penrith, New South Wales, Australia,
2 Graham Centre for Agricultural Innovation, School of Animal and Veterinary Sciences, Charles Sturt University, Locked Bag 588, Wagga Wagga, New South Wales, Australia
Reproductive wastage is a key issue for sheep producers, both regionally and globally. The
reproductive output of farm animals can be influenced by physiological and environmental
factors. Rapid and reliable quantification of physiological stress can provide a useful tool for
designing and testing on-farm management interventions to improve farm animal welfare
and productivity. In this study, we quantified physiological stress non-invasively using faecal
glucocorticoid metabolites-FGMs analysis and body temperature measurements of 15
superovulated donor merino ewes (
Ovis aries) during participation in artificial insemination
(AI) program conducted during 2015/2016 Australian summer. We hypothesized that low
percentage transferable embryos in donor merino ewes will be associated positively with
higher body temperature and/or higher FGMs in these ewes. Temperature humidity index
(THI) was calculated and found within high thermal stress range during the two AI trials.
Overall, results showed none of the factors (ewe ID, AI trial no., THI or FGMs) were significant
for reduced percentage transferrable embryos, except ewe body temperature was
highly significant (p = 0.014). Within AI trial comparisons showed significant positive associations
between higher FGMs and body temperature with reduced transferrable embryos.
These results suggest that Australian merino ewes participating in summer AI trials can
experience physiological stress. Prolonged activation of the stress endocrine response and
high body temperature (e.g. ensued from heat stress) could impact on ewe reproductive output.
Therefore, future research should apply minimally invasive physiological tools to gather
baseline information on physiological stress in merino sheep to enable the development of
new farm-friendly methods of managing stress.