Effect of organic solvents on earwax cortisol extraction in Hanwoo cattle

MOHAMMAD ATAALLAHI1, Geun-Woo Park1, Kyu-Hyun Park1,*
Author Information & Copyright
1Department of Animal Industry Convergence, Kangwon National University, Chuncheon 24341, Korea.
*Corresponding Author: Kyu-Hyun Park, Department of Animal Industry Convergence, Kangwon National University, Chuncheon 24341, Korea, Republic of. Phone: +82-33-250-8621. E-mail:

© Copyright 2023 Korean Society of Animal Science and Technology. This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.


Earwax, a semi-liquid substance, of both humans and non-human animals contains the stress hormone cortisol. Extraction of cortisol from earwax requires the use of organic solvents to eliminate interference factors. This study aimed to investigate the effects of organic solvents on the extraction efficiency of earwax cortisol from Hanwoo cattle. A factorial arrangement was used to determine the effects of solvent source (methyl alcohol, MA; diethyl ether, DE) and assay diluent buffer (ADB) (0 and 1 mL) on earwax cortisol concentration (ECC) in Hanwoo cattle (parity 3, body weight = 462 ± 5.6 kg). A 25 mg portion of the earwax sample was suspended in ADB, while another 25 mg portion was not suspended prior to extraction with MA and DE. ECC was measured using a commercial enzyme-linked immunosorbent assay cortisol kit. The results indicated that cortisol can be extracted from earwax with or without ADB. The extraction yield of cortisol from earwax was higher with MA than with DE (<italic>p</italic> &lt; 0.05). In conclusion, MA is the preferred solvent for cortisol extraction owing to its high extraction yield, simple extraction process, and relatively low solvent consumption. Moreover, earwax can be used as a biomarker to evaluate the degree of chronic stress in Hanwoo cattle.

Keywords: Diethyl ether; Earwax cortisol; Enzyme immunoassay; Extraction method; Hanwoo cattle; Methyl alcohol