Evaluating pharmacological models of high and low anxiety in sheep

Rebecca E. Doyle*, Caroline Lee, David M. McGill, Michael Mendl

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

14 Citations (Scopus)
494 Downloads (Pure)


New tests of animal affect and welfare require validation in subjects experiencing putatively different states. Pharmacological manipulations of affective state are advantageous because they can be administered in a standardised fashion, and the duration of their action can be established and tailored to suit the length of a particular test. To this end, the current study aimed to evaluate a pharmacological model of high and low anxiety in an important agricultural and laboratory species, the sheep. Thirty-five 8-month-old female sheep received either an intramuscular injection of the putatively anxiogenic drug 1-(m-chlorophenyl)piperazine (mCPP; 1 mg/kg; nD12), an intravenous injection of the putatively anxiolytic drug diazepam (0.1 mg/kg; nD12), or acted as a control (saline intramuscular injection nD11). Thirty minutes after the treatments, sheep were individually exposed to a variety of tests assessing their general movement, performance in a 'runway task' (moving down a raceway for a food reward), response to startle, and behaviour in isolation. A test to assess feeding motivation was performed two days later following administration of the drugs to the same animals in the same manner. The mCPP sheep had poorer performance in the two runway tasks (6.8 and 7.7 × slower respectively than control group; p < 0:001), a greater startle response (1.4 vs. 0.6; pD0:02), a higher level of movement during isolation (9.1 steps vs. 5.4; p < 0:001), and a lower feeding motivation (1.8 × slower; p < 0:001) than the control group, all of which act as indicators of anxiety. These results show that mCPP is an effective pharmacological model of high anxiety in sheep. Comparatively, the sheep treated with diazepam did not display any differences compared to the control sheep. Thus, we suggest that mCPP is an effective treatment to validate future tests aimed at assessing anxiety in sheep, and that future studies should include other subtle indicators of positive affective states, as well as dosage studies, so conclusions on the efficacy of diazepam as a model of low anxiety can be drawn.

Original languageEnglish
Article numbere1510
Number of pages19
Issue number12
Publication statusPublished - 14 Dec 2015

Bibliographical note

Date of Acceptance: 26/11/2015


  • Affective state
  • Behaviour
  • Diazepam
  • mCPP
  • Welfare


Dive into the research topics of 'Evaluating pharmacological models of high and low anxiety in sheep'. Together they form a unique fingerprint.

Cite this