Formulating the Question
It may help to think of your research question in four parts. Leenaars, et al suggest four components for a focused research question in the field of animal research.
2.) Disease of interest/health problem
3.) Animal/animal species/population
4.) Outcome measures
A research question including these concepts could be formatted as "What is the effect of [intervention/exposure] on [outcome measures] in [animal species/population] for [disease/health problem]?"
It may be useful to first determine what keywords specific to your research protocol are necessary, and then to add keywords for the reduction, refinement, or replacement of animal research subjects (the "Three R's").
Tips for Research-Specific Keywords
Tips for "Three R's" Keywords
There are many options for keywords in the "3R's". The Health Sciences Library at the University of North Carolina at Chapel Hill has compiled a list of suggested keywords that is replicated in this guide. In addition, you may wish to use the sample MeSH keywords and searches when constructing a PubMed MEDLINE search or consult the National Agricultural Library's Thesaurus for Animal Use Alternatives when searching AGRICOLA or for ideas for keywords to use in other databases.
Leenaars, M., Hooijmans, C., van Veggel, N., ter Riet, G., Leeflang, M., Hooft, L., van der Wilt, G.J., Tillema, A., and Ritskes-Hoitinga, M. (2012). A step-by-step guide to systematically identify all relevant animal studies. Laboratory Animals, 46(1), 24-31. doi:10.1258/la.2011.011087