random effectsrandom matingrangerationrayproreceiver jarreceptorrecessive generecombinationrecrumred pollred sindhiregurgitationrelaxinremainsremasticationrenninrepeat breederrepeatabilityrequirementreserpineresidual milkresiduereswallowingretained placentareticuloperitonitisreticulumretractor penis musclereversionribosericketsridglingridlingriglingringer solutionrnaroanrolledrotaryrotary tandemrotary turnstilerotating platformrotational grazingrotavirusroughagerubber matrumenrumen degradable proteinrumen tympanyrye grass stagger