| | OEIL (1) |
| | OESTROGENE (2) |
| | OESTROSE (3) |
| | OESTRUS (29) |
| | OEUF (19) |
| | OEUF DE CONSOMMATION (1) |
| | OIE (17) |
| | OISEAU (1) |
| | OISEAU DE VOLIERE (1) |
| | OLIGOELEMENT (2) |
| | ONCHOCERCA (1) |
| | ONCHOCERCOSE (1) |
| | ONCOVIRUS BOVIN TYPE C (1) |
| | ONCOVIRUS FELIN TYPE C (1) |
| | OPHTALMOLOGIE (1) |
| | ORDURES MENAGERES (1) |
| | OREILLE (1) |
| | ORGANE REPRODUCTEUR (1) |
| | ORGANISATION SOCIOECONOMIQUE (9) |
| | ORGANISATION SOCIOPROFESSIONNELLE (1) |
| | OS (1) |
| | OS DES MEMBRES (1) |
| | OSTEOLOGIE (1) |
| | OVIN (92) |
| | OVOGENESE (2) |
| | OVULATION (2) |
| | OVULATION INDUITE (4) |
| | OXYTETRACYCLINE (1) |