| Abbreviation | Definition |
|---|---|
| IHA | International Hedgehog Association |
| IHMY | Indian Hill Myna Bird |
| IHP | Independent Husbandry Panel (tuberculosis control in cattle in the UK) |
| IHR | International Hedgehog Registry |
| IHS | International Herpetological Symposium |
| IICAB | Institute for International Cooperation in Animal Biologics |
| IIH | Institute of International Health |
| IIS | International Iguana Society |
| IIVS | Institute for In Vitro Science |
| IIVTG | Industrial In Vitro Toxicology Group |
| IJZ | Israel Journal of Zoology |
| ILAR | Institute of Laboratory Animal Resources |
| ILCA | International Livestock Centre for Africa |
| ILMVL | Institute of Legal Medicine and Veterinary Legislation (Italy) |
| ILPH | International League for the Protection of Horses |
| ILRAD | International Laboratory for Research on Animal Diseases (Nairobi, Kenya) |
| ILT | Infectious Laryngotracheitis |
| IMB | Irish Medicines Board |
| IMRSA | International Medical Regulatory and Shipping Association |
| INAD | Investigational New Animal Drug |