Intoxication in Three Horses: A Case Report Zinc Phosphide Ali Sadeghi-nasab 1* , Farhad Mahra 2 , Reza Solgi 3 , Alireza Nourian 4 , Aliasghar Bahari 1 1 Department of Clinical Sciences, Faculty of Veterinary Science, Bu-Ali Sina University, Hamedan, Iran 2. Equine Veterinary Practitioner, Hamedan, Iran 3. Medicinal Plants and Natural Products Research Center, Hamadan University of Medical Sciences, Hamedan, Iran. 4. Department of Pathobiology, Faculty of Veterinary Science, Bu-Ali Sina University, Hamedan, Iran Correspondence Ali Sadeghi-nasab, Department of Clinical Sciences, Faculty of Veterinary Science, Bu-Ali Sina University, Hamedan, Iran. Tel: +98 (081) 34227350, Fax: +98 (081) 34227475, Email: sadeghinasabali@basu.ac.ir Received: 2020-10-28 Accepted: 2021-01-13 Case History On June 28, 2018, the sudden death of three 8-year-old crossbred Thoroughbred horses, in- cluding two mares and one stallion was reported from a barn at Qerkhler, a village in Hamedan, Iran. The animals were necropsied and thoroughly examined by a large animal in- ternal medicine specialist shortly after the notification call. According to the farm owner's declaration and based on the daily inspections of the farm guard, the animals had probably died during the previous evening. Presentations Clinical The dead horses were laid on the left lateral sides with no signs of post-mortem bloating. 10.22059/IJVM.2020.302634.1005088 Iranian Journal of Veterinary Medicine Volume 15- Issue 02 Case Report Online ISSN: 2252-0554 Abstract Three adult crossbred Thoroughbred horses died in June 2018 at a ranch near Hamedan, Iran. Rigor mortis was evident with no signs of post-mortem bloating in the carcasses. The neck muscles appeared excessively cyanotic in necropsy. In addition, widespread petechiae were observed on the inner surface of the thoracic intercostal muscles. Dropsy was visible in the inner surface of the abdominal wall and peritoneum. The stomach content was watery and dark gray. Furthermore, gastric mucosa was also gray. The livers had a dark appearance and the adjacent duodenum was gaseous and blackened. The kidneys showed autolysis with areas of medullary hyperemia. In addition to decomposition, a specific odor similar to the garlic aroma or natural gas could be smelled from the carcasses. Tissues and contents of various organs, as well as food and water samples, were collected for diagnostic tests. Preliminary toxicological studies showed detectable amounts of phosphide in the samples collected from gastric contents of the animals, and complementary tests confirmed the presence of zinc phos- phide in the concentrate feed. KEYWORDS: Equine, Histopathology, Phosphine, Poison, Rodenticide Copyright © 2020. This is an open-access article distributed under the terms of the Creative Commons Attribution- 4.0 International License which permits Share, copy and redistribution of the material in any medium or format or adapt, remix, transform, and build upon the material for any purpose, even commercially. How to Cite This Article Sadeghi-nasab, A., Mahra, F., Solgi, R., Nourian, A., Bahari, A. (2021). Zinc Phosphide Intoxication in Three Horses: A Case Report. Ira- nian Journal of Veterinary Medicine, 15(2), 254-259.