Sheep are intelligent, social animals whose large size and docile nature make them an attractive model to scientists in a number of areas of research ranging from agricultural to biomedical studies. The United States Department of Agriculture reported 23,516 sheep held or used in research protocols in 2024.
Because of their large size, sheep have been used as surgical models. There are sheep used in research to conduct studies of the heart, including testing of artificial hearts and heart valves, and for studies of heart disease. They have been used as models for the repair of bones and wounds. The large size of the sheep has enabled their use in studies involving implanting medical devices.
There are sheep used in research as models of human disease, including disorders such as hemophilia, asthma, Tay Sachs disease, inherited cataracts and polycystic kidney disease. They have also been used to test treatments for these diseases.
Sheep have been used in studies of reproduction, pregnancy and fetal development. They were used in the genetics research that produced the first mammal cloned from an adult cell, Dolly, who made international headlines in 1996. They are also used as models for vaccine research. In addition, sheep are genetically modified to become bioreactors, generating products such as human proteins in their milk, and have also been modified in ways that have improved their wool production.
Organs and tissues from sheep are harvested for their use as dissection specimens for educational purposes, even though effective dissection alternatives exist.
