Source: Kay Stewart, RVT, RLATG, CMAR; Valerie A. Schroeder, RVT, RLATG. University of Notre Dame, IN

Many animal experiments rely on final data collection time points that are gathered from the harvesting and testing of organs and tissues. The use of appropriate methods for the collection of organs and tissues can impact the quality of the samples and the analysis of the data that is gleaned for the testing of the tissues. The method of euthanasia of the animal can also impact the quality of the samples. This manuscript will outline proper necropsy techniques for rats.

1. External examination

A gross external examination of the body, which includes visual inspection of the body for lesions and masses, should be performed as the initial step in a necropsy. The hair coat should be examined for areas of hair loss. The teeth and nails are evaluated for excessive growth or wear. Any staining of the fur at the mouth, nares, eyes, anal, and genital openings should be noted. Tape tests, skin scraping, and pelt exams should be performed to detect external parasites (se

The final step in many research projects is the necropsy of the experimental animals. A detailed observation of external and internal structures followed by the collection of tissues for further analysis provides a great amount of research data. Proper techniques for tissue removal and preservation with the appropriate fixative solutions are essential for the correct interpretation of findings.

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