Postmortem diagnoses in South American camelids and factors influencing diagnostic rate in the Upper Midwest USA, 2009-2019.

South American camelids (SACs) have become increasingly popular as livestock and companion animals in the Midwestern United States. With increased ownership, postmortem evaluations and samples available for diagnostic assessment are being submitted more frequently to veterinary diagnostic laboratories. We searched archived pathology records at the Wisconsin Veterinary Diagnostic Laboratory (WVDL) between 2009-2019 for SAC cases. Postmortem records from 166 alpacas and 27 llamas were included, with an average of 1.42 diagnoses per animal. The overall average diagnostic rate was 79.8%. Abortion and neonatal cases (fetus to 1-wk-old) had the lowest diagnostic rate (33.3%) and was the only group with a diagnostic rate statistically significantly lower than the average. The most common diagnoses were gastrointestinal parasitism and suboptimal nutritional status or inanition; 78% of cases diagnosed with suboptimal nutritional status were also parasitized. The gastrointestinal parasites identified most frequently were Eimeria sp. and strongyles, especially Nematodirus sp. Our findings may aid allocation of diagnostic resources to better serve regional SAC populations and provide a framework for practitioners who send samples to laboratories for analysis. Submission of whole bodies, euthanized animals, fresh tissue, and inclusion of placental tissues in abortion cases are recommended for optimal diagnostic outcome.