During 2019, the NDSU-VDL received 112 bovine abortion cases, which included whole fetuses submitted for necropsy and general investigation and tissue samples submitted for general investigation only (Figure A). Diagnostic rates showed significantly (P=0.024) more cases with an unknown etiology in field-performed compared to in-house necropsies. Specifically, there were 18/49 lab performed cases (37%) versus 37/63 tissue submission cases (59%) with unknown etiologic diagnoses. The primary reason for the difference in diagnostic rates is the availability of a complete set of tissues for histopathology and ancillary testing when full necropsies were performed by the laboratory.
Abortion trends for 2019 are categorized by cause in Figure B. Notably, abortions with infectious etiologies had higher rates of agent identification/recovery (viral, fungal, bacterial, protozoan) for in-house necropsy and general investigation compared to field-performed necropsy and general investigation only. Causes of infectious abortions are shown in Figure C.
Specimens to include for optimal results:
- Fresh and formalin-fixed placenta
- Whole fetus/neonate (recommended) or fresh and fixed tissues, including:
- Fresh brain, heart, lung, liver, kidney, spleen, abomasal fluid, thymus, thyroid, lymph node, fetal eyeball/vitreous humor (for nitrate analysis), placenta, and any tissue with a suspected lesion
- Formalin-fixed placenta, brain, thymus, heart, lung, liver, kidney, spleen, conjunctiva, adrenal gland, skeletal muscle, and any tissue with a suspected lesion
- Feed and water
- Maternal sera (acute and convalescent)