Peritoneal fluid analysis in peripartum mares

Objective - To characterize, in mares, changes in peritoneal fluid that occurred within the first 7 days after routine foaling. Design - Prospective observational trial. Animals - 15 mares. Procedure - Abdominocentesis was performed within 10 days before foaling and again 12 hours, 3 days, and 7 days after each horse foaled. Data recorded for each sample included total nucleated cell count, differential cell count, specific gravity, fibrinogen concentration, and total protein concentration. Smears of each sample were examined by a single clinical pathologist. Results - There were not any significant differences over time in specific gravity, total protein concentration, fibrinogen concentration, total nucleated cell count, or number of small mononuclear cells. Mean numbers of neutrophils and large mononuclear cells in samples collected after foaling were significantly higher than mean numbers in samples collected before foaling. For 11 of 14 horses, all samples were characterized cytologically as transudates without cytologic abnormalities. Clinical Implications - Results of analysis of peritoneal fluid from peripartum mares suggest that nucleated cell count, protein concentration, and specific gravity of peritoneal fluid from mares that have recently foaled should be normal. Thus, peritoneal fluid abnormalities detected in mares within a week after foaling should usually be attributed to a systemic or gastrointestinal problem and not to the foaling process itself.