Renal failure in a pregnant mare

Although chronic renal disease is uncommon in horses, guidelines for management of the broodmare with kidney disease are needed to ensure successful foaling. Herein, we present a case report of a broodmare with chronic renal disease that produced a live foal, and parturition was predicted by monitoring pH and electrolytes in the milk. A 15-year-old pregnant mare presented with a history of poor body condition and weight loss despite an excellent appetite. At presentation, the mare was bright, alert and responsive, with severe pitting ventral oedema and vital parameters within normal limits. Plasma biochemistry revealed azotaemia, hypercalcaemia and hypophosphataemia. Based on clinical ultrasonographic and biochemical parameters, the mare was diagnosed with renal failure. Pregnancy was assessed by transabdominal ultrasound, and the fetal parameters were within normal limits; however, an increased combined thickness of the uterus and placenta and oedematous fetal membranes were found. Monitoring of mammary secretions accurately predicted the onset of foaling at 326 days of gestation. A healthy filly was delivered, and the fetal membranes were passed in a timely manner without complications. Physical examination and haematological parameters were within the normal limits for a neonate foal, except for a mild elevation in blood urea nitrogen. Two weeks later, the mare was subjected to euthanasia due to worsening of her condition. At necropsy and on histopathological examination, the findings were consistent with chronic renal disease. This case demonstrates that a pregnant horse with chronic renal disease can be managed with supportive care and produce a viable foal. Fetal well-being and mare's prefoaling milk electrolytes were similar to parameters measured in healthy pregnant mares, suggesting that the feto-placental unit may be spared of the dam's systemic disease. Prepartum physiological changes in the milk may be unaltered with concurrent maternal renal disease and still be useful for foaling prediction.