Texas Equine Veterinary Association

www.texasequineva.com • 16 INTRODUCTION Identification of septicemia early in a neonatal foal can be the difference between survival and death. In recent years, a point of care (POC) analyzer has been utilized by veterinarians to investigate newborn foals for the acute phase protein, serum amyloid A (SAA). In healthy foals, an SAA of 0–7 mg/L has been reported in one paper and <100 mg/dL in another site.1,2 Increased levels of SAA usually indicate inflammation or infection, depending on the specific case, and are measured in many neonates to try to detect early septicemia. However, there may be an additional cause for an increased SAA in a neonate. Personal observation led the author to investigate why SAA values in neonates were not always consistent with illness. We tested the hypothesis that the increased values were related to the recent administration of equine biologics. METHODS In order to test this hypothesis, SAA levels were measured in 25 newborn foals between 12 and 36 hours post foaling. Neonatal foals were examined prior to receiving 1 L of a commercial frozen plasma hyperimmunized against Rhodococcus equi as part of the farm biosecurity program. A second peripheral blood sample was collected from each foal immediately post-transfusion.. In 14 of the 25 foals, the SAA value of an aliquot of the administered hyperimmune plasma liter was also measured. All samples were measured using the commercially available SAA cartridges from Stable Lab and the handheld reader. The body weights of the foals were estimated and blood volume (BV) was calculated at 10% of body weight. Total mg of circulating (TC) SAA levels were calculated by multiplying SAA X BV. Total mg of plasma (TP) SAA levels were calculated by multiplying SAA by 1 L. RESULTS Sixteen of 25 foals had an increase in SAA immediately post transfusion. The average SAA value for all foals was 36.5 mg/L (median 7, min 0, max 440) before plasma. The average SAA value was 119 mg/L (median 61, min 0, max 689) post plasma. In the liters of sampled plasma, the average SAA value was 390.6 mg/L (median 281, min 1, max 1682). A comparison of the individual change in TC SAA and TP SAA is shown in figure 1(next page. Conclusion The SAA in the newborn foals ranged from 0 to 440 with an average value EFFECT OF HYPERIMMUNE PLASMA ADMINISTRATION ON SAA BLOOD VALUES IN FOALS ABOUT THE AUTHOR Dr. Ben Buchanan grew up in Navasota, Texas. He went to Texas A&M and graduated from there with his DVM in 2001. Afterward, he completed two residencies; Large Animal Internal Medicine at University of Tennessee, Knoxville in 2004 and Emergency and Critical Care at University of Pennsylvania in 2005. Ben is one of the very few people in the world to be board certified in Internal Medicine and Emergency Critical Care. Ben joined BVEH Navasota in 2005, where he works alongside his father, T-Bone. He is also active in community outreach by speaking at meetings and events around the world regarding equine care. Ben is married to the lovely Shana, whom he met in veterinary school. Shana is a small animal veterinarian and owner of Lake Conroe Vet Group. They have two children, Jane Marie and Terrell. Ben Buchanan, DVM, DACVECC, DACVIM-LA Foals

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