Passive transfer of immunity in horses

Failure of passive immune transfer (FPT) through colostrum absorption is st ill fairly frequent and responsible for a large proportion of cases of neon atal mortality in newborn foals. The most frequent causes of FPT are: low q uality maternal colostrum (IgG < 40 g/l is observed in about 30% of all foo ling mares) and/or a delay in ingestion (> 12 hours after birth). Colostrum quality can be measured reliably and rapidly under field conditions using a modified sugar refractometer (Colotest(R)). If maternal IgG content is to o low, good quality colostrum can be giver (> 1 litre) to the foal within 9 -12 hours post-partum to prevent FTP Ingestion of low quality colostrum, an artificial milk or an electrolyte solution by the foal before ingestion of good quality colostrum does not seem to prevent a correct level of protect ion. To date, there is no satisfactory colostrum substitute for complete co lostrum replacement available on the market and the use of banked frozen co lostrum is recommended. Recent research in our laboratory, however, shows t hat a freeze-dried extract of equine colostral IgG can provide satisfactory immune protection when used as a complete substitute for colostrum. Furthe rmore, the induction of lactation in selected barren mares may offer an alt ernative way to produce colostrum when needed.