Unlike human infants, a newborn foal is dependent on the mare to transfer necessary antibodies in the colostrum within a few hours of birth. These essential antibodies are important for the new foal to withstand the challenges of infectious agents it will encounter during the first few weeks of life. One way to verify that the mare’s colostrum contains adequate levels of these antibodies is to use the Gamma-Check C test. This is an inexpensive, rapid, semi-quantitative screening test that can be performed prior to nursing or to evaluate colostrum prior to freezing or after thawing to ensure quality. In order for a foal to reach optimal antibody levels, approximately 1.5 – 3.5 liters of colostrum with an IgG level of over 3800 mg/dl are required. The Gamma-Check C test consists of a diluent tube used to dilute the milk sample and a test tube to perform the test. The test will give you a positive result by forming a solid clot within 10 minutes if the sample of colostrum has an IgG level of 3800 mg/dl or greater.
Once you are confident that the mare’s colostrum is adequate, it is important to be sure that the foal has absorbed the antibodies. The Gamma-Check E test is an economical, easy-to-perform test similar to the Gamma-Check C. The Gamma-Check E test consists of a single test tube and requires 1.5 ml of the foal’s blood or serum. The test will give a positive result by forming a solid clot in the test tube if the foal’s antibody IgG level is over 800 mg/dl. An IgG level less than 800 mg/dl may be considered a possible Failure of Passive Transfer or FPT.
Unfortunately, the transfer of antibodies from the mare to the foal is not always successful. Because the Gamma-Check tests are semi-quantitative, it is recommended to determine a quantitative IgG antibody level. This can be done using the RID (radial immunodiffusion) test. The laboratory at Plasvacc USA can perform this test for you for a nominal charge or the kit is available for sale to perform on your own.
Failure of Passive Transfer (FPT) is said to exist when the foal’s serum gammaglobulin level (specifically IgG) is less that 400 – 800 mg/dl. If this diagnosis is made before the foal is 12 – 18 hours of age, oral supplementation using good quality colostrum may be beneficial. If the foal is older than 12 – 18 hours old, the gut is no longer able to efficiently absorb the antibodies from an oral supplement. In this case, an intravenous transfusion of high quality equine plasma, such as Equiplas or Equiplas-Plus should be considered. The amount of IgG that is required for protection on your young foal is very dependent on the environment. We recommend a minimum of 400 mg/dl in some situations and over 800 mg/dl in others. This depends on the amount of infectious burden from the immediate environment.
Commercial plasma from Plasvacc USA is proven to be safe and effective and is licensed by the USDA. We have developed sophisticated vaccination strategies to provide antibodies to common neonatal pathogens in our plasma products. Equiplas and Equiplas-Plus are fresh frozen plasma products that have not been altered in any way. Although there are other less expensive or more convenient sources of IgG on the market, they do not have the broad spectrum of components found in plasma that may be essential to a healthy immune system in your foal. One veterinarian in Kentucky aptly described Equiplas as “Life in a Bag”.
Equiplas is plasma (Equine IgG) for the treatment of FPT in newborn foals. The minimum IgG level is 1500 mg/dl and one 950ml bag will increase a healthy foal’s circulating IgG level by about 250 mg/dl. Equiplas-Plus is plasma (Equine IgG) with a high IgG level. Each liter contains a minimum of 2700 mg/dl and one 950ml bag will increase a normal foal’s IgG by about 400-500 mg/dl. This product is available in 600ml and 950ml bags. Be aware that an ill foal will not show the indicated IgG increase because the transfused antibodies are being utilized rapidly in the foal’s system. Repeated transfusions may be required for foals with active infections.
Plasvacc USA produces USDA licensed plasma with high levels of antibodies to specific organisms, as well as providing plasma with a range of antibodies against common neonatal pathogens. Equiplas REA is a plasma product with high titers to Rhodococcus equi. This product is recommended as labeled to protect foals less than 6 months of age against respiratory disease associated with R. equi. We suggest an initial dose be given to your foal on its first day of life and a second dose 4-6 weeks later if you are in an endemic area. Ask your veterinarian if you have concerns. Equiplas R is also available for both R. equi and Failure of Passive Transfer.
Plasvacc USA also has Equiplas B , a Clostridium Botulinum, Type B Antitoxin to aid in the treatment of botulism.