Failure of Passive Transfer – Plasma
Failure of Passive Transfer and Plasma Transfusion in Camelid Neonates
The information provided below is for guidance only, and is not in any way intended to be prescriptive. Advice should be sought from your vet should you have any concerns about failure of passive transfer ( PFT ) and are unsure about it’s treatment.
A crucial component in the survival of the neonate is the concentration of serum immunoglobulin (igG). This specific immunoglobulin is the main source of antibodies against infection for the neonate. Camelid cria are born without igG and must acquire this from the colostrum (first milk produced by the dam).
Ensuring adequate colostrum intake (10 -20% of body weight in the first 24 hours – 5 % of this in the first 6 hours) is vital to protect cria in the first few months of life. Failure to ingest enough colostrum in the first 24 hours of life is probably the most important predisposing cause of cria mortality. However, the window of opportunity is narrow; after about eight hours the cria gut begins to lose the ability to absorb antibodies from the colostrum and after twenty-four hours virtually nothing will be absorbed.
If a cria has failed to nurse by six hours then an attempt should be made to feed colostrum. Ideally this will be milked from the dam (although in practice this is not always possible and it may even be that the lack of colostrum production by the dam is the actual problem). Frozen camelid colostrum is also ideal. Alternatively goat’s colostrum is considered to be the closest in composition to camelid colostrum, but if unavailable then cow’s colostrum may be used. N.B. the source of the colostrum must be scrutinized, it is important to determine that the herd is free of disease and that the colostrum is collected and stored under sanitary conditions.
Ideally the colostrum should be administered via bottle feeding. If this is not possible then the colostrum may be given via an orogastric tube in to the stomach. N.B. colostrum should not be given to a hypothermic cria, the cria must be warmed and be normothermic if the colostrum is to be absorbed.
N.B. it is advisable to weigh newborn cria on a daily basis; weight loss may be the earliest sign that a cria is in trouble.
Failure of Passive Transfer.
In the event of the cria failing to receive adequate colostrum within the first 24 hours, the cria will be said to have a failure of passive transfer (PFT). This may be complete or partial i.e. some colostrum has been received but below the recommended amount. Levels are checked at 24 -48 hours. A basic serum total protein test will give an indication of FPT. A camelid specific igG test will be more accurate but will take longer to get results. A result less than 600 mg/ dl is considered to be a FPT and greater than 800 mg / dl adequate. Anything In between may be considered a partial FPT. N.B if using a camelid specific measurement goat and cow colostrum will not be measured.
Once FPT has been diagnosed (or if there is certainty that inadequate colostrum has been received) the only way to remedy the situation is by plasma transfusion.
Ideally, all alpaca breeders should have a supply of plasma in their freezer that has been collected from their own herd. In this case the plasma donors will have been exposed to the same antigens present on the farm, and will have produced the required antibodies. Blood can also be collected from the dam and spun if time and facilities available.
A plasma donor should be a healthy, fully grown alpaca (ideally aged at least 3 years old and not pregnant). It is advisable that the donor is fully up to date with all vaccinations (e.g. Lambivac/Bravoxin) at the point of collection.
Plasma may be administered via the intravenous route.
The recommended dose is 15 -25 mls/ kg,
IgG levels can be rechecked 48 hours after the plasma is given.
REMEMBER NEVER TO DEFROST PLASMA IN THE MICROWAVE!
Plasma should be gently defrosted in warm water and administered at body temperature. Over heating will destroy the proteins (IgGs).
Anderson David, Cotton Toni, Whitehead Claire. Neonatal Care for Camelids Breeding to Birthing to Weaning.
Hoffman Eric. The Complete Alpaca Book
Evans Norman. Alpaca Field Manual.
Fowler Murray. Medicine and Surgery of South American Camelids.