Failure Of Passive Transfer

What is failure of passive transfer? 

Failure of passive transfer (FPT) occurs when a new-born foal does not consume enough of the mares’ colostrum in the first 24-48 hours of life. The colostrum contains immunoglobulin antibodies (IgG and IgM) that are required for the majority of their immunologic protection against the pathogens they encounter in the first few days of life. The intake of this vital colostrum must occur before 48 hours (ideally in the first 8 hours) after birth as the cells required to transport the antibodies into the bloodstream are lost by the foal.

How do I know if my foal has FPT?

It is almost impossible to tell in the first few days of life if your foal has not ingested enough colostrum. The consequences of this will be seen as various recurrent infections in the first few weeks of life. Therefore what we recommend is that you have a vet perform a blood test on your foal in the first 12-24 hours of life and check the level of the IgG antibody. A reading of less than 200mg/dL indicates complete lack of transfer. A reading in-between 200 and 800 mg/dL indicates partial lack of transfer. Both readings require treatment. A normal reading is one above 800mg/dL.

What to do if my foal is diagnosed with FPT?

In cases where FPT is diagnosed after 12 hours, your foal will require an intravenous plasma transfusion containing the IgG antibody. These commercial sources of plasma are very safe as all donors are free of infectious disease. The amount of plasma given to an FPT foal will depend on the degree of failed transfer and the size of the foal, but is usually in the 2-4L range. The vet will test the blood after treatment to ensure an adequate level of antibodies.

What causes my foal to ingest inadequate colostrum?

Problems with the mare and problems with the foal can cause FPT. Examples of problems with the mare are early production of colostrum so it is expelled before birth, no milk production, poor quality colostrum production, lack of maternal cooperation and unfortunately mare death. With foals, premature birth of the foal can lead to problems such as inability to feed, or inability of the intestine to absorb the antibodies. In cases where you the know foal will not receive colostrum, ie mare death or early production, you can feed the foal colostrum from a previous colostrum bank or commercial frozen colostrum in the first 8 hours of life.

Ways to prevent FPT

As the prognosis for untreated FPT can be very poor, having ideas of how to minimise the risk are very useful. Having a colostrum bank or an alternative source of colostrum is a must. A colostrum bank is achieved by milking 250ml of colostrum off a mare after their foal has had its first suckle. If this is done from multiple mares, you will have enough for one foal. This colostrum can be stored at -4°C for up to 1 year. Other management strategies to undertake are observing all foaling’s to ensure normal parturition and early suckling, and to ensure a clean environment for foaling.