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.

Thinking Of Putting Your Mare In Foal?

Whilst the thought of having a lovely home bred foal which in time matures into your perfect riding horse is a lovely idea this may not be the reality. The decision to put your mare in foal needs much planning, time and effort.

There are four main questions that anyone considering breeding from a particular mare should ask:

  • Is she suitable for breeding? Conformation, temperament and performance are key. A mare shouldn’t be bred from simply because she is no longer suitable for any other purpose!
  • Are suitable facilities/expertise available? Including facilities not just for the in-foal mare but also for foaling, for the new born foal and in time for a growing youngster. Do you have the experience to deal with a foaling mare and potential problems or would she be better at stud?
  • Can I afford it? Stud fees, livery charges and routine and unexpected veterinary bills can add up to a substantial sum and there is no guarantee that a healthy foal will be produced/the foal will mature into a quality horse. Breeding can be a risky business for both mare and foal.
  • What are my plans for the foal? Are you breeding to sell or breeding for yourself? What will your circumstances be in 4 years time when the foal is grown up and ready for riding?

Having considered your options and decided to go ahead your next decision is which stallion to use. This is influenced by your mare in terms of conformation and abilities but also what the foal’s intended use is. Considerations include conformation, soundness, performance, temperament, fertility, cost and terms of the stud fee and availability of chilled/frozen semen.

So you have a suitable mare and have found the ideal stallion to complement her, what next?

Your vet will need to come out and perform some pre-breeding checks prior to commencing the process of actually getting her in foal to ensure the best chance of success. These include;

  • Swabs and blood tests to check for specific bacterial and viral diseases, namely Contagious Equine Metritis (CEM) and Equine Viral Arteritis (EVA) – It is worth getting these done early in the season to save time later on.
  • Gynaecological examination to inspect the mare’s vulva, vagina and cervix.
  • Ultrasound examination per rectum to ensure both the uterus and ovaries are normal and to check the mares stage of the oestrus cycle. Uterine swabs can be taken at this stage if there is any concern over infection/previous fertility issues to allow appropriate treatment.

If your mare is not in season at the first scan then she will be given drugs to bring her in to season. Once she is in season your vet will need to visit regularly to perform repeated ultrasound scans to ensure that she is inseminated at exactly the right time to optimise chances of pregnancy. If you are using frozen semen the number of visits and scans is much increased due to poorer semen quality. It is essential that you have adequate facilities to restrain your mare for these examinations, some mares need sedation for everyone’s safety.

Remember to liaise with the stud and ensure that the semen is available and delivered when requested accompanied by the correct paperwork – contact the stud with plenty of notice!

After insemination we will visit again to ensure that all has gone to plan, that the mare has ovulated and there is no adverse reaction to the semen. Some mares will need further treatment at this stage including further injections and flushing of the uterus.

Assuming all goes to plan then pregnancy diagnosis will be performed between 15-18 days and at 30 days where hopefully we will identify a heartbeat! Unfortunately many mares (especially older ones) won’t get in foal first time so be prepared to go through it all again!

In a nutshell consider your options carefully, contact us in plenty of time to discuss your plans, be aware that your mare will need several visits prior to insemination and then keep your fingers crossed for a happy bouncing foal!