Blood Transfusion in Ferrets
by Dr June McNicholas
Blood transfusions are routine in human medicine and they are becoming more common in the treatment of many species of animals. Until recently, surgery on ferrets has been fairly unusual, not because ferrets do not need surgery, but because owners were reluctant to take ferrets to vets as it was easier to get another ferret.
Happily, these times are changing and more and more people are prepared to take their ferret to a vet when there is a health problem; in some cases this may mean a need for surgery. As in surgery for humans, there is always the need to consider the extent of blood loss during a surgical procedure and a potential need for a transfusion.
It is becoming more common for dogs and cats to receive blood transfusions from suitable donar animals. So far there have been very few cases of transfusions in ferrets in the United Kingdom, but of those that have taken place all have been successful. This procedure is becoming steadily more common not just here in the UK but also abroad, notably in America and Canada.
Since requests for advice on blood transfusion are becoming more frequent I thought it a good idea to outline the procedures here.
Ferrets may need transfusion after surgery or after injury where blood loss is particularly severe. As a general rule, a ferret with a PCV of below 15% should be transfused (PCV = Packed Cell Volume. Blood tests to determine the number and type of blood cells in a standard volume of blood usually include PCV tests which look at the amount of space taken up by the cells compared with plasma when they are allowed to settle).
Good blood donors are large hobs, preferably under four years old. However, since ferrets do not have detectable blood group antigens, it is possible to use more than one donor. In the past I have selected a couple of good sized healthy ferrets in the prime of life for donor purposes and these have been successfully used in operations for both our own and other people's ferrets.
Both donor and recipient will need to be anaesthetised but no pre-transfusion drugs are necessary. Blood collection is usually done via the jugular vein with an 18G catheter. As a rough guide, Lewington (2000 or 2006 editions) suggests collections of around 6ml from a donor jill, and between 9ml and 12ml from medium to large hobs. The blood can then be transfused into the recipient via the jugular vein or, in some instances, into the bone.
Most transfusions will be because the ferret needs both red blood cells and plasma. However, in some cases there may only be a need for plasma such as in some poisoning cases and where clotting agents in the blood are defective (there is some evidence that some ferrets may have the equivalent of Von Willebrand's Disease, a defect in the blood factor 8 which inhibits blood clotting, but that's a topic for another article!). Donor blood can be centrifuged to collect plasma, or it can be allowed to settle for about half an hour in a fridge to let the plasma separate from the red blood cells. This can then be drawn off for transfusion.
Obviously this is an abridged version of the procedure, mainly to illustrate that transfusions can (and are) done sucessfully on ferrets. For those wanting a more complete account there is a very good description included in a section on emergency techniques in Lewington (2000) 'Ferret Husbandry, Medicine and Surgery'.
I would never wish to alarm people about risks of surgery in ferrets as the vast majority sail through with fewer problems than any other species I have known, espcially with 'minor' surgery such as castration, vasectomisation and spaying. In the literally hundreds of cases of ferret surgery that I have encountered, only a minute handful have required a need for transfusion. However, it is also true that a small number of ferret lives have been saved by the availability of a blood donor. Statiscally this may be almost negligible, but it was onviously extremely important to the individual ferrets and their owners! Also, as ferret surgery reaches new levels, the potential need for blood transfusions may increase, so it does not hurt to start elevating awareness sooner rather than later.
(P.S. from Jack, an albino hob who gave blood twice between the ages of three and four years. "I resisted various modified quotes from the famous 'Blood Donor' sketch by Tony Hancock - e.g. 'That's almost a legful!' but I can say that it was no big deal for me apart from having to sit in a carrier and then be knocked out for a little while. All the fuss and cuddles afterwards were well worth it!").