It is vital that newborn crias ingest enough colostrum soon after birth to fight infection during their first few weeks of life. Failure of passive transfer of maternal immunity can occur in crias when they do not ingest enough colostrum from their mother. In this instance, a plasma transfusion containing immunoglobulins, as well as lipids, electrolytes and other plasma proteins, can provide a lifeline.
With support from Claire Whitehead, RCVS Recognised Specialist in Camelid Health and Production, Pet Blood Bank has been providing a plasma processing service for camelid owners and vets since 2015. As part of this service, vets are provided with everything needed to collect blood from camelids and a courier service to return the blood to Pet Blood Bank where it is then processed into plasma before being returned to the vet for treating their client’s newborn crias.
Collecting blood from camelids
To donate, camelids must meet specific criteria; the ideal donor will be a castrated male or unbred female, aged between 2 and 10 years (it is considered that older animals aged three or more may have better developed levels of immunity), fit and healthy, over 50kg, have a good temperament and not be taking any medication.
Prior vaccination against clostridial disease is prudent, though off licence consent needs to be obtained. In an ideal planned scenario, it is thought that vaccinating camelids 21 days prior to donation may lead to good levels of antibody immunity.
Additionally, it is important that donors are assessed for their ability to be handled and examined with preference given to those who are well-handled and able to donate without chemical restraint.
A full health check should be carried out on each donor before the donation takes place. This should include a mucous membrane colour assessment, a temperature check and listening to the heart rate.
For the donation, the jugular groove area of the neck is clipped and cleaned. A local anaesthetic injection or cream can be used to numb the donation site before the needle is placed. It typically takes less than five minutes to collect a 450ml unit of blood from each camelid. This is done in a closed manner using a quad blood bag collection set. Only blood collected in this way can be processed using the Pet Blood Bank service.
Processing the blood
Following the collection, the blood is placed in a transport box and taken to Pet Blood Bank’s processing centre. Here it is split into plasma and packed red blood cells. The plasma is returned to the veterinary practice where it is stored frozen in protective packaging in a temperature-monitored freezer ready for transfusion.
Plasma for immunoglobulin purposes has a shelf life of five years when kept frozen. Packed red blood cell transfusion is rarely performed in camelids but this product is also available if needed, although only has a shelf life of 21 days. Pet Blood Bank stores the red cells for their shelf life.
Plasma produced in this manner, according to Pet Blood Bank’s VMD licence, is for use strictly in the herd of origin only. Forms that state this are signed by both the farm manager and vet performing the collection.
Due to these limitations and the problems created for smallholdings with only a few breeding animals who may not have suitable donors, the VMD has broadened the guidelines for herd of origin to interpret “herd” to include the next generation (only). Blood could be collected for a new young herd from the same original herd within three years of the new herd being established.
Transfusing plasma to crias
Plasma transfusions to crias should always be given intravenously using a filtered giving set. Plasma is stored frozen so this should be defrosted at room temperature if time allows, or using a warm water bath of no more than 37oC before transfusing. Camelid-specific immunoglobulin levels can be measured pre- and post-transfusion to permit assessment of the effectiveness of the treatment.
Although plasma transfusions can be administered on the farm, it is often worthwhile transporting them to a practice for the treatment. Transfusions are often rapidly effective in providing the cria with the strength to stand and suckle, allowing them to ingest the further colostrum that is vital in developing a robust immunity.