Biology, Anatomy & Clinical Examination and Diagnositic Techniques: Part 2
As for other mammals a maximum of 1% of the ferret's body weight may be safely collected. In an adult male this is 10 - 20ml of blood. Sampling sites are listed below. The author prefers to use ketamine and midazolam for sedation in ferrets since isoflurane anaesthesia results in a reduction in red blood cell count, packed cell volume (PCV) and hae-moglobin concentration, falsifying re-sults. Ferrets have a high PCV and slow erythrocyte sedimentation rate compared with other species and consequently whole blood needs to be centrifuged for longer in this species.
|Sample Site||Needle Gauge||Syringe Size||Approach||Sedation/GA Gauge Size necessary?|
|Cephalic Vein||25 - 27g||1ml||Restrain as dogs for||Usually|
|Lateral Saphenous Vein||25 - 27g||1ml||Lateral surface distal hindleg, over hock||Usually|
|Jugular Vein||23 - 25g||2 - 5ml||Restrain as for cats||Not in docile animals|
|Cranial Vena Cava||25g||5ml||Dorsal recumbency, insert at thoracic inlet at 30o angle towards contralateral hindleg||Yes|
Urine may be collected by free catch as in other species. Most ferrets can be easily trained to use a litter tray. On average a ferret produces 24 - 30ml of urine in 24 hours. Being car-nivores the urine pH is acidic (6 - 7.5) and varies according to diet. Other collection techniques (cystocentesis, catheterisation) are performed as for cats and dogs. Catheterisation is more difficult in females.
Lymph Node Aspiration:
The neck, axillary, inguinal and poplit-eal lymph nodes may all be enlarged with lymphoma and fine needle aspirates may be indicated. The technique is performed as in other species, however fat cells only may be obtained due to the large amount of adipose tissue surrounding these nodes in healthy ferrets.
The ferret should be sedated and placed in dorsal or lateral recumbency. The spleen is easily palpated ventrally since it is usually enlarged. Shave the area over the spleen and aseptically prepare the skin. Using one hand to immobilise it, the other is used to guide a 25g 2ml syringe into the spleen. Alternatively ultrasonography may be used to guide the needle. A sample should be aspirated from several sites and slides prepared for cytology. This technique is most commonly used in the diagnosis of lymphoma.
Bone Marrow Aspiration:
The ferret should be anaesthetised for this technique. Sampling sites include the iliac crest, proximal femur and the humerus. A 20g 1.5 inch spinal needle should be used. The needle is advanced under steady pressure using a rotating movement. They stylet is removed and a 5ml or 10ml syringe attached. The sample is aspirated and slides should be made for cytology.
Sedation is essential in ferrets. The thorax is long and thin and the heart is positioned between the 6th and 8th rib with the apex to the left of the mid line. On radiographs the cardiac shadow does not contact the diaphragm or the sternum normally. The ligament between the diaphragm and the heart contains fat and may be misinterpreted as cardiac enlargement. The mediastinum may contain large amounts of fat and this may make interpretation of thoracic radiographs difficult. Abdominal radiographs may be interpreted as in dogs and cats. Male ferrets have a J-shaped os penis which is evident on abdominal radiographs.
Fluid therapy requirements are calculated as in dogs and cats with maintenance of 75 - 100 ml/kg per day. Subcutaneous fluids are resented by ferrets and the animal should be scruffed prior to injection by this route. The skin over the neck is ex-tremely tough and a 23g or 21g needle should be used. In debilitated animals intravenous or intraosseous routes should be used. The author prefers to use the cephalic vein for the former and the proximal femur for the latter. Blood transfusions in ferrets are discussed later.
Nutritional support may be provided in anorexic animals by syringe feeding Hills a/d diet liquidised with electrolyte solutions such as 'Lectade'. 2 - 5ml should be fed three to four times daily.
Drugs may be given orally and should be directly administered rather than mixed in food. Medication may be mixed with food items such as peanut butter to encourage the ferret to take them. Intramuscular injections should be given into the quadriceps or ham-strings.
Owners should be encouraged to have their pet ferret checked by a veterinary surgeon yearly. Older animals are prone to disease and may benefit from twice yearly health checks. Common conditions which should be ruled out include ear mite infections, dental disease, neoplasia and splenic enlargement.
Ferrets should be vaccinated yearly against Distemper virus. There is no product licensed for use in ferrets in the UK. The author uses 'Nobivac DH' - Intervet at half the dog dose. This should be given initially at 12 - 14 weeks old (in endemic areas this should be given at 6 weeks and the dog regime should be followed).
Flea treatments which have been safely used in ferrets include fipronil, imidacloprid and lufenuron. These have all been given at cat doses, however frequency of dosing has been reduced due to the greater sebum layer in ferret skin compared with dogs and cats.
Courtesy of Anna Meredith MA VetMB CertLAS DZooMed MRCVS Royal [Dick] School of Veterinary Studies (2010)