Small Mammal Examination

Introduction

Although the techniques used in small mammals are similar to those used in other pets, these methods are very significant in their veterinary care. Important aspects of their examination include: taking a thorough history, using specific techniques for their examination, using appropriate diagnostic techniques and using special instrumentation.

General Aspects

Many diseases of small mammals arise from poor husbandry, and detailed information on housing and feeding should be gathered.

Before handling the patient, it should be allowed to settle down and relax allowing observation time in its environment. Any signs of dyspnoea or pruritis as well as any lumps, swellings or discharges may be noticed at this stage. A thorough clinical examination can then be performed. All visible external organs should be examined including eyes, ears, skin, mouth, anus and genitalia. The chest should be auscultated and the abdominal organs palpated. A quick anaesthetic with isoflurane will allow a decent examination to be performed without stress or risk of injury to the vet or the patient. This may be particularly valuable in species such as gerbils, mice, hamsters, chinchillas and chipmunks.

This is a good time to obtain any samples that may be required such as skin scrapings, blood, urine, faeces, impression smears or fine needle aspirates. Radiographs may be taken and ultrasound performed. A decent oral examination may also be done at this stage. Cytology and histopathology are extremely valuable diagnostics in exotics.

It is essential to weigh patients accurately in order to calculate the correct dose of medications and anaesthetics. For this purpose, gram scales measuring to 1 gram should be used. They are also useful to monitor response to treatment or to detect the onset of a disease process if there is weight loss e.g. the recurrence of dental disease in chinchillas and guinea pigs. It is useful to place the patient in a cardboard box to ensure that it remains still and that an accurate reading is obtained.

Species Specificities

Rabbit

The majority of rabbits are docile, but some aggressive does or bucks may exist.

Rapid and safe restraint is essential as a struggling rabbit may lash out with its hind legs and fracture or dislocate its spine. Severe stress can also induce cardiac arrest in some individuals.

Usually, a rabbit can be held by placing one hand under the thorax, holding the fore limbs between the first two fingers. The other hand supports the hind legs. The rabbit should be kept close to the handler's chest when being moved.

A towel can also be used to wrap around the rabbit.

Guinea-pig

Guinea pigs are generally used to being handled, but should be approached slowly and with a minimum of fuss. They may bite out of curiosity. They are still prey animals and may struggle vigorously in some cases. Guinea pigs should be restrained by an assistant using both hands to support the body. A towel can also be wrapped around the guinea pig.

Guinea pigs have a low tolerance to pain and handling an ill guinea-pig can be risky.

The animal can be placed in an oxygen cage prior to examination, or oxygen can be administered in a flow-by fashion by an assistant.

Stressful manipulations should be performed under sedation or anaesthesia and pain relief should be used if necessary (meloxicam, flunixin and opioids such as butorphanol or buprenorphine).

Stress can cause milky lacrimal and nasal secretions in this species.

Rat and Mouse

Mice will frequently bite the handler in unfamiliar environments. They can be picked up by grasping the tail at the base and placing the mouse on a surface. The scruff can then be grasped between the thumb and forefinger of the other hand.

Rats rarely bite unless roughly handled. They are best held by encircling the pectoral girdle behind the front limbs with one hand, and supporting the animal's weight by cupping the rear end with the other hand. More fractious rats can also be scruffed.

Degloving injuries may occur if the tip of the tail is grasped in either species.

Gerbil and Hamster

Hamsters can be difficult to handle. Usually they can be cupped between hands to transfer them between cages. They can be scruffed for examination, directly behind the ears with the pull in a cranial direction to avoid proptosis of the eyes which can sometimes occur.

Gerbils can be caught with a cupped hand. They can be caught by the base of the tail, but never the tip as this will result in degloving injuries. Adults can be restrained by using a towel.

Chinchilla

They are easy to hold and do not bite. One hand can be placed around the abdomen and the other around the base of the tail to provide support. Rough handling or grasping of the fur should be avoided as fur slip may occur.

Ferret

Hand protection is rarely necessary when handling pet ferrets. To examine its dorsum, a ferret can be rested along the forearm. To examine the ventrum it is placed on its back by cupping the head and holding it between the forearm and body.

A ferret can also be scruffed by grasping the loose skin behind the head and neck and suspending it above the table.

Small Mammal Examination Learning Resources
Flashcards Test your knowledge using flashcard type questions	Small Mammals Q&A 04

References

Lewis, W. (2011) RVC exotics elective Student Notes

Girling, S. (2003) Veterinary nursing of exotic pets John Wiley and Sons

Banks, R. (2010) Exotic small mammal care and husbandry John Wiley and Sons

Rosenthal, K. (2008) Rapid review of exotic animal medicine and husbandry Manson Publishing

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