Guinea pigs are generally docile and require minimal restraint to perform a physical examination. Typically, a hand on the rump or around the shoulders is sufficient, and many animals sit quietly. When carrying a guinea pig, support its weight in one hand and place the other hand over the dorsum, ensuring the animal feels secure in the handler’s arms. To pick up an animal for examination of the ventrum, place one hand under the rump while the other hand supports the thorax. Avoid excessive handling and picking up if the animal is stressed or in pain. Occasionally, guinea pigs nip or bite, but they generally show signs of stress first.
A distant examination should be performed to evaluate the animal’s movements, mentation, respiratory rate and effort, and demeanor. (See the table .) The examination is similar to that for small animals, following a routine to ensure nothing is missed.
Physiological Data for Guinea Pigs
Average body weight | Sows: 700–900 g; boars: 900–1,200 g |
Lifespan | 5–8 yr |
Body temperature | 38–39.5°C (100.4–103.1°F) |
Adult dental formula | 2 (I 1/1, C 0/0, PM 1/1, M 3/3) = 20 |
GI transit time | Average 20 h |
Heart rate | 200–350 bpm |
Respiratory rate | 40–100 brpm |
Age at sexual maturity | Females: 2 mo; males: 3 mo |
Reproductive lifespan | 4–5 yr for females |
Gestation | 59–72 d; average 68 d |
Average litter size | 2–4 |
Birth weight | 100–120 g; range 45–120 g (inversely related to litter size) |
Age at weaning | 3–5 wk |
Urine specific gravity | 1.005–1.050 |
Urine pH | 8–9 |
Average blood volume | 70 mL/kga |
Daily fluid requirement | 100 mL/kg/d |
a5–7 mL/kg blood (total) can safely be removed from an average guinea pig. | |
Hypothermia is a prognostic indicator and can increase the relative risk of death in guinea pigs, and rectal temperature should be interpreted with the remainder of the physical examination and clinical picture (1).
Guinea pigs should be evaluated for nasal or ocular discharge, as well as for excess saliva around the mouth or on the medial antebrachia, which can indicate respiratory, ocular, or dental disease. The mouth is small with a narrow gape, and practice is required for accurate oral examination. Use of a nasal speculum attached to a transilluminator base is invaluable to evaluate the premolars and molars.
The ventral neck should be palpated for peripheral lymph nodes and an enlarged thyroid gland. The heart and lungs should be auscultated carefully because cardiovascular and respiratory diseases are not uncommon.
The GI tract should be soft and the abdomen round because of the large cecum, which is primarily palpated on the left side. Borborygmi should be constant and prominent.
The rectal area should be evaluated for impacted feces, especially in older boars, and caution should be exercised to ensure correct temperature probe placement within the rectum. Eversion of the rectal pouch can help identify the rectal opening.
Osteoarthritis is common in guinea pigs, and the stifles and shoulders should be palpated carefully. Overgrown nails are common, as is the keratin horn on the forefeet pads.
Several neurological tests can be applied to produce meaningful results in guinea pigs. In a study evaluating neurological examinations in guinea pigs, hopping reaction in the thoracic limbs, wheelbarrowing and hemiwalking, medial and lateral palpebral reflex, auricular sensitivity, maxillary sensitivity, horizontal oculocephalic reflex, tone of the jaw, voluntary movement of the tongue, direct pupillary light reflex, and withdrawal reflexes in thoracic and pelvic limbs were easily elicited (2).
References
Levy IH, Di Girolamo N, Keller KA. Rectal temperature is a prognostic indicator in client‐owned guinea pigs. J Small Anim Pract. 2021;62(10): 861-865. doi:10.1111/jsap.13388
Dietzel J, Grochow T, Böttcher IC. Evaluation of neurologic testing in guinea pigs (Cavia porcellus). J Exot Pet Med. 2024;48(3):31-36. doi:10.1053/j.jepm.2023.12.002
