Ovarian cyst is the most common disease of the genital organs of guinea pigs. It occurs in 80% of females dissected after death. In general, the disease has no clinical manifestations, but sometimes in animals there is a symmetrical loss of hair on the sides, caused by hormonal changes, the cause of which is cystic changes in the ovaries. Sometimes you can feel a cyst the size of a pigeon’s egg. Treatment is only necessary in cases where the disease is clinically apparent (for example, hair loss described above) or if the cyst becomes so large that it begins to negatively affect other organs. Since it cannot be reduced by medication, guinea pigs are often castrated. For this, the animal is euthanized (as described in the chapter “Anesthesia”),put on the back and castrated, making an incision along the midline of the abdomen in the navel. To keep the incision small, it is recommended to pre-empty the ovarian cyst by puncture. Then it is easier to bring the ovary to the position of presentation and take it away with the help of the hook. 

Further treatment for hormonal baldness is injections of 10mg chlormadinone acetate, which must be repeated every 5-6 months. 

Violations of the birth act 

Disorders of the birth act are rare in guinea pigs, this happens if the cubs are too large, and also if the female is too early to be used for reproduction. The diagnosis can be made with an X-ray. However, in most cases it is too late to start treatment. Guinea pigs are brought to the veterinarian already severely weakened, when the chances that they will be able to withstand a caesarean section are very small. 

In most cases, you can already see a blood-brown vaginal discharge. The animals are so weak that they die within 48 hours. 

Toxicosis of pregnancy 

Pregnant guinea pigs receiving nutritionally imperfect food or insufficient amounts of vitamins develop toxicosis a few days before giving birth or soon after. The animals lie on their sides in an apathetic state. Here death also occurs, as a rule, within 24 hours. Protein and ketone bodies can be found in urine, urine pH is between 5 and 6. It is usually too late to start treatment; the body no longer accepts injections of glucose and calcium. As a preventive measure, it is recommended to feed animals rich in vitamins during pregnancy. Pregnancy toxicosis occurs only in the case of a large offspring or if the cubs are very large. 

Castration of male guinea pigs 

After euthanasia by injection (see chapter “Anesthesia”), the guinea pig is tied on the operating table in the supine position; the operating field is shaved and disinfected. Male guinea pigs can move their seminal testes into the abdomen due to the wide Anulus vaginalis so that in some cases it is necessary to push the abdominal cavity caudally so that they are in the presentation position. In the middle of the scrotum, parallel to the midline, a skin incision is made approximately 2 cm long. Now the testicles, epididymis and fatty bodies are in a presentation. After removal of the testicles, epididymis and fatty bodies, a thin catgut ligation is applied, while it is necessary to pay attention to the fact that the ligation must also be applied to Prozessus vaginalis to prevent intestinal and adipose tissue prolapse.No skin suture required. Antibiotic powder is not recommended. However, for the next 48 hours, animals should not be kept on sawdust. Instead, it is better to use newspaper or “kitchen roll” paper as bedding.