The most common metabolic disorders in guinea pigs involve abnormal metabolism of the mineral calcium.
Hardening of the Organs (Metastatic Calcification)
Guinea pigs that suffer from metastatic calcification (a hardening of the internal organs that spreads throughout the body) often die suddenly without any signs of illness. This condition usually occurs in male guinea pigs that are more than 1 year old. If your pet does have signs, they can include weight loss, muscle or joint stiffness, or increased urination (as part of kidney failure). The cause of this condition is uncertain, but is probably related to diets that have too much of the minerals calcium and phosphorus and not enough of the minerals magnesium and potassium. Most high-quality commercial guinea pig feed are formulated to contain the correct amounts of these vitamins and minerals. Check the nutritional information on the package label before buying pellets for your guinea pig, and do not give additional vitamin or mineral supplements.
Pregnancy Toxaemia (Ketosis)
Ketosis, also known as pregnancy toxaemia, occurs when a guinea pig's body produces too many ketones, which are a normal byproduct of metabolism. There are many causes of pregnancy toxaemia in guinea pigs. These include obesity, large litter size, loss of appetite during the late stages of pregnancy, not eating enough, not exercising enough, environmental stress, and underdeveloped blood vessels in the uterus (an inherited condition). This problem usually happens in the last 2 to 3 weeks of pregnancy, or in the first week after a guinea pig gives birth. It most commonly affects guinea pigs that are pregnant with their first or second litters.
Although it occurs most often in pregnant female guinea pigs, ketosis can also happen in obese guinea pigs (male or female). A guinea pig may die suddenly of ketosis without ever demonstrating signs of illness. In other cases, a sick guinea pig has worsening signs that can include loss of energy, lack of appetite, lack of desire to drink, muscle spasms, lack of coordination or clumsiness, coma, and death within 5 days. Ketosis may cause fetal guinea pigs to die in the uterus.
Your veterinarian can diagnose ketosis by a blood test, and may also be able to identify a fatty liver and bleeding or cell death in the uterus or placenta. Treatment does not usually help, but options include giving your pet the medications propylene glycol, calcium glutamate, or steroids. However, once a guinea pig starts showing signs of this illness, the outcome is usually not good. To prevent ketosis, make sure your pet eats a high quality food throughout pregnancy, but limit the amount of food you give your pet in order to prevent obesity. Preventing exposure to stress in the last few weeks of pregnancy may also help.
Calcium Deficiency (Pregnant Females)
Because pregnancy and nursing require extra nutrients, pregnant guinea pigs may develop a sudden calcium deficiency. This happens most often in obese or stressed guinea pigs, or guinea pigs that have already been pregnant several times. The deficiency usually develops in the 1 to 2 weeks before, or shortly after, giving birth. In much the same way as in guinea pigs with pregnancy toxaemia (see Guinea Pigs: Pregnancy Toxaemia (Ketosis)), guinea pigs with this condition may die suddenly without signs, or may get sick slowly, with signs such as dehydration, depression, loss of appetite, muscle spasms, and convulsions. Your veterinarian will be able to identify similar problems as in a guinea pig with pregnancy toxaemia, except they will likely be more severe. Guinea pigs with calcium deficiency should be treated with the mineral calcium gluconate. To prevent calcium deficiency, feed your pet only high-quality commercial guinea pig feed.