Introduction
Common green iguana's frequently have a problem laying their eggs. Most of these problems are the result of poor husbandry. If the problem can not be rectified medically then the eggs are surgically removed.
Cause
In many cases it is environmental factors that are creating an inability for a female iguana to lay her eggs. Some of these causes are:
- Environmental temperature below 90 degrees F
- Humidity below 90%
- Lack of exposure to direct sunshine
- Housing that is too small or overcrowding
- Loud noises and excess activity in the immediate surroundings
- Inadequate substrate to lay eggs in
- Inadequate diet
These factors closely correlate to the causes of iguana bone disease. Click here if you would like to learn about them in detail before continuing on with this page.
This is an example of the type of substrate that can be used for an egg laying iguana.
Medical problems can also be involved. Some eggs are deformed while others are too large to pass through the pelvis. Iguana's that have previously been afflicted with bone disease might have deformed skeletons or inadequate strength to lay eggs
The pelvis on this iguana is too deformed for eggs to pass. This pet has a severe form of iguana bone disease.
Symptoms
For most owners the primary symptom is a pet that has stopped eating and has also become lethargic. A lack of appetite only in an gravid female iguana can be normal. Many of these females will have distended abdomens, a strong clue as to the cause of their lack of appetite. Sometimes the female has layed a few eggs and stopped. These eggs might be normal in shape and size, or they might have deformities or calcium deficiencies.
The egg on the lower left is malformed, and could be an indication of a problem. The substrate in this case is vermiculite.
Diagnosis
An eggbound iguana usually has a distended abdomen (technically the coelomic cavity). Depending on the number of eggs and their level of calcification these eggs can actually be felt when the abdomen is palpated.
Radiography is used commonly to verify the diagnosis.
Can you visualize the numerous round and subtle swellings in the coelomic cavity of this female iguana?
The eggs in this female are a little easier to visualize.
Treatment
Once husbandry problems are corrected medical therapy is usually the first course of action in an otherwise healthy iguana. Calcium injections and supplements, vitamin a injections, and even medications to contract the uterus are used.
If medical therapy is unsuccessful after 3-4 weeks, then surgical intervention is necessary. These eggs can cause an iguana to become ill, and since few pet iguana's are used for breeding, along with the fact that we don't want this problem to repeat itself next year, the iguana is spayed (OVH).
Anesthesia is initially induced with a face mask. Sometimes they are given a tranquilizer before we given them anesthetic via the face mask. The anesthetic works rapidly, as long as they don't hold their breath!
When she has relaxed enough, a special tube (called an endotracheal tube) is placed in the windpipe. The endotracheal tube is gently passed into the opening to the windpipe. This opening is at the back of the tongue, and can be difficult to visualize due to the fleshy tongue. This tube allows us to inflate the lungs and supply adequate amounts of oxygen and anesthetic.
The following area contains graphic pictures of an actual surgical procedure performed at the hospital. It may not be suitable for some children (and some adults also!).
All of our surgeries are performed under sterile conditions. The skin is cleansed numerous times with a special antiseptic agent. The area is covered with a sterile drape and the surgeon uses sterile equipment for the duration of the procedure.
A scalpel blade is used to nick the skin enabling us to use a special scissors to extend the incision. The incision is 4-5 inches long for a typical female with a coelomic cavity filled with eggs.
Great care must be taken when extending the incision with the scissors. Immediately below the skin is a large vein that must be avoided. You can see it here as the dark blue object running horizontally.
The coelomic cavity is distended with eggs that bulge out of the incision as soon as the muscles into the abdomen are opened. If one of these eggs is cut the yolk contents will spill into the coelomic cavity and cause a serious reaction.
Once the first egg comes out the rest are not far behind! This cluster of eggs is only from one side, there are an equal number on the other side of the reproductive tract also! You can see why these females don't eat-there isn't room for food to fit into the digestive tract. During this time they rely heavily on body fat for energy.
All the eggs from one side of the reproductive tract are brought out through the incision. A special clip is used to clamp off the blood supply and allow us to remove the eggs. In this picture the instrument is applying the clip.
It takes several clips to complete the process. This is repeated on the other side also. Sutures can be used in place of the clips but we prefer not to use them. They take longer to apply which means anesthetic time is increased, a situation we try to avoid.
The clips will remain in the coelomic cavity of this pet for the rest of her life. They can easily be seen on an x-ray because they are metallic. Here the surgeon is checking the clips prior to closure to make sure there is no bleeding.
When we perform an OVH on an iguana that does not have a coelomic cavity filled with eggs we remove the ovaries from each side. They appear as a cluster of grapes, and are obviously quite small compared to when there are eggs.
When we perform an OVH we take advantage of the fact that we can see other organs in the coelomic cavity. The pink structure running vertically in the center of this picture is the spleen.
Reptile skin is suture differently than mammalian and avian skin. For reptile skin to heal properly the edges must be "everted". Within a month these sutures are taken out and within three months the scales are back to normal.
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