Egg Binding

Introduction

Egg binding is the most common reproductive disorder of birds, especially caged birds such as cockatiels, budgerigars and lovebirds, although all species are susceptible.

Egg binding occurs when the female is unable to expel the egg from her reproductive tract.

Predisposing factors include: obesity, lack of exercise, genetics, senility, inadequate environment such as unsuitable nesting facilities or a cold draught.

There is frequently a history of poor diet, high in seeds and low in calcium. This calcium deficiency can lead to the formation of soft, thin-shelled eggs that can easily become bound. Persistent laying can also lead to exhaustion and a general depletion of nutritional stores.

Egg binding may also be seen in larger psittacines, although excessive previous laying is not usually associated with the condition in these birds. Obesity, general nutritional inadequacy, behavioral, and husbandry conditions may be involved.

Clinical Signs

Clinical signs include depression, failure to perch, lethargy, sitting at the bottom of the cage.

There may be abdominal swelling, attempts to strain, spreading of legs.

Some birds may show signs of leg paralysis due to the pressure exerted by the egg on the nerve supply to the legs.

Diagnosis

The egg may be palpated if it is in the lower reproductive tract. Clinical signs are usually suggestive.

Radiography is useful for more cranially situated eggs.

Treatment

Supportive care such as rehydration, injectable calcium and warmth, before attempting extraction of the egg is critical.

Antibiotics can also be given for potential sepsis.

Oxytocin and the avian equivalent, arginine vasotocin, both cause uterine contractions and can help induce egg delivery. If the egg is adherent to the uterine wall or unable to descend due to soft tissue swelling or the collection of urates or stool, the administration of these drugs could theoretically lead to uterine rupture, but this has rarely been reported.

Inhalant anesthesia and manual extraction may be used if medical management fails. The decreased stress (due to decreased pain) and increased muscle relaxation warrant the slight anesthetic risk.

The head should be held elevated to aid respiration. Steady digital pressure applied between the end of the sternum and the egg will cause the slow descent of the egg. At this point, the uterus will often evert and reveal the white pinhole where the uterine opening is located. This opening will gradually dilate. Very seldom will any additional pressure or manipulation be required. After the egg is delivered, the uterus will normally involute.

If any hemorrhage has occurred, antibiotics are indicated to prevent cloacal or uterine infection.

Postoperatively, the hen will continue to be depressed, with laboured breathing. By the next day, she will appear clinically normal. A second egg may be produced within the next 24 hr, so repeated palpation is indicated.

Eggs that do not pass with this technique require more aggressive treatment. A needle and syringe can be used to aspirate the egg contents, causing the shell to collapse. The empty egg will usually pass within a few days.

Surgery may need to be performed to remove the egg or shell fragments.

Prevention

Where nutrition is the likely cause, the diet should be changed to a more balanced, containing fewer seeds.

Calcium, phosphorus, vitamin and mineral supplementation may be recommended.

Obesity should also be corrected.

An ovariohysterectomy can also be performed to prevent egg laying and egg binding.

References

Ballard, B. (2003) Exotic animal medicine Wiley-Blackwell

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

Merck and Co (2008) The Merck Veterinary Manual Merial

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