Presenting problem: Shelled Egg Palpable

Understanding dystocia in the bird

Detecting a shelled egg on physical examination is not necessarily a problem—birds lay eggs everyday! However palpation of a shelled egg is an important clinical finding that can be associated with dystocia. The egg is shelled in a distal part of the oviduct called the uterus or shell gland. Therefore a shelled egg would normally be palpable in either the uterus, vagina or cloaca.

Egg binding occurs when the egg fails to pass though the oviduct at a normal rate. In most parrots, an egg typically moves through the oviduct over 24-48 hours. In egg binding, the hen does not show active signs of “oviposition” or “labor”. She is not in distress although an egg moving slowly through the reproductive tract is at an increased risk for problems such as adhesion formation.

In dystocia the egg is stuck in the caudal uterus, vagina, or uterovaginal sphincter (the bird’s analog to the cervix). Dystocia is a critical condition that requires immediate action. The egg (especially an overly large egg) can compress vessels leading to cold, pale feet, or even shock. Nerve compression can lead to paresis or paralysis. An egg can also interfere with elimination leading to metabolic problems, and pressure on the oviductal wall can lead to necrosis and rupture.

 

Key points of urgent care

Direct initial efforts towards stabilizing the patient:

  • Provide pain relief as needed such as meloxicam (0.2-0.5 mg/kg PO, IM, SC q12-24h) and/or butorphanol (1-4 mg/kg IM q6-12h)
  • Give warmed fluids with or without dextrose.
  • Place the bird in a warm, dark, humidified environment.
  • Calcium gluconate (50-100 mg/kg SC, IM diluted with an equal volume of sterile water or saline) is indicated in birds on an all-seed diet, chronic egg layers, or in hens without radiographic evidence of osteomyelosclerosis.

In some cases, heat, steam and calcium will allow the egg to pass. Gentle coelomic massage can also be helpful.

A medium to large-sized parrot may be observed for up to 24 hours as long as the bird is stable. The smaller the patient the more aggressive the approach required. Start drug therapy within an hour or so if an egg has not passed in tiny songbirds like canaries or finches. See therapy below.

 

Case management

Signalment

Reproductive disease is most commonly seen in small parrots:

History and examination

Obtain a complete history including information about husbandry including mineral supplementation as well as a reproductive history. Carefully evaluate droppings. Blood may be seen in the droppings with dystocia.

Reproductive history should include:

  • When was the last clutch (or collection of eggs) laid?
  • How many eggs were laid?
  • Were the eggs normal in size and shape?
  • Has broody (or reproductive) behavior been observed such as a increase in appetite, particularly for calcium-rich foods? Does the bird seek dark places or exhibit nest-building behavior like paper shredding? Some hens may become cage protective or aggressive?

A chronic egg layer produces a larger than normal clutch or it produces repeated clutches, regardless of the existence of a suitable mate or the season. Without special modifications to the diet, repeated egg production leads to a depletion of body calcium and protein stores, which may promote egg binding, dystocia, and weight loss.

Physical examination should include careful evaluation of the oropharynx and crop, coelomic palpation, and inspection of the vent.

Distinguishing normal oviposition from dystocia:
Normal egg laying or oviposition:

  • The bird displays a wide-legged stance
  • A vigorous tail bob is observed secondary to abdominal straining
  • Heavy metal toxicity
  • Dysbiosis (antibiotic use)
Dystocia:

  • Non-specific signs of illness (depression, lethargy, fluffed and ruffled feathers) are often observed
  • Tachypnea
  • Persistent tail bobbing

Blood may be seen from the vent or in the droppings.

Large eggs may cause air sac compression, which can lead to tachypnea or dyspnea. If increased respiratory effort is observed, it may be prudent to postpone physical examination of dyspneic birds until after the bird has rested in an oxygen cage.

Physical examination should include careful evaluation of the oropharynx and crop, coelomic palpation, and inspection of the vent.

Examination of the bird with shelled egg
Oropharynx
  • Evaluate the mucous membranes for pallor.
  • Look for dry, tacky mucus as evidence of dehydration.
Crop
  • Gently palpate the crop for evidence of distension with fluid or food.
  • Crop stasis may be a secondary finding in any ill, stressed bird.
Coelomic palpation
  • A shelled egg is easily detected.
  • Carefully and gently palpate the egg to get a general idea of its size, shape, and orientation.
Vent
  • Is the egg visible?
  • Is there blood coming from the vent?
  • In rare cases of uterine infection, cloacal discharge may also be detected.

Differential diagnoses

A shelled egg should be present at the level of the shell gland or lower. The presence of the egg can be a normal physiologic finding or may be due to egg binding or dystocia.

Multiple factors are believed to be involved in the development of dystocia and egg binding:

  • Chronic egg production
  • Large, misshapen or malformed eggs
  • Obesity or lack of exercise
  • Elderly birds, birds laying their first clutch, and birds bred out of season
  • Calcium deficiency, vitamin E/selenium deficiency
  • Oviductal disease (infection, neoplasia, or trauma)
  • Cloacal masses
  • Systemic disease or other stressors
  • Heredity

Less commonly, a shelled egg may be moved higher within the oviduct by retroperistalsis. In rare instances, a shelled egg may even be found free within the coelom. Ectopic eggs occur secondary to retroperistalsis or after uterine rupture.

Diagnostics

Distinguishing dystocia from egg binding often relies on history, observation of the patient, and careful palpation, however if the bird is sufficiently stable use radiography and clinical pathology, especially calcium levels. Take survey whole body radiographs to evaluate egg size, shape, and position (Fig 1).

Whole Body Radiograph

Figure 1. Take survey whole body radiographs to evaluate egg size, shape, and position. Note: The position of the round and pointed ends of the egg normally varies. Click image to enlarge.

Also look for the presence of osteomyelosclerosis. Ossification of long bones or osteomyelosclerosis is a normal radiographic finding in the hen gearing up to lay eggs is. Bone marrow ossification occurs secondary to rising estrogen levels and provides a critical calcium reserve for the hen to shell and pass the egg through the reproductive tract (Fig 2). The absence of osteomyelosclerosis in a hen with a shelled egg is very significant because this suggests she lacks the calcium reserves needed for normal uterine contraction waves that will expel the egg.

Ossification of long bones

Figure 2. Ossification of long bones or osteomyelosclerosis (yellow arrows) compared to normal radiographic appearance of bone in the bird (red arrows). Click image to enlarge.

Therapy

Stimulate uterine contractions using oxytocin or prostaglandin F2 alpha (Lutalyse®, Pfizer). Remember neither drug relaxes the uterovaginal sphincter, so their use in complicated cases of dystocia (i.e. adhesions, oversized egg, oviductal torsion) can lead to reverse peristalsis or even uterine rupture. Drug therapy can be attempted for 12 to 24 hours in most patients unless the bird’s clinical condition requires more rapid intervention (i.e. cold, pale feet; recumbency, not defecating).

More aggressive techniques that may be practiced by avian veterinarians include:

  • Ovocentesis
  • Manual expression of the egg using gentle digital pressure under general anesthesia.
  • Laparotomy and hysterectomy

For management of egg binding, provide fluids and calcium supplementation to promote movement of the egg. Antibiotics are indicated when metritis or salpingitis are thought to play a role in egg binding.

After the egg has been laid:

  • Administer a drug to inhibit egg laying such as human chorionic gonadotropin (HCG) (500 IU/kg IM on Day 1, 3 and 7), or more commonly, leuprolide acetate (Depo Lupron, TAP Pharmaceuticals) (100-200 µg/kg IM q 2-4 weeks).
  • Consider antibiotics since assisted egg laying may lead to a flaccid cervix allowing the reflux of feces, urine, or urates into the uterus and secondary salpingitis or metritis.
  • Improve the bird’s plane of nutrition, particularly the calcium and protein content of the diet
  • Also recommend behavioral and environmental changes that can halt egg laying (see the Client handout: Chronic egg laying).
  • Identify the underlying cause of dystocia.

 

References

References

Bowles HL. Evaluating and treating the reproductive system. In: GJ Harrison, TL Lightfoot (eds). Clinical Avian Medicine. Palm Beach, FL: Spix Publishing; 2006. Pp. 519-540.

Rosskopf WJ, Woerpel RW. Avian obstetric medicine. Birchard SJ, Sherding RG (eds). Saunder’s Manual of Small Animal Practice. Philadelphia, PA: WB Saunders, 2000. Pp. 1451-1458.

Speer B. Diseases of the urogenital system. In: Altman RB, Clubb SL, Dorrestein GM, Quesenberry K. Avian Medicine and Surgery. Philadelphia, PA: WB Saunders; 1997. Pp. 633-644.

To cite this page:

Pollock C. Presenting problem: Shelled egg palpable. May 25, 2012. LafeberVet Web site. Available at https://lafeber.com/vet/presenting-problem-shelled-egg-palpable/