- Careful, experienced hand feeding technique reduces the risk of many potential problems including crop burn, crop atony, aspiration pneumonia, and some beak malformations.
- Crop burns are induced by feeding hot formula exceeding 110°F.
- Overfeeding can lead to overstretching of the crop and subsequent crop stasis, malnutrition, stunting, and secondary bacterial and fungal infections.
- Gastrointestinal foreign bodies and aspiration pneumonia are important diseases of birds of weaning age.
Conditions affecting the gastrointestinal system and liver
Feeding excessively hot formula (>110°F) causes crop burns. This problem is particularly common when formula is heated in a microwave without thorough mixing. Early signs of crop burn include hyperemia, edema, and blister formation. More often the first sign noticed is a necrotic area at the burn site, or formula spilling from the crop through a fistula after the necrotic tissue sloughs (Fig 1).
Allow a clear line of demarcation to develop between necrotic and healthy tissue before surgical correction. This process usually takes 10-14 days after the initial insult. Surgical correction involves removal of the fistula and closure of the crop and skin in two separate layers.
Foreign body or impaction
Many neonates ingest bedding or small objects within their enclosure due to their curious nature. Clinical signs may include anorexia, lethargy, crop stasis, and vomiting. Radiographs and upper gastrointestinal contrast studies facilitate the identification of foreign bodies and impaction.
- Remove crop foreign bodies such as feeding tubes or large food items using gentle, retrograde manipulation through the oropharynx.
- Severe crop impactions with bedding material or lower gastrointestinal impactions require surgical intervention.
- Remove foreign bodies within the proventriculus and/or ventriculus with the aid of a laparoscope. In small birds the endoscope can be inserted through the oral cavity, but most birds require an incision into the crop.
When baby birds are fed an excessive volume per feeding this leads to over-stretching of the crop. The crop becomes flaccid and extends ventrally over the cranial edge of the sternum (Fig 2). If not corrected, this problem can lead to crop stasis, malnutrition, stunting, and secondary bacterial and fungal infections of the gastrointestinal tract.
Apply a “crop bra” to provide ventral support using a soft cloth or elastic bandage material (Vetrap, 3M). Check the “bra” daily and replace twice weekly until the condition is corrected. Reduce the amount fed and increase the frequency of feedings until the problem is corrected. Severe cases may require surgical resection of a portion of the flaccid crop.
Hepatic hematomas occur most commonly in larger species such as macaws and cockatoos. This injury is usually associated with overzealous handling or blunt trauma, leading to extensive hemorrhage within the hepatic capsule. If the capsule ruptures, the bird often dies as a result of severe hemorrhage. Vitamin K is recommended, and supportive care such as fluids, nutritional support, and warmth is essential for a successful outcome. Severe cases require blood transfusion.
Conditions affecting the beak
The two most common abnormalities of the beak are lateral deviation of the maxilla (“scissor beak”) and mandibular prognathism. “Scissor beak” is most commonly found in macaws, whereas mandibular prognathism is most common in cockatoos. “Scissor beak” has been associated with improper hand feeding technique. Large birds that are always fed from the same side may suffer unilateral damage to the developing beak. In very young birds, physical therapy and corrective grinding may correct the problem. As the beak hardens, acrylic implants or extensions are required for repair.
Beak tip fractures can occur when the beak is caught within the enclosure or if the chick falls “beak-first” on a hard surface. Beak trauma can also be caused by bites from cage mates. Acrylics can be used to repair some defects. Severe fractures can be repaired with cerclage wire or stainless steel suture. If severe beak defects are not repaired they will lead to beak malformation. Extensive trauma to the germinal epithelium often results in permanent damage.
Conditions affecting the musculoskeletal system
Constricted toe syndrome
Constricted toes are commonly seen in macaws, African grey parrots (Psittacus erithacus), and Eclectus parrots. The lesion is characterized by an annular constriction around one or multiple toes (Fig 3). In young birds, a tight band of scar tissue usually causes the constriction. If untreated, this lesion will lead to avascular necrosis distal to the constriction.
Explore the lesion for the presence of a foreign body such as fibrous material, and debride the annular ring. Make two longitudinal incisions through the annular lesion on the lateral and medial aspect of the toe to relieve pressure at the constricted site and allow proper circulation to the affected toe. Bandage the toe and monitor daily. Warm soaks with diluted povidone-iodine or chlorhexidine will reduce swelling and prevent infection.
Folding fractures are a potential sign of metabolic bone disease in chicks. Fractures may also occur when a leg is caught in wiring. Fortunately, most chicks heal quickly. Splint the limb in a functional position and change the splint weekly. If indicated, improve the plane of nutrition and supplement calcium.
Conditions affecting the respiratory tract
Suspect aspiration pneumonia in chicks presented with a history of intermittent dyspnea and recurrent respiratory infections. Chicks near weaning are most commonly presented with aspiration because they tend to resist feeding. Severe cases die shortly after aspiration, while inhalation of a small amount of formula may be associated with a “cough”-like sound after feeding. Provide supportive care and begin antimicrobial therapy. Nebulization will hasten the clearance of the foreign material from the respiratory system. In some cases, signs recur after discontinuation of treatment. These chronic cases may have small granulomas, which may be identified via endoscopy of the air sacs and lungs. Biopsy these lesions to differentiate foreign body granulomas from fungal plaques.
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