Diseases of the Digestive System

Chapter 27 Diseases of the Digestive System


The digestive system of the bird is different from that of mammals. Birds have no teeth for cutting and grinding food. The esophagus, found on the right side of the neck in birds, contains a dilated portion called the crop used for food storage, allowing the bird to eat fast and travel. From the crop the food passes into the proventriculus (the glandular stomach), the ventriculus (the gizzard or grinding stomach), and then into the small intestine. After traveling through the small intestine, large intestine, and colon, the feces pass into the cloaca. Because the renal and reproductive tracts also empty into the cloaca, feces are excreted mixed with urine and urates. Disturbances of the digestive system are among the most common problems of captive birds.




Regurgitation (Courtship Behavior)



CLINICAL SIGNS



• Bird seen regurgitating food onto shiny surfaces in the cage or onto the owner

• Usually a healthy-appearing male bird

• No other signs of disease, normal appetite, feces

• No other vomiting or regurgitation seen at other times


DIAGNOSIS



• Gram stain of crop to rule out bacterial or fungal infection

• History of other breeding behavior


TREATMENT



• Remove the surface from the cage

• Frequent changes in toys and cage furniture

• Avoid activities that stimulate behavior

• Extend the daily period of darkness to reduce mating behavior

• Hormone therapy has been used but with many negative side effects


INFORMATION FOR CLIENTS



• Unless the bird is loosing weight, this is harmless behavior.

• The removal of shiny objects such as mirrors from the cage may cure most birds.

• Decrease light period by covering cage or placing into a dark room.


Crop Stasis/Crop Burns


Crop stasis and crop burns are primarily problems in hand-fed baby birds. Failure of the crop to move food into the lower digestive tract can result in malnutrition and death.



Crop Stasis


Primary causes of crop stasis are:


Foreign objects (such as bedding or large pieces of food)

Infection

Atony from overstretching

Dehydrated food particles

Low environmental temperatures

Feeding food that separates in the crop

Overfeeding in older birds


CLINICAL SIGNS



• Failure of the crop to empty in an appropriate time frame

• Regurgitation of food

• History of ingestion of foreign body


DIAGNOSIS



• Palpation of crop to rule out presence of foreign bodies

• Gram stain/culture and sensitivity for infectious agents

• +/− Radiology to rule out foreign objects


TREATMENT



• Stop feeding until crop motility returns to normal.

• Evacuate crop contents using a feeding tube and syringe.

• Lavage the crop using warm saline and gentle massage to break down any impactions.

• Replace hand-feeding diet with warm fluids to prevent dehydration until crop motility returns.

• Administer antibiotics appropriate for the culture and sensitivity results.

• Foreign objects often can be removed using alligator forceps.

• As crop motility returns, slowly increase the consistency of the handfeeding diet.

• Make sure the environment is temperature controlled (about 85–90° F for most baby birds).

• For crops that are overstretched or pendulous, a crop bra can be fashioned to provide support.


INFORMATION FOR CLIENTS



• Seek instruction from the breeder or pet store on how to hand-feed baby birds.

• Make sure the environmental temperature of the food and cage is appropriate for the bird.

• Do not reheat used food. Throw away any unused food after each feeding.

• Do not feed new food over old food in the crop. Make sure crop is empty before feeding.


Crop Burns


Crop burns occur when owners feed diets that are heated to extreme temperatures. This primarily is a result of using a microwave for heating the diet. Microwaves produce high heat areas in the middle of the food, leaving cooler areas at the surface and sides of the container. If the food is not well mixed after heating, the very hot food may be placed into the crop, causing a severe burn. The damaged tissue will become necrotic and slough, often leaving a fistula in the crop (Fig. 27-1).


image

Figure 27-1 Crop burn with necrosis in a young hand-fed bird.


(From Altman RB, Clubb SL, Dorrestein GM, Quesenberry KE: Avian medicine and surgery, Philadelphia, 1997, WB Saunders, by permission.)



CLINICAL SIGNS



• Discolored areas in the skin over the crop

• Leakage of food or fluid from the crop onto the skin

• Pain on palpation of the crop

• Reluctance to eat


DIAGNOSIS



• Good examination of crop and surrounding tissue

• Demonstration of a fistula opening in the crop


TREATMENT



Severe burn



• Surgical debridement of the damaged area with repair of fistulas opening


Mild burn



• Withhold food for several feedings. Replace it with a balanced electrolyte solution. Treat with antibiotics if needed.


PREVENTION



• After heating hand-fed diet, especially if using a microwave, make sure the diet is well mixed and use a thermometer to assure the temperature is not greater than 105° F (normal temperatures should be between 98° and 100° F).


INFORMATION FOR CLIENTS



• Always check the temperature of the hand-feeding mixture before feeding—use a thermometer.

• Make sure the food is well mixed to eliminate extremely hot areas.

• Young birds may reject food that is cooler than 98° to 100° F.


Beak Deformities


Malformed beaks (Fig. 27-2) are the result of trauma, malnutrition, improper hand-feeding techniques, mite infestation, bacterial or viral disease, or liver dysfunction. Whatever the cause, a malformed beak may result in an inability to eat properly and digestive problems. Beak deformation in young hand-fed birds once thought to be related to hand-feeding from a single side of the beak is more likely related to poor nutritional balances in the hand-feeding diet. In older birds, trauma to the germinal tissue of the beak will cause permanent beak deformities similar to those seen with damage to the cuticle of the fingernail or coronary band of the hoof. Mite infestation with Knemidokoptes can also result in damage to the beak, resulting in deformities that are seen primarily in parakeets.


image

Figure 27-2 Lateral deviation of the maxilla in a macaw.


(From Altman RB, Clubb SL, Dorrestein GM, Quesenberry KE: Avian medicine and surgery, Philadelphia, 1997, WB Saunders, by permission.)



CLINICAL SIGNS



• Observation of a uneven wearing of the beak

• Malocclusion of the beak

• Overgrowth of the beak (upper, lower, or both)

• History of trauma or signs of trauma: bite wounds, bruising of beak soft tissues, or disruption of the horny surface


DIAGNOSIS



• Complete physical examination

• Clinical chemistries, complete blood cell count (CBC) to rule out nutritional disorders

• Gram stain with culture/sensitivity—choanal slit


TREATMENT


Treatment will depend on the cause of the malformation.


• Deformities that have become permanent may be partially corrected by corrective grinding using a Dremel (Dremel, Racine, Wis.).

• Early correction of malnutrition or calcium deficiencies can provide some improvement.

• Fractures or damage to the horny beak can be repaired with medical acrylics. Splinting has been successful in some cases.


INFORMATION FOR CLIENTS



• Malformation of the beak is usually manageable, but permanent return to normal shape and function is not possible.

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Aug 31, 2016 | Posted by in GENERAL | Comments Off on Diseases of the Digestive System
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