Flip-over Disease: Introduction
(Sudden death syndrome, Heart attack, Acute death syndrome, Fatal syncope, Lung edema, Lung congestion, Dead in good condition) |  |
| Flip-over disease has been reported in most areas of the world that intensively raise broilers. Young, healthy, fast-growing broiler chickens die suddenly with a short, terminal, wing-beating convulsion. Many affected broilers just “flip over” and die on their backs; 60-80% are males. The condition is uncommon or unrecognized when low-density feed is used and the ratio of feed intake to weight gain is >2.5 at 6 wk, or when broilers take 8 wk to reach 2 kg. |
| Etiology and Epidemiology: |
| The cause is unknown but probably is a metabolic disease related to carbohydrate metabolism, cell membrane integrity, and intracellular electrolyte balance. Death may result from ventricular fibrillation. The modern broiler tends to overeat and continues to grow rapidly while maintaining a low feed-to-gain ratio. Flip-over appears to be related to high carbohydrate intake. It is not known whether a genetic predisposition exists. |
| Incidence in a rapidly growing healthy broiler flock is typically 1-4%. |
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| Clinical Findings: |
| Broilers show no premonitory signs. They appear healthy and may be feeding, sparring, walking, or resting, but suddenly extend their necks, gasp or squawk, and die rapidly with a short period of wing beating and leg movement, during which they frequently flip onto their backs. They also may be found dead on their sides or breasts. |
| Flip-over may occur as early as day 3 and may continue until 10-12 wk in roaster flocks. Peak mortality varies but usually is between days 12 and 28, although it can be as early as day 9. It may occur after day 28, particularly if growth is restricted in young broilers. Mortality of 0.25-0.5% per day can occur for 1-3 days. |
Lesions:
| Confirmation is difficult because no specific gross or histologic lesions are present. Dead birds are well fleshed, have an empty or partially filled crop containing normal ingesta, and feed in the gizzard. The abdomen is distended because the bird is fat and because the intestines are dilated and filled with semisolid digesta and mucus (as in any broiler that dies with the intestine full of feed). There is no evidence of stasis. The muscles are mottled red and white with
congestion of the dependent muscles. Organs are moderately to severely congested. There may be small hemorrhages in the liver and kidney. The ventricles of the heart are contracted (but not hypertrophied), and the atria are dilated and blood filled. (If autolysis is advanced, the ventricles may be dilated.) The lungs are congested and frequently edematous; however, pulmonary edema increases with time after death and is not prominent in broilers that are examined within a few
minutes after death. The gallbladder may be small or empty (as it is in many broilers on full feed). |
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| Diagnosis: |
| Good broilers found dead on their backs may be assumed to have died of flip-over because that position is rare in death from other causes except cardiac tamponade, asphyxia, and ascites syndrome (
Ascites Syndrome). Birds in good condition on their sides or breasts, scattered in a random fashion in the pen also usually are considered to be dead from flip-over. Diagnosis is supported by the full GI tract (particularly the full intestine); large, pale liver;
large, normal bursa; contracted ventricles and dilated, blood-filled atria; lung congestion and edema; and the lack of pathologic lesions. |
| The condition called sudden death syndrome in Australia in broiler breeders coming into production is a different disease; it is reported to be caused by
potassium deficiency. Similar mortality caused by a combination of high environmental temperature and hypophosphatemia or by acute hypocalcemia has been reported in North America. |
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Sudden death in turkeys can be caused by choke, aortic rupture (
Dissecting Aneurysm: Introduction), focal (obstructive) granulomatous pneumonia, or by hypertrophic cardiomyopathy (
Round Heart Disease of Turkeys: Introduction) with lung congestion and edema, splenomegaly, and perirenal hemorrhage (
Perirenal Hemorrhage Syndrome of Turkeys: Introduction). |
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| Prevention and Control: |
| The incidence of flip-over disease can be minimized by slowing the growth rate of broilers, particularly during the first 3 wk of life. Growth rate can be moderated by controlling nutrient intake. This can be accomplished by reducing day length (number of hours of light per day), providing a ration low in energy and protein, or limiting the amount of feed provided to broilers. |
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