How is chicken gout diagnosed? It is mostly caused by feeding high-calcium feed

In recent years, the phenomenon of chicken gout caused by high-calcium feed has occurred from time to time, with a long disease course and high mortality. Two cases of gout diagnosis are reported as follows.

1. Incidence situation

In May 2000, a farmer in Jinhu Town @#@230@#@ raised 1000 chickens. After 30 days of age, believing that the content of calcium hydrogen phosphate was insufficient, the amount was increased from 1% in the original formula to 3%. After 20 days of feeding, chicken deaths were found, and a total of 210 chickens died successively, with a mortality rate of 21%. After changing the feed, there was improvement. Through testing, it was confirmed to be gout caused by high calcium. In May 2001, a chicken farmer surnamed Zhang in Jianyang Town raised 2000 chickens. At 12 weeks of age, testing of calcium hydrogen phosphate showed low calcium and phosphorus, so 1% pure bone meal was added, and then 0.5% stone powder was added. After more than 20 days of addition, chicken deaths were found. Postmortem examination confirmed gout. After changing the feed, sporadic deaths still occurred after the start of laying, and a total of 400 chickens died successively, with a mortality rate of 20%.

2. Clinical symptoms

Sick chickens are depressed, with pale combs, anemia, fluffy feathers, a preference for lying down, reduced or lost appetite, emaciation, weakness, closed eyes and dazed appearance, empty crop, diarrhea, and white urate in the feces. Most sick chickens show swelling, thickening and deformation of the metatarsal and foot areas, with joint swelling 1 to 1.5 times normal. The joints feel soft when touched, and the chickens dodge and struggle when gently pinched. Those with mild symptoms stand unsteadily, while those with severe symptoms cannot stand, are paralyzed, and cannot feed. Hens show decreased egg production or complete cessation of laying. The normal blood urate content is 1.5 to 3.0 mg/100 mL, while that of sick chickens is 15 mg/100 mL, an increase of 5 to 10 times.

3. Postmortem changes

The subcutaneous tissue, joint capsules, thoracic cavity, abdominal cavity serosa, pericardium, and surfaces of internal organs (such as heart, liver, spleen, lung, kidney, mesentery, etc.) of sick chickens are covered with a layer of white lime-like urate. The liver is mildly enlarged and fragile, with diffuse white small granular material on the cut surface; the lungs are congested; the kidneys are enlarged 2 to 3 times, with alternating red and white patterns, and a sandy sound when cut with a knife. Some kidney surfaces are covered with a rough white membrane. One or both sides of the ureters are dilated and thickened, and the ureters are filled with lime-like sediment blocking the urinary tract. Postmortem examination of the esophagus, proventriculus, and gizzard shows no obvious changes.

4. Laboratory examination

Smears taken from the heart, liver, and swollen joint capsule fluid of sick chickens were microscopically examined, and no pathogenic bacteria were seen, but many needle-like urate crystals were seen. Fecal examination showed no parasitic eggs.

5. Differential diagnosis

The chicken house had good ventilation, was dry, had fresh air, and suitable temperature. The feed contained no more than 20% protein, and the chickens had not eaten sodium bicarbonate, sulfonamide drugs, or moldy corn, etc. Investigation showed no occurrence of infectious bronchitis, coccidiosis, pullorum disease, colibacillosis, etc.

6. Prevention and treatment

1. Immediately pick out sick chickens when found, confirm the diagnosis in time, identify the cause, and then treat.

2. If it is identified as gout caused by high calcium, promptly reduce the added bone meal, stone powder, and calcium hydrogen phosphate.

3. Give kidney-swelling detoxification medicine, once daily from 8:00 to 10:00 in the morning at 0.2% in drinking water, that is, 100 g added to 50 kg of water, with 3 days as one treatment course, and provide enough clean water in the afternoon.

4. For affected chickens, feed more green, succulent feed, and add an appropriate amount of potassium permanganate and 0.5% edible alkali or 0.5% sodium bicarbonate to sufficient drinking water for 3 days, then change the concentration to 0.25% and give for another 3 days, to promote the excretion of urate from the body. (Editor's note: if kidney-swelling detoxification medicine has already been used, it is generally unnecessary to add sodium bicarbonate.)

5. Strengthen scientific feeding management and epidemic prevention hygiene, provide appropriate exercise, ensure sufficient sunlight in the chicken house, and clean frequently.

6. Reasonable formulas according to the different ages of chickens, and attention to the calcium-to-phosphorus ratio, are the key to preventing the occurrence of this disease.