Detailed Explanation of Prevention and Treatment Methods for Major Goose Diseases

Currently, the diseases that seriously harm the @#@232@#@ industry mainly include: gosling plague, egg-drop plague, goose paramyxovirus disease, and goose avian influenza, etc.

I. Gosling Plague

Gosling plague is an acute septicemic infectious disease caused by the gosling plague virus, mainly affecting goslings within 20 days of age, with a mortality rate as high as over 90%. Only a few goslings over three weeks of age are affected, and goslings over one month of age are basically unaffected.

(I) Clinical Features

The typical symptoms seen clinically are: sick geese separate from the flock and stay alone, with ruffled feathers and retracted neck, closing their eyes in a drowsy state; in severe cases they stop eating; they pass yellow-green watery droppings, with filthy secretions adhering around the nostrils, and before death develop neurological symptoms such as twisted neck, paralysis of both legs, or convulsions. Necropsy reveals characteristic lesions of the digestive tract: in the middle and lower sections of the small intestine there is a yellow-white band-like pseudomembrane that blocks the intestinal lumen, forming a plug-like mass, firm in texture and shaped like a sausage; in subacute cases the sausage-like mass is very obvious, based on which a preliminary diagnosis can be made. Confirmation depends on collecting diseased materials such as liver, spleen, and pancreas for virus isolation and identification.

(II) Prevention and Control Measures

1. Emergency treatment: Once gosling plague occurs in a flock of goslings, immediately isolate the goslings that have not shown symptoms from the rearing site and raise them at a clean, uncontaminated site, and inject each gosling subcutaneously with 0.5-0.8 ml of high-titer antiserum, or 1-1.6 ml of yolk antibody; broad-spectrum antibiotics may be appropriately added to the serum or yolk antibody. Each sick gosling should be injected subcutaneously with 1 ml of high-titer antiserum or 2 ml of yolk antibody. For affected young geese, inject 1 ml of antiserum or 2 ml of yolk antibody per 500 grams of body weight.

For emergency prevention, immunisation injection with an inactivated goose paramyxovirus disease vaccine produces immunity faster than using an oil-emulsion vaccine.

2. Immunoprevention:

(1) Breeding goose immunisation

If a live vaccine is used, there are two methods:

Single immunisation method: about 15 days before the breeding geese lay eggs, inject 1 ml of goose-embryo-adapted attenuated breeding goose vaccine (abbreviated as breeding goose vaccine) diluted 1:100 subcutaneously or intramuscularly. From 12 days to 4 months after immunisation, the goslings hatched from eggs laid by the immunised flock can resist viral infection, with a relatively high protection rate. After 4 months the protection rate of the goslings declines somewhat, and immunisation must be carried out again.

Double immunisation method: immunise with 1 ml of 1:100 breeding goose vaccine one month before the breeding geese lay eggs, then immunise with 1 ml of 1:10 breeding goose vaccine 15 days before laying; the protection rate of the goslings can reach 5 months after immunisation. Alternatively, carry out a second immunisation about 100 days after the single immunisation method, immunising with 1 ml of 1:10 breeding goose vaccine, extending the immune period by about another 5 months.

If an inactivated vaccine is used: for a single vaccine, use gosling plague oil-emulsion inactivated vaccine 15-30 days before laying, injecting 1 ml intramuscularly per goose; goslings hatched from 15 days to 5 months after immunisation all have a relatively high protection rate; for a combined vaccine, use a combined gosling plague and goose paramyxovirus disease vaccine about half a month before the breeding geese lay eggs, which also provides immunity. A bivalent oil-emulsion inactivated vaccine of gosling plague and goose paramyxovirus disease, or a bivalent oil-emulsion inactivated vaccine of goose paramyxovirus disease and goose plague, may also be used for immunisation.

(2) Gosling immunisation

For goslings without maternal antibodies, according to the epidemic situation of this disease, the first immunisation may be carried out at 2-7 days of age or 10-15 days of age, injecting goslings subcutaneously with 0.3-0.5 ml of goose paramyxovirus disease oil-emulsion inactivated vaccine. About 2 months after immunisation, immunise once more, injecting 0.5 ml intramuscularly per young goose; goslings from immunised breeding geese should receive their first immunisation at about 15 days of age, and another immunisation at about 2 months. Goose paramyxovirus disease inactivated vaccine, or goose paramyxovirus disease and goose plague inactivated vaccine, may also be used for immunisation.

Gosling plague is mainly spread through hatcheries, so hatcheries must carry out disinfection at every stage. After the disease occurs, hatching should be stopped immediately, and hatching may resume only after thorough disinfection of the whole facility.

II. Goose Colibacillosis (Egg-drop Plague)

Goose colibacillosis, commonly known as "egg-drop plague", is a reproductive organ disease of laying geese caused by several different serotypes of pathogenic Escherichia coli. It mainly occurs in adult geese, but in recent years it has also occasionally occurred in growing geese.

(I) Clinical Features

The occurrence of this disease is closely related to poor rearing management. Factors such as cold weather, sudden temperature changes, insufficient green feed, vitamin A deficiency, excessive crowding of the goose flock, stuffiness, and long-distance transport can all promote the occurrence and spread of this disease. It is mainly transmitted via the digestive tract; the onset of disease in goslings is often related to contaminated breeding eggs. When adult female geese are infected, sporadic cases generally occur in the early laying period, with the most cases occurring at the peak of laying, and the disease also ceases after laying stops. During an epidemic, it often causes the death of most sick geese. After male geese are infected, although death rarely occurs, they can spread the disease through mating.

1. Acute septicemic type: Geese of all ages can be affected, but geese 7-45 days of age are more susceptible. Sick geese are depressed, with ruffled feathers, afraid of cold, often huddling together, constantly screeching, with elevated body temperature 1-2°C higher than normal geese. Droppings are thin and foul-smelling, mixed with blood streaks, blood clots, and bubbles; the area around the vent is covered with droppings; appetite is completely lost, thirst increases, breathing is difficult, and finally they die of exhaustion and suffocation, with a relatively high mortality rate.

2. Colibacillary reproductive organ disease in female geese: Shortly after laying, some laying female geese show listlessness, reduced appetite, unwillingness to move, preference for lying down, often floating on the water surface or staying alone apart from the flock, panting, unsteady standing, head bent downward with the beak touching the ground, and distended abdomen. They pass yellow-white watery droppings, and around the anus there are filthy, foul-smelling excretions mixed with egg white, coagulated protein, or small yolk pieces. Sick geese have sunken eyeballs, dry beak and webbed feet, are emaciated, show symptoms of dehydration, and finally die of exhaustion. Even if a few geese recover naturally, they cannot resume laying.

3. Colibacillary reproductive organ disease in male geese: It mainly manifests as redness, swelling, ulceration, or nodules of the penis. In severe cases, the surface of the penis is covered with necrotic foci the size of mung beans; peeling off the scab exposes the ulcerated foci, the penis cannot be retracted, and the ability to mate is lost.

On necropsy, septicemic cases mainly show fibrinous pericarditis, airsacculitis, and perihepatitis. The characteristic lesion in adult female geese is yolk peritonitis: in the abdominal cavity there is a small amount of pale yellow, foul, turbid fluid, often mixed with damaged yolk; the surface of the internal organs is covered with pale yellow coagulated fibrinous exudate; the mesentery adheres to one another, and there are small hemorrhagic spots on the intestinal serosa. The lesions in male geese are confined to the external genitalia, with redness and swelling of the penis, on which there are necrotic foci and scabs.

(II) Prevention and Treatment Measures

1. Drug treatment: Ciprofloxacin, norfloxacin, streptomycin, chloramphenicol, gentamicin, etc. can be used with relatively good efficacy. However, Escherichia coli has very strong drug resistance, so sensitive drugs should be selected for treatment and prevention based on the results of drug sensitivity tests.

2. Immunisation: A relatively effective method at present is to prepare an inactivated bacterial vaccine from Escherichia coli isolated from diseased geese on the farm, and inject it once each into the reserve breeding goose flock at 2 months and 4 months of age, which can control the occurrence of the disease.

For this disease, immunise with aluminium hydroxide polyvalent egg-drop plague inactivated vaccine about 15 days before laying, injecting 1 ml intramuscularly per goose; the immune period can reach about 5 months, and it can effectively control the epidemic occurrence of the disease. When using the vaccine in an affected flock, antibiotics or sulfonamides may be selected at the same time for emergency prevention and treatment; because geese are very sensitive to Escherichia coli endotoxin, oil-emulsion inactivated vaccines should not be used.

3. Eliminate adverse factors: such as maintaining clean and hygienic goose houses, good ventilation, appropriate density, and strengthening rearing management and disinfection, etc. Carrier male geese can transmit the pathogen to female geese through mating, so male geese with severe lesions should be culled. Treatment: excise the nodules on the copulatory organ, debride and disinfect, and inject antibacterial drugs intramuscularly to help them recover.

III. Goose Paramyxovirus Disease

It is an infectious disease caused by avian paramyxovirus type I. Geese of any age can be infected. When Lion-head geese at the growing stage (40-60 days of age) are infected, it often appears as an outbreak, with large numbers of birds in the flock becoming ill and dying, and the mortality rate can often reach over 40%, causing relatively serious harm.

(I) Clinical Features

Clinically, goose flocks commonly show reduced appetite; individual geese are listless, standing still or squatting on the ground; eyelids are swollen, with tearing, body weight drops rapidly, and drinking desire increases; the droppings of sick geese are watery, dark red, green, yellow, or dark green; some sick geese show neurological symptoms such as twisted neck, circling, and head tilting back; when sick geese are held upside down, a blood-colored viscous liquid flows from the mouth.

Necropsy of dead geese shows millet-sized, pale yellow scabs on the tongue and in the oral cavity, which are easy to peel off. After peeling, purple spots are visible, and there are scabs in the esophagus; the proventriculus and gizzard show congestion and hemorrhage, and in some cases the contents are a dark red paste; the spleen is enlarged and congested, with necrotic foci from sesame-seed size to mung-bean size; the pancreas is enlarged, with grayish-white necrotic foci from millet-seed size to mung-bean size; the entire intestinal wall has diffuse or scattered fibrinous scabs of varying sizes, pale yellow or grayish-white, and after peeling they present hemorrhagic purple spots or ulcerated surfaces; the cecal tonsils are enlarged and hemorrhagic; the liver is enlarged and relatively firm in texture; the myocardium is brittle, and in some cases there are hemorrhagic spots on the myocardium and pericardium.