Health management of poultry
TC Tolenkhomba and Prava Mayengbam
Contd from prev issue
Treatment: A flock can be medicated with a sulfa drug (sulfonamides, especially sulfadimethoxine, sulfaquinoxaline, sulfamethazine, and sulfaquinoxaline) or vaccinated, or both, to stop mortality associated with an outbreak. It must be noted, however, that sulfa drugs are not FDA approved for use in pullets older than 14 weeks or for commercial laying hens. Sulfa drugs leave residues in meat and eggs. Antibiotics can be used, but require higher levels and long term medication to stop the outbreak. Prevention:On fowl cholera endemic farms, vaccination is advisable. Do not vaccinate for fowl cholera unless you have a problem on the farm. Rodent control is essential to prevent future outbreaks.
Omphalitis: Affected chicks may have external navel infection, large unabsorbed yolk sacs, peritonitis with foetid odour, exudates adhering to the navel, oedema of the skin of ventral body area, septicemia and dehydration.
Treatment: There is no specific treatment for omphalitis. Most affected birds die in the first few days of life. Prevention:Control is by prevention through effective hatchery sanitation, hatchery procedures, breeder flock surveillance, and proper pre-incubation handling of eggs. Mushy chicks should be culled from the hatch and destroyed.
Pullorum: Death of infected chicks begins at 5-7 days of age and peaks in another 4-5 days. Clinical signs - huddling, droopiness, diarrhoea, weakness, pasted vent, gasping, and chalk-white feces, sometimes stained with green bile. Affected birds are unthrifty and stunted because they do not eat. Survivors become asymptomatic carriers with localized infection in the ovary.
Treatment: Treatment is for flock salvage only. Several sulfonamides, antibiotics, and antibacterials are effective in reducing mortality, but none eradicates the disease from the flock.
Prevention: Pullorum outbreaks are handled, on an eradication basis. Breeder replacement flocks should be tested before onset of production to assure pullorum-free status.
Necrotic Enteritis: Rapidly growing young birds, especially chickens 2-12 weeks of age, are most susceptible. Initially there is a reduction in feed consumption as well as dark, often blood-stained, faeces. Infected chickens will have diarrhoea. Chronically affected birds become emaciated. The bird, intestines, and faeces emit a fetid odour.
Treatment: The clostridia bacteria involved in necrotic enteritis are sensitive to the antibiotics bacitracin, neomycin, and tetracycline. However, antibiotics such as penicillin, streptomycin, and novobiocin are also effective. Bacitracin is the most commonly used drug for control of necrotic enteritis. Prevention:Prevention is directed toward sanitation, husbandry and management.
To be contd