Health management of poultry
TC Tolenkhomba and Prava Mayengbam
Poultry eggs and meat are important sources of high quality proteins, minerals and vitamins to balance the human diet. Specially developed breeds of egg type chicken are now available with traits of quick growth and high feed conversion efficiency. Depending on the farm-size,poultry farming can be the main source of family income or can provide income and gainful employment to small holder farmers throughout the year. Poultry manure has high fertilizer value and can be used for increasing yield of all crops. In poultry rearing disease is a major factor which causes severe impact on economics of farming. Birds are susceptible to diseases, many of which are highly contagious. Therefore, it is advisable to take up utmost care for prevention and control of disease.
The main sources of disease spread in poultry are wet litter, feed and water, close contact,contaminated equipment, attendants and visitors, air, external parasites, free moving birds, rodents and flies, etc.
General principles for prevention of diseases
· Procure the day old chicks, which are free from diseases from reputed hatcheries
· Feeds must be tested to ensure that they are free from microbial agents or toxins at periodic intervals.
· Storage facilities for feed ingredients/feeds must be managed in a hygienic manner.
· Sheds having infected flocks should be served with feed at the end of a delivery day.
· Always ensure the supply of clean and potable water. If necessary use appropriate sanitizers.
· Periodic inspection of wells, piping and tanks to ensure that water supplied is clean.
· An area specific vaccination schedule as recommended by hatchery doctor must be practised with utmost care.
· Rodent control programmes, wherever necessary, must be adopted by employing mechanical (traps) or chemical techniques along with strict sanitation measures.
· After selling each crop from the sheds, thorough cleaning of sheds should be done by removing all fixtures, equipment, litter dust, debris followed by brooming and burning. The rat holder cracks, and the worn out area should be packed with cement.
· Avoid use of litter as manure around the farms.
· Well cleaning of sheds and equipment with water and appropriate detergent.
· A thorough disinfection of sheds, equipment as well as farm surroundings by formalin spray at recommended concentration.
· Foot baths should always be filled with disinfectant.
· Vehicles visiting the farms should be thoroughly disinfected by appropriate disinfectant spray.
· Personnel working in laying sectors should not be allowed into brooding/growing sectors or feed manufacturing facilities. All visitors must be ensured to walk through foot baths.
· Disposal of dead birds in a hygienic manner either by using an incinerator or by a pit method is very essential.
What to be done at the time of an outbreak
· Restrict the movement of birds (selling and buying)
· Follow strict hygienic measures.
· Take help of Veterinarians.
Week of Vaccination Type of Vaccination
Day old Marek’s
15 days (1/2 dose) Infectious Bursal
20 days (1/2 dose) Infectious Bursal
25 days Bronchitis, New Castle, Infectious Bursal (Typical Brand name Combo Vec. 30)
30 days Bronchitis, New Castle, Infectious Bursal (Typical Brand name Combo Vec. 30)
49 days Bronchitis, New Castle, Infectious Bursal (Typical Brand name Combo Vec. 30)
10 Weeks Fowl Pox and Laryngotracheitis (commonly referred to as LT)
12 Week Combo Vac 30
13 Week Avian Encephalomyelitis (commonly referred to as AE)
16 Week New Castle
IMPORTANT DISEASES OF CHICKEN
Fowl Pox:The dry form of fowl pox is characterized by raised, wart-like lesions on unfeathered areas (head, legs, vent, etc.). In laying hens, infection results in a transient decline in egg production. In the wet form there are canker-like lesions in the mouth, pharynx, larynx, and trachea. The wet form may cause respiratory distress by obstructing the upper air passages. Treatment : No treatment is available. However, fowl pox is relatively slow-spreading. Thus, it is possible to vaccinate to stop an outbreak. Prevention: Fowl pox outbreaks in poultry confined to houses can be controlled by spraying to kill mosquitos. However, if fowl pox is endemic in the area, vaccination is recommended.
Newcastle Disease: Newcastle disease is characterized by a sudden onset of clinical signs which include hoarse chirps (in chicks), watery discharge from nostrils, laboured breathing (gasping), facial swelling, paralysis, trembling, and twisting of the neck (sign of central nervous system involvement). Mortality ranges from 10 to 80 percent depending on the pathogenicity. Treatment: There is no specific treatment for Newcastle disease. Antibiotics can be given for 3-5 days to prevent secondary bacterial infections. For chicks, increasing the brooding temperature 5°F may help reduce losses. Prevention: Prevention programs should include vaccination, good sanitation, and implementation of a comprehensive biosecurity programme.
Infectious Bronchitis:The severity of infectious bronchitis infection is influenced by the age and immune status of the flock, by environmental conditions, and by the presence of other diseases. Feed and water consumption decline. Affected chickens will be chirping, with a watery discharge from the eyes and nostrils, and laboured breathing with some gasping in young chickens. Breathing noises are more noticeable at night while the birds rest. Egg production drops dramatically. Eggshells become rough and the egg white becomes watery.
Treatment: There is no specific treatment. Antibiotics for 3-5 days may aid in combating secondary bacterial infections. Raise the room temperature 5°F for brooding-age chickens until symptoms subside. Baby chicks can be encouraged to eat by using a warm, moist mash.
Prevention:Establish and enforce a biosecurity program. Vaccines are available.
Avian Influenza: Avian influenza is categorized as mild or highly pathogenic. The mild form produces listlessness, loss of appetite, respiratory distress, diarrhoea, transient drops in egg production. The highly pathogenic form produces facial swelling, blue comb and wattles, and dehydration with respiratory distress. Dark red/white spots develop in the legs and combs of chickens. There can be blood-tinged discharge from the nostrils. Mortality can range from low to near 100 percent. Sudden exertion adds to the total mortality. Egg production and hatchability decreases. There can be an increase in production of soft-shelled and shell-less eggs.
Treatment: There is no effective treatment. With the mild form of the disease, good husbandry, proper nutrition, and broad spectrum antibiotics may reduce losses from secondary infections. Recovered flocks continue to shed the virus.
Prevention:A vaccination programme used in conjunction with a strict quarantine has been used to control mild forms of the disease. With the more lethal forms, strict quarantine and rapid destruction of all infected flocks remains the only effective method of stopping an avian influenza outbreak. If you suspect you may have Avian Influenza in your flock, even the mild form, you must report it to the state veterinarian’s office.
Infectious Laryngotracheitis: Chickens 14 weeks and older are more susceptible than young chickens. Most outbreaks occur in mature hens. The clinical sign usually first noticed is watery eyes. Affected birds remain quiet because breathing is difficult. Coughing, sneezing, and shaking of the head to dislodge exudate plugs in the windpipe follow. Birds extend their head and neck to facilitate breathing (commonly referred to as “pump handle respiration”). Inhalation produces a wheezing and gurgling sound. Blood-tinged exudates and serum clots are expelled from the trachea of affected birds. Many birds die from asphyxiation due to a blockage of the trachea when the tracheal plug is freed.
Treatment: Administer antibiotics to control secondary infection, and vaccinate the flock. Vaccination of individual birds by the eye-drop route is suggested. In small poultry flocks, use a swab to remove plugs from gasping birds.
Prevention: Vaccinate replacement birds for outbreak farms.
To be contd