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Poultry diseases

 How to save a profitable industry

By Dr. S.M.Alam,
Dr. R.Ansari and M.A Khan NIA,
 Tando Jam
Aug 28 - Sep 03, 2000

Poultry production can be divided into two major categories, meat production and egg production. Heavy breed chickens, turkeys, ducks and geese are used for meat, while light breed chickens are used primarily for egg production. Several poultry birds including chickens and goose were raised about 3,000 years ago. Poultry men adapted various breeds according to their choice. These include meat, egg dual-purpose and ornamental classes. Popular breeds of meat class are the Brahmas, Cochins, Dorkings, Cornish, Jetsy Black Giants. The eggs breeds of Mediterranean class include the Leghorns, Minorcas, Anconas, and Black Spanish. Dual-purpose breeds are New Hampshire, Plymouth Black, Rhode Island Red, and Wyandott. A few breeds of chickens are raised chiefly for their ornamental appearance as pets. These include the Polish varieties, the Gamecock, raised for fighting and still bred for this purpose where cockfighting is permitted. $cientific breeding has improved the size, resistance to disease, quality of flesh and productivity of poultry. Commercial poultry raising is increasingly a large-scale enterprise. A modern phase of industry is the raising of chicks in highly mechanized indoor batteries where each bird is kept in a separate compartment and temperature, humidity and diet are carefully controlled.

Pakistan has established itself as a complex of profitable industries and obtained a vantage place in the economy of the country through popularizing the poultry industry. In fact, poultry farming is a high risk business. As such, quick disease investigation and diagnostic facilities for undertaking prompt remedial measures are very essential to prevent losses. Poultry raising establishments in and the towns and cities have created of health problems of the hybrid strains of layers and broilers. Recognition of problems and identification of factors responsible for them is getting more and more difficult. Poultry health is of paramount importance in the operation of a successful and profitable poultry farm. Improvements in housing and equipment can provide a more healthful atmosphere for poultry, however death losses from diseases are still heavy in some commercial operations in the country. Emphasis has been given towards the use of disease-resistant stock, vaccination against specific diseases and use of antibiotics and drugs in the feed or drinking water of the chickens. Among diseases common in poultry are roup, colds, bronchitis, coccidiosis, chicken pox, Newcastle, Pullorum (white diarrhoea). Many diseases can be prevented by selecting healthy breeding stock; keeping chicks separate from adult stock., by keeping houses clean; well ventilated and maintaining at proper temperature,, by good brooding practice, i.e care of chicks during the first week of life and by providing an adequate diet in such period. A popular disease named pullorum, has practically been eradicated and respiratory diseases, such as Newcastle disease, bronchitis and laryngotracheitis as well as fowl pox can be controlled by following a sound vaccination programmes. Another very important poultry disease named coccidiosis, a protozoan disease attacking both young and adult stocks, can be controlled safely and fully by using various drugs in the poultry feed. Leucosis, a highly complex disease manifesting itself in paralysis or total disability. A very effective vaccine has been developed to control Mark's disease, which is part of the avian leucosis complex. A brief description of some of the diseases are as follows:

Newcastle disease: An epizootic viral disease of fowls with respiratory, gastrointestinal and central nervous system involvement. It may be transmitted to human-beings, who work with fowls in the farms, usually appearing as a conjunctivitis, recovery is complete in 15 days. The virus is related to other paramyxo-virus in hemagglutination characteristics as well as in size and internal structure. It also shows an antigenic relationship to mumps virus. The disease in adult fowls is influenzalike, in young birds pneumoen-cephalitis is frequent. Mortality rates vary among breeds. A live attenuated virus is available for prevention of the disease in birds. The disease plays a havoc in terms of low production and outright losses through a high rate of depletion. This disease was very common in flocks generally raised in the villages and in the backyards of the houses . The virus of this disease creates respiratory stress and congestion in the larynx. The infection appears to have firmly entrenched itself in the macrocosm of almost every poultry farm and offers a serious challenge to the farm managers. Broilers and layers show high rate of immortality. The layers, soon after peak of laying period suffer a drop in production. There is a high percentage of rough or deformed shelled or shell-less eggs. The possible causes of this disease may, i) Location of poultry farms too close to each other, ii) Overpopulation of birds in a small farm, Non-existence of quarantine system between farms and poultry markets, iii) lack of proper sanitation and absence of facilities for disposal of sick or dead birds or the poultry house waste materials, iv) uses of different strains of virus vaccines indiscriminately v) unhygenic condition in and around the farm premises ,vi) Uses of vaccines by untrained persons, vii) inadequacy of technological development to keep in step with the rapid expansion in the poultry population and their genuine problems. According to expert opinion, facilities for diagnosis and control of poultry diseases did not develop proportionate to the expansion in poultry industry. At present, live virus vaccine prepared locally for Newcastle disease virus has proved effective in controlling epizootics. Literature reveals a schedule programme of three inoculations at 4 days, 4 weeks and 4 months age was an easy and effective formula. With slight modification the different farm owners are following this schedule programme. There is a great need and vigilance to control this disease. It is thus essential to establish at least one poultry disease diagnostic laboratory at each tehsil level fully equipped with equipment and apparatus to handle all types of poultry diseases. There are other infectious diseases. Airborne disease organisms that are prevalent include: bacteria, viruses and fungi all of which can cause respiratory infection. Disease organisms require moistures (humidity) to remain viable through airborne transmission. Lowering relative humidity (RH) from 90 percent to 80 percent will reduce airborne disease organisms by 50 percent, the best range of RH for killing airborne pathogens is 50 to 80 percent. Normally, a target for 65 to 70 percent when adjusting cold-weather ventilation fans is sufficient to ensure proper control of air borne contaminants. Relative humidity in a poultry facility is a function of bird numbers, body weight, ventilation rate and outdoor atr moisture holding capacity. If RH is above 75 percent then please increase fan speed. If RH is below 65 percent decrease fan speed. Control of air temperature during warm or hot weather should be a function of exhaust fans on thermostats.

An understanding of the fundamentals of indoor air quality is necessary for layer producers. Proper measurement and control can pay dividends for both hens and producers short and long term health and production efficiency. A suitable land is needed to set up the farm with an average of 0.5 to one acre (i.e 4840 square yards ) A minimum of 10,000 chicken is needed to fulfil the criteria and it is advised that the bigger the number of chickens reared, the bigger the profit margin will be. However, it has to be borne in mind that the location must not be near a residential area as this would create environmental problems. And there must be infrastructure such as road, water and electricity. In choosing the site, the surrounding must be dry and not subject to flooding. All these pre-requisites will help in reducing the creation of possible poultry diseases.