IMPORTANCE OF VACCINATION IN POULTRY FARMING

IMPORTANCE OF VACCINATION IN POULTRY FARMING

Madhanraj.N^1*, Jayanth K.V¹, Kathiravan.S¹, Hariharan.R²

 and Alimudeen.S¹

• V. Sc Scholars, College of Veterinary and Animal Sciences, Pookode, Kerala Veterinary and Animal Sciences University, Wayanad-673576
• PhD Scholar, College of Veterinary and Animal Sciences, Pookode, Kerala Veterinary and Animal Sciences University, Wayanad-673576

Introduction:

Vaccines are crippled/weakened organisms, dead organisms or individual proteins that are introduced into human/animal to give an immune response that mimics a natural infection without causing disease. All across the world, chickens are raised as a source of animal protein. Furthermore, chickens are inexpensive to acquire, have a quick generation period, a high rate of productivity and don’t need a lot of acreage to grow. They can also adapt to most geographical regions and environmental conditions. Different poultry production methods exist, from small-scale farming to highly industrialized, vertically integrated systems. Domestic chickens, both terrestrial and aquatic, are mostly raised in backyard aviaries throughout the majority of rural and peri-urban parts of the world. Although intensive poultry farming is most prevalent in rich nations, many developing nations have embraced this technique in recent decades to accommodate the rising demand for animal products. Globalization and the potential persistence and expansion of disease agents through domestic and wild reservoirs both have recently increased the danger of transmission of some transboundary pathogens to highly exposed areas. Examples of the detrimental effects of such diseases on the poultry-producing industry and on society at large are the extensive dispersion of Newcastle disease (ND) and the epidemics of avian influenza (AI) that have occurred during the last ten years. At the international, national, and farm levels, a variety of tactics can be used to effectively prevent and control the spread of animal diseases, and vaccination is frequently used in poultry disease management plans. In fact, vaccines play a significant role in the prevention and management of poultry diseases throughout the world. Their traditional use in chicken production is to prevent or minimise the occurrence of clinical disease at the farm level and hence increase productivity. Vaccines and vaccination campaigns come in a wide range, based on a number of regional conditions. (e.g. type of production, level of biosecurity, local pattern of disease, status of maternal immunity, vaccines available, costs, and potential losses). Although the poultry industry normally oversees poultry vaccination, it has only sporadically been used as part of a national or regional disease eradication effort to eliminate a few significant chicken diseases (such as AI and ND). The information on the application of vaccination for the prevention of poultry illnesses in any nation, region, or territory, with a focus on the prevention of transnational poultry diseases, was given here.

Controlling Poultry Diseases:

This paper does not cover all the detailed control measures that can be implemented to contain and eliminate poultry diseases in different agricultural systems, and attempts are limited to summarizing and explaining some basic concepts in the use of poultry vaccines. It is important to emphasize that, even though vaccination is an important tool, it should not be seen as an alternative to good management practices and biosecurity measures when it comes to preventing the spread of a contagious disease. The effectiveness of vaccines against diseases in birds or flocks under field conditions is not realistic to expect. The application of disease prevention management techniques and hygienic practices at the farm level is essential in preventing the spread of disease and the associated economic consequences. The poultry industry involves the trade of poultry products and genetic stock between widespread localities and markets. This is often done under the management of multinational companies. The regular reporting of the World Organisation for Animal Health-listed diseases to international bodies and the definition and application of international and national control policies are essential to minimizing disease impact on human health and poultry production and avoiding unjustified barriers to the trade of live poultry and products.

Role of vaccines in controlling poultry diseases:

Vaccination should generally be designed and modified according to local factors that may influence the strategy, design, and effectiveness of the vaccination program once implemented.

Several different factors should be taken into account, including:

• The type of poultry production (e.g. commercial or rural)
• The organization of the industry (e.g. vertical integration)
• The densities of different bird species
• The prevailing disease situation
• Vaccine availability
• The use of other vaccines
• The prevalence of other diseases
• The resources available (e.g. manpower and equipment)
• The costs involved.

The first expected outcome of the administration of a poultry vaccine is that birds will develop immunity to pathogens and thus be protected against disease. The results that may be achieved through the use of vaccination can be summarised as follows:

• Protection against the clinical form of the disease
• Reduction of susceptibility to infection (a higher infectious dose is required to trigger an infection in vaccinated birds than in those unvaccinated)
• Reduction of infectivity (e.g. shedding) in case of infection.

Properties of good vaccine:

• Vaccines should have the ability to elicit the appropriate immune response for the particular pathogen and to give long-term protection (Production of life-long immunity)

• Providing safety (Vaccine itself should not cause disease)
• It should be stable (Retain immunogenicity) despite adverse storage conditions prior to administration
• Inexpensive
• A good vaccine should not induce autoimmunity or hypersensitivity

Different types of vaccines:

• Living heterologous
• Living vaccines
• Living attenuated organisms
• Killed organisms
• Inactivated toxins
• Capsular polysaccharides
• Subunit vaccines
• DNA vaccines
• Passive immunization
• Non- specific immunotherapy
• Edible vaccines

Vaccines used in poultry production are described as live or inactivated. Table I outlines the general characteristics of live and killed poultry vaccines. The accessibility of different types of vaccines might be one of the main limits to the functioning of effective vaccination programmes. Different types of poultry production or different levels of risk require the use of more than one type of vaccine to obtain a high and long-lasting immunological response. As regards ND control, the immune response initiated by live ND vaccines increments as their pathogenicity increases. Vaccination programmes using vaccine strains of different pathogenicity in addition to immunogenicity must be useful in relation to the amount of virulence of the virus in circulation. To attain an ideal stage of protection devoid of severe adverse reactions, vaccination programmes must include the successive use of progressively more virulent live vaccine strains or live vaccines followed by inactivated vaccines. Generally, inactivated vaccines bring high and equal levels of protection after administration of a live vaccine. This type of programme must be considered in the implementation of vaccination programmes used for breeder and layer flocks due to the fact that they need high and long-lasting immunity for protection during the complete laying phase.

Table 1: General characteristics of live and inactivated vaccines for poultry

EDS: egg drop syndrome IB: infectious bronchitis LT: laryngotracheitis ND: Newcastle disease

Vaccine administration:

After setting up the kind of vaccine to be used, the route, method and frequency of administration must be defined, as well as the good way to combine all these components in the vaccination programme. Vaccine release systems significantly impact the outcome of vaccination. An improper vaccine application is considered one of the most common reasons for vaccination programme failure. Various strategies of administration can be applied as required by different sorts of poultry operations (at the hatchery or farm). The choice of approach will also depend upon other components such as the kind of production, bird species, size of the flock, length of the production cycle, general health status, maternal immunity, vaccines to be applied, and costs. The vaccination techniques most commonly utilized in the poultry segment are illustrated in Table 2.

Table 2. : Vaccination Schedule

Reasons for vaccination failure:

• The recipient is already infected with the virus or is sick or has an immunosuppressive infection.
• Antigenic differences between the vaccine and challenge virus eg influenza.
• Increase in virulence of the challenge virus.
• Breakdown of the cold-chain during transport e.g. tissue-culture vaccines.
• Improper administration- disinfectant in the syringe.
• The vaccine has been overgrown by an irrelevant virus/bacterium,no antigen-potency testing done

Differentiating infected from vaccinated animals:

In order to eliminate main infectious poultry diseases like AI, which contain such a negative influence on poultry production and human health, the vaccination system must allow the detection of field exposure in vaccinated flocks. The demarcation among exposed/unexposed vaccinated birds and flocks requires the application of a suitable ‘marker’ vaccine and a companion discriminatory test. Because this condition is not always satisfied, a monitoring programme that incorporates the use of (unvaccinated) sentinel birds can also be set up. In order to measure the possible exposure to other infections not included in the vaccination programme, a regular monitoring programme focused on to the detection of other diseases (e.g. immunosuppressive infections) might be implemented. This can also allow for the detection of new or re-emergent pathogens. It is harder to assess the efficacy of a vaccination programme conducted in a rural poultry farm because reference data or standards are often unavailable. In this case, assessment must be based on disease reporting, and a comparison of the situation in the vaccination area before and after the execution of the vaccination plan. This implies the presence of a surveillance system capable of detecting the disease and giving comparable historical information on its frequency.

Conclusion:

Vaccines are widely applied in all the various poultry producing systems. Vaccination programmes can be effectively executed in diverse conditions if they are customized to the native conditions and get into account components such as the characteristics of the poultry producing segment, the eco-epidemiological situation, and the availability of enough resources. Even though the application of poultry vaccines is a well-established practice at the farm/flock level, vaccination programmes for the control and possible eradication of poultry diseases are not always properly implemented at the national level. This can be challenging, mainly during the implementation of emergency vaccination programmes, the efficiency of which depends mainly on the level of preparedness, the capacity of the veterinary infrastructure, and the level of teamwork with poultry farmers and the other partners. Vaccination is more successful to the extent that the end population (bird species and type of production) is homogeneous. Unfortunately, field conditions are often unrelated and characterised by many different bird species, various raising practices, and different levels of disease risk. Effective vaccination and monitoring programmes therefore demand considerable effort and high levels of organization.

Please follow and like us: