B I O S E C U R I T Y F O R B R E E D E R F A R M S

Transcription

1 Issue No.1 / February 2010 B I O S E C U R I T Y F O R B R E E D E R F A R M S ~ An Integral Part of the Modern Production System ~ Marcelo PANIAGO, DVM, MSc, MBA. Regional Market Manager - Poultry Ceva Animal Health Asia Pacific INTRODUCTION Biosecurity can be defined as a comprehensive range of clear procedures aiming to minimize the possibility of introduction of undesirable pathogens into a poultry operation. The extent of such biosecurity rules depends mainly on the prevalence of diseases in the area, the value of the birds, short and long-term company goals, customers expectations, level of commitment and availability of resources. One of the most important factors to establish an effective biosecurity program is to understand how the diseases are transmitted. Based on it, clear procedures can be set up and they must be followed by everyone involved in the production, without exceptions. For breeder operations, a comprehensive biosecurity program comprises several different procedures which main objective is to limit the risk of exposing the parent stock (PS) birds to pathogens that can threat their own health and also to those microorganisms that can cause problems to the offspring. This biosecurity program has some key components such as isolation, sanitation, vaccination, auditing and monitoring. They are described in more details here below. KEY COMPONENTS OF A BIOSECURITY PROGRAM a. Isolation Courtesy: Aviagen do Brasil Isolation refers to the confinement of the birds within a controlled environment and it includes the location, lay-out and internal organization of the farms as well as the necessary procedures such as traffic control and sanitation to keep the birds isolated from potential sources of contamination. Hence, the first step for setting up an efficient biosecurity program is the proper location of the breeder farm. Knowing that air borne transmission of pathogens is limited by distance, the farm should to be located in an isolated area, as far as possible from any other poultry operation. It also should to be away from the major roads that are used for transportation of poultry and from waterways used by migratory birds.

2 The lay-out of the farm has to consider minimal distance between houses, which should be at least few hundred meters apart, internal roads, clean and dirt areas etc. Physical barriers such as fences around the farm and around the houses are crucial to prevent any undesirable visitors. Trees surrounding the poultry houses could serve as a vegetative filter and windbreak, but an area of 15 m around the buildings should be kept clean, without vegetation. The design of the poultry houses should be, to the extent possible, without access points for rodents, wild birds, insects and stray animals. As rodents are the major vectors and reservoirs of Salmonella spp. for poultry, consequently the biosecurity program must involve their control. It has to be extremely rigorous not only in the breeder farms but also in the feed mills and it involves several steps as having the facilities rodent proof, eliminating potential harborage for these animals, keeping the whole facility as clean as possible and using appropriate rodent bating and trapping. Besides rodents, other animals and even insects can be potentially carriers of Salmonella spp. and they eventually can introduce these bacteria into a breeder flock. Cleanness and careful use of pesticides are essential to control insect vectors. The contact with wild birds can be avoided by having facilities bird-proof and by preventing their perching outside of the house. Furthermore, feed spills have to be cleaned up immediately to avert attracting them. Pets should also be excluded from the breeder house and even the use of cats as a biological control of rodents should be avoided as these animals can be source of Salmonella spp. for subsequent breeder flocks. Other farm animals, as dairy and beef cattle, should be also kept away from the houses by using fences. Needless to say, unnecessary visits should be avoided at any cost. For farm workers and unavoidable visitors, it is recommended to establish a compulsory shower and the use of clean farm clothes and boots to get entry into the farm. A record should be kept of all visitors and it should include their names, addresses, dates of the visits and the nature of their business. It is well known that equipments and vehicles could be a source of contamination for breeder flocks. Therefore, in order to minimize this risk, all equipments and vehicles have to be completely disinfected before gaining access to either the farm or the poultry houses. New flocks and feed also represent a risk of introduction of pathogens into the breeder farm. As a consequence, day-old chicks should only come from a reliable source and the feed must be produced with high standards of biosecurity and submitted to a decontamination process. Isolation also applies to the practice of separating birds by age groups. Therefore, each age group should have exclusive workers and equipments. However, some equipment such as beak trimmers, scales for weighting birds and crates, which could be used in different flocks, must receive special attention and careful disinfection as they eventually could spread a disease within the farm. The traffic control includes both the traffic onto the farm and the traffic patterns within the farm. If it is absolutely necessary to visit more than one flock or age group per day, the youngest flock should be visited first and then shower and changing clothes procedures should be done between the visits. In summary, as the most common way of introducing a pathogen into poultry operations is doubtless through contaminated people, feed, equipments and vehicles, proper isolation of the breeder farm is by far the best way of controlling diseases over time.

3 b. Sanitation Sanitation program is a key part of the biosecurity program and it comprises the cleaning and disinfection of the facilities (farms and hatcheries), equipments, vehicles, disinfection of hatching eggs etc. Cleaning can be defined as the physical removal of organic material such as litter, feed, dust and blood residues usually using abundant pressurized water and appropriate cleaning aides. Disinfection is the application of products which will destroy the pathogens with which they will have contact. Proper cleaning must be carried out before the use of any disinfecting product because pathogens are often protected by this material and furthermore effectiveness of any disinfectant can be drastically reduced in the presence of organic matter. Therefore, the poultry facilities should be constructed in a way to make them very easy to be cleaned and disinfected. The most common disinfectants commercially available are Quaternary ammonium compounds (QAC), Aldehydes (Formaldehyde, Glutaraldehyde), Chlorine compounds (Sodium hypochlorite, Chlorine dioxide etc), Iodophors, Phenols and Peroxygens (Hydrogen peroxide, Paracetic acid). There are also some combinations of different molecules like Glutaraldehyde + QAC. Thus, choosing the right disinfectant is even more important in case a known pathogen is present. The following table summarizes the effectiveness of some disinfectants against the main pathogens for poultry. Disease Agent Ammonium Compound (New Chlorhexidine Chlorine Phenol Iodophor generation) Salmonelosis Salmonella spp Colibacilosis Escherichia coli Infectious Coryza Haemophilus paragallinarum Clostridiosis Clostridium spp Pasteurelosis Pasteurella multocida Mycoplasmosis Mycoplasma spp Gumboro Disease Infectious Bronchitis Newcastle Disease Marek s Disease Laryngotracheitis Infectious Bursal Disease virus (Birnavirus) Infectious Bronchitis virus (Coronavirus) Newcastle Disease virus (Paramixovirus) Marek s Disease virus (Herpesvirus) Laryngotracheitis virus (Herpesvirus) / / / Aspergilosis Aspergillus spp Extracted from: Gordon, C.G. & Morishita, T. Y. Cleaning and Disinfecting of Poultry Facilities, Ohio State University, 2002.

4 The all-in/all-out management allows simultaneous depopulation of the facilities between flocks and it gives time for periodic clean-up and disinfection to break the cycle of the diseases. Consequently, a complete sanitation comprises cleaning, disinfecting and the down period afterwards. It is recommended to keep the facility empty for at least 2 weeks after disinfection to ensure the success of the sanitation program. Eventually, it is necessary to evaluate the efficacy of cleaning and disinfection procedures. For breeders, which were exposed to Salmonella spp., for instance, it is advisable to take samples of the disinfected facilities and send them to laboratory. Such samples should be taken from the floor, equipments, cages, wire fence etc. In summary, sanitation is a key part of the biosecurity program and the best results can be achieved when cleaning and disinfecting procedures are carefully planned and carried out in a proper way. Moreover, establishing a check-list with key points to be verified during the execution of these procedures could help the breeding companies to achieve the desirable results. c. Vaccination Vaccination can be considered as a biological barrier against some pathogens as it can effectively protect against some negative effects of these microorganisms. Generally, the vaccination of the breeder flocks has three major objectives: to protect the own birds health during their lifespan, to provide maternally derived antibodies (MDA) to their progeny and to prevent (or reduce) the vertical transmission of some microorganisms to the offspring. Vaccination against Marek s Disease, Infectious Laryngotracheitis, Coccidiosis and Pox virus are carried out essentially to protect the PS birds from the negative impact of these diseases as the humoral immunity eventually passed through the yolk is not important to protect the progeny. Additionally, there are other vaccines used to protect the source flock s health and simultaneously to provide humoral antibodies to the offspring. Vaccination against Infectious Bursal Disease, Newcastle Disease and Infectious Bronchitis are among them. Alternatively, the main reason to vaccinate breeder flocks against Chicken Infectious Anemia and Avian Encephalomyelitis is to transfer high and homogeneous level of maternal derived antibodies to the offspring in order to protect it during the first weeks of life. At last, but not at least, it is a common sense that Salmonella Enteritidis (SE*) and Salmonella Typhimurium (ST) do not affect the performance of the PS birds. Nevertheless, these bacteria have an important impact on the food safety as they can cause food borne diseases in human beings after contaminating layer or even broiler flocks. Therefore, whenever it is not feasible to keep the breeder flocks free of these infections, the vaccination against these diseases is advisable and it aims to reduce significantly the contamination of the progeny by reducing dramatically the shedding of these bacteria to the environment. This vaccination could even be used as part of an eradication program. In summary, a comprehensive vaccination program for breeders has to take into consideration not only the epidemiology of the diseases, but the requirements of the poultry producers and the concerns of the consumers. Moreover, it is important be in accordance with the regulations in force in each country. * SE = Salmonella enterica subspecie enterica serovar Enteritidis

5 d. Auditing Audit can be freely defined as an evaluation of a process (or an organization, a project etc) in order to assess its validity and reliability. As it happens in any kind of human activities, it is unlikely to identify eventual flaws in the processes without a detailed assessment of the situation. Hence, regular audits are a key part of a biosecurity program as they help to identify the weaknesses of the program and consequently allowing the managers to set up actions to improve the current procedures. This systematic and deep evaluation should be carried out by people involved in the operation and with specific knowledge of each activity (internal audit). An interesting option is to have external consultants participating of some of these activities (external audit). These assessments should include the breeder farm and all related activities which can affect the biosecurity of the entire production system such as hatchery, feed mill, transportation system, laboratories etc. Furthermore, once a flaw is detected, the company has to show willingness to solve it as the biosecurity program is useless without clear goals and further monitoring procedures. e. Monitoring Ultimately, the main purpose of monitoring the health status of the breeder flocks is to evaluate the effectiveness of the biosecurity program in the farm. Moreover, this regular monitoring assesses the efficacy of the vaccination program and the administration of the vaccines by evaluating the immune response induced in the birds. Finally, it also allows setting up measures to confine any sanitary problem eventually identified in a flock and to trigger a deeper investigation afterwards. There are several tools to monitor the health status of the breeder flocks. Serological tests can be used to check the presence of certain diseases and to indicate the efficacy of vaccination program by measuring the antibody titers. Microbiological cultures are carried out to look for bacteria such as Salmonella spp.. More recently, molecular diagnostic tools have been incorporated in some breeder complexes in order to help in the diagnostic and monitoring programs. The frequency, number of samples, testing material and testing methods should be defined by each operation based on their challenge, resources and objectives, but it must comply with the legislation in force in the country, if any is present. Lastly, it is also important to check the daily performance data of the flocks, such as egg production, feed consumption and mortality as well as the behavior of the birds such as an indication of the health status of the birds. CONCLUSIONS It is a fact that the requirements of the broiler and layer producers are increasing, the concerns of the end users regarding to food poisoning and residues in the meat and eggs are growing quickly and the indiscriminate use of antibiotics has been restricted. In this context, preventive measures have assumed a key role in any production system and thus a well designed biosecurity program can be the difference between the success and the complete failure of a breeding company. Additionally, it is necessary to keep in mind that a biosecurity program is a chain of well defined procedures which involves isolation, sanitation, vaccination, auditing and monitoring, and, as it happens with any chain, the biosecurity program is as strong as its weakest link. It is crucial, then, to achieve full commitment of all involved people and this can only be done through continuous education and training. Last but not least, a biosecurity program is not a static plan. In fact, it is a rather dynamic instrument that helps the breeding companies to achieve their goals and therefore it has to be constantly revised and, if it is necessary, updated. REFERENCES References are available upon request.