Biosecurity increasingly gains importance for the health management of poultry flock. It includes all measures to prevent pathogens from entering the flock and to reduce the spread of pathogens within the flock in order to keep the birds healthy and also to limit the spread of pathogens to the environment. Biosecurity can be divided into 3 different tiers or levels: the conceptual, structural and operation biosecurity. The conceptual biosecurity mostly deals with planning; structural biosecurity deals with measures which prevent pathogens entering the farms physically while operational biosecurity is related to reduce the within-farm spread of pathogens. Therefore it needs careful identification of gaps in each of the level of management practices. Hence the Biosecurity measures in each farm should be audited frequently for compliance to new situation as there is always the risk of new, emerging diseases entering our country that may circumvent our current biosecurity recommendations. And therefore a good evaluation of biosecurity system is required. More often we assess farm biosecurity mostly based on checklist that is based on qualitative basis mostly identify either presence or absence of indicators. Thus qualitative assessment identifies gap in general where quantitative assessment gives more insight of the assessment. A quantitative biosecurity tools is available for pig herd (Dewulf, 2012) or even poultry cluster elsewhere (Wei et al., 2012). No such quantitative risk assessment system is available in Bangladesh situation for commercial poultry farms. This study, therefore attempted to develop a quantitative biosecurity system and assess the bio-security status of middle scale poultry farms in few selected areas of Bangladesh.
Development of biosecurity score form and validation
The study used a simple biosecurity score form which was developed in accordance with the information about the biosecurity system of FAO (2007), Wei and Aengwanich (2012), biosecurity protocol of Bangladesh and beginning with a survey of the actual details about biosecurity system of the poultry farms. The score form was presented to few poultry experts and their suggestions were incorporated. The score form incorporated the indicators of conceptual, structural and operational biosecurity. In scoring system, more emphasis was given to the indicators that directly influence the transmission of pathogenic organism. Most of the indicators have been allocated scores 0, 1 and 2 by experts’ opinion. There are several indicators that have a broader range of scores. The higher score indicates the better biosecurity status. The scores for each conceptual, structural and operational were counted for 55, 50 and 53, respectively and calculated to 100% individually. The status of biosecurity of a poultry farm was ranked as >80 % very good, 60 – 79 % = Good, 50- 59% weak, <50% minimum. The scoring system was validated in 27 FAO demo and adapter poultry farms in Sirajganj, Joypurhat, Kurigram, Nilfamari, Mymensingh, Rajbari, Jessore and Gopalganj districts of Bangladesh. The data were collected by visual inspection of the farms and by interviewing the farmers. The indicators and its value were finalized after further consultation with eminent poultry veterinarian of the country, as well as key informant interview and experiences of the farm visits.
Results and discussion
Conceptual biosecurity occupies apex of the biosecurity triangle. The farmer has no real control over the location of his poultry farm and usually he cannot change it once it is built. Therefore, any mistakes in the conceptual biosecurity cannot be corrected ever. Afterwards it is difficult to maintain the operational biosecurity of the farm. Several poultry pathogens can be transmitted through the air. Poultry density in the vicinity of the farm is an important factor for those pathogens as transmission is density dependent. To reduce the likelihood of air borne transmission between poultry farms, the distance to nearest poultry farm should be at least 200m. When poultry farms are close to each other, care should be given to the predominant direction of wind. Not only industrial poultry but also backyard poultry can pose threat. Besides, vicinity to public road, place, vicinity to a dumping ground, bazaar, etc can pose risk for the introduction of pathogens via air. Therefore, score form was developed in accordance with the biosecurity protocol of Bangladesh and importance of the factors influence the biosecurity (Table 1).
Most of the demo and adapter farms scored <60% number. However these farms were constrained with household and their backyard chickens. Other factors like distance from the main road, absence of public places, direction of sheds etc helped these farms for getting conceptually good status (<60%). Our biosecurity assessment tool identified its constraint backyard poultry which is a potential source of virus exchange between commercial poultry and wild birds (Wang et al., 2013) and thus needs careful surveillance always.
Table 1. Indicators and definition of biosecurity score in conceptual level
Usually disease causing organisms enters into the farms through infected-, carrier-, reservoir birds, mechanical and biological vectors, humans, wild or domestic animals, equipments, vehicle etc. Structural biosecurity serves as primary barrier of the farm against all these elements. It provides healthy environment to the birds in the farm to live. Based on these factors a scoring system for the structural biosecurity was developed (Table 2) and structural biosecurity of all demo and adapter farms of FAO, Bangladesh was reviewed. Structurally all demo layer and broiler farms were very poor, mostly had nothing but shed/s and scored > 40%. All of the farms were constrained with poor structure in farm and shed gate for poor access management, poor in feed-, waste- and sick bird management. This may indicate that pathogens can gain easy access to these farms via different vertebrate vectors, carrier etc. Good structural biosecurity provides good environment for the productivity. Improper environment reduces the chickens’ defenses, making them more vulnerable to diseases (Talukder et al., 2010).
Table 2. Indicators and definition of biosecurity score at structural level
Operational biosecurity includes day to day management and routine procedures intended to prevent introduction and spread of infection within poultry farm premises and to the environment. The following measures should be considered as important in operational biosecurity 1) Traffic control involves both human and vehicle and equipment movement 2) Sanitation and disinfection; the systems that protect health especially those dispose efficiently of wastes. Sanitation includes everything the birds come into contact with pathogens either directly or indirectly 3) Rodent and wild bird control 4) Health monitoring and vaccination and medication. Based on these risk factors, a scoring system for the assessment of operational biosecurity of a poultry farm was developed (Table 3). Operational biosecurity of nine demo farms and nine adapter farms of FAO were reviewed. All farms revealed minimal operational biosecurity, scored <50%. All of these were constrained with poor or no- hand hygiene practices, waste management and sanitation. Poultry farm sanitation plays pivotal role in control and prevention of harmful poultry diseases (Watkins et al, 1999, Pardeshi et al., 2011). A good hand hygiene practices has enormous effect on the control of harmful diseases and productivity.
Table 3. Indicators and definition of biosecurity score at operational level
The farms surveyed in this study revealed very poor structural and operational biosecurity scores which made these farms vulnerable to various infectious diseases. Spread of diseases due to poor biosecurity results in higher chicken mortality and reduces productivity (Shane 1997, Sahin et al., 2006). During our survey it was found that eight of the 27 farms were empty due to frequent outbreaks of Mycoplasma, E. coli, Coccidia etc. The higher incidence of diseases in these farms correlates with the low biosecurity scores calculated using our developed biosecurity scoring tool. These findings underscore good utility of this tool.
This study has developed a scoring tool for the quantitative evaluation of biosecurity of commercial poultry farms. The system could identify the biosecurity status as well as biosecurity gap/s present in the farm. The scoring system includes very simple calculation which could help the veterinarian and eventually farmer to identify the gap/s as well as to implement the biosecurity measures in the farm.
Presented at the 9th International Poultry Show and seminar, Feb 19 -21, 2015, Dhaka, Bangladesh.
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