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5 May 2006 00:00:00 |Poultry Husbandry

Prevention and Treatment of Disease in Organic Flocks

There is an increasing interest in organic poultry production and the following article looks at some of the issues raised in Section 5 of the EU Council Directive 1804/1999 and more recently the proposals by UKROFS regarding disease prevention, veterinary treatment and husbandry practices in organic production. The EU regulations set the minimum standards for organic livestock production with which member states must comply. It emphasises the need to adopt a preventive strategy for the control of health and disease and puts restrictions on the number of allopathic treatments permitted. UKROFS standards have added to this the requirement for a plan agreed between the farmer and a nominated veterinary surgeon ensuring the proper control of disease and the encouragement of positive welfare.
Disease is defined as an unhealthy state of body or mind. The prevention of disease is essential to all livestock husbandry and is of paramount importance in organic systems. Health in farm animals is not simply the absence of disease but also the ability to resist infection, parasitic attack and metabolic disorders, as well as the ability to overcome injury by rapid healing.
Section 5.1.
General principles, including:
· Suitable breed/strains of poultry of a particular production system.
· Husbandry practice to encourage disease resistance and health.
· High quality feed.
· Regular exercise and access to pasture.
· Avoiding overstocking
How do these principles apply in the rearing period?
We need:
· An appropriate hardy, robust strain of bird.
· Good nutrition (in the parent flock and for the chick) for optimum immune system function.
· Exercise encouraged by the use of A frames and perches.
· Low stocking density.
· Access to pasture?
Access to pasture in rear is not common practice in commercial pullet rearing. If we were to adopt this system, possible benefits would be:
· Birds would be encouraged to roam and, thus, more likely to roam and use pasture in lay.
· Fresh air and sunlight for the birds beneficial to health.
· Access to vegetation, insects, worms etc, perhaps a more natural diet.
· Birds get used to the sights and sounds outdoors and may be more calm and "bombproof" on the laying site.
· Birds will be more occupied and less likely to be bored.
Possible drawbacks of access to pasture in rear would include:
· Adverse weather conditions.
· Risk of exposure to bacterial, viral and parasitic diseases from pasture and from wild birds and vermin.
· Predators.
· Difficulty in controlling the light programme prior to the move to the laying site, particularly in the summer.
Section 5.2.
This states that the principles set out in 5.1 should limit animal health problems so that they can be controlled mainly by prevention without the need for treatment. Resistance to disease during the birds’ lifetime is very much dependent on the bird developing immunity to the disease problems it may encounter. In theory, natural exposure to a range of infectious agents and parasites in rear will allow the healthy bird to develop its own immunity to these disease without the need to use vaccines. In practice, this may prove difficult. If we are rearing birds in a very clean, hygienic environment, this is good in many ways but the young bird may not meet a very wide range of infectious agents and does not have the opportunity to develop a broad immunity or perhaps a fully functioning immune system and may be vulnerable to these infections later in life. The problem is to strike a balance. If the environment is too "dirty" for the birds there is a risk of:
· Infection with pathogenic bacteria or bacteria of public health significance such as Salmonella or Campylobacter.
· Heavy early bacterial or viral challenge may lead to mortality problems or stunting and uneveness.
· Early heavy coccidial challenge may lead to mortality and uneveness and early viral challenge may lead to high mortality or permanent damage to the bird, for example, IB affecting the oviduct.
If we were to use no vaccines in the rearing period, we would return to a state where we might see very high mortality due to viral challenge, for example:
· Gumboro disease, up to 80% mortality.
· Mareks disease, up to 40% mortality during the life of the flock.
· IB, high mortality, chronic respiratory disease, chronic damage to kidneys or oviducts.
· Newcastle disease, high mortality, production problems if the flock affected in lay.
Section 5.3.
This states that if, despite preventive measures, animals become sick or injured, they must be treated immediately, if necessary in isolation and in suitable housing. If chickens are removed from the main flock, it may sometimes be difficult to replace them as the flock may not accept the returned strange bird and may bully it possibly triggering an outbreak of cannibalism/pecking.
Section 5.4a.
This covers the use of veterinary medicinal products. Phytotherapeutic, homeopathic and trace elements shall be used in preference to chemically synthesised allopathic veterinary medicinal products or antibiotics provided that their therapeutic effect is effective for the species and condition for which intended. We do not always have much information as to the efficacy of plant herbal and homeopathic remedies and more information is required on these treatments. Allopathy is the treatment of disease using drugs whose effect on the body is opposite to that of the disease as opposed to homeopathy where the treatment is the same as the disease entity, ie treating like with like. As regards to other treatments, antibiotics, wormers and anticoccidial drugs, it is likely these would be considered chemically synthesised allopathic medicines and are restricted in use.
Section 5.4b.
This states that if the use of products as in Section 5.4a should not prove effective in combating illness and treatment is essential to avoid suffering or distress to the animal, chemically synthesised allopathic veterinary medicinal products or antibiotics may be used under the responsibility of a veterinarian. This suggests that treatments are permitted on welfare grounds if directed by a vet. Organic farmers may need approval from certification body before treatment can be allowed.
Section 5.4c.
This states that the use of chemically synthesised allopathic veterinary medicinal products or antibiotics for preventive treatment is prohibited. This should still allow the use of vaccines as a preventive programme and UKROFS will permit vaccination where there is a known disease risk. However, they suggest where possible, there should be a progressive reduction in their use as the organic unit becomes established.
Section 5.6.
This section details the information to be recorded by the farmer when veterinary medicinal products are used. The information is to be declared to the inspection authority or body before the livestock or livestock products are marketed as organically produced.
Section 5.7.
This states that the withdrawal period between the last administration of an allopathic veterinary medicinal product and the production of organically produced foodstuffs from such animals is to be twice the legal withdrawal period or, in a case in which this period is not specified, 48 hours.
Section 5.8.
This section states that flocks receiving "more than two or a maximum of three" courses of treatment with chemically synthesised allopathic veterinary medicinal products or antibiotics within one year will lose their organic status under the regulations.
How should we be looking to prevent disease in our organic flocks?
Prevention of viral disease
· Vaccination - Mareks disease, Newcastle disease, IB, Gumboro and other vaccinations as required. The vaccination programme may be tailored to control known problems on


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