Analysis of black holes in our knowledge concerning animal health in the organic food production chain

Summary

Although a large body of research on health aspects can be found via the web or in conference proceedings, only few papers reach the peer reviewed literature. This aspect makes it difficult to judge the quality of available data that relate to health aspects associated with organic livestock production.
Many data deal with "on farm case type studies" which often do not lead to a direct relation between certain management procedures and incidence of certain health aspects.
The principle that organic held animals are in better condition concerning their health as compared to conventionally held animals has not yet been proven. Well-controlled studies are needed to show the effects of organically held animals on innate and adaptive immune responses and disease susceptibility.
The conditions in organic livestock production lead to novel challenges concerning social interactions, physical requirements, climatic conditions and infectious burden which requires certain breeds of animals that differ considerably from the conventionally held animals. More research is needed to identify these breeds whereby breeding selection criteria specific to organic conditions and principles should be used.
A number of health problems such as infestation with parasites is an important problem that has been noted in organic livestock (poultry and pig) production and more research is needed to both prevent and treat these infections. Although largely recommended, phytotherapy and homeopathy do not have any demonstrated efficacy in managing helminths. A multidisciplinary approach is needed to address these questions. Investigations should be concerned with aspects such as rotation, stocking density, disinfections strategies, genetic predisposition and novel (plant derived or biological) antihelminthics.
A major drawback in the use of phytotherapeuticals is the lack of good clinical trials, most claims are based on traditional use, anecdotal evidence or extrapolation of human data. Another problem is the consistency/standardisation of the product; variations exist in the levels of "active" ingredients between lots.
Extensive studies have shown that garlic has a beneficial effect on human health and therefore would possibly be a suitable candidate to increase the health of animals in organic production. Further research is needed to substantiate this claim.
Although mastitis is not seen more often in organic dairy production compared to conventional farms, it is still frequently encountered and both basic and applied research concerning prevention and cure without the traditional use of antibiotics is needed.
More knowledge is needed concerning effects of alternative treatments in organic livestock production. As long as alternative treatments have not formally been proven to be effective, allopathic treatments should be preferred. Studies are needed concerning the welfare aspects of disease and insufficient or postponed treatment in organic animal production systems.
It is generally accepted that feather picking and cannibalism is a major problem in organic poultry and more research is needed to counter this unwanted behaviour of the animals. The following aspects including genetic influences, housing environment, feed composition and the presence of external parasites may be involved.
Vaccination has been one of the largest success factors in the prevention of disease in production animals. Most vaccines used nowadays are genetically engineered and should thus carry the GMO label. GMO based vaccines produced by incorporating genetic material from bacteria or viruses into plants is an attractive approach but does not comply with the principles of organic farming. Investigations concerning various vaccination strategies with or without GMO approaches should be evaluated to prevent various infectious diseases in organic livestock production systems.
Organic livestock production leads to an increase or re-emergence of certain zoonotic diseases ( Campylobacter, toxoplasma). This is a serious drawback concerning claims that organic products are healthier as compared to conventional products and research into the prevalence of certain zoonotic infections, risk factors, farm management, post slaughter decontamination and consumer perception/education is badly needed.
Several micro-organisms are described to be present in feeds and could be sources of infections of farm animals. Such pathogens can be either present on the outside of the plant (epiphytes) or on the inside of the plant (endophytes). The incidence of pathogenic bacteria in/on plants used for organic animal feed is not clear and therefore research on the incidence of these pathogens is needed.
Biological cycles such as the utilisation of manure from organic farms may potentially lead to the creation of infectious reservoirs. Research is needed to provide evidence for this hypothesis and strategies should be devised to prevent this problem.
Little is known about the role of pests in the occurrence of disease in organic livestock production. Research is needed into the efficacy of alternative pest control strategies since current pest control methods are not in agreement with organic production principles (use of anticoagulants for rodent control).
The obligatory use of straw bedding in swine household management leads to higher dust and bioareosol (endotoxin) levels in stables. This may affect susceptibility to lung disease (farmer and animal) and investigations concerning measures to reduce dust and bioaerosol levels are needed. Current literature on this subject is not concordant and true differences may exist between management systems from different countries.
Piglet mortality is an important problem in organic production systems and research concerning genetic and housing aspects is currently performed but not yet reported in the peer-reviewed literature.
Amino acid imbalance and research into novel feed sources with high protein content is needed. More knowledge is known concerning possible anti-nutritive factors in these feeds and the effects of these new nutrients on gut health of the animals.
Amino acid imbalance may lead to higher excretion of excess amino acids into the environment. On farm research should be performed to substantiate whether these claims also apply to organic production systems.
It has been suggested that organic feeds for animals in organic production systems may contain higher mycotoxin levels thereby adversely affecting their health status. As yet no conclusive data concerning this issue has been published and research into this area is needed to prove or reject this myth.
As yet it is not known whether phytase levels in organic feed for pigs are sufficient to allow optimal utilisation of organic phosphor thereby also leading to a lower environmental pollution; further investigations are needed in this area.