Is the poultry industry making the most of its data?

Investing in research and development is usually seen as key for economic growth, and the poultry industry is no exception to this. But investment in research is of little value if that research is not properly conducted, or if the results are not properly communicated or acted upon.

Investing in research and development is usually seen as key for economic growth, and the poultry industry is no exception to this. But investment in research is of little value if that research is not properly conducted or if the results are not properly communicated or acted upon.

Examples of how the poultry industry could make more of knowledge gathering and dissemination -- and consequently, improve profitability -- were evident at the 18th World Veterinary Poultry Association Congress, held in September in Nantes, France.

Making the most of epidemiology?

The role of epidemiology in the poultry industry and how it could further benefit the sector was examined by Jean-Pierre Vaillancourt of the University of Montreal veterinary medicine faculty.

The characteristics of the methodologies associated with epidemiology make it particularly suited to problem solve in large populations, such as the poultry industry, noted Vaillancourt. However, the poultry industry fails to make full use of its potential, he argued, and even when epidemiological studies are conducted, their results are not always considered in the field. Additionally, those studies carried out are often restricted to well-known diseases.

Numerous epidemiological studies have been conducted for some poultry diseases, yet there are few publications showing how identified risk factors have been successfully acted upon. An example would be coliform cellulitis, where despite studies having first been carried out in the late 1980s, a literature review of the last 20 years revealed nothing on interventions based on risk factor studies to reduce its prevalence.

Recent research on the condition has focused on the agent Escherichia coli and on developing a vaccine. In other words, why make changes to environmental factors if a "silver bullet" can be developed?

Epidemiologic studies can generate practical and timely solutions, but if this is not recognized by decision makers, their relevance to the poultry industry may be greatly reduced. What makes the situation still more difficult is that when literature on biosecurity intervention strategies is published, it is not always of sufficient quality.

Data collection is now easier than ever, but data must be valid. In answering questionnaires, for example, respondents may guess or select the most likely response; therefore response bias is an important consideration in analysis. Additionally, Vaillancourt noted the importance of proper wording in questionnaires and emphasized that clear definitions must be part of a well-designed questionnaire to aid proper understanding.

 

Vaillancourt went on to say that while the output of epidemiologic studies from Asia and Africa can be applauded, the number of studies coming from North America is questionable.

In countries with large, integrated poultry producers, it is often difficult to access data for publication, as epidemiologic work conducted in these integrated poultry businesses may be deemed proprietary and not shared. Yet an integrated environment could be seen as the ideal setting for assessment. Even so, when a large body of data is available, epidemiological and biostatistical methods are not always part of the analytical process.

The need to share

Confidentiality is a sensitive issue. Being suspected of having a diseased flock may be enough to affect exports and agreements, but silence has been shown to be more costly. Although liability will always be a concern, pointing fingers is not an effective disease control strategy, and poultry organizations sharing a region must also share information to prevent and contain contagious diseases. In some states, poultry organizations have worked with local government bodies to form agreements for information exchange and have benefitted from the results, but this is not the case universally.

Applicable to more than major poultry diseases

In addition to the failure to make the most of epidemiology for major diseases, Vaillancourt argued that there are numerous poultry health issues where epidemiology could be successfully used, including non-infectious conditions and syndromes, yet its value is still not recognized. There are also syndromes of infectious origin that are poorly understood and where epidemiologic studies could aid problem-solving.

Yet the potential need for epidemiologic work in the poultry industry may be greater now than ever. Given the slow approval process for veterinary medicines, the poultry industry may have to increasingly focus on environmental problems. New strategies in this area would require more technical applications and appropriate monitoring to succeed.

Poultry welfare, fact and fiction

Werner Bessei, of the University of Hohenheim, Germany, looked at the issue of poultry welfare in Europe and how decisions have often been made in response to emotion, not scientific evidence. He further noted that there are instances where understanding has not been properly or is incompletely applied.

There is no doubt, he said, that the development of legislation governing poultry production and management systems in Europe over recent decades has been driven by subjective feelings rather than rational and scientific thinking.

From the start of the welfare debate, scientists with veterinary, biological and zootechnical backgrounds tried to define welfare on scientific principles. It was thought that these principles would win against emotional arguments, leading to generally accepted animal husbandry systems. This has proved not to be the case.

Space allowances for layers

In Europe, space for layers was the main welfare issue from the 1960s to the late 1990s. In 1999, an EU directive set an increase in space from 450 cm2 in conventional cages to 750 cm2 in enriched cages. In Germany, however, this was set at 890 cm2. A number of other countries, such as Austria and Switzerland, rejected the new minimum space allowance and did not allow enriched cages. A ban on enriched cages is being considered in Germany. 

Making evidence known

Numerous studies have looked at the effect of stocking densities on layers, and there is little evidence to suggest that increasing the space above the range mentioned has a significant impact on welfare and related criteria.

When comparing the behavior of hens in conventional cages and more spacious floor pens, there were no signs of frustration with the exception of pre-laying unrest. This has been confirmed by a large-scale comparative study of conventional cages, deep litter and free-range systems. Additionally, most studies on physiological stress have not found a higher level of stress in caged versus pen-kept hens. This was recently confirmed when conventional cages, enriched cages and deep litter systems were compared.

The increase in space requirements for laying hens in the EU, and the individual bans on enriched cages were based on politics and public opinion rather than on scientific results.

Identifying the real cause and effect

Space allowance for broilers is also regulated in the EU. As with layers, in some countries, maximum stocking numbers are lower than those prescribed at an EU level.

It has been assumed that high stocking density is a major cause of welfare problems, such as hock burns, foot pad dermatitis and problems with walking and resting. There are, however, a number of studies where there was no significant relationship between stocking density and welfare, including behavior, leg problems and skin damage.

Inconsistent and conflicting results have been reported for physiological response and stress due to stocking density. In contrast to the variable response of behavior, morphology and physiology to stocking density, there is a well-documented and consistent effect on stocking density on growth rate.

Under deep litter conditions, growth rate is significantly reduced as stocking density exceeds about 30 kg per square meter of live weight. The effect on growth, however, was lessened when ventilation was increased or when broilers were raised on perforated flooring. The increase in litter temperature has been identified as the causal factor in this reduced growth rate.

In some cases, increasing stocking density depressed feed conversion and increased mortality; however, this was not common across studies. The negative influences of stocking density on productivity can result in a lower return on feed cost per bird. However, when the financial return is calculated on a flock basis, there is a linear increase, even though growth rate and feed conversion are depressed and mortality is increased.

Enriched cages

It is generally accepted that animals depend on external stimuli for normal physiological and behavioral development. There is, however, no information on how much stimulation is required to allow the normal development of farm animals. It is assumed the natural habitat represents an adequate level of stimulation in quantity and quality.

Intensive husbandry systems cannot provide the stimuli of the natural habitat, and it is often assumed that environmentally restricted conditions are the cause of undesirable behaviors such as cannibalism and pecking.

 

It has been assumed that environmental conditions that provide opportunities for pecking, through the provision of a variety of objects, for example, would further reduce feather pecking and cannibalism. The beneficial effect of litter and other enrichment objects on feather pecking and cannibalism has been found in many experiments; however, it has not been possible to confirm this by empirical studies. It is obvious that the availability of litter to peck is only one of a multitude of causal factors for this behavior.

The basic problem of enrichment is that environmental stimuli are perceived as incentives only when there is an added value. Birds adapt to the quantity and quality of environmental stimuli. Only change in stimulation is perceived as an incentive, and this improves subjective welfare. Therefore, temporary presentations of enrichment materials may have a more beneficial effect on the behavior and welfare than continuous exposure of the birds to a rich environment.

Page 1 of 358
Next Page