The Council for Agricultural Science and Technology (CAST) released a report this morning that says more research needs to be done to determine whether less confinement will lead to healthier animals and greater food safety.
To opponents of confinement agriculture, the benefits of outside systems seem clear. But the six authors, led by Scott Hurd of Iowa State University, say less confinement does not automatically mean healthier animals.
"Increased exposure to the soil and vermin may increase the prevalence of zoonotic diseases in livestock," say the authors. For example, open water troughs can lead to salmonella contamination from bird droppings while nipple waterers prevent this type of contamination. Dairy cattle housed outside can have greater levels of environmental mastitis during periods of wet weather and muddy conditions.
The authors report other examples as well. "Internal parasite loads also are decreased with the use of slatted or mesh floors (Moncol 1993). Hurd and colleagues (2003) observed that swine held in abattoirs (two to four hours) on slatted floors had a lower prevalence of Salmonella compared with swine maintained on solid floors for the same period of time."
The report concludes more work needs to be done:
• Research is necessary on the frequency of these subclinical or "not visibly ill conditions" during harvest of pork, beef, and poultry.
• Data are needed on the correlation of these "not visibly ill conditions" during harvest and the actual contamination related to the conditions to assist in determining if anything can be done prior to slaughter to prevent these concerns.
• Research on nutrient regulation of gene expression will bring forth new improvements in efficient animal production and health.
• Ecological studies and quantitative risk assessments on the role of low-dose antibiotic use in food-producing animals and human health are needed.
• More information is necessary regarding the effects of production practices perceived to be more humane, such as free range and outdoor production, on zoonotic and foodborne pathogen load and persistence, as well as presence of internal parasites.
• The possible changes leading to the adoption of less restrictive animal housing systems will require investment in research efforts to find ways of ensuring high standards of welfare but also maximizing animal health.
• Examination of the unintended consequences of changes to current production practices without thorough scientific research and risk analysis is needed.