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Animal welfare and food safety - is there a link? Part 2

By Food Safety Magazine on 19 September 2016

Part 2: Happy animals – the scientists against the activists

There is an ongoing debate about the “organic” or “country-reared” animals. This series looks at research conducted on consumer perceptions and how this correlates to food safety.

Natural animal behaviors and safe food

Animal scientists and consumers often have different notions about what makes for a happy animal. According to many animal scientists in the U.S., high welfare primarily requires a clean, healthy environment where animals are provided with all their physiological needs, are provided adequate shelter and are protected from predators. According to this perspective, there are synergies between animal welfare and food safety, as both can be provided in the same environment.

According to our survey work, roughly 40 percent of Americans agree with this perspective (another 11 percent say they care little about the well-being of farm animals). This leaves 48 percent of Americans who disagree with our depiction of the animal scientists’ view, and believe animals must also be allowed to exhibit natural behaviors if they are to experience high levels of well-being.[9] These behaviors include the ability to move around freely, access to the outdoors and the opportunity to socialize with animals of their species.

Allowing free expression of natural animal behaviors should reduce stress in the animal, and as a consequence may[10] (but may not[11]) reduce the shedding of pathogens.[12] These improvements, however, often come at a cost. Layers raised in a cage-free setting can suffer from injury by other hens, creating stress and even death. Sows moved from a gestation stall into a group pen can now turn around freely, but may turn to encounter an aggressive sow—again, creating stress. We once visited a free-range egg farm where the birds had access to pasture but were continually preyed upon by hawks—this fear would certainly create stress. While there is no guarantee that these improvements are good for animal welfare or food safety, most published research contends that replacing battery cages with cage-free systems (or enhanced cages)[13] and converting gestation stalls to group pens[14] improve animal welfare. And if animal welfare is improved, it is reasonable to believe stress and the shedding of pathogens are lowered—but there are no guarantees. We once talked to an egg farmer raising both caged and cage-free eggs, and his employees would not eat the eggs from the cage-free system, believing the difficulty of identifying and culling sick hens in a cage-free system makes the average egg more risky to eat.

Free range - the answer?

The relationship between animal well-being and food safety becomes more complex when a farm uses a free-range system, where animals have access to both comfortable shelter and the outdoors. Hogs love mud, and mud is rarely sterile. Hogs eagerly root and engage in continuous social interactions. While such a “natural” setting is likely to increase animal well-being in one dimension, it may also make a hog sick, as hogs can more easily come into contact with the feces of other hogs and wildlife, as well as a broad array of worms and other parasites not normally found on a concrete floor. Increased prospects for disease, infection and parasites can turn a happy hog into a sick hog.

One of the original motivations for confining hogs to concrete floors inside buildings (i.e., today’s conventional hog farm) was to separate hogs from parasites and pathogens. Lungworms were once found in at least one-half of hogs in the 1940s, but today the parasite is a rarity. The same can be said for kidney worms. Pork was once thought dangerous to eat if undercooked. The threat was trichinosis—another threat that is today almost nonexistent.[15, 16] Farmers once deliberately raised hogs in the same pastures as cows, knowing hogs would eat undigested grain from cow feces. Chickens would do the same.[17] An egg study found greater Salmonella contamination in free-range eggs, probably due to the easy access rodents have to the chicken feed. Not only do the rodents defecate in the chicken feed, but “mice droppings can be actively sought out by birds when mixed in the feed and or bedding because of their seed-like size and appearance.”[18] However pleasant the small, diversified farm seems, most consumers don’t like to eat animals that ate the feces of other animals. Farmers did not confine animals to cramped cages on hard floors out of malevolence but to reduce parasites and disease. Animal welfare may be compromised by confinement, but animal health is improved, and with it food safety.

Comparing hog health today with 70 years ago isn’t an entirely fair comparison. Given the scientific advancements in animal production since the 1940s, it might be possible to allow hogs outdoor access without the concomitant pathogens and parasites experienced by the 1940 farmer. Yet even today, research finds that hogs given outdoor access experience higher rates of Salmonella, Toxoplasma and Trichinella than hogs on conventional farms.[19, 20] In outdoor systems, Salmonella is spread through sows’ wallowing in the same mudhole,[21] presenting a dilemma for farmers who want to produce safe pork in an outdoor environment.

Free-range systems for layers and broilers face similar problems. Some of these systems confine the birds at night in large cages on wheels, taking the birds to different locations where they may forage naturally. This more “natural” existence, however, brings the birds in contact with the feces of deer, rodents and feral hogs, and because these wild animals can contaminate vegetables with Salmonella,[22] then free-range poultry can be contaminated also. Free-range poultry often share the pasture with cattle, sheep or goats, allowing cross-contamination between species.

Scientists have measured Salmonella prevalence in poultry meat derived from pasture and organic systems, and tend to find the rates are comparable or higher than in conventionally produced poultry meat.[23] Another study tested broiler chickens for Salmonella and found that 60 percent from an organic-free range producer tested positive, leading them to conclude, “Consumers should not assume that free-range or organic conditions will have anything to do with the Salmonella status of the chicken.”[24] While organic meats are generally more contaminated with pathogens, those pathogens are less likely to be resistant to antibiotics, so it is difficult to say whether organic meats are riskier to eat.[25] The point is that one cannot assume organics are safer.

Other articles on the welfare-safety link[26] considered animal treatment before slaughter, so we concentrate on other production stages in this paper. Contrary to other discussions on this issue, we also ignore antibiotic resistance in livestock. There is a widely held notion that animals can be raised in cramped confinement only if they are routinely fed antibiotics to prevent the spread of disease. This does not seem to be the case. Our European contacts testify that the ban on antibiotics in Sweden, Denmark, the United Kingdom and other nations has not altered the production systems used.[27]

References

9. Prickett, R.W., F.B. Norwood and J.L. Lusk. 2010. Consumer preferences for farm animal welfare: results from a telephone survey of U.S. households. Animal Welfare 19:335–347.
10. Gallaway, T.R., J.L. Morrow, T.S. Edrington, K.J. Genovese, S. Dowd, J. Carroll, J.W. Dailey, R.B. Harvey, T.L. Poole, R.C. Anderson and D.J. Nisbet. 2006. Social stress increases fecal shedding of Salmonella Typhimurium by early weaned piglets. Current Issues Intest Microbiol 7:65–72.
11. Brown-Brandl, T.M., E.D. Berry, J.E. Wells, T.M. Arthur and J.A. Nienaber. 2009. Impacts of individual animal response to heat and handling stresses on Escherichia coli and E. coli O157:H7 fecal shedding by feedlot cattle.Foodborne Pathog Dis 6(7):855–864.
12. Rostagno, M. 2009. Can stress in farm animals increase food safety risk? Foodborne Pathog Dis 6(7):767–776.
13. De Mol, R.M., W.G.P. Schouten, E. Evers, H. Drost, H.W.J. Houwers and A.C. Smits. 2006. A computer model for welfare assessment of poultry production systems for laying hens. Netherlands J Ag Sci 54:157–168.
14. Bracke, M.B.M., B.M. Spruijt, J.H.M. Metz and W.G.P. Schouten. 2002. Decision support system for overall welfare assessment in pregnant sows: A model structure and weighting procedure. J Animal Sci 80:1819–1834.
15. Welshans, K. 2011. Modern hog production results in safer pork. Feedstuffs 14.
16. Davies, P.R. 2011. Intensive swine production and pork safety. Foodborne Pathog Dis 8(2), DOI:10.1089/fpd.2010.0717.
17. Davis et al. 1928. Livestock enterprises. Chicago: J.B. Lippincott Company, pp. 284 and 391.
18. Kinde, H., D.H. Read, R.P. Chin, A.A. Bickford, R.L. Walker, A. Ardans, R.E. Breitmeyer, D. Willoughby, H.E. Little, D. Kerr and I.A. Gardner. 1996. Sewage effluent: Likely source of Salmonella enteritidis, phage type 4 infection in a commercial chicken layer flock in southern California: Bacteriologic and epidemiologic findings. Avian Dis 40(3):665–671.
19. It should be noted these outdoor systems also did not receive regular supplements of antibiotics at the subtherapeutic level. Most outdoor production systems do not administer growth hormones or antibiotics to healthy hogs, as being able to label pork “antibiotic-free” and “hormone-free” allows retailers to charge higher premiums.
20. Gebreyes, W.A., P.B. Bahnson, J.A. Funk, J. McKean and P. Patchanee. 2008. Seroprevalence of Trichinella, Toxoplasma and Salmonella in antimicrobial-free and conventional swine production systems. Foodborne Pathog Dis5(2):199–203, DOI: 10.1089/fpd.2007.0071.
21. Callaway, T.R., J.L. Morrow, A.K. Johnson, J.W. Dailey, F.M. Wallace, E.A. Wagstrom, J.J. Mcglone, A.R. Lewis, S.E. Dowd, T.L. Poole, T.S. Edrington, R.C. Anderson, K.J. Genovese, J.A. Byrd, R.B. Harvey and D.J. Nisbet. 2005. Environmental prevalence and persistence of Salmonella spp. in outdoor swine wallows. Foodborne Pathog Dis2(3):264–273.
22. Hanning, I.B., J.D. Nutt and S.C. Ricke. 2009. Salmonellosis outbreaks in the United States due to fresh produce: Sources and potential intervention measures. Foodborne Pathog Dis 6(6), DOI:10.1089/fpd.2008.0232.
23. Melendez, S.N., I. Hanning, J. Han, R. Nayak, A.R. Clement, A. Wooming, P. Hererra, F.T. Jones, S.L. Foley and S.C. Ricke. 2010. Salmonella enterica isolates from pasture-raised poultry exhibit antimicrobial resistance from class I integrons. J Appl Microbiol, DOI:10.1111/j.1365-2672.2010.04825.x.
24. Bailey, J.S. and D.E. Cosby. 2005. Salmonella prevalence in free-range and certified organic chickens. J Food Prot68(11):2451–2453.
25. Van Loo, E.J., W. Alali and S.C. Ricke. 2012. Food safety and organic meats. Ann Rev Food Sci Technol 3:203–225.
26. Voogd, E. 2009. Does animal welfare affect food safety? Food Safety Magazine February/March 42–53.
27. This information is based on an e-mail exchange with Frank Aarestrup, whom we consider the most informed European on antibiotic use in agriculture.

 

Article reproduced with premission from Food Safety Magazine

Source: Food Safety Magazine

 

We would love to hear your thoughts on this in the South African context.


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