Barn cleaning more complex than thought

Study shows necrotic enteritis precursor not being managed by sanitation protocols

Recent research findings show that bacteria that can cause the potentially damaging necrotic enteritis is more likely to be present on a barn floor that has been cleaned and sanitized, as opposed to one from which the litter from the previous flock was simply swept clear.

“I don’t exactly know how or why this is happening,” said University of Guelph Associate Professor Michele Guerin, who addressed the annual Poultry Industry Council Health Day in Stratford, presenting as-yet-unpublished results from a study undertaken by one of her PhD candidate students, Chelsea Course.

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Why it matters: Necrotic enteritis consistently ranks among the top disease concerns for poultry producers across North America, particularly for those raising poultry without antibiotics.

The study saw one-metre-square barn floor spaces tested for three different disease-causing bacteria immediately after post-flock litter removal, two days post-cleaning, and six days post-cleaning.

The On-Farm Food Safety Assurance Program of the Chicken Farmers of Ontario (CFO) of guidelines for between-flock clean-out and once-per-year complete sanitation of barns.

For her study, Course did not include built-up litter environments. The 36 sites at which floor swabs were taken included 16 dry cleanings, 17 sanitations, and just three wet cleanings.

Guerin said the sample of wet cleaning sites wasn’t sufficient to provide meaningful results. As well, she said Course learned about a variability in the use of detergent during wet cleaning. If only hot water is used, she noted, there are almost certainly some potentially disease-carrying biofilms, which will not be disturbed during the cleaning event.

When it comes to E. coli — chosen partly because it has potential human health repercussions, but also because it can be a factor in bird health — the study provided clear evidence that sanitation is effective. Of equal importance related to E. coli, Guerin reported, is an ongoing move away from wooden floors in poultry barns, since the study revealed a higher incidence of the bacteria on cleaned and/or sanitized wood as opposed to concrete.

The E. coli findings, though, “tell us that we probably can’t do one-stop shopping when it comes to recommendations for cleaning and sanitation,” Guerin said.

That’s because the findings when it came to C. perfringens, a well-known causal agent for necrotic enteritis, suggested the risk for persistence on the barn floor was highest among sanitized buildings.

One possible reason for this is the unique spore-forming lifecycle of C. perfringens.

“We do know that bacteria can survive in spore form and, after sanitation, it re-infects the new litter,” Guerin said.

If you have a barn that has had problems with C. perfringens and you’re targeting antibiotic-free production, she suggested, maybe consider dry cleaning only.

The implication is that some form of resistance to the bacteria may be persisting in the organic material left behind by dry cleaning. This organic matter effectively “inoculates” the incoming litter material with resistance, thereby protecting the incoming flock.

The concept isn’t new to Poultry Industry Council members. Two of the presenters at the June 25 event came from the southern United States, where built-up litter from one flock to the next is the norm.

Dr. Tim Cummings, a Tennessee-based poultry veterinarian, listed litter acidification and a between-flock downtime of at least two weeks as best management practices when raising birds without antibiotics. But he stressed that producers have found success in what are referred to as “no antibiotics ever” or “antibiotic-free” programs, using built-up litter management.

Dr. Brian Fairchild of the University of Georgia explored strategies for minimizing disease pressure through the management in built-up litter systems of relative humidity and litter moisture — two of the potential drawbacks cited by Canadian poultry sector advocates of the every-flock-cleanout approach.

Cummings and Fairchild both admitted they don’t know enough about Canada’s predominant approach to be sure how built-up litter systems might work for them. But Cummings noted, “this (no antibiotics ever) train is out and it’s rolling down the track, and there ain’t no going back.”

Both also agreed that a failure to control necrotic enteritis is a real risk in committing to not use antibiotics.

Cummings said his early lessons when helping those getting into no-antibiotics-ever production included:

  • Longer between-flock downtime
  • Selecting breeds not characterized by rapid early-life growth
  • Acidification of built-up litter
  • An effective vaccination program that targets every bird
  • Decreased bird density
  • A vegetarian diet
  • Increased brooding temperatures for no-antibiotics-ever production
  • Constant low-intensity lighting as a way of encouraging continuous feeding during the two-to-four-week age range
  • Ensuring water quality is maintained at a high level throughout the water-supply system

Looking at various products aimed at replacing antibiotics, ranging from prebiotics to probiotics to essential oils and minerals, led to a conclusion that there may be some that are effective on a barn-by-barn basis but none that can be recommended on a wide scale.

Instead of reaching for replacement products, he concluded, “it’s coming down to management. A lot of it is.” He paused, then added emphatically in his southern drawl, “Can I get an amen on this? Seriously.”

About the author

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Stew Slater operates a small dairy farm on 150 acres near St. Marys, Ont., and has been writing about rural and agricultural issues since 1999.

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