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Use of a simple “causal” pie chart is proving to be a helpful tool for controlling necrotic enteritis (NE), Joel L. Cline, DVM, a veterinarian with Wayne Farms, told Poultry Health Today.







Cline uses

the causal pie as a visual to help poultry farmers and managers understand the many factors that can lead to NE. He has found that, in turn, managers have found the chart useful for educating their employees about NE.  







He learned about the pie chart from a student riding with him, Cline noted.  He thought she’d made it up, but when he went home and searched for it on the Internet, he found “it’s a real thing that epidemiologists use to describe and understand diseases that have many

contributing factors.”







The first

slice of pie Cline puts on an NE chart is Clostridium perfringens. “That’s the piece of the pie you have to have...and maybe when we pull the antibiotics, that piece gets larger. It fills in more of the pie because we don’t control that Clostridium as well or maybe it’s there, but we just don’t make it behave like we do with antibiotics,” he said.







Coccidiosis — an important piece of the pie







Coccidiosis is another important piece of the pie. “You can have necrotic enteritis without coccidia, but for us it’s usually there and it’s usually a contributing factor,” he continued.







There are many other factors that can contribute to NE ranging from vaccination programs to a flock’s immune status to litter management or how drinkers and feed ingredients are managed. Pieces of the pie may differ for different farms.







Cline

acknowledged that not all contributing factors can be controlled, but he emphasizes

managing those that can be moderated.







“We formulate our management processes for any issue we think might be contributing to necrotic enteritis. And then we put programs in place to manage each of those issues, and we go back and check to make sure we’re doing what we think we’re doing...” Cline said.







Making progress







Wayne Farms is now raising a significant portion of its flocks without antibiotics. Cline indicated that while it’s been challenging, “I think we’re making progress.” He also thinks that the experience has made him a better veterinarian.







Antibiotics were a “kind of crutch,” and with that taken away, the hatcheries are cleaner and there’s a better understanding of what’s going on in the intestines. “It’s given me a deeper knowledge, and I just think it’s helped me learn to pay attention to the details better,” he said.







Using coccidiosis as an example, Cline said, “If we’re vaccinating, it’s how we handle the vaccine. The right temperatures...how we apply the vaccine. It’s how [we manage] exposure in the field, turn-out times, things like that. Just managing those tightly. If we’re using coccidiostats…it’s how we apply those, how we rotate, making sure we have in the feed what we think we have in the feed and just managing all those small parts more closely.”

A new label under development for meat and poultry products will represent production that seeks a balanced approach to poultry production and marketing — one that ensures good health and welfare for the chickens while demonstrating responsible antibiotic usage under veterinary oversight to consumers, Don Ritter, DVM, director of technical marketing, Mountaire Farms, told Poultry Health Today.



Called One Health Certified, the new USDA Agricultural Marketing Service (USDA-AMS)-certified label is in part a response to arbitrary standards in production criteria, such as prohibiting the use of antibiotics to prevent, control or treat disease.



Ritter believes the supply chain from “no antibiotics ever” (NAE) production systems is not predictable nor sustainable. When the focus is only on never using antibiotics, the health of the animal suffers. There may be increased mortality. Those that survive require more feed and take longer to get to market, and the environment suffers too.

Okay but outdated

At the other end of the spectrum is what’s often referred to as “conventional” production, where veterinarians have the option of using all FDA-approved antibiotics for managing poultry diseases.  This approach to production has declined in recent years as poultry companies have sought to meet increasing consumer demand for chickens raised without antibiotics.



The One Health Certified label advocates responsible use of antibiotics, where needed, while giving consumers an audited, transparent program built upon five core pillars: biosecurity, veterinary care, antibiotic stewardship, animal welfare and environmental measurements.



The program has “action thresholds,” which make it unique, Ritter continued. For instance, when the health status of an animal group changes, actions are required. If it’s a disease process, there has to be veterinary involvement within 24 hours, and animals are properly taken care of. Everything is documented.



There are similar but not identical guidelines for all species. “I see it as an umbrella program…over the multiple protein classes,” he said.

Sustainable, practical

Nothing will fall through the cracks in this system, Ritter maintained, but he acknowledged it will require poultry companies to provide documentation about production practices.



The program is intended to avoid extra costs for consumers and has options that make it sustainable and practical, Ritter said. Mandating extreme practices for the entire supply chain that raise the cost of food takes away choice from people who don't have resources.



Consumer research with about 1,000 people has indicated that 83% would buy products with the One Health Certified label. Respondents said they most valued veterinary care and want animals taken care of, he said.

Saturated NAE market

Asked if the trend toward NAE production can ever be reversed, considering it now accounts for over 50% of the US poultry market, Ritter said, “To me, gravity is a very powerful force, and I really do think the pendulum swung a little too far...” when that much of production became NAE.



Even though over 50% of chickens are produced now in NAE systems, NAE chicken meat accounts for only 10% of pounds sold, Ritter noted. NAE producers are selling 20% of their meat labeled as NAE and they’re getting a premium, but the meat is more expensive because producers have to recover the cost of running that type of production system. That premium is being eroded as this segment of the market becomes saturated, he said.



One Health Certified, which has been designed by a coalition that includes animal agriculture, nonprofit groups and university scientists, will require education and supportive messaging. The goal is to get it through the USDA-AMS auditing process and launch a website.

More young people need to be encouraged to take up careers in poultry science if the sector is to properly tackle disease challenges which have plagued it for decades, according to a leading academic.



Oscar Fletcher, DVM, PhD, professor of poultry health management at North Carolina State University, said he is concerned that over his 50-year career in poultry science and academia, diseases such as coccidiosis and histomoniasis continue to be a problem for producers.



And without new people coming into the industry to study and find ways to manage the diseases, he fears they could continue to pose significant problems for producers for years to come.



Speaking to Poultry Health Today, Fletcher said the biggest question for him in the future of poultry disease control is whether there is enough scientific manpower to deal with the issues the poultry industry faces.



“I would argue that we don’t,” he said. “And even though I’m [working] in a place that’s engaged in producing some of those people, I still have concerns that we don’t have as many scientists working worldwide to solve some of these problems.”



To tackle the issue, Fletcher said universities need to do more to help students recognize that poultry science can offer interesting and rewarding careers.



“What we’re doing in our institution is looking to attract students that have been pre-veterinary students at an undergraduate level and have done that work in poultry science,” he said.



“So they already come to us with an interest in poultry, and we work hard to keep them interested.”



Looking at the changes over his career — which includes stints teaching at the University of Georgia and North Carolina State, as well as 15 years as dean of both Iowa State University’s and North Carolina State’s veterinary colleges — Fletcher said while the diseases he is seeing haven’t necessarily changed, birds’ responses to them have.



“Viral tenosynovitis is an example where the agent was the same…but the clinical presentation and the histopathology were very different” over the years, he said.



To help students manage change, he said he is focusing on teaching them to recognize basic bird health responses, as well as what’s in the bird that shouldn’t be there.



“In most cases we’re looking for things that are not bird, such as bacteria, fungi, protozoa and other parasites,” he said.



“So my basic approach to teaching was to make it less focused on recognizing specific diseases up front, and get focused on how do you recognize what a birds telling you? What’s the response to injury?



“And once you do that, you can begin to figure out what might be causing those responses.”



With data making it easier to monitor and diagnose diseases faster than ever before, and consumer demand for poultry products remaining strong, Fletcher said there was much to be positive about in the poultry sector — particularly for producers.



“Keep utilizing your diagnostic laboratories and your veterinary pathologists and keep hiring the best people that you can find,” he added. “And keep attuned to what the consumer issues are.



“You're producing protein at a relatively low cost to feed a lot of people. So, you're having an impact worldwide and you need to keep up that good work.”



 

Food safety challenges linked to Salmonella could be tackled more effectively by better understanding the sex life of bacteria, according to a leading US government veterinarian.

Researchers have known for some time that Salmonella and other bacteria have a sexual form of reproduction called homologous recombination.

However it seems the process, which sees bacteria swap sections of their chromosome with each other and ultimately create hybrid strains, could be much more common than initially believed.

Jean Guard, DVM, PhD, veterinary medical officer at the US Department of Agriculture’s Agricultural Research Service, said the development of diagnostic techniques and genome databases has led scientists to discover strains of Salmonella which don’t fit traditional bacterial categories.

By studying cellular differentiation — in other words, how bacteria cells change shape — she and her team have realized there are “worker” and “queen” bacteria, similar to bees in a hive.

And while the worker bacteria reproduce through binary fission, the queens have the potential to swap sections of genomes in a form of bacterial sex to produce new strains and new workers.

Speaking to Poultry Health Today at the American Association of Avian Pathologists conference, Guard said there are only a small number of queen bacteria in a bacterial population, which is why they have so far evaded detection.

Their low numbers also make it difficult to identify where hybrid Salmonella strains originate from, making it an important area for future research.

“We’re excellent at detecting workers which are out there infecting us, but what we’re not good at is recognizing the origin of all these new strains,” she said.

“So I feel like we’re caught in a cycle where we’re seeing Salmonella expand at certain times through the food safety system… but there has to be a cycle of chromosomal repair as all those workers get damaged and accumulate mutations.

“So what we’re not really figuring out is how does Salmonella repeat the repair of its chromosome to keep coming back around and around. And that’s a cycle I want to break.”

To take control of Salmonella — outbreaks of which haven’t shown any signs of reducing in humans over the past 15 years — Guard said more testing is needed across the food production system to identify the “oddball” bacteria that could be the source of hybrid strains.

“On farm and in the processing plant, what I would be looking for is areas that may be producing a variety of Salmonella serotypes,” she explained. “Where are you seeing unusual clusters of multiple serotypes emerging? Because that’s probably your nest.”

While the majority of these newcomer strains don’t survive, it just needs one hybrid to match with its environment before the bacteria can begin clonal expansion, she added.

On top of increased testing throughout the food chain, Guard also stressed the need to teach consumers about how to handle food properly.

“We can do everything that we do, and at the end of the day if the consumer doesn't handle the product correctly, then they are adding to the problem. So education is always an important part of this picture.”

An unusual presentation of bacterial septicemia in broilers underscores the importance of obtaining a good history and obtaining input from bird caretakers, David French, DVM, a staff veterinarian with Sanderson Farms, told Poultry Health Today.



Broilers in two of the company’s divisions started getting sick at 35 to 40 days of age. There were respiratory signs as well as severe fibrin production in the abdominal cavity, particularly around the heart. “They had a pericarditis, a perihepatitis and a polyserositis that was so dramatic that visiting veterinarians were grabbing their cameras to get pictures of it,” French said.



The company’s two divisions are about 120 miles apart, and no connection to the problem could be found regarding movement of birds, people or other epidemiological factors. Two of the breeder flocks were up in age, but another was not, French noted.



One company division, however, recognized immediately that the problem was linked to broiler breeder flocks. The other division did not think breeders were the source and thought a short downtime, which can increase the disease challenge, was involved, he said.

‘Got our attention’

“It doesn’t make sense for a bacteria that comes from a breeder flock to not kill chicks in the first week of age but to kill them later at 35 to 40 [days]. So that was the thing that made it unique, and that's what got our attention,” he said.



Testing was conducted for a long list of viral diseases. In one of the breeder flocks, infectious bursal disease was thought to be involved but wasn’t found in the other two breeder flocks.



In about 14% to 25% of cases, however, Enterococcus cecorum was found. No definitive diagnosis was made, but it was on the list of highly suspicious organisms.  E. cecorum is usually associated with spinal abscess, leading to leg paralysis. “But we didn't see that in these birds. It was a totally different picture. It was more of a respiratory presentation,” French continued.



Treatment with oxytetracycline of birds in all affected houses and breeder flocks was successful. “In fact, I did not have a case where I had to treat a specific house that was breaking that didn't respond to oxytetracycline,” he said.



French added that in unique cases such as these, it takes asking the right questions and epidemiology to lead toward an approach to solving the problem. “I think that history is critically important. And gaining input from the locals that are dealing with the disease and putting together your epidemiological strategy...is critical.”



 

Taking a closer look at why incidence of Salmonella and Campylobacter varied widely on farms in the same production system helped to demonstrate the importance of management and communication with growers, Bruce Stewart-Brown, DVM, senior vice president, food safety, quality and live production, Perdue Farms, told Poultry Health Today.

In a study of 150 farms over the course of 2 years, Perdue found that for Salmonella, some farms rarely had any, some had a lot and others were in the middle with inconsistent patterns. The company noted similar trends with Campylobacter.

“These are [birds from] the same breeder flocks [and] the same breeds, the same feed, coming from the same hatchery, yet they turn out differently” when analyzed for foodborne pathogen trends. “So, there's something about the farm that's significant,” Stewart-Brown said.

Fusing NAE, food safety

Perdue, which has been at the forefront of “no antibiotics ever” (NAE) production, has found that managing the flock environment is critical for reducing levels of all bacteria, including Salmonella and Campylobacter. 

Houses need to have dry litter with good air quality, Stewart-Brown said. Chickens also need ample space to minimize the buildup of pathogens in the litter. 

Good paw quality is especially important, he continued, because it correlates with dry litter and the presence of foodborne pathogens.  “Bacteria such as Salmonella and Campylobacter are inhibited or reduced in really dry-litter flocks.”

Still, there are differences in the presence of these bacterial organisms. A house with a low prevalence of Salmonella, for instance, doesn’t necessarily have a low prevalence of Campylobacter, Stewart-Brown noted.  Likewise, some live-side interventions are effective against both pathogens but not always. One similarity is that both pathogens dislike dry litter. The same holds true for Escherichia coli.

Perdue has also found that smaller farms tend to have less bacteria, but Stewart-Brown thinks that has more to do with fewer personnel. “It probably wasn't the size of the farm as much as the number of people working within the context of the number of chickens.” Some big farms are very well-managed and would be in the low range for Salmonella, but it depends on how many people help them and how well their workers are trained.

Scores farms

Stewart-Brown thinks a farm’s bacterial load is directly related to biosecurity and the level of farm management.  He said contract farmers need to understand how they can make a difference in flock health and food safety. Toward that end, Perdue created a biosecurity risk-assessment score, which involves posting a number on the barn wall. “And that risk has to do with food-safety organisms as well,” the veterinarian continued.

“One of the things we found is that whenever you give a farmer a score, now you have a little bit of their attention,” Stewart-Brown said. If their number is high, the farmer won’t like having a bad score and will want to know what made the score high. Conversely, farmers with a low score are told, “That’s fantastic...you’re doing a great job.”

These discussions can be part of the conversation about usual production metrics like feed conversion and livability, as well as food safety. Providing growers with feedback about how they’re doing and communicating about what makes a difference is key, he advised.

‘Be simple and clear’

“Be very simple and clear with it. Don’t get too complicated too fast. ‘Look — here’s what I think of your farm as it relates to food safety. Here’s why, and here’s how it could better,’” he said. Then list two or three steps they can take and show them via feedback over time that they’re making a difference. “That’s really a powerful thing.”

To bring live production and processing together to