Poultry “raised without antibiotics” now account for more than 50% of the broilers in US production, but those reductions in antibiotics usage have consequences.

Poultry “raised without antibiotics” (RWA) or “no antibiotics ever” (NAE) now account for more than 50% of the broilers in US production, but “those reductions [in antibiotics usage] have consequences,” Randall Singer, DVM, PhD, told Poultry Health Today.

“Are we continuing to ensure animal health and welfare as we reduce our usage, and more importantly, are we using antibiotics more responsibly?” asked the veterinarian and professor of epidemiology at the University of Minnesota.

To answer that question, Singer and his associates did a research study, “Potential Impacts of No Antibiotics Ever/Raised Without Antibiotics Production on Animal Health and Welfare,” to investigate producers’ and veterinarians’ views on the impact of removing antibiotics from the food-animal supply chain. The researchers asked questions related to key parameters such as animal health and welfare, food safety, consumer demand and cost of food production.

A majority of survey respondents believe there are times when the RWA label takes priority over animal health and welfare. “Less than half in the broiler industry said there were effective interventions against their most important diseases, which means that now you’re going to need an antibiotic to treat the ill animals,” Singer said.

Respondents in all commodities indicated that RWA production would have negative impacts on animals, including increased morbidity, mortality and culling rates.

Perception and reality

Retail demand has created a market for NAE poultry because consumers perceive these labels mean higher welfare standards, but that may not be the case.

“Simply going to ‘no antibiotics ever’ doesn’t necessarily put animal health at the forefront,” Singer said. “We really should be thinking about how to keep these animals healthy [in terms of] major disease challenges and the tools we have.”

Across all surveyed commodities (565 producers and veterinarians involved with broiler, turkey, pig, beef and dairy production), preliminary results show the main reasons for raising animals without antibiotics were market driven. The survey included both conventional and RWA producers; just over half of all respondents reported having past or current experiences working with animals in an RWA program.

The paradox

Most veterinarians and producers indicated, however, that they think retail, restaurant and foodservice company leadership believe that animal health and welfare are significantly improved with RWA programs. These discrepancies indicate that veterinarians and producers feel that retailers do not understand the potential negative impacts of RWA programs on animal health and welfare, Singer reported.

The study overview said respondents indicated RWA programs would slightly to significantly increase the cost of production. However, they felt that demand for their RWA products would only slightly increase or not change at all.

“In general, across all surveyed commodities, respondents generally felt that there was a need for increased auditing/assessment of animal health and welfare in RWA systems,” the study report said.

Not a black-or-white, all-or-none issue

Discussions in the US about responsible antibiotic use seem to have evolved into not using antibiotics at all, but Singer doesn’t believe that’s the case on a global scale.

“If we look at Europe, for example, producers can use an antibiotic to treat sick animals in organic production,” he said. “For some reason here in the US if you raise animals organically, you can’t use an antibiotic. And I don’t really understand…why we would want to put these animals at risk and sacrifice animal health and welfare.”

Singer told Poultry Health Today that the US needs to “find that balance, where the entire system of animal production,

Vaccination of broilers against Salmonella may be the best and most expedient option for producers struggling to meet USDA performance standards at the processing plant, said Chuck Hofacre, DVM, PhD, president of the Southern Poultry Research Group Inc., Athens, Georgia.

Vaccination of broilers against Salmonella may be the best and most expedient option for producers struggling to meet USDA performance standards at the processing plant, said Chuck Hofacre, DVM, PhD, president of the Southern Poultry Research Group Inc., Athens, Georgia.

Hofacre also recommended vaccinating broilers against Salmonella if producers have breeders shedding the types of Salmonella that pose a risk to human health, which could lead to salmonellosis in people and a recall — at least until Salmonella in breeders is under control.

“Salmonella Enteritidis, Heidelberg and Typhimurium are the ‘big three’ that can cause human foodborne illness. If you have one of those three...one of the quicker ways we can intervene to reduce that is to use a live Salmonella vaccine [in broilers],” he told Poultry Health Today.

The level of Salmonella coming into the processing plant is what dictates the plant’s success meeting USDA performance standards. If a particular complex or group of breeders is shedding Salmonella, their broilers will potentially have a higher level of the pathogen, posing a risk to human health, Hofacre continued.

‘Good protection’

The live vaccines are all Typhimurium based and give good immunity protection to broilers, especially against the big three types of foodborne Salmonella, continued Hofacre, a professor emeritus, University of Georgia. The vaccines are generally administered at day-of-age followed by a booster dose again at 10 or 14 days of age, he said.

The risk for Salmonella tends to be greater on large farms with all breeders in the same place compared to farms with only one or two breeder houses. The vectors of Salmonella, which include beetles, mice and people, tend to drag the pathogen around more into breeder houses, which means there’s a larger amount of Salmonella that makes its way to the broiler operation, Hofacre noted.

Need live-side help

Since USDA tightened the performance standards for Salmonella as well as Campylobacter, processing plants aren’t able to control these foodborne pathogens as they did in the past. They need live production to lower the amount coming into the plant, he said.

Vaccination is “quicker and easier” than other Salmonella-control options, but producers may also want to consider using probiotics, organic acids and some of the plant-based essential oils that have an anti-Salmonella effect. These types of products are used in antibiotic-free production to control Salmonella but may benefit conventional flocks too, Hofacre indicated.

Feed isn’t a big source of Salmonella, in his experience. At companies he’s worked with that had a Salmonella problem, feed may have been what initially introduced the pathogen to breeders, but generally it’s not feed that maintains Salmonella or is responsible for it reaching broilers.

 

 

 

Higher government standards for Salmonella control have put more pressure on poultry companies to reduce incidence on broiler farms and lower the pathogen load going into processing.

Higher government standards for Salmonella control have put more pressure on poultry companies to reduce incidence on broiler farms and lower the pathogen load going into processing.

Vaccination of broilers for the bacterium has skyrocketed over the past 2 years, but other tools and management practices — good sanitation, rodent control, litter management, stepped-up biosecurity and feed additives — are also critical.

Grayson Walker, a DVM candidate at North Carolina State University, spoke with Poultry Health Today about the research he’s done on a feed additive that he said can serve as a “sentinel” for Salmonella control.

He explained that appropriate enzymatic hydrolysis of yeasts — a process where enzymes facilitate the cleavage of bonds in molecules with the addition of water — has been used to produce refined functional carbohydrates (RFC) that have activities against Gram-negative bacteria.

Specifically, these products possess sugars that interfere with Salmonella attachment to the intestinal lumen.

“Yeast-cell walls have been used as a feed additive for quite some time now,” Walker said. “They have nutritional and immunological effects that have been demonstrated, mainly due to the complex of sugars in the yeast-cell wall. If you subject this complex to…an enzymatic hydrolysis process, you can selectively expose the sugars that Salmonella actually used to colonize animal and human intestines.

“These sugars out-compete the intestinal carbohydrate receptors and intestines for Salmonella to bind to. It's a way to inhibit intestinal colonization of Salmonella,” Walker continued.

Testing the theory

Walker’s master’s project at North Carolina State evaluated the feed additive at different stages of poultry production in three trials. He feels it’s important with a pathogen such as Salmonella to have an integrated, multifactorial control approach. The first trial was with broiler breeders through an entire rearing period; the second experiment investigated chick-progeny intestines; and the third experiment further investigated RFC effects on Salmonella proliferation when fed to broilers.

In all three trials, when diets were supplemented with the RFC additive (Celmanax) throughout the growing process, Salmonella were reduced, he reported at the 2018 America Association of Avian Pathologists conference.

Salmonella were not detected in hens fed a RFC diet, while control-fed hens were confirmed 71.4% and 40% positive for cecal Salmonella at 23 weeks and 64 weeks, respectively.

“We were unable to find Salmonella in the GI tracts of breeders that were fed this additive, and we found it had the same effect in the broilers,” Walker said.

In Trial 2, Salmonella were not detected in progeny-chick intestines upon hatching; and in Trial 3, Salmonella Senftenberg was isolated in 14.6% of the litter of control-fed broiler pens and not isolated in the litter of RFC-fed pens using novel litter-sampling methods.

Management still key

“Salmonella is one of those issues that we can significantly impact on a human-health level by also managing our animals appropriately,” Walker said.

For veterinarians and producers, Walker said it reinforces the idea of using best management practices and proper sanitation to reduce pathogens that can affect humans.

“While this product does indeed reduce Salmonella colonization in live animals, you have to have good control on your Salmonella problem before you go into it. This additive is more like a sentinel system: It should be used as a precaution, not so much as a treatment,” Walker said.

He added that it’s still important to use good management to keep Salmonella levels as low as possible.

Field experience with infectious bronchitis in broilers during a harsh winter demonstrated that vaccination for secondary Escherichia coli infection helped stem losses

Field experience with infectious bronchitis (IB) in broilers during a harsh winter demonstrated that vaccination for secondary Escherichia coli infection helped stem losses, according to Kalen Cookson, DVM, MAM.

Broiler flocks in the poultry-dense Delmarva region of the US had been affected by the DMV-1639 IB strain.

At the time, no vaccines were available to protect against the emerging pathogen, which gained momentum throughout the winter, Cookson, director of clinical research, Zoetis, told Poultry Health Today at the 2018 International Avian Respiratory Disease Conference.

The producer opted to implement a controlled field trial and vaccinated against E. coli to minimize losses from this secondary infection, common in broilers with IB.

“If you look real closely, you can see that at first you have head snicking, conjunctivitis [in the flock]. You can have shaking heads and coughing — all the classic symptoms of a bronchitis outbreak...But that’s not usually what the birds succumb to. It’s usually the E. coli infection that comes in behind all of that damage...,” Cookson said.

Classic E. coli signs

The first sign of a secondary E. coli infection is usually increased mortality. In post-mortem examinations, Cookson said, there’s often “cheesy” material in the air sacs, as well as other findings such as pericarditis and perihepatitis — classic signs of E. coli infection, he said.

In his presentation at the conference, Cookson reported that livability for the Delmarva producer increased in birds of all sizes vaccinated for E. coli. For comparison, some in each weight group received one and some two doses of the vaccine. Overall, they were four times less likely to have excessive grower mortality compared to controls.

In most situations, one-time administration of the E. coli vaccine for broilers is probably sufficient, but in flocks with significant mortality — which occurred among large birds in the Delmarva flocks — day-of-age vaccination followed by a booster at 16 days of age “really cut down on...what some people might call ‘train-wreck flocks,’” he said.

Pen studies in broilers have also been conducted to compare E. colic vaccination protocols. Administration only at day-of-age, only at 18 days of age or when the vaccine is administered at both ages will all reduce E. coli lesions, but the two-dose protocol provided almost entire protection, Cookson said.

Asked about the impact of the trend toward elimination of antibiotics from the hatchery, he said it has “absolutely” opened the door for more problems with bacteria.

“When we don’t have those tools to diminish the loads of bacteria starting from the hatchery all the way through production, then naturally the level of exposure is going to be higher in our systems and on our birds. If there’s any level of immune suppression, that’s going to compound things and create more opportunities for E. coli...and other bacterial infections.”

 

 

Improved communication between poultry company veterinarians and backyard chicken growers could help improve biosecurity and reduce disease spread for all flocks.

Improved communication between poultry company veterinarians and backyard chicken growers could help improve biosecurity and reduce disease spread for all flocks, Tom Tabler, PhD, an extension professor with Mississippi State University, told Poultry Health Today.

Tabler acknowledged that commercial poultry veterinarians already have a full plate, but he would like to see a way for them to help educate backyard growers who often know little about biosecurity, its importance or how biosecurity procedures can be implemented.

“The two worlds are pretty far apart,” he said. At meetings or conferences for backyard chickens, there are rarely veterinarians from commercial growers present, nor are any backyard growers ever present at gatherings frequented by commercial poultry veterinarians.

In his experience, backyard growers are inquisitive and would welcome information that poultry company veterinarians could provide about biosecurity. Backyard growers may not realize they can pick up disease and track it to their flocks if they fail to change boots and clothes after a visit to the feed store or coffee shop where other chicken growers are present. They may not understand that delivery trucks can bring disease to their farm or why it’s important to restrict who comes near their chickens, Tabler said.

“Now, you can't control what your neighbors do, or what the person down the road does...but you can control your own, and you can at least eliminate your operation as a threat to everyone else close to you and in the commercial world as well,” he said.

Tabler added, “If you've never known any better, and no one's ever told you any different, you may be doing the wrong the thing and not know you're doing the wrong thing...if you've never been taught, it's hard to understand what's right and what's wrong.”