How much is E. coli costing your layer operation?

Learn what industry professionals say about E. coli mortality and what preventative measures should be taken to win the battle.

Veterinarian Dan Wilson wonders if production managers might overlook investing in E. coli control as an opportunity to make a significant financial impact. (Courtesy Wilson Veterinary Co.)
Veterinarian Dan Wilson wonders if production managers might overlook investing in E. coli control as an opportunity to make a significant financial impact. (Courtesy Wilson Veterinary Co.)

As E. coli mortality is not always dramatic with a sudden spike or doesn’t present itself with an “observable outbreak,” Dan Wilson of Wilson Veterinary Co. wonders if production managers might overlook investing in E. coli control as an opportunity to make a significant bottom line impact.

“Birds with secondary respiratory challenges or peritonitis may or may not die but waste many resources as they combat the disease and fail to produce to their genetic potential,” he said.

When posting daily mortality, sometimes Wilson finds E. coli lesions in 10 to 30 percent of the birds.

“You can justify additional expenses in an E. coli control program if you are able to reduce cumulative mortality and increase production numbers, even by small percentages,” he said.

Caused by a gram-negative bacterium Escherichia coli, this disease is one of the most challenging to control with vaccines due to many diverse serotypes with innumerable strains, often untypeable. Not all strains cause disease. Most common avian pathogenic E. coli (APEC) strains fall into O1, O2 and O78 serotypes. E. coli is commonly found in the intestinal tract and, hence, in feces, making it always present in a poultry house.

Birds can be exposed in the hatchery from infected or dirty eggs. While E. coli can be a primary cause of disease, it generally manifests itself as a secondary infection after a respiratory disease, vaccine reaction or environmental stress such as poor ventilation, high ammonia levels or dusty conditions (which aerosolize the E. coli). Once an infection moves into the bloodstream from the respiratory or intestinal tract, E. coli colonizes on interior organs, which impairs the birds’ health or may cause death. More common lesions observed include airsacculitis, pericarditis and perihepatitis often with cheesy, fibrous materials.

Caseous Peritonitis B

Lesions like this are often seen as the effects of Caseous peritonitis with cloudy airsacs. (Courtesy of Eric Gingerich)

Wilson advocates a multi-faceted prevention approach to achieve good control of the disease. He suggests considering use of several of the many available tools together which offer a cumulative effect of reducing effects of pathogenic E. coli challenge.

Basic tools for disease control

Treatment of feed with heat or chemicals is important to reduce/eliminate E. coli and other serious pathogens, such as Salmonella. Likewise, if not chlorinated, the water source needs to be evaluated for contaminants.

Control of other respiratory pathogens such as Mycoplasma, Newcastle disease and infectious bronchitis is important as even a mild infection and/or vaccine reaction can set up an opportunity for E. coli infection. Proper ventilation and air exchange should be constantly monitored to avoid ammonia and dust issues which can compromise the respiratory tract.

Genetic differences 

While not proven scientifically, industry field observers agree that some layer strains are more susceptible to E. coli infection. An overall impression is that brown egg layers are slightly more susceptible. However, there are notable differences between strains in white and brown egg layers.

Housing factors

Jim Sandstrom, managing director of Epitopix, said: “E. coli peritonitis is more of an issue than two years ago.” Aviary housing includes litter access and, sometimes, increased dust and ammonia. There is a wide variety of designs -- some aviary designs offer greater litter access than others. Depending on egg customer requirements, depth of litter can vary. Manure scrapers are included in some designs, which help maintain good litter quality.

Traditional housing in deep pit houses can have dust and ammonia challenges. Timing of manure pit cleaning is crucial as that process can create environmental havoc. Leaking water lines and poor ventilation contribute to higher ammonia levels.

Cage Free Hens In Scratch Area

Activities like dustbathing in the scratch area of cage-free houses increases the amount of dust in the air and exposes birds to higher concentrations of airborne bacteria, like E. coli. (Austin Alonzo)

Control of other diseases

John Brown of Zoetis reports that he has seen peritonitis in flocks vaccinated with an E. coli vaccine and customers are concerned the vaccine didn’t stimulate immunity. He always recommends a bacterial culture be performed in this situation. Fowl cholera (Pasteurella multocida), which has similar clinical signs, has been isolated from organic flocks. He predicts that the industry will see more fowl cholera in free-range flocks and small holdings that produce organic eggs. Those flocks need to have a good fowl cholera vaccination program to keep this disease under control.

Also, customers following Brown’s recommendation have found Gallibacterium anatis (formerly known as Pasteurella haemolytica). This disease causes similar clinical symptoms as E. coli and fowl cholera (such as peritonitis, salpingitis, septicemia, pericarditis, hepatitis, respiratory tract lesions and enteritis). No licensed bacterins are available, but some producers are working with autogenous bacterins.

Treatment for E. coli infection

Aureomycin is the only approved drug labeled for E. coli control and must be used under a Veterinary Feed Directive issued by a licensed veterinarian. This product is effective in controlling the disease when being fed, but when withdrawn, producers often see the problem return.

Vaccination 

A live vaccine, Poulvac E. coli, produced by Zoetis, is available for protecting layers. Producers generally give two doses during grow-out, the first early in the vaccination program and the second close to housing. Although not labeled for use in combination, the lack of an observable reaction has allowed many producers to save labor costs and combine the vaccine with live Newcastle disease and infectious bronchitis vaccines via spray administration. If a farm has a history of severe E. coli challenge, some producers give a final boost in the layer house. The product has also been used in face of an outbreak and it has been reported to successfully lower mortality caused by E. coli resulting from the outbreak.

Autogenous inactivated bacterins represent another tool that can be used independently or in combination with live vaccine. As autogenous bacterins are derived from strains isolated on the specific farm, these products do not have to pass efficacy testing required for U.S. Department of Agriculture licensing.

Several vaccine manufacturers offer this service to their clients. The process is quite lengthy and requires detailed recordkeeping by the layer operation and the bacterin manufacturer.

A challenge with autogenous products is that protection seems to be fairly serogroup specific. So, many E. coli isolates from a house or farm need screening to identify those which are pathogenic and then only one to three are usually selected to be included in a product.

An important tool is continually improving diagnostic capabilities. Polymerase chain reaction (PCR) analysis and whole genome sequencing are available at an accessible price. These technologies have made it possible to identify the most pathogenic strains on a farm and create better autogenous bacterins.

Epitopix manufactures autogenous products using a patented technology that isolates specific proteins that are common to a variety of serotypes. Siderophore receptor and porin proteins common to many E. coli serotypes are harvested and purified to be included into the bacterin.

The bird’s immune system responds to these proteins and interferes with iron transfer of pathogenic E. coli, which prevents it from establishing itself and causing pathological damage. Customers have reported that when using Epitopix autogenous products, E. coli mortality has been reduced by about 50 percent compared with sister flocks in side-by-side houses. The company is pursuing a licensed product utilizing this technology with a claim against peritonitis.

Autogenous bacterins offer an opportunity to protect against Gallibacterium anatis as well. The presence of G. anatis seems to be very common and is easy to isolate. Hence, if an autogenous E. coli bacterin doesn’t completely solve a farm’s challenges, adding a G. anatis strain into the product has helped producers reduce losses.

Probiotics

Another tool to help manage E. coli infections is the use of probiotics. These products are used to colonize the gut with “good bacteria” and prevent the colonization of pathogenic bacteria such as E. coli, Clostridium, Salmonella, etc. Jordon Gruber of DuPont Animal Nutrition explains how probiotics assist the bird with microbiology concepts.

“The law of addition tells us that if we offer more barriers to gut colonization, the bird will be better able to resist a pathogen," he said. "Likewise the law of subtraction suggests that probiotic use is effective when you have poor environmental conditions, stress, etc., that lower the bar for disease susceptibility.”

Using the diagnostic tools previously mentioned to classify E. coli isolated from specific farms or operations, companies such as DuPont and Arm & Hammer Animal and Food Production are now offering customized probiotics in the U.S. market. Customers submit gut and environmental samples with a goal of understanding E. coli genetic diversity and pathogenicity. Chris Kromm of Arm & Hammer has observed significant differences in the bird’s gut microbiome when comparing different housing systems.

“As birds come in contact with the litter, it is clear that there are implications for health and performance," Kromm said. "Producers need to utilize tools to mitigate this impact.”

As the industry moves to more aviary housing, the possibility of increased E. coli problems is an important issue for egg producers to evaluate. There are many tools that allow those losses to be minimized and increase livability, production and profits.

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