Life without antibiotics in poultry production

A big challenge in antibiotic-free poultry production is the control ofcoccidiosis, which can lead to necrotic enteritis.

How are broiler producers coping with the flock health challenges in antibiotic-free production?

U.S. poultry producers are using fewer and less antibiotics in broiler flocks as public concern over the use of antibiotics in food-producing animals intensifies. Broiler flocks are being grown without the use of antibiotics in antibiotic-free (ABF) production programs. Broiler producers are still learning how to manage ABF flocks, which present greater disease control challenges.

Speaking at the 2013 Poultry Health & Production Seminar, Dr. Tim Cummings, senior technical services veterinarian, Zoetis, presented the results of an informal survey of veterinarians, researchers and consultants with experience in antibiotic-free poultry production programs.

Experiences with ABF poultry production

Cummings shared the early experiences reported by five broiler companies and two experts involved in ABF broiler production. He drew a number of conclusions from their responses:

• All-vegetable diets seem to work best.
• Husbandry plays a pivotal role in keeping flocks healthy.
• It helps to reduce bird density and maintain adequate downtime between flocks.
• Litter management is critical to success of ABF production programs.
• Coccidiosis vaccination works, when properly administered.

“There is definite variability in the way that companies grow ABF flocks but some similarities as well,” he said. “It is important to realize that every poultry complex will be different and may require its own tailored approach.”

It is important to keep in mind that ABF poultry production is evolving. The survey results reported here might not be indicative of current practices and experiences on all points.

Southeastern company rotates vaccines, chemical coccidiostats

One of the five broiler companies that Cummings surveyed started with a small percentage of flocks in an ABF program but now has nearly 100 percent committed to ABF production.

Necrotic enteritis/enteritis remains a significant, seasonal problem, which is worse in the winter.

ABF program basics included the following:

• Feeds an all-vegetable diet
• Bird density reduced
• Coccivaccine administered, in rotation with chemical coccidiostats
• Built-up litter is maintained; litter is acidified
• Tries to maintain a minimum of 14 days downtime between flocks 

This company gives growers a “conventional program break” when a farm’s flock performance deteriorates or necrotic enteritis becomes severe.

One breed of broiler seems to perform the best in ABF conditions, the company reported to Cummings.

Southeastern complex administers probiotic at hatchery

Another broiler company that Cummings surveyed has a complex in the Southeast with production that is half ABF and half conventional. The company’s ABF flocks experience some enteritis but practically no necrotic enteritis.

While broilers are grown to 6.5 pounds with good livability, the company reported feed conversion is 2 points less in ABF flocks.

ABF program basics included the following:

• No animal by-products in the diet, only corn and soy
• No antibiotics are administered at the hatchery
• At least 18 days downtime maintained between flocks
• Bird density is reduced compared to conventional flocks
• Built-up litter maintained; litter is acidified
• SIS (non-defined probiotic approved for use on litter) sprayed on the chicks at the hatchery 

Cummings reported that the company rotates farms between ABF and conventional production when enteritis and/or necrotic enteritis become more severe. It reported a 5-point improvement in feed conversion with the rotation.

Upper Midwest company: No cocci vaccination

A broiler company surveyed by Cummings in the Upper Midwest has 50 percent of production antibiotic free. 

The company has used chemical coccidiostats in the starter/grower feeds for a couple of years in the ABF birds without cocci vaccination without major problems, he reported. 

In the company’s conventional flocks, in which ionophores are used, there is gangrenous dermatitis but no necrotic enteritis. In the company’s ABF flocks there is some necrotic enteritis but no gangrenous dermatitis. Nonetheless, necrotic enteritis has not been a significant problem in the ABF flocks and performance is good, according to Cummings’ survey. 

ABF program basics at the Midwest company included the following:

• All-vegetable diets with no meat and bone meal are fed.
• Prime hatching eggs are used for the ABF program.
• No antibiotic is used in the hatchery for ABF birds (0.3 percent higher first-week mortality experienced in ABF flocks).
• A probiotic is used in the feed.
• Bird density is reduced compared to conventional flocks.

The brood chamber is cleaned out after every flock, and the litter is a mixture of rice/oat hulls and/or pine shavings. No litter treatments are used.

Necrotic enteritis outbreaks are treated with copper sulfate/acidifier and in a preventative program on days 3-7 as well as 21-28.

West Coast company stresses superior husbandry

All production is ABF at this West Coast broiler company, where the emphasis is on close attention to flock management, according to Cummings. 

When the company first adopted ABF production, necrotic enteritis was very severe in the flocks. By closely managing the birds’ gut flora and the grow-out environment, flock health and performance has improved.

The production program at the West Coast company included the following:

• There should be no fluctuations in house temperature.
• Brooding temperatures are 2 degrees higher than conventional.
• Any disruption in eating pattern is avoided.
• Water quality is key and adjusted to pH 4-6.
• Flocks are managed to reduce stress, especially days 14-21.
• There is a strict downtime policy of 15-17 days.
• Immunosuppressive pathogens are monitored and controlled
• The proper application of cocci vaccine is considered to be vital.

“The company has learned that gut flora and house litter management is a key to the ABF program’s success,” Cummings said. “Some probiotics, prebiotics and acidifiers have been used in the feed and/or water successfully but in conjunction with the total overall management program."

It is critical that litter be kept dry and an acidifier be applied to the litter, the company told Cummings. Where litter is cleaned out on a dirt floor, salt is put down.

East Coast company: Close management required

This East Coast broiler company stresses flock management in ABF production, according to Cummings.

Necrotic enteritis is experienced in ABF flocks, more so in the winter, the company reported. 

ABF program basics at the East Coast company included the following:

• No animal by-products are used in diets.
• The company administers cocci vaccines, but rarely uses chemical coccidiostats and tends not to use ionophores.
• Probiotics in the feed seem to provide some benefit, but prebiotics are not used.
• Antibiotics in the hatchery are generally not used.
• Bird density is reduced in certain grow-out areas.
• Downtime is variable, but must be adequate.
• Litter acidification and windrowing is used.

Close attention must be paid to the management of air, water, litter and feed in ABF flocks. A company manager told Cummings: “Don’t just go to ABF production and hope for the best."

Consultant: Consider adjusting bird density

A consultant with experience in ABF production shared a number of recommendations with Cummings. 

Bird density:  The consultant recommended bird density of a little over 6 pounds per square foot versus the industry average of 7.5 pounds per square foot. Reducing square footage is best and really doesn’t lose as much as the increased gain which often offsets the reduction in placement density.

Timing of litter acidification:  Clostridium perfringens levels in the litter need to be reduced to promote flock health. While litter acidifiers are widely used, the timing of application is an often overlooked factor in their effectiveness. The consultant recommended windrowing or treating litter with an acidifier immediately after birds are harvested. Application at this time destroys the most Clostridia before spore formation, he said. 

Downtime:  While downtime between broiler flocks on farms is often not a discretionary management factor, the longer the downtime the better. The consultant said downtime longer than two weeks is preferred.

Other recommendations from the consultant included the following:

• Most cocci vaccines can work but must be properly administered.
• All-vegetable diets and enzymes are strongly recommended.
• The consultant’s program involves feeding a commercially available yeast cell wall mannan oligosaccharide.
• Probiotics should be given as early as possible, preferably sprayed at the hatchery with cocci vaccine
• Acidify the flock’s drinking water for the first three days or a week. This promotes the establishment of microflora in the bird’s gut and the effectiveness of probiotics.

Researcher: Consider the production situation

A researcher, who conducts extensive research involving gut health and necrotic enteritis, offered observations and recommendations for ABF broiler production.

The management of ABF production can be aided by an understanding of the disease challenge.

• Necrotic enteritis is more likely to occur on new litter.
• More light will increase the necrotic enteritis challenge.
• The use of rice or oat hulls will increase litter consumption, which can increase the risk of necrotic enteritis.
• Increased litter moisture will result in more necrotic enteritis.
• Necrotic enteritis can occur in hot spots in the chicken house, so manage the house environment.
• Birds are less susceptible to necrotic enteritis after four weeks of age, so manage the flock so as to delay the development of cocci lesions.
• Breed is a factor in that early, rapid growth predisposes birds to necrotic enteritis.
• Minor turn-out mismanagement may set the birds up for the disease.
• Increased protein levels increase susceptibility to necrotic enteritis.
• Low temperature or chilled chicks predisposes the birds to necrotic enteritis.
• Feed outages during peak susceptible periods will predispose birds to necrotic enteritis once they are back on feed.

Cummings offers ABF production principles

Feed additive antibiotics have been used over the years because they work, according to Cummings. As poultry producers move to the use of fewer and less antibiotics, he offered the following principles:

• Intestinal and litter microflora are involved, so new programs may take some time to fully assess.
• Experience teaches that not all programs work in all poultry production complexes.
• Alternative products definitely have a role but the strengths and weaknesses of each product must be understood.
• Although some products or product combinations have demonstrated efficacy, they need to demonstrate an economic return.
• No product will work consistently without total program support including management.

No endorsement of products or brands is intended or implied by citation or mention in this article. The survey of industry practices conducted by Dr. Cummings in a prior year may not be indicative of current practices and experience in all cases.