Identification of variant infectious bronchitis viruses (IBVs) has improved with the development of a real-time PCR (qPCR) test that can distinguish the type of virus and determine if it’s vaccine- or field-related.

The test will enable producers to select more appropriate vaccines for the IBV variants circulating in specific areas, leading to better control of IBV, Dr. Mark Jackwood, PhD, head of the Department of Population Health at the Poultry Diagnostic Research Center (PDRC), University of Georgia, told Poultry Health Today.

Previous tests could only reveal whether infectious bronchitis virus was present or not. Surveillance with the new qPCR test, available at PDRC, will enable poultry companies to better plan their vaccination programs, Jackwood said.

IBV is an RNA virus and is prone to change, creating new strains. Poor vaccination technique can allow field viruses to replicate and change, he continued. Examples of poor vaccination technique include malfunctioning hatchery vaccination equipment, cutting the vaccine dosage that should be used or using the wrong vaccine at the wrong time.

Jackson also addressed bacterial infections secondary to IBV infections. By stopping IBV, producers can also stop the secondary infections that commonly occur, leading to condemnations and generally a lot of losses for producers, he said.

“We’re going to have to do an even better job now of controlling the primary pathogens like IBV with the vaccines that we have available because our tools downstream [such as antibiotics] to treat the secondary pathogens like an Escherichia coli are going to be limited,” he said. “We have to…do a much better job of vaccinating.”

 

The NAE production movement has helped reduce antibiotic use in poultry for good reason, but veterinarians need to make sure the pendulum doesn’t swing so far they have no antibiotics left to manage disease in flocks.

The “no antibiotics ever” (NAE) production movement has helped to reduce antibiotic use in poultry.

Even so, veterinarians need to make sure the pendulum doesn’t swing so far they have no antibiotics left to manage disease in flocks, cautions Suzanne Dougherty, DVM, poultry veterinary consultant and executive vice president of the American Association of Avian Pathologists (AAAP).

Dougherty emphasized that veterinarians feel strongly about using antibiotics judiciously — specifically, when veterinarians determine they’re needed for disease treatment or prevention.

The AAAP is working to help consumers understand there’s a place for antibiotics in poultry production, and live-production veterinarians are constantly communicating this message to their customers. The AAAP also communicates with legislators in Washington, DC, and meets with the FDA and USDA to make its presence known.

Veterinarians can help further reduce Salmonella and Campylobacter during live production and at the processing plant, and they can provide a communication bridge between these two production phases. In turn, this will help producers meet new USDA standards for the two pathogens, Dougherty said, noting that over the past 10 years, the industry has already greatly reduced Salmonella levels.

Alternative treatments may be the only long-term hope for managing blackhead in turkeys, said Robert Beckstead, PhD, turkey health specialist, North Carolina State University.

Alternative treatments may be the only long-term hope for managing blackhead in turkeys, said Robert Beckstead, PhD, turkey health specialist, North Carolina State University.

For now, however, biosecurity is the only available option for preventing the disease, he told Poultry Health Today.

Blackhead disease is caused by the protozoan parasite Histomonas meleagridis and usually causes mortality between 70% and 100%. The last medication licensed for treating the disease, nitrasone, was removed from the market at the end of 2015.

No figures are officially kept on the number of turkeys that have blackhead disease, which tends to be sporadic, but some years are worse than others. In 2015 — the same year avian influenza affected the turkey industry — the losses due to blackhead disease were particularly high, Beckstead said.

He does not foresee a new drug ever becoming available to treat blackhead disease and said many companies are testing alternative products to see if they have the ability to prevent transmission of the disease.

“Our lab is really busy at the moment, running through a lot of these different feed additives, essential oils [and] plant extracts to see if they have anti-histomonal activity, and whether actually they can be used in the turkeys to prevent the disease,” Beckstead said.

Because biosecurity is currently the only line of defense against the disease, producers must make sure that contaminated mechanical vectors, such as farm equipment, vehicles or workers’ boot, don’t bring the disease onto their farms, he said.

On a positive note, Beckstead said the avian influenza outbreak prompted the turkey industry to initiate better biosecurity measures, which will also help prevent blackhead disease.

 

The poultry industry is rife with job openings for veterinarians that can’t be filled, according to Mark Jackwood, PhD, University of Georgia.

The poultry industry is rife with job openings for veterinarians that can’t be filled, according to Mark Jackwood, PhD, University of Georgia.

The increased demand for poultry veterinarians is partly due to the updated veterinary feed directive (VFD) rules that took effect January 1, 2017, he told Poultry Health Today.

Several in-feed medications that were once available over the counter are now considered medically important by FDA and require a VFD — a process that requires a valid veterinarian-client-patient relationship. Several poultry companies that didn’t have a veterinarian on staff now need one, he explained.

Longer term, however, the bigger issue is the limited resources available to train enough people to meet the poultry industry’s rapidly growing need for veterinarians, Jackwood said.

When most students today graduate as doctors of veterinary medicine, they’ve had very little, if any, exposure to poultry diseases, he said. Some go on to obtain a master’s degree  in avian medicine — an MAM, as it’s known at the University of Georgia — or equivalent degree, he said.

That’s an 18-month commitment, however, which is hard for students to afford after completing their undergraduate and veterinary degrees. In addition, universities aren’t equipped to handle the surge in demand for poultry veterinarians, Jackwood said.

Last year at the University of Georgia, for example, there were 20 applicants for the MAM program, but only three students could be accepted because of limited resources. Other universities with similar programs only take on one student, he continued.

In the past, universities have turned to the poultry industry for assistance, but there still remains a serious shortfall of funding, Jackwood said.

 

Producers raising flocks without antibiotics are finding new ways to manage gut health and coccidiosis with vaccination and anticoccidials, said Greg Mathis, PhD, coccidiosis specialist.

Producers raising flocks without antibiotics are finding new ways to manage gut health and coccidiosis with vaccination and anticoccidials, Greg Mathis, PhD, coccidiosis specialist, Southern Poultry Research, told Poultry Health Today.

Some producers using a coccidiosis vaccine, for instance, apply a field boost. They spray the vaccine on the feed or on litter to cover the birds that may have been missed during the initial hatchery application, he said.

Producers have also learned that increased lighting improves preening and ingestion of the vaccine; the faster birds preen, the more coccidia they get into their systems to create immunity sooner, Mathis said.

Other producers use a coccidiosis vaccine during the spring, summer and fall, then switch to a non-ionophore anticoccidial program before going back to the vaccine, he said. However, nothing has been as effective for managing gut health as a traditional, full-spectrum program involving ionophores and other approved antibiotics effective against enteric disease.

Many companies raising poultry without antibiotics are also using bio-shuttle (hybrid) programs. They administer a vaccine in the hatchery and then follow with a non-ionophore anticoccidial.

When using a bio-shuttle program, timing is very important, Mathis emphasized. Using the anticoccidial too early will kill off too much of the vaccine’s live coccidial oocysts before they’ve completed their cycle. If the medication is used too late — at 22 to 28 days — the birds could develop an early Clostridium infection, he observed.

The non-ionophore anticoccidial in birds vaccinated for coccidiosis should be started between 16 and 20 days of age, the researcher advised.

A non-ionophore anticoccidial with a full spectrum of activity which helps birds develop immunity and works well in bio-shuttle programs is Zoalene (Zoamix), which has recently been reintroduced after being out of the market for almost a decade, he said.

By Tak Niino, VMD

Technical services veterinarian

Zoetis Inc.

Respiratory disease in broilers can occur any time of year, but it’s especially problematic in winter months, when air and environmental conditions may become compromised as producers try to keep costs under control.

Maintaining good air quality is essential and is heavily influenced by ventilation techniques. When a house is underventilated, ammonia levels and litter moisture can rise to the point where they’re detrimental to the health of birds, predisposing them to respiratory disease.

Elevated ammonia levels damage the cilia, those brush-like structures responsible for clearing debris out of the trachea. When the cilia are damaged or destroyed, birds may succumb to viral infections such as infectious bronchitis (IB), infectious laryngotracheitis (ILT) or Newcastle disease (ND). These viral pathogens can also cause ciliostasis, which can result in chickens displaying signs of lethargy, depression or coughing and snicking.

Poor litter quality due to inadequate ventilation is favorable for bacterial growth. That’s why it’s not uncommon for birds that have a respiratory virus to develop a secondary bacterial infection — usually Escherichia coli — which can lead to severe polyserositis, septicemia and even death.

Evidence of respiratory disease can show up at the processing plant as well as in the poultry house. Condemnation due to airsacculitis, often due to an underlying respiratory disease, may trend upward during cooler months, when maintaining an optimal environment becomes a challenge. An increased number of birds with airsacculitis can affect the efficiency of the processing plant. More birds will have to be rerouted and salvaged for parts, which can slow the line speed, and that’s costly.

Bigger houses, aging equipment

One trend that may influence ventilation practice is variation in house size. Today, many poultry growers are choosing to build larger houses in an effort to efficiently raise more birds. However, the methods traditionally used to ventilate smaller houses may not yield the same results in larger houses. Care must be taken to ensure that longer and wider poultry houses have the proper equipment and ventilation settings necessary to adequately move and exchange air. Air has to travel further and if airflow is uneven, birds at one end of the house might have fresh air, while birds at the other end don’t.

Poorly maintained equipment is another problem that can lead to difficulty heating and ventilating the house. Old and unmaintained fans might still run, but that’s no guarantee that the cubic feet of air moved per minute is the same as it was when the fans were first installed. A fan may not be capable of moving the intended amount of air if shutters are dirty and belts need replacing. Air flow can be easily monitored using an air flow meter. Proper and regular maintenance is critical to make sure the systems are working properly.

Computerized, automated systems with preset programs are handy and can work well if used appropriately. Advancements in farm equipment make it easy for growers to monitor the house condition and ventilation settings without having to enter the house. However, never assume birds are comfortable just because the computer indicates everything is running smoothly. There is no one-size-fits-all setting since the conditions for keeping birds comfortable and healthy can vary flock to flock. Because of this, it’s important to look at the birds regularly to make sure they are comfortable. Visually checking birds is a fail-proof way to confirm that house conditions, including ventilation and litter quality, are appropriate.

Monitor ammonia

As for ammonia levels, those of us who spend a lot of time in poultry houses can easily become desensitized to the smell and may not realize ammon...