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Tailoring control measures key to managing Salmonella

29 May 2020, at 9:22am

Producers need to take more care in matching Salmonella vaccines for broiler breeders to the strain of the pathogen challenging their flocks, according to a poultry health expert.

Charles Hofacre, DVM, PhD, president of the Southern Poultry Research Group Inc, said the US broiler breeder industry has done a good job of using vaccines to tackle Salmonella in birds.

But he advises that producers should work harder at tailoring vaccination protocols to ensure broilers are protected as effectively as possible.

Speaking to Poultry Health Today, Hofacre said there were a number of things the broiler industry could be doing differently to improve its approach to tackling Salmonella. Matching vaccines to the bacterial challenge is a major issue.

“Let’s say [a company] has Salmonella Typhimurium and Salmonella Enteritidis as the two main [strains] coming into the processing plant. They might just be using the Salmonella Enteritidis vaccine and not have as much immunity to the Salmonella Typhimurium.

“The other thing is they forget about insects and rodents,” he said. “They may say ‘I have a rodent-control program, and I’ve got the basics out there’.

“[But they face serious problems if] they get a challenge that’s greater than the immunity the birds have developed through the vaccine.”

However, one of the biggest forgotten areas of Salmonella control in broiler breeder production is drinking water, Hofacre said.

“We went to nipple drinkers, and everyone knows that it’s a much cleaner water system,” he explained.

“But if you open up the end of a nipple-drinker line, there’s that slippery film. And if there’s Salmonella in there, that Salmonella is going to find its way back up from that nipple into the water line. So now every chicken that drinks out of that line is [potentially] going to get a small dose of Salmonella.”

With tougher Food Safety and Inspection Service regulations around Salmonella in the processing plant leading to greater expectations for on-farm control, Hofacre said taking action against the pathogen in flocks is more important than ever.

And with Salmonella shown to pass from parents to offspring, focusing on controlling the bacteria in parent flocks through multiple measures - including vaccines, managing pests and other biosecurity measures - is critical for long-term success.

“Very few, if any, single intervention will significantly lower Salmonella,” Hofacre said. “But if I can have an intervention that lowers the numbers, and I do another intervention that lowers the numbers more, and another…. Then I’m starting to have a significant impact and reduce the risk.

“Many interventions I’ll use on broilers because in breeders the interventions can take a year or more [before the benefits of vaccinating breeders can be seen throughout the production chain],” Hofacre added.

“So these interim interventions in broilers can be live vaccination, competitive exclusion, water treatments — combinations of these. One thing is generally not going to help you be successful.”