44 Our Advertisers Appreciate Your Business Better Farming | April 2024 cent of bulk tank samples were positive for Salmonella Dublin, suggest that prevention of transmission is extremely important for naïve herds that have not yet been exposed. Managing on-farm Canada does not currently have any approved vaccines for Salmonella Dublin, which means hygiene and good biosecurity are the best strategies to avoid the disease. “Currently there are no vaccines specifically for Salmonella Dublin available in Canada. There are vaccines for other strains of Salmonella, but it is currently unclear whether they provide any cross-protection,” explains Gillies. Renaud’s research identified herd-level risk factors for Salmonella Dublin, which emphasizes areas of focus for prevention of transmission. Based on these risk factors, farmers should: prioritize calving area cleanliness and minimize manure; avoid having more than three cows in a maternity pen as it increases the chances of having a positive cow in the calving area; avoid buying in cattle, loaning out cattle, or sending them to shows, with the risk being sending cattle off-farm and bringing them back into the herd. The main route of transmission to calves is fecal-oral. Davidson explains that this commonly occurs in the calving pen. “It seems that the calving pen is the highest risk area,” says Davidson. “The cow calves and then the calf takes a nosedive into the contaminated pen. It is also dose-dependent – the more the calf is exposed, the sicker it’ll be.” Keeping calving areas clean should be a priority for keeping calves healthy. Maintaining a closed herd, particularly in those still naïve to Salmonella Dublin, will also reduce the risk of bringing in the bacteria with healthy-appearing carrier cows. “A lot of outbreaks can be traced back to the introduction of a new animal. You want to be conscientious if an animal is coming from the U.S. or Quebec, or another known area with Salmonella Dublin,” says Davidson. Renaud adds, “The biggest thing to prevent transmission is to try to prevent it from coming on the farm in the first place.” Biosecurity for all visitors, including advisors, vets, and feed salespeople, entailing wearing clean boots and coveralls and any necessary disinfection, should also be considered to avoid transmission between herds. If the bacteria does enter the herd, Gillies explains that indications of Salmonella Dublin infection would be “BRD (bovine respiratory disease) that is unresponsive to treatment and very sudden death. “There may be an outbreak that affects entire groups of calves with high levels of mortality.” He also explains that, due to its resistance to antibiotics, the bacteria can be very challenging to treat. Because of this, if a producer suspects that they have Salmonella Dublin on their farm, they should contact their vet. In Ontario, if a farm is determined to have a positive case of Salmonella Dublin, either the vet or the lab that performs testing will report the exposed herd to OMAFRA. Renaud says that this is just for surveillance purposes. “There’s no labelling of farms and no formal eradication program that’s underway in Canada, but there are some in other countries,” says Renaud. On the farm, producers should work with their vet to develop a plan for managing and treating infected animals and minimizing further spread within the herd. This would likely involve improving hygiene and additional cleaning of housing and shared equipment. With increased awareness and attention to biosecurity and cleanliness, producers can protect their herds from Salmonella Dublin. BF Livestock WWW.GLENGARRY.CA Let's make it work. When other doors seem closed, ours are open. Sometimes finances are best discussed over a cup of coffee at the kitchen table. It’s where you dream big, and it’s where we sketch out a plan to restructure debt and make the numbers work. We don’t hide behind a big desk. We’re closer than that. We get farming.
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