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Take steps to prevent the salmonella cycle in calves

Ruby Wu for Progressive Dairy Published on 23 March 2021

Salmonella is a potential concern on many dairy operations. It’s important for all dairy producers to understand and manage this devastating disease – not only to protect herd health, but also to prevent potential impact on food safety for consumers.

Although many salmonella serovars affect dairy cattle, of particular concern is serovar Dublin. Once rarely seen in dairy herds, serovar Dublin is now the most common form of salmonella found on dairies. It also is growing in prevalence among foodborne infections in humans.

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Animals can contract salmonella at any point in their lives and become active, asymptomatic shedders. These shedders then pass the pathogen on to other animals that become shedders too. This invisible salmonella cycle often creates endemic infections in herds, leading to significant losses even if cases are subclinical. Clinical salmonellosis is rarely fatal in cows, but it can be deadly for young calves. 

Calves are most susceptible to salmonella in the first 30 days of life, although infections can occur throughout the first six months. Clinical manifestations are also common during the seven- to 10-week period when calves transition to full grain rations. Symptoms include off-feed, fever and watery diarrhea. 

When these signs of salmonella occur, administer electrolytes and antibiotics as soon as possible, as directed by your veterinarian. Without prompt treatment, dehydration sets in very quickly, and animals may succumb in as little as 12 to 48 hours. When planning antibiotic treatment, consider asking your veterinarian to perform anti-microbial susceptibility tests to ensure selected treatments are effective against the strains on your operation.

Prevention before treatment

The best way to control salmonella in calves is through prevention. Focus on a systematic approach that includes animal care and effective sanitation protocols.

Like many pathogens, salmonella is opportunistic, attacking animals under stress or with compromised immunity. Calves are most susceptible to salmonella at the time of birth due to their immature immune systems.

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Protecting calves against salmonella protection starts with the cow, with vaccinations at pregnancy check and again at day 55 of the dry period. The initial vaccination will help the cow develop her own immunity, while the second will help build immunity to pass on to her calf through colostrum. 

Calving-time considerations

Follow these steps to control salmonella infections at calving:

  • Sanitize calving pens. While it is impossible to completely sanitize calving areas, take steps to make sure the calf is born into a clean environment. 

o If possible, only calve one cow per pen at a time. After calving, clean the area thoroughly and replenish with clean, dry bedding. 

o Move calves to a clean, sanitized pen or hutch within the first day of calving. 

  • Feed high-quality colostrum. One of the most important ways to protect a calf from salmonella is to provide adequate amounts of clean colostrum immediately after birth. 

o Feed up to 10% of the calf’s bodyweight (4 quarts for a 90-pound, average-sized calf) within the first two hours of birth. Follow six to eight hours later with additional colostrum at 5% of bodyweight (2 quarts).

o Follow hygienic practices when collecting colostrum. Thoroughly clean and sanitize feeding equipment, bottles, nipples and esophageal feeders. Read the label on the sanitizing product you use to ensure it is labeled as a disinfectant or sanitizer, not just a cleaner. Use sanitizers at temperatures and dilutions as directed on the label. 

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o Where possible, pasteurize the colostrum. Place colostrum in a pasteurizer for 30 to 60 minutes at 140ºF, then cool it down and feed. 

o Avoid the potential for spreading contaminated colostrum by keeping colostrum from each cow separate. Only feed colostrum from a single cow to a single calf.

Ongoing prevention practices

If adequate levels of high-quality colostrum are administered properly and timely, the calf should be well-protected in the first few weeks of life. Ongoing management practices will help protect the calf against the threat of salmonella.

  • Continue to clean. Proper sanitizing procedures should be part of any calf-care protocol. After every feeding, make sure anything that contacts calves or their environment is sanitized.

  • Consider calf handling. If calves are sick, make sure you care for those calves separately. Feed or care for them after all other animals are cared for, or dedicate one employee to only managing sick calves.

  • Watch grain transition. After birth, calves are most susceptible to salmonella during weaning. Make the transition as easy as possible by slowly stepping down milk feeding and stepping up starter intake. Avoid abrupt pen changes from single pens to large group housing that can add to stress. Slowly making changes over time will help reduce the stress of weaning.

  • Build resiliency. A healthy rumen environment helps establish strong immune function and can be a first line of defense against salmonella infection. In a University of Florida study, feeding refined functional carbohydrates (RFCs) was shown to bind pathogens and significantly reduce incidence of serovar Newport and serovar Dublin in calves.

Protect your workforce

Finally, keep in mind that salmonella can easily transfer to humans. Train your employees in proper hygiene practices, and provide designated areas to wash up with soaps and sanitizers. 

Attention to detail from birth through calfhood can help break the cycle of salmonella infection. Contact your veterinarian for further guidance.  end mark

Ruby Wu
  • Ruby Wu

  • Technical Services Manager
  • Arm & Hammer Animal and Food Production
  • Email Ruby Wu

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