Salmonella in Dairy Cattle

Posted by Dr. Sara Barber on June 14 2003 13:40

What is Salmonella?

• Salmonella is a bacteria
• There are many types of Salmonella
• There are NO normal strains of Salmonella but there are strains that cows can carry which do not cause disease
• Salmonella is more common during July-October

How prevalent is Salmonella?

• 93% of farms had at least one-positive isolate
• High levels are found on only a few farms
• 3% of positive samples were Salmonella typhimurium

What types of Salmonella are a problem in cattle?

• Salmonella typhimurium
  
  • Systemic illness
• Salmonella dublin
  • Very pathogenic to humans
  • Severe calf diarrhea

• Culture will determine that the Salmonella are present but the type must be determined by advanced testing
• This testing is only done at NVSL in Ames, IA
• This testing takes 4-6 weeks to complete

Two most susceptible animals on the diary farm

• Baby calves
• Fresh cows

What problems would I see with a Salmonella infection?

• Systemic Salmonella infection
  • Salmonella typhimurium (1-2 months)
• Fever
• Invasive, infammatory Diarrhea
• SICK- Salmonella produces endotoxin
• Pneumonia
• Dehydration

What problems would I see with a Salmonella infection?

• Salmonella dublin
• Can have subclinical carriers
• Normally only shed a few bacteria unless they are stressed
• May be poor-doers in times of stress (such as freshening, post surgery) 
• Shed in feces
• Can cause severe diarrhea in calves

How is a cow infected with Salmonella?

• Fecal-oral transmission
• Sick cows shed very high numbers of Salmonella
• Will shed in the milk- WASTE milk will infect calves
• Very contagious
• Can get in the bloodstream and become sytemic
• Feedstuffs have been found to be contaminated with Salmonella

How can Salmonella infection be diagnosed?

• Culture tissues or fecal samples
• Blood test to determine carriers
  
  • Will be seronegative in 4-5 months

How can I treat Salmonella?

• Banamine
• Oral Fluids
• Antibiotics- Run sensitivities
  • Ceftiofur, florfenicol, ampicillin
• Probiotics
• Nursing Care

Salmonella Prevention

• Bacteria killed by sunlight and drying
• Don't house sick cows with fresh cows
• Purchased animal biosecurity and history
• Calf vaccinations

Salmonella Summary

• A positive culture needs to be correlated with clinical signs
• Transmitted via feces
• Clinical and subclinical types
• Treat aggressively
• Purchased animal biosecurity and vaccination on positive farms