Botulism in an Oregon dairy cow herd

Area of Science:

• Veterinary Medicine
• Animal Toxicology
• Food Safety

Background:

• Dairy herds are susceptible to various diseases affecting cattle health and productivity.
• Forage preservation methods, such as using pit silos for high-moisture feed, can influence microbial contamination.
• Botulism is a severe neuroparalytic disease caused by Clostridium botulinum toxins.

Observation:

• A dairy herd in Oregon experienced a high mortality rate (14 out of 18 sick cows) despite treatment.
• Clinical signs included anorexia, severe depression, and reduced milk production.
• Necropsy findings were limited to abomasal hyperemia and a dilated, gas-filled large intestine.

Findings:

• A tentative diagnosis of botulism was made based on clinical signs, necropsy, and response to treatment.
• Laboratory confirmation was achieved through mouse inoculation tests, where corn extract proved lethal to unprotected mice.
• The outbreak was linked to the consumption of high-moisture whole corn and haylage stored in pit silos.

Implications:

• This case highlights the risk of botulism in cattle associated with specific feed preservation and storage methods.
• Implementing strict feed hygiene and testing protocols is crucial for preventing botulism outbreaks in dairy operations.
• Understanding the source of contamination is vital for effective treatment and future prevention strategies in livestock management.