Salmonella bacteria are a major cause of diarrhea in recently freshened cows — that is, those that have just calved — as well as calves less than a month old. Both groups have weakened immune systems, making them vulnerable to infection. Changes to a cow’s feed during this transition can also alter protective gut bacteria, leaving the digestive tract vulnerable to salmonella infection.

Affected animals shed these bad bacteria into the environment along with their waste. Therefore, flushing that material down barn alleys and recycling water for drinking practically invites infection. In fact, any part of the environment contaminated by bacteria-laden waste is a potential new source of illness.

That’s why strict environmental management and isolation protocols for affected animals are key parts of breaking the cycle of salmonella infections.