Calves get more than one kind of scours

Scours is probably the most predictable part of raising calves – so predictable that maybe the only way to not have scours is to not have calves.

Dairy producers tend to see scours arrive on their farms at the same days of age for each batch of newborns, but that age tends to vary for each dairy. Few are likely to know what kind of scours they’re dealing with, even though the age at onset and the severity are big clues to which bacteria are involved.

There are actually four main pathogens that cause scours and several other minor ones, says Jerry Olson, a senior veterinarian with Pfizer Animal Health:

• During the first week of life, the prime suspect of scours is Escherichia coli K99.
• In later cases (up to a month of age) the prime suspects are rotavirus serotypes G6 and G10.
• Coronavirus also tends to be seen in calves over a week old, but it generally produces more severe scours because it affects both the small and large intestine, whereas rotavirus affects only the small intestine.

The most efficient way to manage scours is to prevent it. Veterinarians recommend doing this by vaccinating the dam against all four pathogens, so that passive immunity is transferred to the calf in its colostrum.

Ideally, says Olson, this should occur far enough ahead of the closeup cow’s “colostrum concentration window” which peaks about two weeks before calving, so that maximum antibody levels are also present in the blood.