An Unexpected Guest - Giardia
Several farms in our vet practice area have experienced unusually heavy periods of rainfall in the past month - repeatedly. This precipitation resulted in runoff and flooding in places on the farm that are normally "high and dry."
The first dairy had their one of their well heads flooded. After a day of murky water all seemed to be back to normal. This well provides the water for calves. Currently we are watching the older milk-fed calves closely for diarrhea - giardia is a possible parasite about which we need to be concerned.
The second dairy had their hutches flooded. Water from fields above the hutches came downhill across a couple of hedgerows bringing mud and trash - what a mess. After hutches were moved and the mess cleaned up supposedly all was back to normal. Currenly we are watching the older milk-fed calves closely for diarrhea - we will follow up with fecal samples looking for giardia.
I am more oriented toward finding giardia problems when I discover a farm using pond water for calves during an extended dry period. I just was not thinking about how these unusual precipitation events would expose calves to giardia cysts (an egg-like structure) from the environment.
The spread of the parasite from calf to calf can be made worse if there is a delay in diagnosing the source of the diarrhea. Because coccidia are the most obvious culprits for diarrhea in older milk-fed calves frequently there is no fecal sampling done to confirm the cause - just treat for coccidiosis. Only when that does not work then fecal sampling is done - guess what? We can turn up the unexpected guests.
Fenbendazole treatments usually work. However, I am writing about this as a reminder not to make too many assumptions when diagnosing a problem.
Just a reminder if you have not worked with giardia recently - the cyst shedding does not stop when symptoms end. We have to be careful not to carry manure from these animals back into the calf barn or into the hutch areas.
For a primer on Giardia click HERE.