The clinical case presentation that has been reported is:

1. Sudden reduction in feed intake with decreased ruminations evident on physical exam and rumination monitors.
2. Sudden decrease in milk production on a herd level. Individual cows that are more severely affected have milk that is yellow and concentrated with the appearance of colostrum.
3. Variations in manure consistency with the most common finding being tacky to dry manure, although some cows appear to have diarrhea.
4. Secondary infections such as pneumonia and mastitis.

The affected cases appear to be in lactation 2 or greater animals that are more than 150 days in milk. Calves, heifers, and dry cows appear not to be affected. Morbidity is around 10% of the animals. Cases present over a 7-10 day time period and the first herds report a return to near normal production in 3 weeks. Mortality is very low, however individual cows who do not return to production are being culled. Diagnostic labs that have received submissions have not identified an etiology.