cELISAs sold by VMRD are licensed for use in defined species. For instance, the test for antibody to Anaplasma is approved for use with bovi

Malignant Catarrhal Fever Virus Infection of Domestic Cattle and Other Susceptible Ruminants 

Question: Why is the IFA positive using VMRD E. canis substrate slides while with the same sample I get a negative reaction with an E. canis