Herd Testing

What do we test for?

 

I am a big believer in herd testing. I have tested yearly for CAE/CL/Johne's since 2021. I test CAE and CL on everyone older than 6 months of age by blood. I have historically tested Johne's by ELISA, but I had what I believe is my first "false positive" ELISA Johne's* this year.  As a result, after consultation with Dr. Michael Collins, DVM, PhD at the Johne's Information Center, annual screenings for Johne's will be tested only by fecal PCR. Per his recommendation, I will do pooled fecal PCRs on everyone 1 year of age and older going forward. I also like to test does that will be in milk for Q Fever, but I do not consistently test every doe, every year for this. I like to test for all 4 diseases on animals in winter. This is at least 3 months after show season, and milking season has slowed down or stopped. It also is the perfect time to test my does within a couple months of kidding to make sure everyone is clear before the avalanche of babies happens. Testing for CL is more accurate by testing abscesses. I have had 2 abscesses since I started raising goats. Every abscess has been sent for culture. Both were negative.

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*WADDL has stopped using VMRD ELISA test because of it's lack of specificity (too many false positives) as of June 1. 2025.

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So, what are these diseases?

​​Johne's Disease pronounced "yo-knees"

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https://johnes.org/goats/faqs/

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Here is a great video about Johne's Disease (MAP) by Dr. Michael Collins DVM at Johne's Information Center

https://johnes.org/presentations-and-mini-lectures 

(scroll down to Johne's disease in goats)​

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Click here to go to Cornell's website

​​A few quotes from Dr. Michael Collins, DVM, PhD, DACVM 

"Many people test for Johne's disease using a blood test, called ELISA. What they fail to understand is that the ELISA is only a rapid, low-cost screening test and cannot definitively diagnose Johne's Disease. Only by using fecal sample can a diagnosis of Johne's disease be confirmed. A single negative fecal PCR indicates that the goat is not shedding MAP in its feces at the time of sampling. It significantly raises the probability the goat is not MAP-infected. However, due to the chronic nature of this bacterial infection, repeat testing at one year intervals is advisable. After 3 negative fecal PCR tests done a year apart by qualified labs you can be 99+% sure the goat is not MAP-infected. I recommend breeders not use the ELISA but only use the fecal PCR."

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Click here to go to USDA page for list of approved labs. Scroll down to one labeled "Johne's disease-pooling methods'.

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CAE

Click here to go to Merck's Vet Manual

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CL

Click here to go to Merck's Vet Manual

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Q Fever

Click here to go to Merck's vet manual

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Information on Disease testing for goat owners

Click here to hear the podcast The Big 3:Testing your goats for CAE, CL, and Johnes 

Ringside with Dr. Melissa Holahan DVM

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