I would still test for johnnes , as I bought a Jersey heifer and bred her to calve at 2 , she had a nice heifer , I sent off a milk sample for mycoplasma testing because her calf developed an ear infection , and had them run BLV,BVD, and johnnes at the same time , she came back suspect on johnnes , so had fecal testing done and she was positive so both her and her calf went to butcher , luckily she had been kept seperated most of the time since she had calved , my other 2 cows were neg , and I am testing every 6 months , also left my pasture un irrigated with just a couple steers that went to butcher , I had always tested new cows in milk while they were in quarantine, but had bought this one at 300lbs so to young for testing , and there was nothing for me to think johnnes , she was a little thin but that is normal on some first calf dairy heifers
Suzanne