A producer in the Young district recently rang up enquiring about his liver fluke and worm test results. On discussion with him, he was suspecting liver fluke or heavy worm burdens in a mob of 6 year old merino ewes because 4-5 of these ewes had died recently showing signs of bottle jaw. The liver fluke and worm test results were negative ... and these ewes were also considerably light in body condition in comparison to the rest of the mob. Cases had been spread over a couple of months, not a few days / week as first implied.
A property visit and a post-mortem on one affected ewe was undertaken. The affected mob consisted of approximately 500 ewes with about 30 affected and 5 dead. Most of the ewes were in condition score 2.5 - 3.0 but the affected 2000 drop ewe was score 1.5.
The ewe had no internal abdominal fat remaining despite heavy hand feeding. There was moderate to severe thickening of the terminal jejunum, ileum and ileo-cecal valve. Lymphatic cording was quite obvious.
Histopathology reported severe granulomatous enteritis and lymphadenitis; mild granulomatous hepatitis and large numbers of acid fast bacteria on ZN Stain. All leading to a positive histological diagnosis for Johne's Disease.
This flock has been vaccinating lambs for 3 years and usually culls older ewes at 4-5 years but because of the drought and reduced numbers, they decided to keep ewes to a bit older age. This was a previously undiagnosed flock and had never seen losses previously of this kind.