CASE NOTES
Erysipelas Arthritis in Two Year Old Crossbred Ewes
Bruce Watt, District Veterinarian RLPB Central Tablelands
Posted Flock & Herd August 2007
Introduction
Erysipelas arthritis is a common disease in Australian lambs and young weaned sheep. In most flocks, the prevalence is in the order of 1-2% but overall it causes significant wastage, as affected sheep are usually unsaleable.
History
The owner from northeast of Bathurst purchased 200, 10 month old Border Leicester cross Merino ewes from western NSW in February 2005. The ewes were shorn within a few weeks of arrival, treated off-shears with Magnum and were then joined. The owner shore the ewes again in October and treated them offshears with Magnum.
When he bought the ewes, the owner considered that they were in excellent body condition with no lameness. I was asked to look at the flock in February 2006 as most of them were in poor condition. As the ewes had large lambs at foot and pasture availability was limited, I advised the owner to wean the lambs. No lame ewes were noticed at this time although the flock was not thoroughly examined for lameness.
While most of the ewes recovered condition after the owner weaned the lambs, about 12 did not. Over the ensuing six months these ewes deteriorated and became so lame they could not walk. Four of these ewes died in the last two months.
Clinical findings
I re-examined this mob of ewes in August 2006. Three ewes of the flock of 180 were lame. Two ewes were in good body condition and were lame one only one leg with a swollen hock. However, one ewe was emaciated and was so lame she was reluctant to stand. If helped to her feet she was most reluctant to walk. Both stifles were firm and enlarged and crepitant on flexion. The right carpus was also swollen.
Crossbred ewe severely affected by Erysipelas arthritis
Post-mortem and pathology findings
This ewe was euthanased and post-mortemed. Both stifle joints and the right carpus were submitted intact for laboratory examination. The cortex of the bones above and below all joints were very thin and easily cut with a saw. Both stifle joints contained excessive reddish joint fluid while the joint cartilage showed multiple erosions. The joint capsule was also thickened. Erysipelothrix rhusiopathiae was cultured from one stifle joint and the carpus.
Discussion
Erysipelas arthritis occurs after a break in the skin becomes contaminated with the bacteria Erysipelothrix rhusiopathiae. In my experience most cases occur after marking and mulesing in young sheep. This case affected 2-3 year old ewes and has slowly become obvious after shearing, which it is presumed initiated this disease.