There were many calls from sheep producers last year concerned about the number of lambs they had affected by arthritis, particularly in late lambing flocks.
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Most cases seemed to develop after marking or mulesing, although some producers noticed lambs affected before these events.
Animals are at risk of developing arthritis when any open wound becomes contaminated with bacteria, as this can allow entry into the blood stream.
Young animals are particularly susceptible because blood vessels in developing joints are very small, and bacteria can get stuck and lodge to set up infection.
Any open wound is a risk, although the bigger and deeper it is, the greater the risk - a wet navel after birth, wounds from marking or particularly mulesing, or even grass seed and shearing wounds.
Suppurative arthritis occurs when everyday environmental bacteria are involved. It causes large, knobbly, painful joint/joints which may ooze 'pus' if they burst.
There is also erysipelas arthritis, which is caused by a specific bacteria - Erysipelas rhusiopathiae. This bacteria survives in the environment too, but can also be carried and spread by healthy, adult sheep. Erysipelas causes joint swellings, but over a longer period of time, resulting in a more chronic arthritis. Joints are thickened and firm, and will contain a cloudy fluid rather than pus.
There is a vaccine available for erysipelas which can be given both to pre-lambing ewes, and lambs usually at marking and weaning. There is no vaccine for the various types of environmental bacteria which cause suppurative arthritis.
Key points to minimising arthritis:
- Choice of lambing paddock - A heavily contaminated environment will predispose newborn lambs to navel infections. It is also suspected that wet paddocks with long, lush feed last year created problems, firstly by not allowing navels to dry and heal, and then later interfering with healing of marking/mulesing wounds.
- Excellent principles at marking/mulesing
- extreme care with handling both before and after the event,
- marking in the cleanest environment possible - avoid sheep yards where possible!
- aseptic and sound techniques for marking/mulesing - particularly docking tail length,
- best practice use of pain relief.
- Timing is also critical, with flies more likely to be a contributing factor the later in the season that marking/mulesing occurs.
- extreme care with handling both before and after the event,
- marking in the cleanest environment possible - avoid sheep yards where possible!
- aseptic and sound techniques for marking/mulesing - particularly docking tail length,
- best practice use of pain relief.
- Timing is also critical, with flies more likely to be a contributing factor the later in the season that marking/mulesing occurs.
- Vaccination against erysipelas - While it appeared that the most 'obvious' cases of arthritis in lambs last year were attributed to suppurative arthritis, production losses related to erysipelas arthritis while usually more subtle, can also be significant, and there is evidence to suggest that including erysipelas vaccine in your program will be of benefit.
If you have any questions on this topic, please get in contact by calling the Central West Local Land Services Forbes Office on 6850 1600.
