This season’s lambs are beginning to arrive, so for many it’s time to think about lamb marking. For most producers, tail docking is part of the marking procedure. It’s a management tool that has great benefits in reducing the likelihood of blowfly strike – a disease dreaded by sheep cockies because of its serious welfare implications.
When planning to tail dock, there are a few things to consider, such as what tool to use (knives, elastrator bands, or gas knives are all commonly used), and what age to mark. Another important consideration is tail length.
If you dock tails too long, you run the risk of a higher incidence of the problems associated with undocked sheep – faecal dags and fly strike. But I don’t often see tails left too long; it’s tails that are too short which are usually the problem.
Excessively short tails predispose sheep to a range of health issues.
Ewes with very short tails are more likely to develop skin cancers around the vulva, which can make them unsuitable for breeding. The simple fact that a longer tail stump covers hairless skin in these areas means that there is far less sun exposure and discomfort.
Docking tails too short can also increase the incidence of bacterial arthritis in lambs. Recent work from South Australia showed an association between short tail docking and arthritis. Arthritis in lambs often begins with an infected skin wound (such as those caused by marking, mulesing, or shearing), which spreads to joints via the bloodstream. The economic cost can be significant, due to carcass trimming, downgrading, or condemnation at the abattoir.
A third problem potentially associated with short tail docking is rectal prolapse. I have seen a number of cases – both in lambs and older sheep. I’ve found excessively short tail docking (often leaving no tail stump at all) resulting in rectal prolapse most common in meat breeds of sheep, including stud animals.
I think this is because, in these breeds, tails are docked short to (in the words of one researcher) “create an illusion of greater rear leg muscularity”. This supposed cosmetic improvement just isn’t worth the potential side effects.
All well and good, but what is the correct length to dock? A common recommendation (advice given from way back in at least the 1940s) is to dock below the third palpable joint. This means that there are three tail bones in the tail stump. This advice is still pretty sound.
Visually, another way to make sure the tail is long enough is to ensure that, in ewes, it covers the entire vulva.
Getting tail length right isn’t hard, but can have significant benefits for your sheep.