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"Prepared" sale rams - how can you assess their flystrike-resistance?

There are many studs whose ram sale team are prepared to look their best on sale day. Unfortunately, that preparation can prevent an accurate assessment of a ram’s susceptibility to flystrike.

Rams that are jetted, shedded or coated will not be subject to the challenges that expose their ability to withstand body strike.

Jetting, crutching and mulesing can mask any hint of susceptibility to breech strike.

Certainly, not all “sale-prepared” rams are susceptible to flystrike, but how do you assess those that are?

1. Ask your stud exactly what they do in the few months before the sale to prepare their rams, so you know what to look for.

Rams are generally described as housed or unhoused. However, unhoused may not mean they have been exposed to rain. Coats may be applied—though they are generally removed some weeks before the sale so that the wool acquires a more natural looking tip. The rams may also have been run under cover every time rain is expected. Preventative flystrike products may also have been applied.

Note: Chemical applications to prevent poll strike in rams, especially those with horns, are a wise option.

2. Look for signs of body strike susceptibility

Fleece rot is the number one indicator of susceptibility to body strike, regardless that not all fleece rot advances to flystrike.

Fleece rot won’t be seen in rams that have been coated or kept out of the rain. Instead, you must rely on other less accurate indicators that could lead to fleece rot and flystrike. The important indicators are:

  • Poor conformation of the back or shoulders, with dips and creases that would hold moisture after rain.
  • Darker wool colour, as this reflects more sweat (suint), which can hold moisture.
  • Skin folds—while finer body wrinkle is not a cause of fleece rot, skin folds can contribute, especially just in front of the shoulder, over and down the side of the neck.

If the rams have been exposed to all the seasonal rain, but have received a preventative fly treatment on the backline, evidence of fleece rot could still be apparent in rams that are more susceptible.

Rams that have been housed are difficult to assess for bodystrike susceptibility.
Rams that have been housed are difficult to assess for bodystrike susceptibility.

3. Look for signs of breech strike susceptibility

The more of each of the following factors, the more susceptible the sheep will be to breech strike:

  • Breech wrinkle
  • Dag
  • Breech cover (bare area)

If the sheep are un-mulesed and well-crutched, you should be able to clearly see the level of breech wrinkle and breech cover (bare area), however, it will disguise dag.

Where sheep are crutched and dag has been removed, look for:

  • tell-tale remnants of dag down the legs
  • some sheep with bigger crutched areas than others.

For mulesed sheep (those with a scar line between the bare and woolly skin) look at the neck. Neck wrinkle and breech wrinkle are strongly correlated.

Some studs also provide Australian Sheep Breeding Values (ASBV) for breech wrinkle,  dag and  breech cover. EBWR (early breech wrinkle) is typically assessed at lamb marking, as is EBCOV (early breech cover). Dag is usually scored at a later age and the ASBV is LDAG (late dag).

For each of these ASBVs, lower, more negative, values will indicate greater resistance to breech strike.