Thursday, October 09, 2008

Crutching, it's not a dirty word

Why have we been so busy recently?
"Farm stuff" is the usual explanation, but I thought I might provide a bit more detail on what that "stuff" actually is.

Recently it has been pretty wet down here. We've had some unseasonal late rains, which is good for filling dams to capacity before summer, but not so good for poor suckers who've cut their hay in the last couple of weeks. The hay lies on the ground to dry out for a little while before its baled, but if it was cut just before these weird storms started, it will be all wet and soggy and starting to go mouldy, and might be unusable. Luckily we haven't cut ours yet (we were thinking about it, but procrastination can sometimes be a wonderful thing).

More importantly, all those alternating heavy storms and hot sunny days provides the perfect breeding weather for the evil blowfly (Lucilia cuprina) and its cousins. It might have a pretty name, but its a very nasty little creature.

Sheep who have been going all-out on the lush tasty green things in the paddocks tend to get an upset tummy around this time of year. Because they are pretty woolly coming up to shearing time, they can get a bit dirty around their backsides, and Evil Lucy and her family take the opportunity to infest the dirty britches. The warm, moist, stinky environment of a dirty sheep bum is perfect for maggots to hatch, grow and start eating the sheep flesh. That's called flystrike. First it causes pain to the sheep and extreme nausea to people smelling it, and then it kills the sheep.

This is what it looks like, once cleaned up:

Imagine that area of your body being chewed up by maggots. It isn't very nice.

Flystrike tends to be worst in sheep who have the runs (diet and worms are big factors here), in sheep with long tails and wrinkly bottoms with lots of wool (merinos in general and particular lines especially), and there seems to be a genetic susceptibility to flystrike in some sheep.

Various methods are used to reduce rates of flystrike:
- Docking tails of young lambs short

- Reducing the wrinkliness and wooliness of the skin around the sheep's bum has traditionally been achieved by mulesing (cutting away a small patch of skin in this area when merino sheep are lambs). This pulls that skin tight and reduces the wool growth in the area, and is one of the most effective methods of preventing flystrike in susceptible sheep. Mulesing is generally done by trained, accredited people, and in recent years we've been using a local anaesthetic/antiseptic spray called Tri-Solfen to minimise discomfort for the lambs. Due to campaigning by PETA, mulesing is supposed to be phased out by 2010, although alternatives such as intradermal injections and clips to achieve the same effect are not yet available, and the RSPCA still supports mulesing as a preferable option to flystrike.

- Effective worm control to minimise dirty bottoms can be achieved by drenching appropriately with medication, and by breeding for worm resistant sheep. Drench resistance among worms is becoming an increasing problem, and cleverer drugs are always needed.

- Breeding sheep that are naturally bare-breeched or less wrinkly ("plain"), and sheep that are otherwise resistant to flystrike. There are all sorts of breeding programs trying to achieve this at present, from merino-only selection programs to crossbreeding.

- Regular cleaning of sheep's bottoms, by shearing away the daggy wool. This is called crutching.

- Applying chemicals to the sheep at high-risk times, either by jetting (soaking the sheep in the liquid chemical mix with a big hose and pump) or backlining (more localised spraying of concentrated chemical, usually just after shearing).
From The Boys

We run a fairly plain sort of merino, based on Merinotech genetics, which aims for worm and fly resistant sheep. As of this year, we've stopped mulesing our merino lambs (crossbred lambs are never mulesed) and we're going to see how we cope. Part of coping will probably be crutching more frequently- and after the weather we've had in recent weeks, the flies were starting to go mad and we had some rather urgent universal bum-trimming to do.

This is how we do it:

A mob of sheep in the yards:

They are brought through the yards, along a race and up a ramp to the crutching cradle. Our crutching cradle is a 3 stand Harrington (I think). The whole thing is mounted on a trailer, so you can just pack it up and move it around wherever the sheep are. The rolly thing on the top is an extendable shade cloth.

Basically it's like a long race with cut out sections on the side, covered by curtains so the sheep don't know they can jump out. There is a "Judas sheep" penned at the far end to encourage the others to walk up the ramp and along the race, where they stand beside the curtains. One minute they're standing quietly in this enclosed race, the next minute a pair of hands reach in from the side, pull them sideways off their feet through a plastic curtain and onto their back on a cradle, where their hind legs are hooked behind a bar and before they know it, they're having their bottom groomed. Then with the pull of a lever, the cradle tips up and the sheep is plonked unceremoniously onto the ground, free to run off and join its clean-bottomed mates.

At least that's the way its supposed to work. In practice, the sheep are unenthusiastic about walking up the ramp, let alone all the way along the race, especially with the shearing machines whining loudly on both sides, and they don't enjoy being tipped into the cradle or having their bums shorn, so they tend to react by kicking out. Tempers can fray on all sides of the cradle.

The dogs and I are in charge of "pushing up", which means keeping the sheep flowing, from the big yards, into the force pen, along the race and up into the cradle. Sometimes this involves barking, and backing up along the race to encourage sheep to stand up, turn around, and just get up to the b@#$%y cradle. Usually I leave that to the dogs. Sometimes we muzzle the dogs to avoid any marks of "encouragement" on the lambs which will be heading off for sale. Its good for dogs to get used to working with a muzzle on anyway, because a lot of feedlots and saleyards require all dogs to be muzzled.

Pinky in the force:

Bill in the force:

Bonnie and Charlie pushing up in the force:

Bonnie in the race:

Muddy in the race:

Jim being bored:

Young Tom enjoying his first day in the yards:

Esme is in charge of eating sheep poo:

"No sir, I wasn't staring at you, sir, I swear!"

And BabyJ is in charge of splashing in the dogs' bucket, looking adorable, and not eating anything poisonous in the shearing shed:

The end result, a clean bummed crossie heading back to his mum:

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