SPRAY RACE PUTS
ITS MOST NEEDED
With sheep producers on the lookout for effective alternatives
to dipping and pour-ons, mobile spray-races are becoming
more popular. David Cousins talked to a Worcs farming and
contracting family who designed and built their own
LACK of labour, health fears and the difficulty of disposing of used dip are making dipping steadily less popular.
The alternatives when it comes to fly control are two-fold: Pour-on chemicals, which are easy to use, but relatively expensive and can miss the underside of the animal. Or shower units, which drench the top and bottom of the animal, but can be slow to set up and bulky to transport.
Neither of them particularly appealed to Worcs-based farmer and shearing contractor James Brodrick and his father-in-law, Martin Jones. James and his wife, Rebecca, keep sheep on 80ha (200-acre) Newlands House Farm, near Droitwich. But the other string to his bow is contract shearing 30,000 sheep a year throughout Worcestershire. Martin, meanwhile, runs the family livestock farm at Hindlip.
When it came to adding sheep-jetting to their contract repertoire, the family decided to build their own from scratch. Both Martin (who, usefully, has a background in agricultural engineering, too) and James have years of experience of sheep in all their different forms and it did not take long to come up with a list of requirements. In particular, any machine needed to have a self-contained 1000-litre (220gal) tank, fast switch-on-and-off pumps, somewhere to store the used dip and be quick to set up and transport.
While design was a joint affair, it was Martin Jones who did the building. The final machine was finished in May after two weeks of fairly continuous work. Based on a tandem axle trailer, it has a plastic 1000-litre tank and twin electric-powered 1.1kW submersible pumps.
Strictly speaking, one pump would have done the job, but James and Martin wanted to have surplus pressure on hand, plus a back-up should either pump pack up. Liquid goes to a total of seven 15í pencil jets, five on top and two underneath.
Getting the jets to play on the right parts of the sheep for the right length of time was the tricky bit. A magic eye tells a solenoid valve to open as soon as its beam is broken. The jets then start spraying just behind the sheeps ears and finish by meeting at the tail area. That way, liquid is kept out of the eyes and maximum spray goes where it is needed.
"About 1 litre of liquid goes on to each sheep, so we can treat 1000 sheep with one tankful" says Martin. "We know that very little runs off, as even after 1000 sheep have been through, there is very little liquid left in the returns tray underneath the trailer."
One of the potential shortcomings of any spray system is that chemical does not reach the parts that it would with a dip. But the two men say the chemical penetrates through the wool on to the skin and then back through the wool again. Mr Brodrick adds that his own sheep that have been through the sheep jetter now go longer between fly-control treatments than they used to, even in a bad fly year like 1999.
No need to recycle
With wastage negligible, there was no need to recycle liquid either. Which means no need for extra filters on the pumps and no worries about exhausted chemical either.
Benefits? "It only takes about five minutes to set up," says Mr Brodrick, "and you can set up anywhere. It is also less stressful on the sheep and the handlers than dipping."
Any drawbacks? "Not really. Sheep that are only handled rarely can be a problem, but once you get the first one through, the rest seem to follow. You can sometimes get a sheep that is slow to pass through, and there will be run-off with that. We are hoping to have treated 40,000 sheep by the end of September."
James Brodrick and Martin Jones plan to market the machine and have a smaller, farm-scale machine in the pipeline for those with 500 ewes plus. They can be contacted on 01905-798398.
• For details of off-label use of dip products, see FW July 30 p37.