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FARMER EXPERIENCE - CHEMICAL RESISTANCE IN LIVESTOCK

Bert Barnes

“Waterloo”, Hay

We bought ‘Waterloo’ in 1951. We also bought the Merino sheep. The property had a plunge dip.

The only sheep brought onto the place were Merino rams. We dipped every second year, about three weeks off shears, with arsenic-based dip, and had no lice problems. It was just a formality to dip. This went on until 1968.

During the 1967 drought we had our sheep on the road for twelve months. We brought them home in May 1968. They were shorn in July and had a light infestation of lice. They were dipped in arsenic-based dip in the plunge dip. Next shearing there was no sign of lice. We went on dipping every second year.

We sent the sheep on the roads again in 197 1, brought them home in January 1972, shore and dipped them. In August 1972 we bought a Sunbeam shower dip, because it was getting hard to find labour to work the plunge dip.

The years 1973 and 1974 were very wet and mustering conditions were very bad, both for us and our neighbours. There was lice in the area and we used Harts 400 arsenic-based dip in the shower dip and had no problems with lice. Both the spray and plunge dips operated well when the chemical was satisfactory.

In October 1981 we bought 600 wethers from the Hay saleyards. When we shore them in March they were lousy. We used Red Clout, and when we put them back in the Hay saleyards in June, the Ranger checked them and found no lice.

We spray dipped our own breed of sheep with arsenic dip until 1985.

Clout-S was used in 1986. A stray sheep was later found in our mob and it was lousy.

We are always conscious that clean musters are essential and whenever stray sheep

are found in our mobs they are brought home and dipped by hand. When we shore in

1987 there were quite a few sheep showing lice.

We got in touch with Paul Kingston, the Cooper representative. We decided to use Clout-S to double strength, with the information that it would not affect the sheep - it did not affect the lice either! This may have been when the strong resistance to the chemical started! On inspection six months later, there were signs of lice again, so Paul suggested to hand jet with Grenade to see us through the shearing. In February 1988 he came out and demonstrated how to do it. By shearing time the sheep were rubbing and we had seven bales of lousy wool.

The ewes shorn in January 1989 still had lice but not as bad. We shower dipped them with Top Clip Blue. We shore the lambs in September and shower dipped them in Asuntol, which seems to be holding OK, so hopefully we are winning at last.

What I would like to see is that, before something that works is taken off the market, something else as good or better should be available.

The manufacturers of new products should have them well tested and tried out to make sure they are effective before they go onto the market, so that the farmers have some protection.

A report from the Western Australian Department of Agriculture in “The Southern Rural” paper of January 27, 1989 indicated that some pour-ons needed to be used at eight times the recommended dose rate to achieve eradication.

When we were having the earlier lice problem, I saw the Vanquish advertisement which read: “Introducing Vanquish long wool treatment. The first and only backline long wool lice treatment that gives you a total kill of lice”. The same advertisement also read: “Vanquish long wool backline treatment gives you the means to eliminate lice completely in virtually any wool length”. This sounded too good to be true, so I rang the representative in Echuca and asked him if the chemical was that good and would he guarantee it? He said no, the advertisement did not mean that it would kill all lice. I said the advertisement did say it! With advertisements like that what protection has the farmer got?

On November 16, 1988 we had the lice tested for resistance by Dan Salmon, the Pastures Protection Board Veterinarian from Deniliquin. The result confirmed that the lice were resistant.

George Downing, Sheep and Wool Officer, Department of Agriculture, brought some blue dye out to check our shower dip. On inspection, after the first shower, some dry patches were found on a couple of rams. They were dipped again and came out satisfactorily. On January 3,1989 he also conducted two trials on lice from our ewes for resistance to Grenade. Tubes containing pads with different concentrations of Cyhalothrin were kept refrigerated, following arrival, until required.

The results of both tests showed some degrees of resistance.

We also sent two sheep to Glenfield Veterinary Laboratory for the lice to be tested for resistance. There were varying degrees of resistance.

We live 52 miles out of Hay and on the way in and out of town we see lousy sheep in paddocks. From speaking to people, we find that a lot of them are also having trouble with lice resistance.

Since more people are acknowledging that they have a lice problem, we are of the opinion that, to date, there is no really satisfactory solution for lice control!

Our lice problem has cost us a considerable amount of money, both in chemical costs and loss of wool price. Now with the lower wool prices, it is more essential to be able to present our clip free of lice-affected wool.

We attended a lice demonstration at the Deniliquin CSIRO Field Station and the lecturer recommended Asuntol dip, mainly because the directions were clear and easy to follow.

We think the instructions on the use of the various stripping dips could be clearer!

We had something that was good and it was taken away before there was an effective replacement!

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