PRUDENT PROCEDURES FOR DIPPING

Press, Volume CI, Issue 29994, 1 December 1962, Page 6

PRUDENT PROCEDURES FOR DIPPING

For the benefit of sheepfarmers the Department of Agriculture has prepared a brochure about dips and dipping. The brochure offers no new or easy answers to problems associated with dipping but sets out prudent procedures that should be adopted with the various methods of dipping and spraying and dusting that are now in vogue. The brochure is the outcome of a survey conducted throughout the country in July and August when lice infestation in breeding ewes and sheep in general reached alarming proportions in many areas, and particularly in stronger woolled sheep in the drier areas.

Details of the brochure were discussed in Christchurch this week by the livestock superintendent of the department, Mr M. C. Armstrong. As a result of the survey the department found that failures had occurred with all registered dipping materials and all methods of application, including complete saturation in plunge and shower dips, but on the other hand trials had proved the efficiency of the registered materials which were available.

Investigations of the reasons for these failures had shown a lack of appreciation of the basic requirements for effective parasite control on a flock basis. The department makes it crystal clear that there is no chance of dieldrin or aldrin being reinstated. It states that they are “absolutely prohibited and there is no possibility of their re-approval.” Of the dipping materials now available it is emphasised that arsenic, Asuntol and Delnav are suitable for plunge and shower dipping only and only Diazinon and Nankor are suitable for all methods of application. Basic requirements laid down in approaching treatment of sheep for external parasites are that the user should read and follow instructions set out on the label, the method of treatment should be efficient, and the maximum wool growth specified on the label should not be exceeded. It is noted that arsenic alone is not completely effective against keds or ticks.

Dealing with plunge dipping the department says that it is very effective, gives complete saturation, and the fleece is loaded with insecticide.

For efficient plunge dipping it says that the capacity of the dip must be accurately known. Reinforcement and replenishment of wash must be according to instructions. Reinforcement is the addition of extra dip concentrate without extra water to replace the insecticide removed by the sheep and replenishment is the addition of insecticide and water to restore the working level of the wash. Reinforcement was essential with all dips except arsenic and Asuntol. The constant replenishment method using a supply tank was a recommended pro-

cedure. It was simple and effective. Constant replenishment was obtained when fresh dip was constantly added and the wash was maintained at a constant level

In addition the department recommends that hot, timed or thirsty sheep should not be dipped, a start on dipping should be made early in the day and it should also stop early. a good drying day should be ahosen for dipping but not an extremely cold or hot one, the dip Should be clean before dipping and sheep should be clean and daigged before dipping and, if possible, held in the yards overnight before dipping. Dipping should not be hurried and each sheep should be ducked twice. The dipping crutch should be used carefully and a sheep should never be J ducked when it is coughing. Wet sheep should also not be moved far.

The department says that shower dipping is also a very reliable method. When it is used properly it will ensure complete saturation. It is best done soon after shearing.

Here the recommendations are to follow the directions for mixing the dip carefully, pay attention to reinforcement as well as replenishment, make sure the pressure is adequate, check for clogged nozzles or foot valve regularly throughout dipping, check that strainers are doing their job, keep sheep in long enough to saturate the skin (three to five minutes according to the wool growth) and inspect a few sheep from time to time to see that they ane saturated. On tip spraying, the department says that this is effective but extra care is required with every sheep having to be sprayed all over —a sheep missed or partially sprayed may be a lousy sheep. Spraying should also be done within the time recommended by the dip manufacturers —it is only effective on sheep soon after shearing. Other precautions recommended include checking that no nozzles are blocked, checking the pressure on the gauge before starting and at regular intervals, following the mixing directions exactly, the race should have guide rails to keep sheep in single file, the race should be silted uphill and away from the sun, the race should be

shielded from the wind, sheep should be moved through steadily and no effort should be made to break records, pressure should be built up before each nun of sheep enters the race and there should be enough manpower to do the job properly Dusting is described as being effective if properly used at the right time. It must be used on short woolled sheep only within the recommended time off shears, there must be protection from the wind, sheep must be fed into the race steadily, the race should be sited carefully uphill and away from the sun, it is necessary to check that the motor is running properly and the rate of delivery of the dust.

It is stated that farmers should regard blow-fly strike as a separate problem from lice and ked control. Preventive treatment should be timed as near as possible to the expected fly wave, plunge or shower dipping and jetting are all effective, only the organo-phosphorus compounds give useful protection and concentrations used are higher than in normal plunge or shower dipping. Jetting has advantages for the farmer who sprays or dusts off shears, it is stated. It allows accurate placement of insecticide on the localised susceptible areas crutch, body or head—later in the season when the fly is active. Use of the multiple nozzle "combing” or "raking” method is essential, the treated areas should be soaked to the skin, correct placement of the dip is important, and the concentration of the wash must be in accordance with instructions and a pressure of 601 b to 801 b is recommended, with a lower pressure for lambs. Itch Mite Good control of itch mite can be obtained with arsenical dips, according to the brochure, with eradication being possible with lime sulphur dips used within three weeks off shears.

"Even if you use an approved dip at the right strength—reinforced and replenished as directed —at the right time after shearing with every precaution—you will not get rid of lice if your management fails to ensure that every sheep on the property is dipped at or about the same time.” adds the department. “If only one or two sheep are missed, if the rams are not dipped, if the killers or the pet lambs are left out. or if the main flock is dipped and others left until later, you will fail. One lousy sheep can reinfest the whole flock when the residual effect of the dip wears off. All sheep brought on to the property must be dipped before entering the flock, and this includes rams.”

And on a key issue, the department expresses the hope that farmers should try to dip their sheep at or about the same time as their neighbours.