Spray

• Used to treat most ectoparasites including ticks, lice, buffalo flies and occasionally mites.
• Some sprays are high volume and require several litres be applied as a full body spray, all over the body for good effect, for example with ticks and lice, whereas others, usually for buffalo flies, may require lower volumes applied along the backline.
• Some insecticide spray products come as ready-to-use formulations, but most must be diluted with water before application.
• Sprays have the advantage that they give a rapid reduction in pest numbers. However residual effect is usually less than 2-4 weeks and frequent re-applications may be required.
• Experienced, careful management is important for effective application.
• Follow label instructions and ensure appropriate personal protective equipment is used.

Resistance

A parasite population can develop resistance to a chemical through:

• repeated use of the same active.
• repeated overuse of a chemical (unnecessary treatments).
• Under-dosing of chemical (eg by poor application technique, under-estimating the weight of animals being treated, uncalibrated dosing).
• unintentionally exposing non-target parasites to chemicals (eg some products used to treat ticks or lice can also affect worms).
• widespread or repeated use of the same chemical group.

What is resistance?

Pros

• On contact kill provides instant relief.
• Relatively cheap.

Cons

• Most products require dilution prior to application.
• Chemical concentration of spray fluid must be maintained.
• Repeat treatments may be required.
• May have longer export slaughter interval (ESI).
• Some products may be toxic to dung beetles.

Safety

• Risk of inadvertent chemical exposure. With hand spraying, close proximity of the operator to the spray wand and treated cattle presents a significant risk from deflected sprays and inhalation of aerosol droplets.

Everyone working in the rural industry has a ‘duty of care’; a legal obligation to provide a safe workplace for everyone on the property.

Other information

How it works

Spraying for parasites can be conducted with handheld sprayers, desirably powered by a fuel or electric pump, or with the use of a spray race where cattle walk through a ‘tunnel’ of spray nozzles strategically mounted to give complete body wetting of treated animals.

Hand spraying and race spraying is generally relatively inexpensive and can be used for opportunistic treatments, when cattle are in yards for other husbandry purposes, or where only low numbers of cattle are to be treated.

Hand spray

Handheld sprays are a relatively cheap option, but formulations must be mixed carefully according to label instructions and applied thoroughly to achieve good effect. Cattle should be treated in a race rather than a holding yard to ensure correct application and make sure that all areas on the animal where lice may be present are thoroughly treated. As a guide, and depending on animal size and hair coat, between 4 and 10 litres of spray may be needed per animal for good effect. Ensure there is sufficient pressure to completely saturate the hair coat to skin level. Thorough application will be particularly critical for good effect on animals with a winter coat.

Figure 1. Spray race. Image courtesy of Queensland Department of Agriculture and Fisheries

Spray race

Where available, and where a larger number of animals are to be treated, spray races may also be a suitable option for treating lice. When using spray races, it is important to ensure that each animal is calm and walks slowly enough through the race to get properly treated. Check periodically to ensure that all of the jets are working properly, and none have become blocked. Ensure there is sufficient pressure to completely saturate the hair coat to skin level. Thorough application will be particularly critical for good effect on animals with a winter coat. The chemical active in some products can ‘strip’ from the dip, meaning the concentration of chemical active in the returned wash may decrease as spraying proceeds, so pay particular attention to the label instructions to ensure that correct concentrations are used when the chemical sump is ‘topped up’.

 

Figure 2. The spray race completely coats the animal as it walks through the race. Image courtesy of Queensland Department of Agriculture and Fisheries