Pesticide usage report: Sheep treatments 2005

Summary

This report presents information from a survey of the practices and types of control for ectoparasites on sheep in Northern Ireland in 2005. It will also provide comparative data to that obtained in the previous survey in 1997 (Jess et al., 2000).

The total number of sheep in Northern Ireland decreased by 25% to 8,822 farms with a consequent 26% reduction in total sheep population to 2.1 million sheep compared with the previous survey in 1997. During this period, the number of sheep treated for ectoparasites decreased by 40%. The total quantity of organophosphates (OP) compounds used for ectoparasite control decreased by approximately 67% from 7.8 tonnes in 1997 to 2.6 tonnes in 2005, during which, an estimated 38% of all sheep treated for ectoparasites received the OP active ingredient diazinon.

The survey results indicate a decline in the practice of plunge-dipping sheep for ectoparasite control with the proportion of farms using this treatment method decreasing from 58% to 16% between 1997 and 2005. In 1997, an estimated 80% of all sheep treated for ectoparasites in Northern Ireland were plunge dipped, which reduced significantly to 28% in 2005. Conversely, the use of alternative methods have increased with pour-on formulations of insecticides, macrocyclic lactones and growth regulators being applied to 33% of all sheep treated in 2005 compared with 9% in 1997. Use of intramuscular or subcutaneous injections of macrocyclic lactones for ectoparasite control has also increased to 24% of all sheep treated in 2005 compared with 10% in 1997. The proportion of sheep treated in communal spray showers also increased from 1% in 1997 to 14% in 2005.

Control of blowfly maggots, (Lucilia spp.) and prevention of sheep scab (Psoroptes ovis) were the main reasons given by farmers for sheep treatments.

Of the farms that plunge-dipped, an estimated 68% of surplus dip wash was disposed of immediately after dipping took place, with 80% of farms emptying the dipping tanks using a vacuum tanker and 54% spreading the dip wash directly onto land. An estimated 35% of farmers mixed the dip wash with slurry pre-disposal.

The survey suggests that the products used for spray showers are those recommended for plunge-dipping as there are no contemporary products recommended for use in spray showers. Macrocyclic lactone injections recorded in the survey had the dual function of controlling both endo- and ectoparasites.

For further information on this work please contact: Pesticide usage monitoring group