Aussi flies strike

Ruapehu Bulletin, Volume 6, Issue 310, 24 October 1989, Page 13

Aussi flies strike

An increase in the problem of flystrike in sheep in the Waimarino prompted a recent seminar in Raetihi. The seminar was addressed by Dr Allen Heath of the Wallaceville Animal Research Centre, supported by technical representatives of Youngs Animal Health, Coopers Animal Health, Ciba Geigy and the T aihape- W aimarino Veterinary Club. There is an increase in the flystrike problem due to temperature changes and increased rainfall, factors which are likely to be exacerbated by the Greenhouse effect. In those conditions there is an excellent breeding ground for flies with ample sugar from flowering scrub and protein from excreta and carcasses. According to Dr Heath some farmers are over-optimistic in their dip performance expectations. He said 4-6 weeks is the maximum

period of fly dip protection and that the criteria is different from one farm to another for techniques depending on sheep and wool types. Dip exposure time is generally too short, with the longer an animal is in the dip solution the better the chemical transfer to cover and protect the animal. The period should be at least six to eight minutes for sheep with eight weeks' wool growth. Other useful dip tips given were: the sump should be cleaned out regularly and animals should be emptied out before dipping to prevent contamination of dip solution; don't provide any drain out time and this can lead to dip solution contamination; the longer the wool the longer the dip time; dip at appropriate period (ie before flystrike period). The Australian fly Lucilia cuprina, the Australian Green Blowfly, has arrived in the country and is

resistant to organophosphate insecticides. It is noted as being very aggressive, only breeds on living sheep, and farmers need to be wary as it is effective from November to April, requiring weekly livestock inspection. Lambs should be dipped pre-Christmas as the researchers have found that 90 per cent of lambs are struck before then, usually in the rear end.