Acaricidal treatments for protection of sheep against Psoroptes ovis
Roberts, I.H.; Meleney, W.P.
Journal of the American Veterinary Medical Association 158(3): 372-378
1971
ISSN/ISBN: 0003-1488 PMID: 4100508 Document Number: 31336
During a 2-year period, 248 healthy, normal sheep were allocated to 25 groups and were dipped or dusted with preparations of accepted or candidate acaricides. At different times in the autumn and winter months, the groups, including both shorn and unshorn sheep, were exposed to scabies by introducing them into a flock of 200 to 400 sheep heavily parasitized with a vigorous strain of Psoroptes ovis. Two control groups of 20 sheep each were similarly exposed without benefit of treatment. The agents providing up to five months of protection against infestation in the unshorn state were (in descending order): crotoxyphos 0.1%; toxaphene 0.5%; diazinon 0.06%; lindane 0.06%. Those protecting shorn sheep (up to 72 days) were (in descending order): lindane 0.06%; crotoxyphos 0.3%; diazinon 0.06%; toxaphene 0.5%. All materials were formulated as aqueous emulsions or suspensions and the sheep were dipped in them. Virtually no protection was afforded by 0.3% crotoxyphos dust on either unshorn or shorn sheep. All unshorn and shorn control sheep became infested within 34 and 32 days, respectively, after exposure.