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OJVRTM
Online Journal of Veterinary Research
Volume 4 : 30-38, 2000. Redacted 2018.
Effect of azadirachtin
on Damalinia ovis
in sheep
V. H. Guerrini*
*Pestsearch International,
Research Division, Queensland, Australia
ABSTRACT
Guerrini VH., Effect of azadirachtin on Damalinia ovis in sheep, Onl J Vet
Res., 4: 30-38, 2000. Azadirachtin neem seed extract is a powerful
insect growth regulator, feeding deterrent and repellent with reported low
toxicity. However, azadirachtin degrades rapidly in
light, excessive heat or alkalinity. Evaluations of azadirachtin
on ectoparasites on animals have been scarce. The effects
of normal and UV protected azadirachtin on Damalinia ovis were
evaluated on sheep in a lice contaminated environment for 6 months.
Retention, lice control and repellency was evaluated by periodically counting
lice in treated sheep tied to untreated lousy sheep. Sheep infested by Damalinia ovis
were sprayed once with methanolic neem seed extracts
of 40, 80, 160, 320, 640, 1280 ppm azadirachtin and
tween-wool wax formulations containing 2000 ppm azadirachtin.
For 6 days after treatment, increased azadirachtin
concentrations correlated (P < 0.0001) with reductions in lice. After Day 6,
azadirachtin concentrations ranging from 80 to 1280
ppm reduced lice 98-100% and prevented re-infestation for 6 months. In tween or
wool fat, azadirachtin reduced lice 100% from Day 2
to 95 and 94-96% from Day 96 to Day 170. The findings suggest that relatively
low concentrations of azadirachtin inhibit lice on
sheep for long periods. On long wooled sheep, azadirachtin may be retained in lanolin and be protected
from UV light and oxidation.
Key
words: Azadirachtin, Damalinia
ovis, sheep.
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