Red Lice (Bovicola ovis, Bovocola limbata) is the most important lice species in sheep and goats. It has a major economic impact on wool, hair and meat production.
Lice spend their entire life cycle on sheep / goats and move constantly through the fleece. This free movement facilitates the transfer of lice from infected to non-infected animals. To complete their life cycle (from egg to an adult louse that lay eggs again) takes ± 29 days. A light lice infestation (± 5000 red lice) can become major problem within 2-3 months due to the short life cycle.
Autumn and winter months are the most favourable times for red lice to multiply, the reason being is that:
Lice cause:
The effect on wool production, clean yield and price (Joshua, 2001 NSW)
A light lice infestation cause:
The total R-value loss per sheep with light lice infection is ± R19.50 (The value is calculated at R75 / kg wool, average 5kg of wool per sheep)
LICE CONTROL
The largest source of reinfection in sheep and goats are the remaining lice that were not effectively controlled by previous treatments.
INSECT GROWTH REGULATORS:
Insect growth regulators (IGRs), such as Trigger Strike are used to reduce lice numbers. The product do not kill lice on contact, but prevent the development of immature lice present in the fleece during application as well as those that will hatch in the next 20 weeks.
POUR-ON'S
Pour-on’s (Amipor) are ready-to-use products that are applied with an applicator on the back in a broad band from between the ears to the tail. Regardless of the label claims, the best use for pour-on remedies is within 24 hours from shearing. This will distribute a higher concentration of the active ingredient all over the body in the lanolin layer and ensure the best control.
The advantage of pour-on remedies is that
DIP REMEDIES
Dip remedies can be applied through plunge dipping, a spray race or 'jetting'. Sheep can only be dipped 3-4 weeks after shearing and up to ± 2 months before shearing.
Key factors for success with dipping is
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