Rate of spread of sheep lice (Damalinia ovis) and their effects on wool quality

Essential oils in the management of the donkey louse, Bovicola ocellatus

“…This suggests that the reinfestation pressure was not sufficiently high to alter the level of decline seen at the Devon farm. In sheep, the spread of Bovicola ovis has been shown to be relatively gradual, with only 63% of a flock of 100 animals being infested 44 weeks after the introduction of 2 infected sheep . Alternatively, the oils may provide a level of louse repellence; indeed, many essential oils have shown repellence characteristics against other ectoparasites .…”

On-farm factors affecting physical quality of Merino wool. 1. Nutrition, reproduction, health and management

“…The effect of louse infestation on SS remains less clear. Cleland et al (1989) and James et al (2011) found no significant effect of lice on SS, but other studies have demonstrated some small negative effect. Niven and Pritchard (1985) reported sheep with moderate to heavy infestations produced less sound wool (1.7 vs 3.0 kg/head) and more cast wool (0.4 vs 0.1 kg/head) than sheep with few lice present.…”

“…Greasy wool from lousy sheep is more yellow (Kettle and Lukies, 1982;James et al, 2011) and less bright (Kettle and Lukies, 1982), though when scoured it has been reported that no difference in colour exists when objectively measured (James et al, 2011). SL appears to be slightly reduced by louse infestation (Wilkinson et al, 1982;James et al, 2011) although some studies report no effect (Cleland et al, 1989). The effect of louse infestation on SS remains less clear.…”

“…Niven and Pritchard (1985) reported sheep with moderate to heavy infestations produced less sound wool (1.7 vs 3.0 kg/head) and more cast wool (0.4 vs 0.1 kg/head) than sheep with few lice present. Several reports indicate lice have no effect on FD (Wilkinson et al, 1982;Niven and Pritchard, 1985;Cleland et al, 1989;James et al, 2011).…”

A preliminary investigation into resistance to synthetic pyrethroids by the sheep biting louse (Bovicola ovis) in New Zealand

“…Wilson, unpublished data). Cleland et al (10) showed that spread oflice was slow within a flock so, in the absence of rapid genetic mixing, it is likely that there may be more variation between than within sheep in a louse population in response to synthetic pyrethroids. The fmdings in the present study show that there is some tolerance to cypermethrin (high-cis) in New Zealand strains of sheep biting lice.…”