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When to treat for Cattle Lice
Cattle Lice
The life cycle of cattle lice. The skin temperature of the cattle is of great importance in its effect on the dormancy of lice eggs. Lice prefer skin temperatures of 35 degrees or below. In summer when temperatures are above 37 degrees, lice cannot survive for more than a few hours. As a protection mechanism, over the summer months the eggs tend to remain dormant, to ensure the lice population survives from winter to winter. Once the temperature drops to 16-18 degrees the skin temperature of the cattle drops below 35 degrees. If the temperature stays at this degree for a continued period, the lice eggs are triggered to hatch. The life cycle of cattle lice is 21 to 30 days so lice population can build quite quickly if the cold conditions are maintained unbroken. It takes 10 to 14 days for the lice eggs to hatch and about another 3 weeks for the hatched nymph to mature into a reproductive adult.
It is important to treat the cattle at the optimum time. Once the cold weather sets in, most lice eggs that have laid dormant over the summer months in the coat of the cattle, hatch within one or two weeks. Treat within 3 or 4 weeks of continuos cold weather. If you treat to early prior to a period of continuos cold weather, a large number of unhatched eggs can remain on the cattle, and may not hatch until after the applied lousicide’s effective period has ended. If you treat to late, a month or more after the onset of cold weather, there will be a growing population of adult lice, immature nymphs and eggs. It is then likely that some of the lice eggs will not hatch until after the lousicides effective period is finished. Therefore, six to eight weeks later, a significant lice problem may be re-established.
If the winter becomes mild, after treatment, skin temperature can drop back to 37 degrees and the lice eggs will resume dormancy. Once the temperature turns cool again the dormancy of the eggs is broken and the lice population will re-establish. Because of these factors inspect the cattle two weeks after the resumption of cold weather and if lice are found a second treatment may be required
Lice feed on the skin tissue and blood of cattle. There are 6 different species of lice in Australia. Biting lice, long nosed sucking lice and short nosed sucking lice are the most common.
Biting lice feed on skin cells of the cattle. The sucking lice have mouthparts that puncture the skin and suck the blood of the animal. As they are only 2 to 5cm long it is difficult to tell which type of lice are affecting your cattle. For this reason it is best when treating to use a product, which will control both the biting and sucking lice.
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