Population dynamics and production effects of sheep lice (Bovicola ovis Schrank) in extensively grazed flocks
P. J. James A F , B. J. Horton B , N. J. Campbell C , D. L. Evans D , J. Winkleman E and R. McPhie EA The University of Queensland, Queensland Alliance for Agriculture and Food Innovation (QAAFI), GPO Box 46, Brisbane, Qld 4001, Australia.
B Tasmanian Institute of Agricultural Research, University of Tasmania, PO Box 46, Kings Meadows, Tas. 7249, Australia.
C 5 Anka Close, Eltham, Vic. 3095, Australia.
D Department of Agriculture & Food WA, PO Box 609, Denmark, WA 6333, Australia.
E Department of Employment, Economic Development and Innovation, Landsborough Highway, Longreach, Qld 4730, Australia.
F Corresponding author. Email: p.james1@uq.edu.au
Animal Production Science 51(8) 753-762 https://doi.org/10.1071/AN11008
Submitted: 19 January 2011 Accepted: 12 May 2011 Published: 5 August 2011
Abstract
An experiment was conducted to characterise population dynamics of lice and associated production loss in extensively grazed flocks infested at different times after shearing. Merino wethers were allocated to six groups of 31 sheep. In the first year (Y1), one sheep in each of two groups was infested with 2500 lice at 6 weeks after shearing (September), sheep in two groups were infested at 4 months (December) and two groups remained uninfested. In year 2 (Y2), infestations carried over from Y1, but a lousy sheep was added to each 6-week infestation mob. In year 3 (Y3), the infested mobs were treated and remained lice free, while lousy donor sheep were added to the two previously uninfested mobs. In Y1, lice appeared to die out in one 6-week-infestation group and were found on only two sheep before next shearing in the other. Lice persisted and spread in the two 4-month-infestation flocks, reaching mean counts (±s.e.) of 0.5 (±0.2) and 0.2 (±0.1) per part before shearing. In Y2 and Y3, lice persisted and increased in all infested flocks, reaching mean counts of 2.3 (±0.6), 8.5 (±1.5), 3.6 (±0.6) and 2.8 (±0.7) per part in Y2 and 1.0 (±0.2) and 1.2 (±0.4) per part in Y3. The count of 8.5 was in the flock with both a carry-over infestation and an infestor sheep. Exponential and logistic models were fitted to describe lice increase; differences in fleece derangement reflected louse numbers. Clean fleece weight was higher in flocks without lice in all years (0.12 kg/head in Y1; 0.22 kg/head in Y2 and Y3; P < 0.05). Classer-assigned colour scores (although not measured colour), cott score and line into which the wool was classed also differed significantly (P < 0.05) between infested and non-infested flocks and there was an indication that staple length was reduced in more heavily infested flocks. In spring-shorn flocks in environments with high solar radiation and no lice present at shearing, even if lice subsequently enter the mob, it appears unlikely that they will increase to levels where serious economic loss will be experienced before next shearing. The study also indicated that lice could persist in flocks at levels unlikely to be detected by most commercial wool producers for extended periods, possibly through one season, which may help to explain reports of new infestations with no apparent source.
References
Cleland PC, Dobson KJ, Meade RJ (1989) Rate of spread of sheep lice (Damalina ovis) and their effects on wool quality. Australian Veterinary Journal 66, 298–299.| Rate of spread of sheep lice (Damalina ovis) and their effects on wool quality.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DyaK3c%2Fls1Wmtw%3D%3D&md5=a815bfbbb63b08f0a691ed8513de69cfCAS |
Elliott J, Jones AL, Pauley JR (1986) The effect of body lice on wool production. In ‘Australian Advances in Veterinary Science, 1986’. (Ed. PM Outeridge) pp. 125–126. (Australian Veterinary Association: Melbourne)
Hansford K (1987) ‘Collation and analyses of available information on additional measurement relevant to improved management of sheep.’ (Australian Wool Corporation: Melbourne)
Horton B, James P, Evans D, Campbell N (2007) LiceBoss: a lice decision support system. In: ‘Proceedings of the Australian sheep veterinarians 2007 conference’, Melbourne. pp. 53–57. (Australian Sheep Veterinarians, Australian Veterinary Association: Eight Mile Plains, Qld)
Horton BJ, Evans DL, James PJ, Campbell NJ (2009) Development of a model based on Bayesian networks to estimate the probability of sheep lice presence at shearing. Animal Production Science 49, 48–55.
| Development of a model based on Bayesian networks to estimate the probability of sheep lice presence at shearing.Crossref | GoogleScholarGoogle Scholar |
James PJ (1999) Do sheep regulate the size of their Mallophagan louse populations? International Journal for Parasitology 29, 869–875.
| Do sheep regulate the size of their Mallophagan louse populations?Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DyaK1MvgvVKjsw%3D%3D&md5=de3be687503a5196265c74fc93b805aaCAS |
James PJ (2002) Sheep lice: changing control practices and wool industry implications. Wool Technology and Sheep Breeding 50, 567–573.
James PJ (2008) Why control sheep lice? Economic effects of lice on production. Available at http://images.wool.com/pub/Impact.pdf [verified 23 November 2010].
James PJ (2010) Issues and advances in the integrated control of sheep lice. Animal Production Science 50, 435–439.
| Issues and advances in the integrated control of sheep lice.Crossref | GoogleScholarGoogle Scholar |
James PJ, Moon RD (1999) Spatial distribution and spread of sheep biting lice, Bovicola ovis, from point infestations. Veterinary Parasitology 81, 323–339.
| Spatial distribution and spread of sheep biting lice, Bovicola ovis, from point infestations.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK1MXjsVKrs78%3D&md5=6aacdc7cae7bd866a15483cb12db40afCAS |
James PJ, Ponzoni RW, Walkley JRW, Whiteley KJ (1990) Genetic and phenotypic parameters for greasy and scoured wool colour in South Australian Merino Sheep. Proceedings of the Australian Association of Animal Breeding and Genetics 8, 521–523.
James PJ, Carmichael IHC, Pfeffer A, Martin RR, O’Callaghan MG (2002) Variation among merino sheep in susceptibility to lice (Bovicola ovis) and association with susceptibility to trichostrongylid gastrointestinal parasites. Veterinary Parasitology 103, 355–365.
| Variation among merino sheep in susceptibility to lice (Bovicola ovis) and association with susceptibility to trichostrongylid gastrointestinal parasites.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD38%2Flt1amtQ%3D%3D&md5=76428c3d0901ef9e6013f18b070f956cCAS |
James PJ, Bartholomaeus FB, Karlsson LJE (2007) Temporal relationship between infestation with lice (Bovicola ovis Schrank) and the development of pruritic behaviour and fleece derangement in sheep. Veterinary Parasitology 149, 251–257.
| Temporal relationship between infestation with lice (Bovicola ovis Schrank) and the development of pruritic behaviour and fleece derangement in sheep.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD2srpvVyrtg%3D%3D&md5=e365905d0400bd18b4088799d843e8c0CAS |
James PJ, Cramp AP, Hook SE (2008) Resistance to insect growth regulator insecticides in populations of sheep lice as assessed by a moulting disruption assay. Medical and Veterinary Entomology 22, 326–330.
| Resistance to insect growth regulator insecticides in populations of sheep lice as assessed by a moulting disruption assay.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD1M%2FltVyhtQ%3D%3D&md5=a5d80b1e4e3520c64003fc16991ca9d3CAS |
Kettle PR, Lukies JM (1982) Long term effects of sheep lice Damalinia ovis on body weight and wool production. New Zealand Journal of Agricultural Research 25, 531–534.
Levot GW (1995) Resistance and the control of sheep ectoparasites. International Journal for Parasitology 25, 1355–1362.
| Resistance and the control of sheep ectoparasites.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK28XktlGkug%3D%3D&md5=e6211501e496d48f7cf8d6045d1a5dfdCAS |
Murray MD (1963) Ecology of lice on sheep V. The influence of heavy rain on populations of Damalinia ovis. Australian Journal of Zoology 11, 173–182.
| Ecology of lice on sheep V. The influence of heavy rain on populations of Damalinia ovis.Crossref | GoogleScholarGoogle Scholar |
Murray MD (1968) Ecology of lice on sheep VI The influence of shearing and solar radiation on populations and transmission of Damalinia ovis. Australian Journal of Zoology 16, 725–738.
| Ecology of lice on sheep VI The influence of shearing and solar radiation on populations and transmission of Damalinia ovis.Crossref | GoogleScholarGoogle Scholar |
Niven DR, Pritchard DA (1985) Effects of control of the sheep body louse (Damalina ovis) on wool production and quality. Australian Journal of Experimental Agriculture 25, 27–31.
| Effects of control of the sheep body louse (Damalina ovis) on wool production and quality.Crossref | GoogleScholarGoogle Scholar |
Payne RW, Harding SA, Murray DA, Soutar DM, Baird DB, Welham SJ, Kane AF, Gilmour AR, Thompson R, Webster R, Wilson GT (2007) ‘The guide to Genstat release 10, part 2: statistics.’ (VSN International: Hemel Hempstead, UK)
Russell IM (2001) Ecolabels – An opportunity to indentify low residue wools in the marketplace. In ‘FLICS – proceedings of the conference on flystrike and lice IPM control strategies, Launceston, Tas.’. (Ed. S Champion) pp. 7–10. (University of Tasmania: Hobart)
Sackett D, Holmes P, Abbott K, Jephcott S, Barber M (2006) Assessing the economic cost of endemic disease on the profitability of Australian beef cattle and sheep producers. MLA Report AHW.087 Meat and Livestock Australia Limited, North Sydney.
Savage G (1998) The residue implications of sheep ectoparasiticides. National Registration Authority report to the Woolmark Company, 1998. National Registration Authority Quality Assurance and Compliance Section, Canberra.
Walkden-Brown SW, Reeve I, Thompson LJ, Kahn L, Crampton A, Larsen J, Woodgate R, James PJ, de Fegely C, Williams S (2006) IPM-s project benchmarking survey: a national survey of parasite control practices. In: ‘Proceedings of the Australian sheep veterinarians 2006 conference’, Wagga Wagga, NSW. pp. 38-41. (Australian Sheep Veterinarians, Australian Veterinary Association: Eight Mile Plains, Qld)
Wilkinson FC, de Chaneet GC, Beetson BR (1982) Growth of populations of lice, Damalina ovis, on sheep and their effects on production and processing performance of wool. Veterinary Parasitology 9, 171–177.
| Growth of populations of lice, Damalina ovis, on sheep and their effects on production and processing performance of wool.Crossref | GoogleScholarGoogle Scholar |
