Hostname: page-component-cd9895bd7-jkksz Total loading time: 0 Render date: 2024-12-28T03:03:38.016Z Has data issue: false hasContentIssue false
  • English
  • Français

Responses of Romney sheep to selection for resistance or susceptibility to nematode infection

Published online by Cambridge University Press:  02 September 2010

C. A. Morris ,
A. Vlassoff ,
S. A. Bisset ,
R. L. Baker ,
C. J. West  and
A. P. Hurford
C. A. Morris
Affiliation:
AgResearch, Ruakura Agricultural Research Centre, PB 3123, Hamilton, New Zealand
A. Vlassoff
Affiliation:
AgResearch, Wallaceville Animal Research Centre, PO Box 40063, Upper Hutt, New Zealand
S. A. Bisset
Affiliation:
AgResearch, Wallaceville Animal Research Centre, PO Box 40063, Upper Hutt, New Zealand
R. L. Baker
Affiliation:
AgResearch, Ruakura Agricultural Research Centre, PB 3123, Hamilton, New Zealand
C. J. West
Affiliation:
AgResearch, Wallaceville Animal Research Centre, PO Box 40063, Upper Hutt, New Zealand
A. P. Hurford
Affiliation:
AgResearch, Ruakura Agricultural Research Centre, PB 3123, Hamilton, New Zealand
Get access

Abstract

Divergent breeding lines of Romney sheep, selected as lambs for consistently low or high faecal worm egg count (FEC) following natural multispecific challenge by nematode parasites, have been maintained at Wallaceville Animal Research Centre since 1979. From the start of the trial until 1992, 821 and 736 experimental lambs in lines selected for increased resistance (R) and increased susceptibility (S), respectively, were generated, with the use of 44 different sires. In order to assess genetic responses to selection, FEC and productivity data were analysed using restricted maximum likelihood procedures. By 1988 the two lines had diverged in average loge (FEC+100) by 0·67 log units, and by 1992 divergence had increased to 1·48 log units, representing 2·90 genetic standard deviations of divergence. No significant correlated responses were observed in live weights. However, by 1992 the mean score for breech soiling (dags) in the R line was proportionally 0·41 greater than in the S line (F < 0·001). Yearling fleece weight was proportionally 0·15 greater in S-line than in R-line animals when grazed together under identical levels of challenge (P < 0·001) but the lines did not differ significantly in fleece weight when they were grazed apart. The R line had significantly higher reproductive success than the S line (P < 0·05), as measured by lambs weaned per ewe mated (1·01 v. 0·92, respectively). It is concluded that selective breeding can change the degree of resistance or susceptibility to nematode infection in Romney sheep, and selection for productivity needs to be continued at the same time in any practical breeding programme.

Keywords

nematodaparasitesresistanceselectionsheep
Type
Research Article
Information
Animal Science , Volume 64 , Issue 2 , April 1997 , pp. 319 - 329
Copyright
Copyright © British Society of Animal Science 1997

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Baker, R. L., Watson, T. G., Bisset, S. A. and Vlassoff, A. 1990. Breeding Romney sheep which are resistant to gastro-intestinal parasites. Proceedings of the Australian Association of Animal Breeding and Genetics 8: 173–178.Google Scholar
Bisset, S. A. and Morris, C. A. 1996. Feasibility and implications of breeding sheep for resilience to nematode challenge. International journal for Parasitology 26: 857–868.CrossRefGoogle ScholarPubMed
Bisset, S. A., Vlassoff, A., Douch, P. G. C., Jonas, W. E., West, C. J. and Green, R. S. 1996. Nematode burdens and immunological responses following natural challenge in Romney lambs selectively bred for low or high faecal worm egg count. Veterinary Parasitology 61: 249–263.CrossRefGoogle ScholarPubMed
Bisset, S. A., Vlassoff, A., Morris, C. A., Southey, B. R., Baker, R. L. and Parker, A. G. H. 1992. Heritability of and genetic correlations among faecal egg counts and productivity traits in Romney sheep. New Zealand Journal Agricultural Research 35: 51–58.CrossRefGoogle Scholar
Bisset, S. A., Vlassoff, A. and West, C. J. 1991. Progress in selective breeding of sheep for increased natural resistance to infection with nematode parasites. New Zealand Journal Zoology 18: 85–86 (abstr.).Google Scholar
Brunsdon, R. V. 1988. The economic impact of nematode infection in sheep: implications for future research and control. In The economic importance of parasites of livestock New Zealand (ed. Heath, A. C. G.), New Zealand Society Parasitology, miscellaneous publication no. 1, pp. 4–16.Google Scholar
Cummins, L. J., Thompson, R. L., Yong, W. K., Riffkin, G. G., Goddard, M. E., Callinan, A. P. L. and Saunders, M. J. 1991. Genetics of Ostertagia selection lines. In Breeding for disease resistance in sheep (ed. Gray, G. D. and Woolaston, R. R.), pp. 11–18. Australian Wool Corporation, Melbourne.Google Scholar
Douch, P. G. C., Green, R. S., Morris, C. A., Bisset, S. A., Vlassoff, A., Baker, R. L., Watson, T. G., Hurford, A. P. and Wheeler, M. 1995. Genetic and phenotypic relationships among anti-Trichostrongylus colubriformis antibody level, faecal egg count and body weight traits in grazing Romney sheep. Livestock Production Science 41: 121–132.CrossRefGoogle Scholar
Eady, S. J., Woolaston, R. R. and Mortimer, S. J. 1994. Internal parasite resistance of Merino flocks selected for production. Proceedings of the fifth world congress on genetics applied to livestock production, vol. 20, pp. 289–292.Google Scholar
, Genstat. 1990. Statistical package: Genstat 5, release 2.2. Lawes Agricultural Trust, Rothamsted Experimental Station, UK.Google Scholar
Howse, S. W., Blair, H. T., Garrick, D. J. and Pomroy, W. E. 1992. A comparison of internal parasitism in fleeceweight-selected and control Romney sheep. Proceedings of the New Zealand Society of Animal Production 52: 57–60.Google Scholar
Johnson, D. L., Hight, G. K., Dobbie, J. L., Jones, K. R. and Wrigglesworth, A. L. 1995. Single trait selection for yearling fleece weight or liveweight in Romney sheep — direct responses. New Zealand Journal of Agricultural Research 38: 115–122.CrossRefGoogle Scholar
Johnson, D. L. and Thompson, R. 1995. Restricted maximum likelihood estimation of variance components for univariate animal models using sparse matrix techniques and average information. Journal of Dairy Science 78: 449–456.CrossRefGoogle Scholar
Larsen, J. W. A., Anderson, N., Vizard, A. L., Anderson, G. A. and Hoste, H. 1994. Diarrhoea in Merino ewes during winter: association with trichostrongylid larvae. Australian Veterinary journal 71: 365–372.CrossRefGoogle ScholarPubMed
McEwan, J. C., Dodds, K. G., Greer, G. J., Bain, W. E., Duncan, S. J., Wheeler, R., Knowler, K. J., Reid, P. J., Green, R. S. and Douch, P. G. C. 1995. Genetic estimates for parasite resistance traits in sheep and their correlations with production traits. New Zealand Journal of Zoology 22: 177 (abstr.).Google Scholar
McEwan, J. C., Mason, P., Baker, R. L., Clarke, J. N., Hickey, S. M. and Turner, K. 1992. Effect of selection for productive traits on internal parasite resistance in sheep. Proceedings of the New Zealand Society of Animal Production 52: 53–56.Google Scholar
McKenna, P. B. 1994. The occurrence of anthelmintic-resistant sheep nematodes in the southern North Island of New Zealand. Neiv Zealand Veterinary journal 42: 151–152.CrossRefGoogle ScholarPubMed
McKenna, P. B., Allan, C. M., Taylor, M. J. and Townsend, K. G. 1995. The prevalence of anthelmintic resistance in ovine case submissions to animal health laboratories in New Zealand in 1993. New Zealand Veterinary journal 43: 96–98.CrossRefGoogle ScholarPubMed
Morris, C. A., Clarke, J. N., Watson, T. G., Wrigglesworth, A. L. and Dobbie, J. L. 1996. Faecal egg count and food intake comparisons of Romney single-trait selection and control lines. New Zealand Journal of Agricultural Research 39: 371–378.CrossRefGoogle Scholar
Morris, C. A., Towers, N. R., Wesselink, C. and Southey, B. R. 1991. Effects of facial eczema on ewe reproduction and postnatal lamb survival in Romney sheep. New Zealand Journal of Agricultural Research 34: 407–412.CrossRefGoogle Scholar
Morris, C. A., Watson, T. G., Baker, R. L., Hurford, A. P. and Hosking, B. C. 1993. Repeatability estimates and selection flock effects for faecal nematode egg counts in Romney breeding ewes. Proceedings of the New Zealand Society of Animal Production 53: 227–229.Google Scholar
Morris, C. A., Watson, T. G., Bisset, S. A., Vlassoff, A. and Douch, P. G. C. 1995. Breeding sheep in New Zealand for resistance or resilience to nematode parasites. In Breeding for resistance to infectious diseases in small ruminants (ed. Gray, G. D., Woolaston, R. R. and Eaton, B. T.), pp. 77–98. Australian Centre for International Agricultural Research.Google Scholar
Schwaiger, F. W., Gostomski, D., Stear, M. J., Duncan, J. L., McKellar, Q. A., Epplen, J. L. and Buitkamp, J. 1995. An ovine major histocompatibility complex DRBl allele is associated with low faecal egg counts following natural, predominantly Ostertagia circumcincta infection. International journal for Parasitologi/ 25: 815–822.CrossRefGoogle Scholar
Watson, T. G., Baker, R. L. and Harvey, T. G. 1986. Genetic variation in resistance or tolerance to internal nematode parasites in strains of sheep at Rotomahana. Proceedings of the New Zealand Society of Animal Production 46: 23–26.Google Scholar
Whitlock, H. V. 1948. Some modifications of the McMaster helminth egg-counting technique and apparatus. Journal of the Council for Scientific and Industrial Research 21: 177–180.Google Scholar
Williamson, J. F., Blair, H. T., Garrick, D. J., Pomroy, W. E., Douch, P. G. C., Green, R. S. and Simpson, H. V. 1995. Parasitism and production in fleece-weight-selected and control sheep. New Zealand Journal of Agricultural Research 38: 381–387.CrossRefGoogle Scholar
Woolaston, R. R. 1990. Genetic improvement of resistance to internal parasites in sheep. Proceedings of the Australian Association of Animal Breeding and Genetics 8: 163–171.Google Scholar
Woolaston, R. R. and Eady, S. J. 1995. Australian research on genetic resistance to nematode parasites. In Breeding for resistance to infectious diseases in small ruminants (ed. Gray, G. D., Woolaston, R. R. and Eaton, B. T.), pp. 53–75. Australian Centre for International Agricultural Research.Google Scholar
Woolaston, R. R. and Piper, L. R. 1996. Selection of Merino sheep for resistance to Haemonchus contortus: genetic variation. Animal Science 62: 451–460.CrossRefGoogle Scholar
Woolaston, R. R., Windon, R. G. and Gray, G. D. 1991. Genetic variation in resistance to internal parasites in Armidale experimental flocks. In Breeding for disease resistance in sheep (ed. Gray, G. D. and Woolaston, R. R.), pp. 1–9. Australian Wool Corporation, Melbourne.Google Scholar