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Selection of dairy sheep in Greece for parasitic nematode resistance: defining the aggregate genotype and evaluating selection schemes

Published online by Cambridge University Press:  18 August 2016

A. Kominakis  and
G. Theodoropoulos
A. Kominakis
Affiliation:
Department of Animal Breeding and Husbandry
G. Theodoropoulos
Affiliation:
Department of Animal Anatomy and Physiology of Farm Animals, Faculty of Animal Science, Agricultural University of Athens, 75 lera Odos, 1185 5 Athens, Greece
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Abstract

The effects on genetic and economic responses of adding faecal egg count (FEC) in the aggregate genotype of dairy sheep in Greece were investigated. The extra responses obtained in the full aggregate genotype were expressed as a percentage change of the responses in terms of genetic gain, profit and selection response of single traits before adding the trait. The initial aggregate genotype included the traits milk fat yield (FY) and number of lambs weaned per ewe per year (NLW). Inclusion of FEC in the aggregate genotype resulted always in increased genetic gain and profit. The extra responses from adding the FEC in the index selection were variable and often very large, depending on the parameters varied i.e. the economic weight of FEC and the genetic correlation of FEC with the other production traits. For a wide range in the size of the genetic correlations between FEC and other traits, gains of FEC and no appreciable losses of responses for FY and NLW were predicted when FEC accounted proportionately for 0·10 to 0·20 of the total monetary genetic deviation. While FEC showed a wide range of change, selection responses of FY and NLW remained remarkably insensitive under various weightings of FEC and different genetic correlations of FEC with the production traits. The genetic and economic efficiency of alternative selection schemes were also evaluated. A two-stage selection procedure involving preliminary selection of rams on dam’s FEC, FY, NLW and on their own FEC and final culling on progeny’s FEC, FY and NLW was predicted to be the most efficient in both genetic and economic terms. Female replacements should be selected on dam’s FEC, FY and NLW (first stage) and their own FEC, FY and NLW (second stage). When repeated measurements of FEC are taken, the recommended number of FEC measurements was found to be 4.

Keywords

breeding programmesgenetic resistanceGreeceparasitessheep
Type
Research Article
Information
Animal Science , Volume 69 , Issue 3 , December 1999 , pp. 535 - 542
Copyright
Copyright © British Society of Animal Science 1999

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References

Baker, R.L., Watson, T.G., Bisset, S.A., Vlassof, A. and Douch, P.G.C. 1991. Breeding sheep in New Zealand for resistance to internal parasites: research results and commercial application. In Breeding for resistance in sheep (ed. Gray, G. D. and Woolaston, R. R.), pp. 19–32. Australian Wool Corporation, Melbourne.Google Scholar
Baker, R. L., Watson, T. G. and Harvey, T. G. 1988. Genetic variation in, and selection for, resistance or tolerance to internal nematode parasites in sheep. Proceedings of the third world congress on sheep and beef cattle breeding, Paris, vol. 1, pp. 637–639.Google Scholar
Bishop, S. C., Bairden, K., McKellar, Q. A., Park, M. and Stear, M. J. 1996. Genetic parameters for faecal egg count following mixed, natural, predominantly Ostertagia circumcincta infection and relationships with live weight in young lambs. Animal Science 63: 423–428.Google Scholar
Bishop, S. C. and Stear, M. J. 1998. Modelling genetic and epidemiological relationships between productivity and nematode infection in lambs. Proceedings of the sixth world congress on genetics applied to livestock production, Annidale, vol. 27, pp. 291–294.Google Scholar
Douch, P. G. C., Green, R. S., Morris, C. A., Bisset, S. A., Vlassof, 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.Google Scholar
Eady, S. L., Woolaston, R.R. and Mortimer, S. I. 1994. Internal parasite resistance of Merino flocks selected for production. Proceedings of the fifth world congress on genetics applied to livestock production, Guelph, vol. 20, pp. 289–292.Google Scholar
Endang, Romjali, Pandey, V. S., Gatenby, R. M., Doloksaribu, M., Sakul, H., Wilson, A. and Verhuist, A. 1997. Genetic resistance of different genotypes of sheep to natural infections with gastro-intestinal nematodes. Animal Science 64: 97–104.Google Scholar
Gibson, J. P. and Kennedy, B. W. 1990. The use of constrained selection indexes in breeding for economic merit. Theoretical and Applied Genetics 80: 801–805.Google Scholar
Gjedrem, T. 1972. A study on the definition of the aggregate genotype in the selection index. Acta Agriculturæ Scandinavica 22: 11–16.Google Scholar
Heckenberger, G. and Fewson, D. 1988. Zuchtplanungsrechnungen zur Effectivitaet von offenen MOET - Nukleus Zuchtprogrammen in Abhaengigkeit von der Populationsstruktur. DGfZ Ausschuss fuer genetisch -statistische Methode in der Tierzucht. Sitzung im Oktober 1988 in Friedrichsruh.Google Scholar
Henze, A., Zeddies, D., Fewson, D. and Niebel, E. 1980. Nutzen-Kosten Untersuchungen ueber die Leistungspruefungen in der tierischen Erzeugung, dargestellt am Beispiel der Milchleistungspreufung beim Rind. Schriftenreihe des Bundesministeriums für Ernährung, Landwirtschaft und Forsten. Reihe A: Landwirtschaft -Angewandte Wissenschaft, H. 234, s. 1–331.Google Scholar
James, J. W. 1982. Economie aspects of developing aggregate genotypes: general considerations. In Future developments in the genetic improvement of animals (ed. Barker, J. S. F., Hammond, K. and McClintock, A. E.), pp. 107–116. Academic Press, Australia.Google Scholar
Jeraruban, M.G., Gibson, J. P. and Gowe, R. S. 1995. Comparison of index selection and best linear unbiased prediction for simulated layer poultry data. Poultry Science 74: 1566–1576.Google Scholar
Karras, K. 1984. [ZPLAN - a computer program for optimizing breeding schemes]. Polykopie Universitaet Hohenheim.Google Scholar
Kominakis, A., Nitter, G., Fewson, D. and Rogdakis, E. 1997. Evaluation of the efficiency of alternative selection schemes and breeding objectives in dairy sheep of Greece. Animal Science 64: 453–461.CrossRefGoogle Scholar
Lasdon, L. S. and Smith, S. 1992. Solving sparse nonlinear programs using GRG. ORSA Journal on Computing 4: 2–15.Google Scholar
Morris, C. A., Vlassoff, A., Bisset, S. A., Baker, R. L., West, C. J. and Hurford, A. P. 1997. Responses of Romney sheep to selection for resistance or susceptibility to nematode infection. Animal Science 64: 319–329.Google Scholar
Niebel, E., Karras, K. and Fewson, D. 1989. ZUPLAN. A computer program for optimisation of breeding plans. Institut fuer Tierhaltung and Tierzuechtung der Universitaet Hohenheim. Polykopie Universitaet Hohenheim.Google Scholar
Piper, L. R. and Barger, I. A. 1988. Resistance to gastrointestinal strongyles: feasibility of a breeding programme. Proceedings of the third world congress on sheep and beef cattle breeding, Paris, vol. 1, pp. 593–611.Google Scholar
Ponzoni, W. R. 1986. Economic evaluation of aggregate genotypes in sheep and goats. Summary and commentary. Proceedings of the third world congress on genetics applied to livestock production, Lincoln, pp. 465–469.Google Scholar
Rogdakis, E., Kominakis, A. and Bizelis, J. 1993. Genetic and economic optimization of breeding plans in the population of Karagouniko sheep. I. Methods and assumptions. Animal Science Review 17: 5–20.Google Scholar
Sivanadian, B. and Smith, C. 1997. The effect of adding further traits in index selection. Journal of Animal Science 75: 2016–2023.CrossRefGoogle ScholarPubMed
Smith, C., 1983. Effects of changes in economic weights on the efficiency of index selection. Journal of Animal Science 56: 1057–1064.Google Scholar
Sorensen, D. A. 1988. Effect of selection index versus mixed model methods of prediction of breeding value on response to selection in a simulated pig population. Livestock Production Science 20: 135–148.Google Scholar
Stear, M. J. and Murray, M. 1994. Genetic resistance to parasitic disease: particularly resistance of ruminants to gastrointestinal nematodes. Veterinary Parasitology 54: 161–176.Google Scholar
Theodoropoulos, G., Koutsotolis, K., Nikolaou, E., Kalogiannis, D. and Petrakos, G. 1998. Seasonal variation of gastrointestinal nematodes of sheep in the region of Ioannina, Greece. International Journal of Parasitology 28: 1287–1292.Google Scholar
Vandepitte, W. M. and Hazel, L. N. 1977. The effect of errors in the economic weights on the accuracy of selection indexes. Annales de Génétique Selection Animal 9: 87–93.Google Scholar
Windon, R. C., Dineen, J. K. and Wagland, B. M. 1987. Genetic control of immunological responsiveness against the intestinal nematode Trichostrongylus colubriformis in lambs. In Merino improvement programs in Australia (ed. McGuirk, B. J.), pp. 371–375. Australian Wool Corporation.Google Scholar
Woolaston, R. R. 1994. Preliminary evaluation of strategies to breed Merinos for resistance to round worms. Proceedings of the fifth world congress on genetics applied to livestock production, Guelph, 1994, vol. 20, pp. 281–284.Google Scholar
Woolaston, R. R. 1998. Breeding livestock for reduced reliance on chemicals. Proceedings of the sixth world congress on genetics applied to livestock production, Armidale, vol. 27, pp. 145–152.Google Scholar
Woolaston, R. R. and Baker, R. L. 1996. Prospects of breeding small ruminants for resistance to internal parasites. International Journal for Parasitology 26: 845–850.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 resistance in sheep (ed. Gray, G. D. and Woolaston, R. R.), pp. 1–9. Australian Wool Corporation, Melbourne.Google Scholar