Production benefits of breeding for worm resistance in Merino sheep
J. C. Greeff
A C and L. J. E. Karlsson B
A Department of Primary Industries and Regional Development Western Australia, 3 Baron Hay Court, South Perth, WA 6151, Australia.
B 1549 Berry Brow Road, York, WA 6302, Australia.
C Corresponding author. Email: Johan.greeff@dpird.wa.gov.au
Animal Production Science 60(13) 1643-1653 https://doi.org/10.1071/AN19368
Submitted: 28 June 2019 Accepted: 29 January 2020 Published: 6 May 2020
Abstract
Context: Production losses, due to worms and anthelmintic costs to control the infection, can affect the profitability of sheep production systems.
Aims: This study was carried out to quantify the production benefits of worm-resistant sheep.
Methods: Genetically worm-resistant and unselected control Merino rams were mated annually to 150 ewes in each of the Resistant and Control lines respectively over an 8-year period. All ewes and their progeny were managed in small replicated paddocks to prevent any cross-contamination between paddocks and groups. Fertility, growth, wool production, wool quality and worm resistance were measured on the ewes and their progeny. The data were analysed using mixed model methodology.
Key results: The progeny of the Resistant sires were on average 21–25% more worm resistant than the progeny of the Control sires. No significant differences were recorded in reproduction between mature ewes of the Resistant and Control lines, or in the survival rate of their lambs. Resistant line progeny were on average 1.6 kg heavier at weaning, received 15–17% less drenching during the experiment and produced on average 0.3 μm finer wool at hogget shearing than the Control line progeny.
Conclusions: It is concluded that the Resistant line coped better with a worm challenge and that this resulted in increased production.
Implications: This study shows that apart from improved worm resistance, there are associated production benefits in breeding for worm resistance.
Additional keywords: anthelmintics, gastrointestinal, nematodes, sheep production.
References
Amer PR, Woolaston RR, Eady SJ, McEwan JC (1999) Economic values for sheep internal parasites resistance traits in New Zealand and Australia. Proceedings of the Association for the Advancement of Animal Breeding and Genetics. 13, 504–507.AWI (2007) ‘Visual sheep scores.’ (Australian Wool Innovation and Meat and Livestock Australia: Sydney)
Besier RB, Lyon J, McQuade N (1996) Drench resistance: a large economic cost. WA Journal of Agriculture 37, 60–63.
Bishop SC, Stear MJ (1999) Genetic and epidemiological relationships between productivity and disease resistance: gastrointestinal parasite infection in growing lambs Animal Science 69, 515–524.
| Genetic and epidemiological relationships between productivity and disease resistance: gastrointestinal parasite infection in growing lambsCrossref | GoogleScholarGoogle Scholar |
Bishop SC, Stear MJ (2003) Modelling of host genetic and resistance to infectious diseases: understanding and controlling nematode infections. Veterinary Parasitology 115, 147–166.
| Modelling of host genetic and resistance to infectious diseases: understanding and controlling nematode infections.Crossref | GoogleScholarGoogle Scholar | 12878420PubMed |
Bisset SA, Vlassoff A, West CJ (1997) Epidemiology of nematodosis in lambs selectively bred for genetic resistance or susceptibility to nematode infection. Veterinary Parasitology 70, 255–269.
| Epidemiology of nematodosis in lambs selectively bred for genetic resistance or susceptibility to nematode infection.Crossref | GoogleScholarGoogle Scholar | 9211651PubMed |
Ferguson MB, Thompson AN, Gordon DJ, Hyder MW, Kearney GA, Oldham CM, Paganoni BL (2011) The wool production and reproduction of Merino ewes can be predicted from changes in live weight during pregnancy and lactation. Animal Production Science 51, 763–775.
| The wool production and reproduction of Merino ewes can be predicted from changes in live weight during pregnancy and lactation.Crossref | GoogleScholarGoogle Scholar |
Gilmour AR, Gogel BJ, Cullis BR, Thompson R (2009) ASReml user guide release 3.0. (VSN International: Hemel Hempstead, UK) Available at www.vsni.co.uk [Verified 10 April 2018].
Greeff JC, Karlsson LJE (1998) The genetic relationship between faecal consistency, faecal worm egg counts and wool traits in Merino sheep. In ‘6th world congress on genetics applied to livestock production’, 11–16 January 1998, Armidale, NSW, Australia. Vol. 24. pp. 63–66. Available at http://www.wcgalp.org/proceedings/1998/genetic-relationship-between-faecal-consistency-faecal-worm-egg-counts-and-wool [Verified 3 April 2020]
Greeff JC, Karlsson LJE, Harris JF (1995) Heritability of faecal worm egg count at different times of the year in a Mediterranean environment. In ‘Proceedings of the 11th Congress Australian Association of Animal Breeding and Genetics’, 3–5 July 1995, Roseworthy, SA, Australia. pp. 117–121. Available at http://www.aaabg.org/proceedings/1995/ab95021.pdf [Verified 3 April 2020]
Greeff JC, Karlsson LJE, Schlink AC (2013) Identifying indicator traits for breech strike in Merino sheep in a Mediterranean environment. Animal Production Science 54, 125–140.
| Identifying indicator traits for breech strike in Merino sheep in a Mediterranean environment.Crossref | GoogleScholarGoogle Scholar |
Greeff JC, Karlsson LJE, Schlink AC, Gilmour AR (2017) Factors explaining the variation in breech strike in Merino sheep in a Mediterranean environment. Animal Production Science 58, 1279–1288.
| Factors explaining the variation in breech strike in Merino sheep in a Mediterranean environment.Crossref | GoogleScholarGoogle Scholar |
Greeff JC, Liu SM, Palmer DG, Karlsson LJE (2019) Expression of worm resistance in sheep selected for low worm egg counts fed at maintenance or above-maintenance level. Animal Production Science
| Expression of worm resistance in sheep selected for low worm egg counts fed at maintenance or above-maintenance level.Crossref | GoogleScholarGoogle Scholar |
Groeneveld E (1990) ‘PEST user’s manual.’ (Institute of Animal Husbandry and Animal Behaviour, Federal Agricultural Research Centre: Neustadt, Germany)
Karlsson LJE, Greeff JC (2006) Selection response in faecal worm egg counts in the Rylington Merino parasite resistant flock. Australian Journal of Experimental Agriculture 46, 809–811.
| Selection response in faecal worm egg counts in the Rylington Merino parasite resistant flock.Crossref | GoogleScholarGoogle Scholar |
Kemper KE, Palmer DG, Lui SM, Greeff JC, Bishop SC, Karlsson LJE (2010) Reduction in faecal worm egg count, worm numbers and worm fecundity in sheep selected for worm resistance following artificial infection with Teladorsagia circumcinta and Trichostrongylus colubriformis. Veterinary Parasitology 171, 238–246.
| Reduction in faecal worm egg count, worm numbers and worm fecundity in sheep selected for worm resistance following artificial infection with Teladorsagia circumcinta and Trichostrongylus colubriformis.Crossref | GoogleScholarGoogle Scholar | 20471175PubMed |
Kotze AC, Ruffell A, Lamb J, Elliot TP (2018) Response of drug-susceptible and -resistant Haemonchus contortus larvae to monepantel and abamectin alone or in combination in vitro. Veterinary Parasitology 249, 57–62.
| Response of drug-susceptible and -resistant Haemonchus contortus larvae to monepantel and abamectin alone or in combination in vitro.Crossref | GoogleScholarGoogle Scholar | 29279087PubMed |
Lane J, Jubb T, Shephard R, Webb-Ware J, Fordyce G (2015) ‘Priority list of endemic disease for the red meat industries. Final report B.AHE.0010.’ (Meat and Livestock Australia: Sydney)
Leathwick DM, Atkinson DS, Miller CM, Brown AE, Sutherland IA (2002) Benefits of reduced larval challenge through breeding for low faecal egg count in sheep. Novel approaches III. A workshop meeting on helminth control in livestock in the new Millennium. Moredun Research Institute, 2–5 July 2002, Edinburgh, UK.
Oldham CM, Thompson AN, Paganoni BL, Ferguson MB, Kearney GA (2011) The birth weight and survival of Merino lambs can be predicted from the pattern of change of live weight of their mothers during pregnancy. Animal Production Science 51, 776–783.
| The birth weight and survival of Merino lambs can be predicted from the pattern of change of live weight of their mothers during pregnancy.Crossref | GoogleScholarGoogle Scholar |
Whitlock HV (1948) Some modifications of the McMaster helminth egg counting technique and apparatus. Journal. Council for Scientific and Industrial Research (Australia) 21, 177–180.
Williams AR, Greeff JC, Vercoe PE, Dobson RJ, Karlsson LJE (2010) Merino ewes bred for parasite resistance reduce larval contamination onto pasture during the peri-parturient period. Animal 4, 122–127.
| Merino ewes bred for parasite resistance reduce larval contamination onto pasture during the peri-parturient period.Crossref | GoogleScholarGoogle Scholar | 22443626PubMed |
