The effects of parasitism on ewes for prime lamb production in western Victoria
B. Kirk
A D , J. W. A. Larsen A , N. Anderson B and M. A. Stevenson C
+ Author Affiliations
- Author Affiliations
A Mackinnon Project, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Werribee, Vic. 3030, Australia.
B Deceased. Formerly of Mackinnon Project, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Werribee, Vic. 3030, Australia.
C Asia Pacific Centre for Animal Health, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Vic. 3010, Australia.
D Corresponding author. Email: kbeata@unimelb.edu.au
Animal Production Science 61(15) 1592-1605 https://doi.org/10.1071/AN20414
Submitted: 17 July 2020 Accepted: 14 June 2021 Published: 3 August 2021
Journal Compilation © CSIRO 2021 Open Access CC BY
Abstract
Context: Internal parasites are estimated to cost the Australian sheep industry AUD436 million per annum (p.a.).
Aims: To assess the effects of parasitism in flocks producing prime lambs in the 500–700 mm p.a rainfall. area of Victoria.
Methods: Ewes on two farms that followed ‘best practice’ gastrointestinal parasite control programs (BP) and two farms that did not (regionally typical, TYP) were compared. Separate cohorts of ewes were monitored from pregnancy scanning to their subsequent joining each year for three consecutive seasons. Observations included worm egg count (WEC), bodyweight, condition score and presence of breech soiling (dag). These were compared between groups that were treated to suppress parasitism (SUP) and those treated according to the usual program used on that farm (NSUP). Data from individual ewes were analysed using a multivariable, mixed-effects regression model.
Key results: After adjusting for known confounders, SUP ewes were 1.2 (95% CI 0.80–1.6) kg heavier than NSUP ewes. Mature SUP ewes were significantly heavier than NSUP ewes at their next joining on 6 of 18 occasions, mostly following winters when ewes experienced nutritional stress. Ewe hoggets and Merino ewes were generally more susceptible to parasitism than mature non-Merino ewes; single-bearing ewes were less susceptible than those bearing twins. The effects of parasitism were reduced when peri-parturient ewes had an optimal condition score and grazed adequate pastures.
Conclusions: Ewes were more vulnerable to parasitism when immature, twin-bearing, or under nutritional stress. Some of the greatest differences between SUP and NSUP ewes occurred following periods of low feed availability and/or ewe condition score. The difference between the mean bodyweight of SUP and NSUP Merinos was not always greater than that of the non-Merinos. WECs are not a sole reliable indicator of the effects of parasitism in this class of sheep.
Implications: Immature or twin-bearing ewes, and those in suboptimal body condition, should be managed considering their increased vulnerability to parasitism, and WEC interpreted alongside other factors. Controlled release capsules were not cost effective in reducing production loss from gastrointestinal nematodes in most years but may be effective in reducing the effects of clinical parasitism in some cases.
Key words: gastro-intestinal nematodes; worms; worm egg counts, lamb production, sheep.
References
ABARES (2019) ‘Value of Agricultural Commodities Produced - Australia 2017–18.’ Available at https://www.abs.gov.au/AUSSTATS/abs@.nsf/DetailsPage/7503.02017-18?OpenDocument [Accessed 13 July 2020].ABS 2013. 7501.0 - Value of Principal Agricultural Commodities Produced, Australia, Preliminary, 2012–13. Canberra.
Anderson N (1972) Trichostrongylid Infections of Sheep in a winter rainfall region: I. Epizootiological studies in the western district of Victoria, 1966–67. Australian Journal of Agricultural Research 23, 1113–1129.
| Trichostrongylid Infections of Sheep in a winter rainfall region: I. Epizootiological studies in the western district of Victoria, 1966–67.Crossref | GoogleScholarGoogle Scholar |
Anderson N, Martin PJ, Jarrett RG (1988) Mixtures of anthelmintics: A strategy against resistance. Australian Veterinary Journal 65, 62–64.
| Mixtures of anthelmintics: A strategy against resistance.Crossref | GoogleScholarGoogle Scholar | 3355455PubMed |
Anderson N, Martin P, Jarrett RG (1991) The efficacy of mixtures of albendazole sulphoxide and levamisole against sheep nematodes resistant to benzimidazole and levamisole. Australian Veterinary Journal 68, 127–132.
| The efficacy of mixtures of albendazole sulphoxide and levamisole against sheep nematodes resistant to benzimidazole and levamisole.Crossref | GoogleScholarGoogle Scholar | 2069539PubMed |
Anon (2010) ‘Managing ewes in late pregnancy.’ Available at https://web.archive.org.au/awa/20190913044845mp_/http://pandora.nla.gov.au/pan/59698/20191030-0039/www.sheepcrc.org.au/files/pages/fact-sheets/pw13-reproduction-series/Managing_ewes_in_late_pregnancy_for_web.pdf [Accessed 13 July 2020].
Anon (2011a) ‘Condition Scoring of Sheep.’ Available at http://www.lifetimewool.com.au/conditionscore.aspx [Accessed November 13 2015].
Anon (2011b) ‘Managing twin-bearing ewes for increased production.’ Available at http://www.lifetimewool.com.au/Ewe%20Management/twins.aspx [Accessed November 25 2015].
Anon (2014a) ‘Sheep Genetics: ASBVs and Indexes explained.’ Available at http://www.sheepgenetics.org.au/Getting-started/ASBVs-and-Indexes [Accessed 18 August 2014].
Anon (2014b) ‘Sheep Industry Profile - December 2014.’ Available at http://agriculture.vic.gov.au/__data/assets/pdf_file/0007/292174/2-Sheep-Industry-Profile_December-2014-Update_MASTER1.pdf [Accessed 13 July 2020].
Arundel JH, Ford GE (1969) The use of a Single Anthelmintic Treatment to control the Post-Parturient Rise in Faecal Worm Egg Count of Sheep. Australian Veterinary Journal 45, 89–93.
| The use of a Single Anthelmintic Treatment to control the Post-Parturient Rise in Faecal Worm Egg Count of Sheep.Crossref | GoogleScholarGoogle Scholar | 5814051PubMed |
Barger IA (1993) Influence of sex and reproductive status on susceptibility of ruminants to nematode parasitism. International Journal for Parasitology 23, 463–469.
| Influence of sex and reproductive status on susceptibility of ruminants to nematode parasitism.Crossref | GoogleScholarGoogle Scholar | 8354597PubMed |
Bates D, Mächler M, Bolker B, Walker S (2014) Fitting linear mixed-effects models using lme4. Journal of Statistical Software 67, 1–48.
Beasley AM, Kahn LP, Windon RG (2010) The periparturient relaxation of immunity in Merino ewes infected with Trichostrongylus colubriformis: Parasitological and immunological responses. Veterinary Parasitology 168, 60–70.
| The periparturient relaxation of immunity in Merino ewes infected with Trichostrongylus colubriformis: Parasitological and immunological responses.Crossref | GoogleScholarGoogle Scholar | 19775817PubMed |
Behrendt R, Van Burgel AJ, Bailey A, Barber P, Curnow M, Gordon DJ, Hocking Edwards J, Oldham CM, Thompson AN (2011) On-farm paddock-scale comparisons across southern Australia confirm that increasing the nutrition of Merino ewes improves their production and the lifetime performance of their progeny. Animal Production Science 51, 805–812.
| On-farm paddock-scale comparisons across southern Australia confirm that increasing the nutrition of Merino ewes improves their production and the lifetime performance of their progeny.Crossref | GoogleScholarGoogle Scholar |
Bishop K, Avery A, Dunstan M, Foot J, Halls M, Hamilton L, Ransom K, Saul G, O’Sullivan J, Walsh S 1995. Prograze Manual Victoria. Agriculture Victoria. NSW Agriculture, Orange.
Bott NJ, Campbell BE, Beveridge I, Chilton NB, Rees D, Hunt PW, Gasser RB (2009) A combined microscopic-molecular method for the diagnosis of strongylid infections in sheep. International Journal for Parasitology 39, 1277–1287.
| A combined microscopic-molecular method for the diagnosis of strongylid infections in sheep.Crossref | GoogleScholarGoogle Scholar | 19328802PubMed |
Caple I (1994) Nutrition of grazing sheep. In ‘Merinos, Money & Management.’ (Ed. FHW Morley.) pp. 201. (Postgraduate Committee in Veterinary Science University of Sydney: Sydney)
Dever ML, Kahn LP, Doyle EK (2017) Integrated parasite management improves control of gastrointestinal nematodes in lamb production systems in a high summer rainfall region, on the Northern Tablelands, New South Wales. Animal Production Science 57, 958–968.
| Integrated parasite management improves control of gastrointestinal nematodes in lamb production systems in a high summer rainfall region, on the Northern Tablelands, New South Wales.Crossref | GoogleScholarGoogle Scholar |
Donald AD, Morley FHW, Waller PJ, Axelsen A, Dobson RJ, Donnelly JR (1982) Effects of reproduction, genotype and anthelmintic treatment of ewes on Ostertagia spp. populations. International Journal for Parasitology 12, 403–411.
| Effects of reproduction, genotype and anthelmintic treatment of ewes on Ostertagia spp. populations.Crossref | GoogleScholarGoogle Scholar | 7141779PubMed |
Donnelly JR, McKinney GT, Morley FHW (1972) Lamb growth and ewe production following anthelmintic drenching before and after lambing. Proceedings of the Australian Society of Animal Production 9, 392–396.
Greeff JC, Karlsson LJ, Schlink AC (2014) 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 |
Hocking Edwards J, Copping KJ, Thompson AN (2011) Managing the nutrition of twin-bearing ewes during pregnancy using Lifetimewool recommendations increases production of twin lambs. Animal Production Science 51, 813–820.
| Managing the nutrition of twin-bearing ewes during pregnancy using Lifetimewool recommendations increases production of twin lambs.Crossref | GoogleScholarGoogle Scholar |
Kirk B (2016) Internal Parasitism and Production in Prime Lamb Flocks. Thesis. University of Melbourne, Melbourne.
Lane J, Jubb T, Shephard R, Webb Ware J, Fordyce G (2015). Priority list of endemic diseases for the red meat industries. Meat and Livestock Australia Limited, North Sydney, NSW.
Larsen JWA, Anderson N (2009) Worm infections in high and low bodyweight Merino ewes during winter and spring. Australian Veterinary Journal 87, 102–109.
| Worm infections in high and low bodyweight Merino ewes during winter and spring.Crossref | GoogleScholarGoogle Scholar | 19245622PubMed |
Larsen JWA, Anderson N, Vizard AL, Anderson GA, Hoste H (1994) Diarrhoea in Merino ewes during winter: association with trichostrongylid larvae. Australian Veterinary Journal 71, 365–372.
| Diarrhoea in Merino ewes during winter: association with trichostrongylid larvae.Crossref | GoogleScholarGoogle Scholar |
Larsen JWA, Vizard AL, Anderson N (1995) Production losses in Merino ewes and financial penalties caused by trichostrongylid infections during winter and spring. Australian Veterinary Journal 72, 58–63.
| Production losses in Merino ewes and financial penalties caused by trichostrongylid infections during winter and spring.Crossref | GoogleScholarGoogle Scholar |
Lawrence KE, Leathwick DM, Rhodes AP, Jackson R, Heuer C, Pomroy WE, West DM, Waghorn TS, Moffat JR (2007) Management of gastrointestinal nematode parasites on sheep farms in New Zealand. New Zealand Veterinary Journal 55, 228–234.
| Management of gastrointestinal nematode parasites on sheep farms in New Zealand.Crossref | GoogleScholarGoogle Scholar | 17928899PubMed |
Leathwick DM, Miller CM, Atkinson DS, Haack NA, Alexander RA, Oliver AM, Waghorn TS, Potter JF, Sutherland IA (2006) Drenching adult ewes: implications of anthelmintic treatments pre- and post-lambing on the development of anthelmintic resistance. New Zealand Veterinary Journal 54, 297–304.
| Drenching adult ewes: implications of anthelmintic treatments pre- and post-lambing on the development of anthelmintic resistance.Crossref | GoogleScholarGoogle Scholar | 17151728PubMed |
Miller CM, Ganesh S, Garland CB, Leathwick DM (2015) Production benefits from pre- and post-lambing anthelmintic treatment of ewes on commercial farms in the southern North Island of New Zealand. New Zealand Veterinary Journal 63, 211–219.
| Production benefits from pre- and post-lambing anthelmintic treatment of ewes on commercial farms in the southern North Island of New Zealand.Crossref | GoogleScholarGoogle Scholar | 25589215PubMed |
Morley FHW, White DH, Kenney PA, Davis IF (1978) Predicting ovulation rate from liveweight in ewes. Agricultural Systems 3, 27–45.
| Predicting ovulation rate from liveweight in ewes.Crossref | GoogleScholarGoogle Scholar |
Morris RS, Anderson N, McTaggart IK (1977) An economic analysis of two schemes for the control of helminthiasis in breeding ewes. Veterinary Parasitology 3, 349–363.
| An economic analysis of two schemes for the control of helminthiasis in breeding ewes.Crossref | GoogleScholarGoogle Scholar |
Mulvaney FJ, Morris ST, Kenyon PR, Morel PCH, West DM (2012) Effect of nutrition from mid-pregnancy to parturition on the live weight of twin-bearing hoggets and the live weight and survival of their lambs. New Zealand Journal of Agricultural Research 55, 385–392.
| Effect of nutrition from mid-pregnancy to parturition on the live weight of twin-bearing hoggets and the live weight and survival of their lambs.Crossref | GoogleScholarGoogle Scholar |
Niven P, Anderson N, Vizard AL (2002) The integration of grazing management and summer treatments for the control of trichostrongylid infections in Merino weaners. Australian Veterinary Journal 80, 559–566.
| The integration of grazing management and summer treatments for the control of trichostrongylid infections in Merino weaners.Crossref | GoogleScholarGoogle Scholar | 12398320PubMed |
Oldham CM, Thompson AN, Ferguson MB, Gordon DJ, Kearney GA, Paganoni BL (2011) The birthweight and survival of Merino lambs can be predicted from the profile of liveweight change of their mothers during pregnancy. Animal Production Science 51, 776–783.
| The birthweight and survival of Merino lambs can be predicted from the profile of liveweight change of their mothers during pregnancy.Crossref | GoogleScholarGoogle Scholar |
R Core Team (2021) R: A Language and Environment for Statistical Computing. R Foundation for Statistical Computing, Vienna, Austria.
Rowe J (2010) The Australian sheep industry - undergoing transformation. Animal Production Science 50, 991–997.
| The Australian sheep industry - undergoing transformation.Crossref | GoogleScholarGoogle Scholar |
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. Meat and Livestock Australia Limited, North Sydney, NSW.
Salisbury JR, Arundel JH (1970) Peri-parturient deposition of nematode eggs by ewes and residual pasture contamination as sources of infection for lambs. Australian Veterinary Journal 46, 523–529.
| Peri-parturient deposition of nematode eggs by ewes and residual pasture contamination as sources of infection for lambs.Crossref | GoogleScholarGoogle Scholar | 5530548PubMed |
Trompf JP, Gordon DJ, Behrendt R, Curnow M, Kildey LC, Thompson AN (2011) Participation in Lifetime Ewe Management results in changes in stocking rate, ewe management and reproductive performance on commercial farms. Animal Production Science 51, 866–872.
| Participation in Lifetime Ewe Management results in changes in stocking rate, ewe management and reproductive performance on commercial farms.Crossref | GoogleScholarGoogle Scholar |
Tyrell LD, Larsen JW, Anderson N (2014) Breech-strike on mulesed, clipped and unmulesed Merino ewes and hoggets in south-eastern Australia. Australian Veterinary Journal 92, 348–356.
| Breech-strike on mulesed, clipped and unmulesed Merino ewes and hoggets in south-eastern Australia.Crossref | GoogleScholarGoogle Scholar | 25156054PubMed |
van Burgel AJ, Oldham CM, Behrendt R, Curnow M, Gordon DJ, Thompson AN (2011) The merit of condition score and fat score as alternatives to liveweight for managing the nutrition of ewes. Animal Production Science 51, 834–841.
| The merit of condition score and fat score as alternatives to liveweight for managing the nutrition of ewes.Crossref | GoogleScholarGoogle Scholar |
Warn LK, Geenty KG, McEachern S (2006) What is the optimum wool-meat enterprise mix? International Journal of Sheep and Wool Science 54, 38–49.
West DM, Pomroy WE, Kenyon PR, Morris ST, Smith SL, Burnham DL (2009) Estimating the cost of subclinical parasitism in grazing ewes. Small Ruminant Research 86, 84–86.
| Estimating the cost of subclinical parasitism in grazing ewes.Crossref | GoogleScholarGoogle Scholar |
Wood S, Sheipl F (2014) ‘gamm4: Generalised additive mixed models using mgcv and lme4.’ R package version 0.2-5. Available at https://CRAN.R-project.org/package=gamm4. [Verified 1 October 2019]
