Long‐acting moxidectin for the control of trichostrongylid infections of sheep in south‐eastern Australia

Larsen, J. B.; Anderson, Norman H.; Preshaw, A. R.

doi:10.1111/j.1751-0813.2009.00395.x

Cited by 9 publications

(7 citation statements)

References 14 publications

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“…In China, poultry industry had to face billions of dollars annual loss due to almost 100% chicken morbidity by coccidiosis (Zhang et al, 2013). Sheep helminthiasis led to a loss of 2.22 million dollars annually in Australia (Hosking et al, 2009; Larsen et al, 2009). …”

Section: Benefits Of Antimicrobial Drugsmentioning

confidence: 99%

Benefits and risks of antimicrobial use in food-producing animals

et al. 2014

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Benefits and risks of antimicrobial drugs, used in food-producing animals, continue to be complex and controversial issues. This review comprehensively presents the benefits of antimicrobials drugs regarding control of animal diseases, protection of public health, enhancement of animal production, improvement of environment, and effects of the drugs on biogas production and public health associated with antimicrobial resistance. The positive and negative impacts, due to ban issue of antimicrobial agents used in food-producing animals, are also included in the discussion. As a double-edged sword, use of these drugs in food-animals persists as a great challenge.

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Section: Benefits Of Antimicrobial Drugsmentioning

confidence: 99%

Benefits and risks of antimicrobial use in food-producing animals

et al. 2014

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“…before the most recent strategic or summer anthelmintic treatments and so, by definition, 'in refugia' from those treatments) or from late summer and autumn deposition of eggs (the autumn generation, by definition not in refugia because they are deposited after the summer treatments) were recently summarised. 35 These results, plus those of Anderson,36 show that the proportion of spring-derived refugia population is, on average, from 30% to 50% of the total larval populations the following winter, as judged by tracer worm counts. It would appear that this proportion is high enough to have prevented the rapid selection for ML resistance in T. circumcincta, unlike in many areas of WA that have a more pronounced Mediterranean climate and where ML resistance developed more rapidly and is considered common.…”

Section: Simulations Bymentioning

confidence: 72%

“…comm.). Estimates were recently summarised 35 from two separate two-year studies in this region of the proportion of nematodes in winter that were derived from either the previous spring (i.e. before the most recent strategic or summer anthelmintic treatments, and so, by definition, in 'refugia' from those treatments), or from late summer and autumn deposition of eggs (the autumn generation, by definition not in 'refugia' as they are deposited after the summer treatments).…”

Section: Discussionmentioning

confidence: 99%

A multi‐species model to assess the effect of refugia on worm control and anthelmintic resistance in sheep grazing systems

et al. 2011

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1A multi-species model to assess the impact of refugia on worm control and anthelmintic resistance in sheep grazing systems. RJ ObjectiveDevelop a computer simulation model that uses daily meteorological data and farm management practices to predict populations of Trichostrongylus colubriformis, Haemonchus contortus and Teladorsagia (Ostertagia) circumcincta and the evolution of anthelmintic resistance within a sheep flock. Use the model to explore if increased refugia, provided by leaving some adult sheep untreated, would delay development of anthelmintic resistance without compromising nematode control. ProceduresCompare model predictions with field observations from a breeding flock in Armidale, NSW. Simulate the impact of leaving 1-10% of adult sheep untreated in diverse sheep grazing systems. ResultsPredicted populations of T. colubriformis and T. circumcincta were less than those observed in the field. Attributed to nutritional stress experienced by sheep during drought, and not accounted for by the model. Observed variation in faecal egg count explained by the model (R 2 ) for these species was 40-50%. H. contortus populations and R 2 were both low.Leaving some sheep untreated worked best in situations where animals were already grazing or were moved on to pastures with low populations of infective larvae. In these cases anthelmintic resistance was delayed and nematode control was maintained when 1-4% of adult stock remained untreated. ConclusionsIn general, the model predicted that leaving more than 4% of adults untreated did not sufficiently delay the development of anthelmintic resistance to justify the increased 2 production risk from such a strategy. The choice of a drug rotation strategy had an equal or larger impact on nematode control, and selection for resistance, than leaving 1-10% of adults untreated. The multi-species model described here allows for these phenomena and estimates host mortalities and inappetence based on the total worm populations. To determine the utility of the model, worm populations were monitored in flocks of breeding ewes and weaners that were managed under typical grazing systems in north-eastern Australia. Daily meteorological and management records were kept so that worm populations could be predicted using the multispecies model. Keywords 3In this simulation study, the model was used to: a) estimate the consequences of leaving a proportion of adult stock untreated (as a source of refugia) on the development of anthelmintic resistance and effectiveness of parasite control; b) determine how best to use a new anthelmintic class (amino-acetonitrile derivatives (AAD), represented by monepantel; Zolvix ® , Novartis Animal Health Inc., Switzerland) to control gastro-intestinal nematodes while minimising selection for drug resistance; and c) examine these issues in four environments to determine if there are common principles that can be applied and/or how they need to be modified to suit local environments. The aim was to fully explore the interaction between the fundamen...

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“…This study compares single injection of the long-acting anthelminthic moxidectin either in summer or winter, with a standard program of two oral treatments of moxidectin in summer. 3 Egg counts and tracer worm counts for the double oral treatment were consistently high and counts for both of the groups treated in summer were lower and production indices were better. Long acting moxidectin in summer reduced infective larvae on the pasture, as worm counts in tracer sheep during winter are reduced.…”

Section: Long-acting Moxidectin In Sheepmentioning

confidence: 90%

In This Issue – April 2009

2009

Aust Veterinary J

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The laboratory network in Australia and New Zealand ▪ Difficulties in tracing pigs after auction ▪ Long‐acting moxidectin in sheep ▪ Crutching and dicyclanil for breech strike ▪ Nonsurgical alternative to mulesing ▪ Heimlich valve drainage in dogs ▪ Extradural haematoma after snake bite ▪ Metastatic mast cell neoplasia ▪ Ectoparasitic dermatitis in wallabies

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Long‐acting moxidectin for the control of trichostrongylid infections of sheep in south‐eastern Australia

Abstract: A single injection of long-acting moxidectin in December is an effective treatment strategy for Merino ewes lambing in spring.

Cited by 9 publications

References 14 publications

Benefits and risks of antimicrobial use in food-producing animals

Benefits and risks of antimicrobial use in food-producing animals

A multi‐species model to assess the effect of refugia on worm control and anthelmintic resistance in sheep grazing systems

In This Issue – April 2009

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