Exploring the limitations of pathophysiological indicators used for targeted selective treatment in sheep experimentally infected with Haemonchus contortus

Chylinski, Caroline; Cortet, Jacques; Neveu, Cédric; Cabaret, Jacques

doi:10.1016/j.vetpar.2014.10.029

Cited by 15 publications

(13 citation statements)

References 39 publications

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“…ADG was the best determinant criterion for treating individuals who cross a given threshold for treatment, in accordance with previous work on sheep (Cabaret et al., 2006, Greer et al., 2009, Chylinski et al., 2015). However, ADG was the worst determinant criterion when treating a fixed percentage of the population, in accordance with Laurenson et al.…”

Section: Discussionmentioning

confidence: 99%

Modelling the consequences of targeted selective treatment strategies on performance and emergence of anthelmintic resistance amongst grazing calves

Berk

Laurenson

Forbes

et al. 2016

International Journal for Parasitology: Drugs and Drug Resistan

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The development of anthelmintic resistance by helminths can be slowed by maintaining refugia on pasture or in untreated hosts. Targeted selective treatments (TST) may achieve this through the treatment only of individuals that would benefit most from anthelmintic, according to certain criteria. However TST consequences on cattle are uncertain, mainly due to difficulties of comparison between alternative strategies. We developed a mathematical model to compare: 1) the most ‘beneficial’ indicator for treatment selection and 2) the method of selection of calves exposed to Ostertagia ostertagi, i.e. treating a fixed percentage of the population with the lowest (or highest) indicator values versus treating individuals who exceed (or are below) a given indicator threshold. The indicators evaluated were average daily gain (ADG), faecal egg counts (FEC), plasma pepsinogen, combined FEC and plasma pepsinogen, versus random selection of individuals. Treatment success was assessed in terms of benefit per R (BPR), the ratio of average benefit in weight gain to change in frequency of resistance alleles R (relative to an untreated population). The optimal indicator in terms of BPR for fixed percentages of calves treated was plasma pepsinogen and the worst ADG; in the latter case treatment was applied to some individuals who were not in need of treatment. The reverse was found when calves were treated according to threshold criteria, with ADG being the best target indicator for treatment. This was also the most beneficial strategy overall, with a significantly higher BPR value than any other strategy, but its degree of success depended on the chosen threshold of the indicator. The study shows strong support for TST, with all strategies showing improvements on calves treated selectively, compared with whole-herd treatment at 3, 8, 13 weeks post-turnout. The developed model appeared capable of assessing the consequences of other TST strategies on calf populations.

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Section: Discussionmentioning

confidence: 99%

Modelling the consequences of targeted selective treatment strategies on performance and emergence of anthelmintic resistance amongst grazing calves

Berk

Laurenson

Forbes

et al. 2016

International Journal for Parasitology: Drugs and Drug Resistan

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“…The FAMACHA score has been proposed to be a reliable indicator to identify sheep, which are in need of treatment due to infections with H. contortus ( Bath and Van Wyk, 2001 ). This has been shown in several studies, where significant correlations between FAMACHA and packed cell volume (PCV) have been found ( Kaplan et al, 2004 , Papadopoulos et al, 2013 , Chylinski et al, 2015 ). As TST indicator, the FAMACHA score should also be able to reflect H. contortus -related EPG, but findings are not consistent across studies.…”

Section: Introductionmentioning

confidence: 53%

Potentials of using milk performance data and FAMACHA score as indicators for Targeted Selective Treatment in Lacaune dairy sheep in Switzerland

Schwarz

Bapst²,

Holinger

et al. 2020

Veterinary Parasitology

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“…Alternative methods of control in sheep are necessary in the tropics to reduce the negative effect of parasitism and to improve the efficiency of production systems. In this context, selective deworming has been gaining importance in the world (Whitley et al 2014;Chylinski et al 2015;Maia et al 2015). The advantage of this system is important for a sustainable use of drugs because the treatments are applied only to the most susceptible animals to gastrointestinal parasitism.…”

Section: Discussionmentioning

confidence: 99%

Effect of selective anthelmintic treatments on health and production parameters in Pelibuey ewes during lactation

Arece-García

López-Leyva

González-Gardúño

et al. 2015

Trop Anim Health Prod

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A study was conducted from December to April 2013, with the aim of evaluating a system of selective antiparasitic treatments using the FAMACHA© color chart compared with a conventional suppressive deworming system every 30 days in Pelibuey ewes during lactation. For the study, 54 ewes were used. They were randomly divided into two groups: FAMACHA and chemical treatments. The ewes in the first group received selective treatment depending on the ocular mucosa coloration (FAMACHA) and body condition score (BCS), while in the second group (chemical) all the animals remained under routine deworming every 30 days. Fecal nematode egg counts, proportion of third-stage trichostrongylid larvae, body condition, coloration of the ocular mucosa, and packed cell volume in the ewes were determined, while in lambs only body weight (BW) was recorded. No significant differences (p > 0.05) were observed in any of the studied variables between groups; however, the use of antiparasitic drugs was reduced during the experimental period in the FAMACHA group and no deaths of lambs or ewes were recorded. The results indicate that during the lactation of ewes, a strategy of selective treatments can be implemented without showing deterioration in major health and productive parameters of these animals.

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Exploring the limitations of pathophysiological indicators used for targeted selective treatment in sheep experimentally infected with Haemonchus contortus

Cited by 15 publications

References 39 publications

Modelling the consequences of targeted selective treatment strategies on performance and emergence of anthelmintic resistance amongst grazing calves

Modelling the consequences of targeted selective treatment strategies on performance and emergence of anthelmintic resistance amongst grazing calves

Potentials of using milk performance data and FAMACHA score as indicators for Targeted Selective Treatment in Lacaune dairy sheep in Switzerland

Effect of selective anthelmintic treatments on health and production parameters in Pelibuey ewes during lactation

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