Detection of anthelmintic resistance on two Irish beef research farms

Abstract

Beef and milk production systems in Ireland are largely dependent on a grass-based diet with cattle spending long periods of the year at pasture (Drennan and McGee 2009). As a result, cattle are frequently exposed to gastrointestinal nematode (GIN) challenge. Within grassbased production systems, anthelmintics are essential to optimising performance and any reduction in their efficacy may lead to reduced animal performance. Although anthelmintic resistance (AR) is more commonly reported in sheep (Sutherland and Leathwick 2011), it has been increasingly reported in cattle worldwide (Stafford and Coles 1999, Loveridge and others 2003, Soutello and others 2007, Demeler and others 2009, edmonds and others 2010). To date, there have been no published reports of AR in cattle in Ireland. We report the findings of a faecal egg count reduction test (feCRT) conducted at two Irish agricultural research farms (Study A and B). Two different software programmes were used to determine anthelmintic efficacy. All animal procedures performed in this study were conducted under experimental license (B100/2869) from the Irish Department of Health and Children, in accordance with the Cruelty to Animals Act 1876 and the european Communities (Amendment of Cruelty to Animals Act 1876) Regulation 2002 and 2005. Study A was conducted at Teagasc, Johnstown Castle, Wexford, Co. Wexford, Ireland (longitude 6°30′ W; latitude 52°17′ N; elevation 65 m above sea level (asl)). Sixty Holstein-friesian male calves, naive to anthelmintics, were used in this study. Calves were randomised by age, weight and feC to one of four treatment groups (n=15 per treatment

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

“…With the emergence of anthelmintic resistance in GI parasites of cattle (Edmonds et al., 2010, Sutherland and Leathwick, 2011, O'Shaughnessy et al., 2014b, Rose et al., 2015) there have been attempts towards developing TST strategies for cattle. This is important, as although resistance has been slow to develop amongst cattle parasites, it appears that multi-drug resistance for multiple parasite species is developing more rapidly than expected (Sutherland and Leathwick, 2011).…”

“…However, in recent years it has become evident that this is also an emerging problem for cattle (Edmonds et al., 2010, Sutherland and Leathwick, 2011, O'Shaughnessy et al., 2014b, Rose et al., 2015). With nematode resistance now present to all three of the broad spectrum anthelmintic classes (benzimidazoles, levamisole and macrocyclic lactones) used on cattle (Sutherland and Leathwick, 2011), control strategies aiming to sustain effective parasitic control are of key importance.…”

Efficacy of ivermectin against gastrointestinal nematodes of cattle in Denmark evaluated by different methods for analysis of faecal egg count reduction

“…More recently, Bayesian modelling using Markov chain Monte Carlo (MCMC) methods have been advocated as robust statistical analyses to cope with low and aggregated FEC data (Denwood et al., 2010, Torgerson et al., 2014). These MCMC-based procedures, available as open-source R packages or web-interface software, are being increasingly used to infer drug efficacy and to monitor AR in horse nematodes (Denwood et al., 2010, Fischer et al., 2015) and cattle helminths (Neves et al., 2014, O'Shaughnessy et al., 2014, Geurden et al., 2015, Novobilský and Höglund, 2015, Ramos et al., 2016). However, the performance of these MCMC procedures with the low mean FEC and parasite aggregation levels commonly found in cattle has not yet been evaluated.…”

Widespread anthelmintic resistance in European farmed ruminants: a systematic review

“…Bartley and others 2003, Keane and others 2014) and increasingly reported in cattle (e.g. O'Shaughnessy and others 2014). There is, therefore, a need to develop and adopt GIN control strategies that maintain the efficacy of anthelmintics and to identify risk factors for the development of AR.…”