Helminthic control on grazing ruminants and environmental risks in South America

Abstract

-The control of ruminant gastrointestinal nematodes and ectoparasites, one of the major production health problems, are heavily reliant on the systematic and sometimes abusive use of anthelmintic drugs. Endectocides are the most frequently used drugs, having high potency against arthropods and nematodes. Their dung pat residues enhance the risk of adverse effects on non-target invertebrates and on the general grazing cattle ecosystem. In this scenario, our objective is to review current knowledge of the agro-environmental and biodiversity impact and risks of endectocides in South America. The effects of faecal drug residues of ivermectin and doramectin on dung colonising invertebrates and dung degradation have been reported in studies carried out in the temperate centre of Argentina and in the subtropical region of Brazil. The results from Argentina showed a depression in invertebrate colonisation and degradation of dung recovered from endectocide treated cattle during the autumn. Comparisons have shown that ivermectin and doramectin have similar adverse effects. A decrease of Coleoptera larvae, Diptera larvae, Staphylinidae, Collembola, Acari and dung specific nematodes was noted in pats from both endectocides. The results from Brazil showed that dipterous larvae, Polyphaga coleopteran larvae and adults and mites were significantly reduced in the ivermectin treated group. The disturbances that macrocyclic lactones can produce on non-targeted invertebrates and on their associated participation in dung degradation and soil element recycling, are unpredictable and can negatively influence biodiversity and the agricultural ecosystem sustainability.endectocide / environmental risk / South America / cattle grazing system / dung fauna Résumé -Contrôle des helminthes chez les ruminants à l'herbe et risques environnementaux en Amérique du Sud. Le contrôle des nématodes gastro-intestinaux et des ectoparasites, qui est l'un des problèmes de santé majeurs dans la production bovine, repose largement sur l'utilisation systé-matique et parfois abusive d'anthelmintiques. Les endectocides, qui ont un effet puissant contre les arthropodes et les nématodes, sont les médicaments le plus fréquemment utilisés. Leurs résidus dans les matières fécales augmentent les risques d'effets nocifs sur des invertébrés qui ne sont pas la cible 563

Managing helminths of ruminants in organic farming

“…The rules are also stringent in organic certified farms in Denmark: oral anthelmintics are preferred, preventive use of anthelmintics is prohibited, a specific diagnostic by a veterinarian is necessary before treatment and withdrawal time following treatment is three times the statutory time [1]. The per os is preferred to the injection formulations (boluses being forbidden), and molecules that are environmentally friendly are also preferred (most macrocylic lactones are then bad candidates [36,54]). According to the present regulations, ewes, adult goats and cows can be treated twice a year for parasites, and when ectoparasites are to be controlled, exceptionally an additional external antiparasitic treatment is allowed.…”

Multispecies and multiple anthelmintic resistance on cattle nematodes in a farm in Argentina: the beginning of high resistance?

“…These conditions do not favour the appearance of resistance [23]. During the last 15 years in South America, technologies for gastrointestinal control in livestock have been sustained by the large use of broad-spectrum anthelmintics [25]. This is particularly true in the temperate plains of Argentina, where mixed cattlecrop production predominates, management is very intensive, and drugs have been frequently used for many years [9,10,22,25].…”

“…During the last 15 years in South America, technologies for gastrointestinal control in livestock have been sustained by the large use of broad-spectrum anthelmintics [25]. This is particularly true in the temperate plains of Argentina, where mixed cattlecrop production predominates, management is very intensive, and drugs have been frequently used for many years [9,10,22,25]. Resistance of Cooperia to macrocyclic lactones has been recorded in Argentina [1,2,[13][14][15]20] and treatment using benzimidazoles has regained favour among farmers.…”

In vitro nematophagous activity of predatory fungi on infective larvae of Strongyloides papillosus

“…However, the public health significance of anthelmintic drug residues in products of animal origin, the presence of these drugs in animal feces, their negative influence on biodiversity and agricultural ecosystem sustainability (due to the heavy reliance on systematic and sometimes abusive therapeutic use) and reports of helminth strains tolerant or resistant to different anthelmintic groups have triggered investigation into alternative methods for the sustainable control of gastrointestinal nematodes of ruminants (CAI et al, 2016;GRONVOLD et al, 1996;SUAREZ, 2002). The non-chemotherapeutic approach to the control of nematode gastrointestinal parasites of ruminants using nematophagous fungi as biological Campos et al Acta Veterinaria Brasilica March 11 (2017) [213][214][215][216][217][218] 214 control agents showed consistent results (LARSEN, 2000;PAZ-SILVA et al, 2011).…”