Volume 204, Issues 1–2, 30 July 2014, Pages 34–43
SpeciaI
Issue: Antiparasitic Drug Use and Resistance in Cattle, Small Ruminants
and Equines in the United States - Current Status and Global
Perspectives
Abstract
Contemporary
management of nematode parasitism in cattle relies heavily on a single
class of drugs, the macrocyclic lactones (MLs). The potency and
convenience of the MLs, along with the low cost of generic formulations,
have largely supplanted the need for critical thinking about parasite
control, and rote treatment has become the default ‘strategy’. This
approach to parasite control has exerted substantial pressure to select
populations of nematodes that can survive recommended dosages of ML
products. Although macrocyclic lactones have been available for over 30
years, putative ML resistance in U.S. cattle was not reported until
fairly recently. This pattern begs the question, “Is this a new,
emergent problem, or an old issue that is finally commanding some
attention?”
The implications of bovine anthelmintic
resistance should stimulate a paradigm shift for U.S. cattle producers
and their advisors. However, there are significant obstacles to changes
in current thinking. It is anticipated that cattle producers will be
extremely reluctant to abandon historical practices unless they can be
convinced of the value of alternatives that are communicated through
targeted education, practical demonstrations, economic analyses, and
scientific evidence. Historically, the management advice of
practitioners has not relied strongly on parasite epidemiology, and
practitioners may not have the knowledge to implement evidence-based
recommendations. Pharmaceutical companies could play a significant role
in helping to shape and shift the thinking about sustainable use of
anthelmintics. However, their primary responsibility is to stockholders,
and they have strong economic incentives for maintaining the status quo.
It
is complicated and difficult to change attitudes and practices, and it
will take more than logic or fear to shift the parasite control paradigm
in the U.S. cattle industry. Achieving that goal will require
collaboration among stakeholders, a consistent, straightforward and
understandable message about resistance, and recommendations that are
practical as well as effective. But if we hope to ultimately influence
producers and their advisors, we need to be conscious of how individuals
and groups change their minds.
Keywords
- Bovine;
- Parasite;
- Control;
- Anthelmintic;
- Resistance;
- Change
Copyright © 2013 Elsevier B.V. All rights reserved.