Controlling the Introduction and Augmentation of Parasites in and on Domesticated Livestock

Abstract

Parasites are one of the most important threats to domesticated livestock worldwide. For several decades, their control has been based only on therapeutic interventions using chemical products at fixed intervals throughout the year. Results have demonstrated that dependence on these chemical products, as a single form of control, is not economically and ecologically sustainable. The problem has been augmented due to the emergence of endoparasite and ectoparasite populations resistant and multiresistant to the primary families of chemical products used to control them. Yet, these chemicals continue to be overused as the primary method for parasite control. Even more, their toxicity to animals, environmental contamination, and economic cost are of increasing concern. This limited approach to parasite control has environmental consequences with likely negative impacts to human and animal health. For example, most endectocides used to control parasites (endoparasites and ectoparasites) in domesticated animals are eliminated in the milk produced by females. Thus, there is strong concern regarding human consumption of dairy products containing such chemicals. Currently, market demands focus on healthy livestock production with emphases on the high standards in animal health and welfare based on quality production practices. The sustainable production of domesticated livestock needs strong changes, such as considering agroecologically oriented as well as novel approaches for parasite control. Thus, the use of existing drugs should be more strategically implemented and combined with other nonchemical alternatives for ruminant livestock. New strategies for controlling parasites in ruminant livestock should begin with the premise of not eliminating or eradicating parasitic organisms, but instead basing actions on economic thresholds (similar to IPM strategies for agricultural crops). In this review, we discuss the problem and current situation regarding parasites and their control using ranching operation methods. We discuss regions where the problem of chemical resistance is of strong concern and include the ecological and socioeconomic effects of parasite control (or lack therefore). We present information about novel approaches such as improving the nutritional status of the host and biological control methods for integration with domestic livestock in order to decrease the use of and reliance on chemical products.