Small Ruminant Farms as Managed Ecosystems: A Conceptual Framework for Components and Interactions, and the Role of Health Management.

Livestock farms are a distinctive type of agricultural ecosystem wherein farmed animals interact continuously with other living organisms and with the physical environment of the farm under the influence of human management. The objectives of this paper are the proposal of a framework in which small ruminant farms are considered as managed ecosystems, the identification, definition and characterization of the principal biotic components and abiotic environmental compartments, the examination of interactions occurring within and between these components and the description of the role of health management in modifying interactions within these systems. Within the proposed approach, the ecosystem of small ruminant farms can be considered to be characterized by five principal elements: components and compartments, interactions and flows and their directionality, inputs and outputs crossing the physical or functional boundaries of the system, and human management and feedback. Small ruminant farms can function as networks of ecosystem interactions, in which complex interactions occur among and between their biotic components and abiotic environmental compartments. In brief, the biotic components of the farm ecosystem include the livestock (sheep, goats), other domestic or synanthropic animals on farms, wildlife near farms, people working on farms or visiting, vegetation and other primary producers, pathogens, arthropods and other biotic communities. The abiotic environmental compartments include animal housing and associated areas and materials, farm systems, machinery and light equipment, feed and water, climate variables and farm waste. Various interactions connect those components. Health management acts upon ecosystem components and their interactions and is a principal means through which humans deliberately modify the farm ecosystem; it is based on human decisions, which influence multiple components of the ecosystem and direct the interactions within the system. Health management can modify interactions throughout the farm ecosystem, with effects that may extend beyond their immediately intended targets. The consideration of these wider relationships can support better-informed and integrated health management of sheep and goat farms and their animal populations.