Characterizing sheep production environments Defining production environments in U.S. sheep populations: clustering climate conditions and management practices

Abstract

Sheep production in the U.S. spans diverse geographies and management practices, which are traditionally classified by climate alone. By combining information on climatic conditions and their management practices, we assigned groups of flocks to distinct eco-management clusters that characterized their shared production environments. Ninety-seven producers, whose geographically distributed flocks represented five breeds enrolled in the National Sheep Improvement Program, completed an online management survey. Breeds included Katahdin (n = 50), Polypay (n = 21), Suffolk (n = 13), Rambouillet (n = 8), and Targhee (n = 5). The questionnaire considered parasite control, lambing and udder health management, culling strategies, feeding methods, and climate mitigation practices. We characterized the climates at producer locations based on elevation, seasonal precipitation, soil moisture, and the Comprehensive Climate Index (CCI). The CCI integrated ambient temperature, humidity, wind speed, and solar radiation to reflect thermal stress. Clusters were first formed based on climate or management data via Principal Component Analysis and Multiple Correspondence Analysis, respectively. Both sources of information were then combined to form eco-management clusters using Factorial Analysis of Mixed Data. Cluster quality was assessed using silhouette widths. Differences among clustering approaches were tested with chi-square cross-tabulations and permutation tests. Flock assignments to climate and to management clusters were, statistically, independent within breeds (P > 0.16). Flock allocations to eco-management and management clusters, however, typically aligned (P ≤ 0.01), although less so in Targhee-Rambouillet (P = 0.18). Such was also the case for climate-based clusters (P ≤ 0.04) except in Suffolk (P = 0.50). Overall, coupling of climate and management appeared weakest in Suffolk flocks. Across eco-management clusters, differences in management practices were found for 26 husbandry practices in Katahdin, 21 in Polypay, 7 in Suffolk, and 5 jointly in Rambouillet and Targhee (P < 0.05). Although climate influenced husbandry strategies, producers often adopted unique management practices in response to local conditions. Collectively, climate and management defined distinct yet complementary drivers of environmental heterogeneity, supporting the concept of eco-management clustering as a holistic approach to characterizing the production environments of sheep flocks.