Sheep Industry News August 2025

tion. These results could aid producers in genetically screening breeding animals to reduce the occurrence of this economically important condition. Follow-up research at the Wyoming ram test found no differences in growth rate or feed intake between rams with and without ALD. However, affected rams showed higher blood levels of vitamin D later in the test period, sug gesting a potential disruption in vitamin D metabolism. These results point to a possible nutritional-metabolic bone disorder, similar to Type 1 rickets, though further research is needed to confirm this connection. In conclusion, ALD is a complex disease where both genetics and nutrition have important, and likely interacting, roles. Nevertheless, rams with ALD should be avoided in breeding programs. Looking to the Future: Adapting Tools for Evolving Needs The tools and systems used to drive genetic and phenotypic improvement must continue to evolve. International models provide a glimpse into what may lie ahead. For example, prog eny testing programs abroad use artificial insemination to mate elite sires to standardized ewe groups. This enables stud ram prospects to be more comprehensively evaluated by consider ing the performance of both them and their offspring across a wide spectrum of traits. Environmental challenge tests are another frontier. The Virginia Tech performance test challenges rams with a known amount of infective gastrointestinal nematode (GIN) larvae and measures their immune response. In many ways, this more clearly identifies GIN resistant animals than natural infection under less controlled settings. Similarly, programs in New Zealand expose rams to footrot-prone pastures or fungal toxins (e.g., facial eczema) to evaluate underlying mechanisms as sociated with genetic resilience. Aligning innovation with the realities of U.S. production constraints is an important consid eration. Recent efforts in the Wyoming ram test have included grazing trials and supplementation efficiency studies to mimic realistic production settings. Tying data collected from central performance tests, both on standard and more refined traits, into larger genetic evaluation programs like the NSIP is a criti cal next step. Public–Private Partnership: Art and Science in Prac tice In the words of the late University of Wyoming Sheep Specialist, LeRoy Johnson, “sheep production is an art and a science”. The Wyoming Ram Test, now over 60 years strong, exemplifies this blend of innovation and intuition through one of the sheep industry’s longest-standing public–private partner ships. This reciprocal relationship is more than an operational success—it’s a model for how land-grant institutions can re

main relevant by staying connected to the producers they serve. While genetic merit may be calculated on paper, the lasting values of central performance tests lies in the trust they build, the questions they raise, and the progress they make possible.

If you have any questions regarding background information cited here, please do not hesitate to contact the authors.

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Figure 3. Yearling Western white-faced rams diagnosed with bent-leg for displaying inward bowing of the left forelimb (top) and outward bowing of the right forelimb (bottom).

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