ReviewAnimals : an open access journal from MDPI2026
Advances in Semen Extenders for Small Ruminant Sperm Preservation: Biological Mechanisms and Emerging Strategies.
Review in Animals : an open access journal from MDPI, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
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Authors and funding
4 authors.
Funding
Abstract
Semen preservation represents a fundamental component of reproductive biotechnology in small ruminants, supporting artificial insemination programs, genetic improvement, germplasm conservation, and sustainable livestock production. However, ram and buck spermatozoa are highly susceptible to cryoinjury induced by cold shock, oxidative stress, osmotic imbalance, and membrane destabilization during cooling, freezing, and thawing procedures. Consequently, semen extenders play a critical role in maintaining sperm viability, motility, membrane integrity, mitochondrial activity, and fertilizing capacity during preservation. This narrative review summarizes the biological basis of sperm preservation in sheep and goats and discusses the principal conventional and emerging extender systems used in small ruminant semen cryopreservation. Conventional extender components, including buffering systems, energy substrates, cryoprotective agents, egg yolk, and milk proteins, are reviewed with emphasis on their mechanisms of action and protective effects against cryodamage. Particular attention is given to species-specific limitations associated with buck seminal plasma enzymes and their interactions with egg yolk- and milk-based extenders. In addition, recent advances involving chemically defined extenders, soy lecithin formulations, antioxidants, synthetic membrane stabilizers, and nanotechnology-derived additives are discussed as promising alternatives aimed at improving cryosurvival, reducing oxidative stress, and enhancing extender standardization and biosafety. Practical applications of semen extenders in artificial insemination and semen banking are also discussed together with current methodological limitations, species-specific challenges, and future research priorities. Although numerous emerging strategies have demonstrated promising improvements in laboratory sperm-quality parameters, evidence supporting consistent fertility benefits under field conditions remains limited. Overall, this review critically evaluates current knowledge and highlights the need for species-specific, protocol-oriented, and well-standardized approaches to advance semen preservation in small ruminants.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.