Embryonic Mortality and Adverse Reproductive Outcomes in Domestic Farm Animal Species

Embryonic mortality (EM) is a major cause of pregnancy loss in farm animal species and may result from infectious or non-infectious insults. Despite decades of research, significant knowledge gaps remain regarding its full impact on reproductive efficiency. Experimental, pathological, and epidemiological studies have primarily focused on abortions occurring during mid- to late gestation. In contrast, the contribution of embryonic mortality to reproductive failure occurring before abortion becomes clinically detectable remains poorly understood. Impaired reproductive performance is commonly documented in infected herds and flocks, yet embryonic mortality and implantation failure may represent under-diagnosed outcomes that have received limited scientific attention. Their occurrence is often reflected only indirectly, through broader parameters such as decreased fertility rates; extended calving, lambing, weaning-to-service, or weaning-to-farrowing intervals; increased return-to-oestrus rates; repeat breeding; infertility; reduced litter size; and a higher number of mummified piglets. Consequently, distinguishing EM occurring during the first weeks of gestation from other reproductive disorders remains challenging.The inherent difficulties associated with diagnosing EM under field conditions contribute substantially to this knowledge gap. Serial pregnancy assessments using ultrasonography or other sensitive monitoring techniques are rarely incorporated into studies investigating EM. Early maternal infection, local inflammatory responses, or disruptions in maternal recognition, embryo-to-maternal communication, and maintenance of pregnancy may compromise embryonic development and survival before placental pathology or abortion becomes clinically apparent. Given that early embryonic mortality is one of the most economically significant reproductive problems in livestock production, with many cases remaining undiagnosed, this knowledge gap has important implications for both veterinary medicine and animal production. Clarifying the contribution of embryonic losses would advance our understanding of pregnancy failure, improve the differential diagnosis of reproductive inefficiency, and support the development of more effective monitoring, prevention, and herd health management strategies.The aim of this Research Topic is to gather multidisciplinary contributions that expand current knowledge and improve our understanding of reproductive performance in ruminants and pigs, with particular emphasis on early and late embryonic death and other under-investigated adverse reproductive outcomes. We welcome original research articles, experimental studies, epidemiological investigations, systematic reviews, and translational approaches that integrate reproductive biology, veterinary medicine, and pathology with microbiology, immunology, molecular diagnostics, and herd-level epidemiology. This collection aims to promote interdisciplinary collaboration, stimulate innovative research approaches, and advance our understanding of one of the most significant, yet incompletely characterized, contributors to impaired reproductive performance in domestic farm animal species.We welcome submissions addressing, but not limited to, the following themes:• Mechanisms and timing of early and late embryonic mortality in ruminants and pigs;• Infectious and non-infectious contributors to impaired embryo survival and implantation failure;• Maternal recognition of pregnancy, embryo–maternal communication, and local inflammatory/immune responses;• Diagnostic innovations for detecting early pregnancy loss under field conditions (e.g., serial ultrasonography, molecular and biomarker approaches);• Epidemiological assessment of EM and its link to herd- and flock-level reproductive performance parameters;• Translational and interdisciplinary approaches integrating molecular, pathological, and herd-management data. Topic editors: Athina Basioura, Georgios Tsousis, Junwei Li Source: https://www.frontiersin.org/research-topics/83650/embryonic-mortality-and-adverse-reproductive-outcomes-in-domestic-farm-animal-species