Neonatal assessment in donkey foals is essential for reducing perinatal mortality and improving early management, yet breed-specific data remain scarce, particularly for indigenous Chinese breeds such as the Luxi Black donkey—an economically and genetically valuable breed of Shandong Province for which neonatal vitality has not been previously characterized. This prospective observational study aimed to describe the distribution of a modified four-parameter Apgar score and to summarize early physiological and morphometric parameters in Luxi Black donkey foals at birth. The study further explored whether these early parameters differed across Apgar score categories, with the aim of providing preliminary breed-specific reference data for neonatal assessment in this indigenous donkey breed. Fifty Jennies and the resulting 51 foals were enrolled at the National Black Donkey Breeding Center in Dong’e County, Shandong, China. Within 5 min of delivery, each foal was scored using a modified Apgar system (heart rate, respiratory rate, muscle tone, reflex response; maximum 8), and heart rate, respiratory rate, time to first suckling, rectal temperature, birth weight, body height, body length, chest girth, and abdomen girth were recorded. Foals were grouped according to their observed modified Apgar score categories (8/8, 7/8, 6/8, and 0/8). All 51 foals were included in the descriptive analysis of Apgar score distribution, while the three stillborn foals with an Apgar score of 0/8 were described separately and excluded from statistical comparisons. Physiological and morphometric parameters were compared only among live-born foals with Apgar scores of 8/8, 7/8, and 6/8. Of the 51 foals, 35 (68.63%) scored 8/8, 7 (13.73%) scored 7/8, 6 (11.76%) scored 6/8, and 3 (5.88%) were stillborn. Among live-born foals, respiratory rate (p = 0.008), time to first suckling (p < 0.001), and rectal temperature (p = 0.001) differed significantly among Apgar score categories, whereas heart rate showed no significant difference (p = 0.052). Birth weight and morphometric measurements did not differ significantly among live Apgar score categories. These preliminary findings suggest that the modified Apgar score may support early descriptive observation of neonatal status in Luxi Black donkey foals, although further studies with larger cohorts and objective outcome-based measures are needed.

Dezhou donkey is a premium indigenous Chinese livestock breed with high economic value for meat, hide and medicinal uses, and growth rate is a core trait determining farming profitability. However, the molecular and metabolic mechanisms underlying divergent growth rates in this breed have not been fully characterized, with no integrated transcriptomic and metabolomic studies reported. Here, 12 age-matched healthy male Dezhou donkeys were assigned to faster-growing (n = 6) and slower-growing (n = 6) groups by average daily gain, followed by plasma transcriptome sequencing and untargeted LC-MS/MS metabolomics. We identified 480 differentially expressed genes, with the slower-growing group enriching in immune/inflammatory/apoptotic pathways, and the faster-growing group in energy metabolism and transmembrane transport. Lipids and lipid-like molecules represented the largest proportion (44.9%) of the differential metabolites; the slower-growing group was enriched in lipid peroxidation and pro-inflammatory mediators, while the faster-growing group was enriched in unsaturated fatty acids and antioxidants. Integrated analysis revealed core pathways (cAMP signaling, arachidonic acid/unsaturated fatty acid biosynthesis) and key candidate genes/metabolites. Our findings clarify that excessive lipid peroxidation and inflammatory imbalance restrict growth, while efficient energy metabolism promotes faster growth, providing theoretical support for genetic improvement and precision nutrition of Dezhou donkeys.

The major histocompatibility complex (MHC) represents a critical genetic locus that orchestrates adaptive immune responses through antigen presentation and T cell activation, characterized by exceptional polymorphism and species-specific diversity. In herbivores, MHC polymorphisms constitute fundamental determinants of resistance to parasitic, viral, and bacterial infections while serving as crucial indicators of genetic diversity and breeding value in animal populations. Recent advances in high-throughput sequencing technologies, single-cell omics, and population genetics have substantially advanced understanding of MHC gene structure, allelic polymorphism, evolutionary patterns, and associations with disease susceptibility and vaccine responsiveness. This comprehensive review systematically examines the structural characteristics and regulatory mechanisms of MHC genes, their associations with infectious disease resistance, their role in vaccine responses, and their practical applications in molecular breeding programs, conservation genetics, and immunological research. We identify current technical limitations and outline future research directions to establish a robust theoretical foundation for disease resistance breeding and immune regulation strategies in herbivore populations.