Search Results (207)

Prolonged high temperature and humidity pose significant challenges to sheep health and productivity due to heat stress. This research assessed the physiological regulatory impact of supplementing heat-stressed Hu sheep with rumen-protected taurine. Forty-eight animals were assigned to four groups receiving different taurine doses over a 63-day period. A comprehensive evaluation was conducted on growth performance, nutrient digestibility, serum biochemical parameters, antioxidant and immune indices, transcriptomic profiles, and gut microbiota composition. Dietary supplementation with 0.4% RPT significantly enhanced feed intake, daily weight gain, and feed efficiency. Serum analysis revealed increased taurine and high-density lipoprotein levels, reduced cortisol and inflammatory cytokines, and elevated antioxidant enzyme activity. Transcriptomic analysis identified differentially expressed genes enriched in immune and antiviral pathways, including JAK-STAT signaling pathway being among those highlighted. Gut microbiota profiling showed increased diversity and improved composition, particularly Olsenella and its several species were positively correlated with anti-inflammatory responses. These findings demonstrate that rumen-protected taurine supplementation at 0.4% can effectively alleviate heat stress by improving physiological resilience, immune balance, and gut health in sheep. This research provides a scientific basis for developing nutritional strategies to enhance animal welfare and productivity under climate stress conditions. Full article

This study focuses on the selection of hybrid combinations of Hu sheep and meat quality analysis. A comparative analysis of meat quality and volatile flavor compounds was conducted using three hybrid groups—Australian White–Hu (AH), White Suffolk–Hu (SH), and Southdown–Hu (NH)—and a pure Hu sheep group (HH) as research subjects. The results show that in terms of basic nutritional quality, the moisture content in the NH group was significantly higher than that in the HH group (p < 0.05), and the crude protein content in the NH group was significantly higher than that in the HH group (p < 0.05). Regarding physicochemical properties, the NH group had significantly higher meat color scores, L*, a*, and b* values, than the other groups (p < 0.05), along with the best tenderness and cooking yield. An analysis of amino acids, fatty acids, and volatile flavor compounds in lambs from different hybrid combinations revealed significant differences in the contents of lys, thr, asp, and his (p < 0.01). Although no significant differences were found in the fatty acid composition scores among the AH, SH, NH, and HH groups, all groups met the FAO/WHO recommended values. The NH group not only had the highest MUFA and total fatty acid content but also the highest levels of trans-petroselinic acid and trans-vaccenic acid, the two most abundant trans fatty acids. A total of 43 volatile organic compounds were detected in the four groups, among which 10 were identified as differential compounds. This study provides a scientific basis for the hybrid utilization of Hu sheep and offers technical support for the transformation and upgrading of the regional meat sheep industry. Full article

Hybridization effectively enhances breeding efficiency and significantly boosts sheep productivity. However, the epigenetic mechanisms underlying the superior production performance of crossbreds remain largely elusive. In this study, Hu sheep were crossbred with Suffolk rams used as the paternal line. We integrated RNA-seq, ATAC-seq, and CUT&Tag (H3K4me3, H3K4me1, H3K27ac, and H3K27me3) techniques to characterize epigenetic regulatory differences in the longissimus dorsi muscle between Hu sheep (HU) and crossbred progeny (SH). Phenotypic and transcriptomic analyses revealed that SH crossbred sheep exhibited superior growth performance (p < 0.05), and the upregulated genes in the Apelin signaling pathway were significantly correlated with eye muscle area (p < 0.05). Utilizing a Hidden Markov Model, we annotated 15 distinct chromatin states in both HU and SH sheep, systematically characterizing the dynamic epigenomic landscapes across the two breeds. In contrast to SH sheep, the genome of HU sheep exhibited enrichment of repressive chromatin modifications typified by H3K27me3. Strong active enhancers (EnhA) were significantly enriched within upregulated genes in SH. A total of 1862 SH-specific and 691 HU-specific EnhA elements were characterized in this study. Motif analysis revealed that SH-specific EnhA were enriched for myogenic MEF2 family motifs (p < 0.05), which promote muscle and vascular development. By integrating multi-omics data, we constructed a putative regulatory network potentially modulated by SH-specific enhancers, identifying CMKLR1, PPARGC1A, and TLE3 as the core hub genes. Collectively, this study provides a robust data resource, identifying candidate genes and regulatory elements associated with crossbreeding-related muscle phenotypes. Full article

With the increasing consumer demand for high-quality lamb, crossbreeding has become a key technology for improving the production performance and meat quality of sheep. To evaluate the meat quality advantages and characteristics of Suffolk (SFK) and Hu sheep (HH) and their F₁ crossbreds (SH), thirty-six 3-month-old male lambs of SFK (n = 12), HH (n = 12), and SH (n = 12) were selected and raised in individual pens under the same nutritional and management conditions. After standardized feeding until 6 months of age, the Longissimus dorsi muscle was collected to determine meat quality traits, amino acid and fatty acid profiles, and volatile flavor compounds. The results indicated that the L*, a* and b* values of the SH group were significantly lower than those of the parental breeds (p < 0.05), with tenderness being intermediate between the two parent breeds. Notably, drip loss and cooking loss were significantly lower in the SH group (p < 0.05), indicating superior water-holding capacity. In terms of amino acid profiles, the contents of non-essential amino acids (NEAAs) and sweet-tasting amino acids in the SH group were significantly higher than those of the parent breeds (p < 0.05), with the overall profile meeting the FAO/WHO ideal protein pattern. Analysis of fatty acid profiles revealed that the SH group had significantly lower total saturated fatty acids (SFAs) (p < 0.05) and significantly higher levels of functional fatty acids (such as CLA), resulting in a significantly higher UFAs (unsaturated fatty acids)/SFAs (saturated fatty acids) ratio (p < 0.05) and superior nutritional value of fat. Furthermore, 32 volatile flavor compounds were detected in the SH group; among them, key aroma-active compounds such as isoamyl formate, 3-methyl-1-butanol, and acetoin were significantly higher than in the parental breeds (p < 0.05), contributing to a unique flavor profile. Consequently, this study systematically reveals the advantages of Suffolk × Hu F₁ crossbreds in terms of meat quality, nutritional value, and flavor characteristics, providing fundamental data for the optimization of crossbreeding systems, breeding selection, and the quality improvement of sheep meat products. Full article

The sensory quality and flavor of lamb meat, critical to market competitiveness, are influenced by rumen microbial fermentation and dietary management strategies. Coated betaine (CBet), a rumen-protected methyl donor, exerts systemic nutritional regulation in ruminants. This study explored the effects of CBet supplementation on lamb meat quality using 18 Dorset ♂ × Hu sheep ♀ F1 crossbred lambs, randomly assigned to either a control group (basal diet) or a 0.20% CBet-supplemented diet for 60 days (n = 9 per group). The results demonstrated that CBet significantly increased ruminal concentrations of total volatile fatty acids (TVFAs), acetic acid, propionic acid, and butyric acid (p < 0.05). Additionally, CBet supplementation enhanced muscle redness (a*), crude fat, crude ash, heptadecanoic acid (C17:0), and tricosanoic acid (C23:0) (p < 0.05) while decreasing shear force and the concentration of cis-13,16-docosadienoic acid (C22:2) (p < 0.05). Furthermore, CBet elevated characteristic flavor compounds (e.g., nonanal) and their relative odor activity values (ROAVs), and decreased undesirable odors (e.g., dodecanal) (p < 0.05). As illustrated in the graphical abstract, these improvements were mediated through regulatory effects of CBet on rumen microbiota composition, muscle fatty acids, amino acids, and volatile flavor compounds. Specifically, CBet significantly increased the relative abundances of Firmicutes, Proteobacteria, Prevotella, and Bifidobacterium in the rumen (p < 0.05) and altered the Firmicutes/Bacteroidota ratio. In conclusion, dietary supplementation with 0.20% CBet effectively enhances lamb meat quality and flavor, effects closely associated with changes in the abundance of key ruminal microbial taxa. Full article

Semen quality and fecal microbial composition were compared between native Oula rams reared on the Qinghai–Tibet Plateau and Hu sheep rams introduced from lowland regions. Semen quality was analyzed in eight adult Oula rams and eight Hu rams, and fecal microbial composition was assessed via 16S rRNA sequencing. Results indicated that sperm acrosome integrity was significantly higher in Hu sheep than in Oula sheep (p < 0.001); other semen parameters showed no significant differences. Significant differences were also observed in fecal microbial communities between the two breeds. Compared with Hu sheep, Oula sheep exhibited higher microbial abundance and diversity at the phylum level, particularly Campylobacterota, Euryarchaeota, Planctomycetota, Verrucomicrobiota, Myxococcota, and Deferibacterota (p < 0.05). At the genus level, Oula sheep had significantly higher abundances of Treponema, Campylobacter, Methanobrevibacter, UCG-009, Family_XIII_AD3011_group, [Eubacterium]nodatum group, Candidatus Soleaferrea, Akkermansia, and unidentified_Ruminococcaceae (p < 0.05). Correlation analysis indicated associations between sheep semen quality and the top 30 abundant fecal microbial genera. Six genera showed significant positive correlations with acrosome integrity rate, and eight genera exhibited significant negative correlations (p < 0.05). Two genera were correlated positively with plasma membrane integrity rate (p < 0.05). Prevotellaceae_UCG-004 was positively correlated with sperm motility and Progressive Motility spermatozoa proportion (p < 0.05); Ruminococcus showed a significant positive correlation with sperm linear motility and a significant negative correlation with acrosome integrity rate (p < 0.05). These findings indicate that the microbial groups enriched in Oula sheep fecal samples and exhibiting negative correlations with acrosome integrity—including Ruminococcus, Treponema, Akkermansia, and Euryarchaeota—are associated with sperm quality through physiological adaptation mechanisms specific to high-altitude environments. Full article

Grain byproducts can serve as cost-effective alternatives to corn, but may lead to reduced production performance and increased greenhouse gas emissions. This study aimed to investigate the effects of replacing corn with the grain byproducts (wheat bran, sprayed corn bran) subjected to bacterial-enzymatic fermentation treatment or not in Hu sheep, mainly focusing on production performance, energy-nitrogen metabolism, rumen fermentation and greenhouse gas emissions. A total of fifty-four 6-month-old Hu sheep were divided into three groups, with 6 pens per group and 3 sheep per pen, and then randomly allocated to one of the three dietary groups for 60 days, i.e., a control group (CON), a group (RC) that corn was partially (~42%) replaced with grain byproducts, and a group (BF) that corn was partially replaced by fermented grain byproducts. Compared with the CON group, the RC group showed numerically lower rumen total volatile fatty acid (TVFA) concentration and its propionate proportion, nitrogen retention content (NR; −10.22%) and its retention ratio (NR/NI decreased by 4.27 percentage points, absolute reduction from 24.30% to 20.04%), corresponding to a relative decrease of 17.6%.) as well as a numerically reduced net profit (−2.18%) with a decreased feed price (−¥0.16/kg TMR). Meanwhile, the RC group showed a significant increase in the relative abundance of Methanobrevibacter (p < 0.05), accompanied by numerically higher daily methane emissions (+6.14%) and emission intensity (+4.08%), although these methane-related differences did not reach statistical significance (p > 0.05). Compared to the RC group, the BF group resulted in a numerical increase in feed price (+¥0.03/kg TMR), net profit (+27.93%), TVFA concentration, propionate proportion, NR (+28.17%), NR/NI (an increase of 5.38 percentage points), the relative abundance of Prevotella, Shuttleworthia and Succinivibrio as well as the decrease of fecal nitrogen (FN; −12.29%), daily methane emissions (−8.75%), emission intensity (−5.83%) and the relative abundance of Methanobrevibacter. In summary, replacing dietary corn by 42% with wheat bran and sprayed corn bran numerically reduced formula cost and nitrogen utilization, while increasing methane emissions and methanogens abundance, without significantly affecting growth performance. This combination led to no improvement in economic returns for fattening Hu sheep. Bacterial-enzymatic fermentation treatment of these byproducts could mitigate these drawbacks, being superior energy-nitrogen metabolism and lower greenhouse gas emissions intensity, presenting a potential strategy for cost reduction and efficiency enhancement. Further research with larger sample sizes is warranted to confirm these findings and support broader application. Full article

This study investigated the effects of tributyrin supplementation on the immune and antioxidant status of lambs born to perinatal Hu ewes with negative energy balance (NEB) at 75%. Twenty healthy Hu ewes (average body weight 45.00 ± 5.00 kg) with similar body condition score, pregnant for 100 days with twin lambs, were randomly allocated into two groups: NEB group and 0.5% tributyrin supplementation group (TB). Lambs were artificially fed with milk from their respective maternal groups for 42 days and were classified as L-NEB (n = 20) and L-TB (n = 20). The experimental period lasted from 40 days before delivery to 42 days after delivery. At 42 days of age, five male lambs from each group were randomly selected and euthanized for analysis. Tributyrin supplementation significantly increased fat-corrected milk yield, milk fat content, and colostrum fat yield in perinatal ewes (p < 0.01). Lambs in the L-TB group exhibited improved growth performance compared with L-NEB lambs (p < 0.05). Serum triglyceride concentration at 7 days of age was 68.4% higher, and serum triglyceride and glucose concentrations at 42 days of age were 42.9% and 13.9% higher, respectively, in the L-TB group than in the L-NEB group (p < 0.05). In addition, the L-TB group showed a 39.2% lower serum IL-1β concentration at 7 days and significantly downregulated hepatic IL-8 mRNA expression at 42 days, together with enhanced antioxidant capacity (p < 0.05). These findings suggest that dietary tributyrin supplementation at 0.5% in perinatal undernourished ewes, applied under a controlled NEB feeding regimen, may improve milk composition and, consequently, enhance growth performance, immune status, and antioxidant capacity in lambs. Full article

Objective: Although Hu sheep are renowned for their high fecundity, the multi-tissue regulatory networks governing spermatogenesis, particularly within the hypothalamic–pituitary–testicular (HPT) axis, remain poorly understood. This study aimed to elucidate these mechanisms by performing a comparative proteomic analysis of the HPT axis in Hu sheep and three other breeds. Methods: We utilized data-independent acquisition (DIA) proteomics to analyze hypothalamic, pituitary, and testis tissues from 36 samples across four breeds. The experimental workflow included protein extraction, enzymatic digestion, LC-MS/MS, and subsequent bioinformatic analyses, complemented by histological examination. Results: Hu sheep exhibited accelerated testicular development and an earlier onset of spermatogenesis. Comprehensive proteomic profiling identified a total of 10,528 proteins, with 771 differentially expressed proteins (DEPs) detected in the testis. These testicular DEPs were significantly enriched in pathways related to spermatogenesis, the blood–testis barrier, and steroid hormone biosynthesis. Notably, the cAMP signaling pathway was consistently enriched across all three tissues, underscoring its pivotal role in regulating spermatogenesis. Protein–protein interaction (PPI) network analysis further highlighted hub proteins, such as MET, suggesting their potential involvement in somatic cell functions and the spermatogenic microenvironment. Key findings were validated by Western blot analysis. Conclusion: This study is the first multi-tissue proteomic investigation proposing a model in which the high reproductive performance of Hu sheep is potentially linked to the efficient, coordinated regulation of spermatogenesis-related proteins and signaling pathways—particularly in the testis. These findings offer novel insights into the molecular mechanisms of male reproduction in sheep and identify potential targets for future research and breeding applications. Full article

This study evaluated the effects of dietary glycerol fatty acid esters (GFAs) on growth performance, nutrient digestibility, nitrogen metabolism, jejunal microbiota, and intestinal transcriptome in Hu sheep. Thirty-six 4–5-month-old male Hu sheep were randomly assigned to three groups receiving a basal diet (GFA0%) or diets supplemented with 0.15% (GFA0.15%) or 0.20% (GFA0.20%) GFA for 52 days following a 7-day adaptation period. Growth performance parameters were unaffected (p > 0.05); however, feed-to-gain ratio decreased linearly and quadratically with increasing GFA levels (p < 0.001). GFA supplementation improved ether extract (EE) and neutral detergent fiber (NDF) digestibility (p < 0.05), neutral detergent fiber ADF digestibility showed a linear increase(linear = 0.025), significantly reduced fecal and urinary nitrogen excretion, and enhanced nitrogen utilization (p < 0.05). Jejunal microbiota analysis revealed significant genus-level separation among groups, with increased Bacillota abundance and the enrichment of Acetitomaculum and [Ruminococcus]_gauvreauii_group in the GFA0.20% group. Functional prediction indicated enhanced fiber degradation, nitrogen metabolism, and host interaction functions. Transcriptomic analysis showed dose-dependent gene regulation, with GFA0.15% primarily enriching immune-related pathways, while GFA0.20% additionally activated lipid and steroid metabolism pathways. Integrated microbiome-host analyses demonstrated coordinated regulation of nutrient metabolism and immune responses. Overall, dietary inclusion of 0.20% GFAs optimized feed efficiency, nutrient utilization, and intestinal metabolic-immune function in Hu sheep. Full article

The aim of this study was to investigate the effects of dietary supplementation with 0.11% N-carbamylglutamate (NCG) during early pregnancy (0–90 days) on reproductive performance and fetal development, and to elucidate the underlying placental regulatory mechanisms in primiparous Hu sheep. Twenty-two 10-month-old sexually mature primiparous Hu sheep meeting the mating criteria were randomly assigned to two groups. The control group was fed a basal diet, while the NCG group received the basal diet supplemented with 0.11% NCG, with both feeding regimens maintained for 90 days. By measuring uterine and fetal growth indices, maternal plasma biochemical parameters, and amino acid levels, as well as assessing cotyledon indices and observing cotyledon morphology and histological structure, basic data related to placental function and fetal growth in pregnant ewes was collected. Combined with transcriptomic sequencing of maternal placental tissue, the mechanism by which NCG influences placental function and fetal growth and development in pregnant ewes was further investigated. The supplementation of NCG could increase the number of fetuses, total weight of fetuses, the number of corpus luteum and the ratio of fetuses to corpus luteum, but the difference was not significant (p > 0.05). The levels of plasma NO, inducible Nitric Oxide Synthase (iNOS) and several amino acids were significantly increased (p < 0.05). In ewes’ uteri, the average uterine weight, number of uterine glands, total cotyledon weight, and average weight per cotyledon were significantly increased (p < 0.05), whereas uterine mucosal thickness was markedly decreased. The Quantitative Real-time PCR (q-PCR) results for differentially expressed genes were consistent with those of transcriptomic analysis, showing significant changes in the expression levels of certain differentially expressed genes in maternal placental tissues. These changes regulated pathways such as vascular endothelial growth factor (VEGF), insulin-like growth factor (IGF), phosphatidylinositol 3-kinase–protein kinase B (PI3K–AKT) signaling pathways and Mitogen-Activated Protein Kinase (MAPK) pathway, which are involved in angiogenesis, energy supply and metabolism, and somatic growth and development. Dietary supplementation with NCG during early pregnancy can significantly improve the reproductive performance of primiparous Hu sheep, optimize the intrauterine environment and nutrient supply, and thereby facilitate pregnancy maintenance and fetal development. The underlying mechanism may involve promoting endogenous arginine synthesis in ewes, increasing plasma levels of NO, arginine, and certain amino acids, which collectively validate the positive effects of NCG on the reproductive performance and growth of Hu sheep during early pregnancy at the molecular level. Full article

Accurate measurement of sheep body dimensions is fundamental for growth monitoring and breeding management. To address the limited segmentation accuracy and the trade-off between lightweight design and precision in existing non-contact measurement methods, this study proposes an improved model, YOLOv12n-Seg-SSM, for the automatic measurement of body height, body length, and chest circumference from side-view images of sheep. The model employs a synergistic strategy that combines semantic segmentation with 3D point cloud geometric fitting. It incorporates the SegLinearSimAM feature enhancement module, the SEAttention channel optimization module, and the ENMPDIoU loss function to improve measurement robustness under complex backgrounds and occlusions. After segmentation, valid RGB-D point clouds are generated through depth completion and point cloud filtering, enabling 3D computation of key body measurements. Experimental results demonstrate that the improved model outperforms the baseline YOLOv12n-Seg: the mAP@0.5 for segmentation reaches 94.20%, the mAP@0.5 for detection reaches 95.00% (improvements of 0.5 and 1.3 percentage points, respectively), and the recall increases to 99.00%. In validation tests on 43 Hu sheep, the R² values for chest circumference, body height, and body length were 0.925, 0.888 and 0.819, respectively, with measurement errors within 5%. The model requires only 10.71 MB of memory and 9.9 GFLOPs of computation, enabling real-time operation on edge devices. This study demonstrates that the proposed method achieves non-contact automatic measurement of sheep body dimensions, providing a practical solution for on-site growth monitoring and intelligent management in livestock farms. Full article

Research has demonstrated that incorporating nitrate into animal feed can effectively decrease methane production in ruminants, though its impact on carcass characteristics and meat attributes in Hu sheep requires further investigation. This experiment examined how a dietary inclusion of 3% calcium nitrate (CN) influenced slaughter parameters, meat properties, gut microbial populations, and host gene regulation in Hu sheep. The study involved sixty healthy male Hu sheep aged 120 days with comparable body weights (31.11 ± 3.39 kg), randomly allocated into two groups: a control group receiving standard feed (CON) and a CN-supplemented group. The trial lasted 60 days, including a 15-day adaptation period and a 45-day formal trial period. They were housed individually and fed twice daily (at 8:00 and 18:00). The findings revealed that CN supplementation notably reduced the water loss rate in the longissimus dorsi muscle (LD), elevated meat color brightness, and enhanced the proportion of polyunsaturated fatty acids (PUFA), particularly n-6 PUFA, along with the n-3/n-6 PUFA ratio. Conversely, it reduced the levels of saturated fatty acids such as myristic acid (C14:0) and oleic acid (C18:1n9t). Additionally, the treatment boosted ruminal Ammoniacal nitrogen content and total short-chain fatty acid production, thereby contributing to energy metabolism in the animals. Microbiological examination demonstrated that CN supplementation led to a decrease in Fibrobacterota and Methanobrevibacter populations within the ruminal environment, while promoting the growth of Proteobacteria in the duodenal region. The gene expression profiling of digestive tract tissues showed an increased activity in nitrogen processing genes (including CA4) and oxidative phosphorylation pathways (such as ATP6), indicating an improved metabolic efficiency and acid–base homeostasis in the host animals. These findings demonstrate that CN-enriched diets enhance the carcass characteristics of Hu sheep by modifying intramuscular lipid profiles through gastrointestinal microbial community restructuring and metabolic pathway adjustments. Such modifications affect energy utilization and acid–base equilibrium, ultimately impacting muscle characteristics and adipose tissue distribution, presenting viable approaches for eco-friendly livestock farming practices. Full article

Mycoplasma ovipneumoniae poses a major threat to sheep respiratory health, contributing to significant economic losses in farming communities. In this study, we isolated a novel strain, IM-DMQ, from a Hu sheep in Inner Mongolia that exhibited pulmonary adenomatous-like lesions, which is an uncommon pathological manifestation for this pathogen. The complete genome was sequenced using a hybrid Nanopore and Illumina approach, revealing a 1,039,804 bp circular chromosome with a GC content of 29.15%, encoding 1529 genes. Functional annotation highlighted genes involved in essential metabolic processes and potential virulence mechanisms. Comparative genomic analysis demonstrated that IM-DMQ shares the closest ancestry (ANI: 98.3%) with the Chinese strain NXNK2203, while structural variations and 14 unique genes distinguished it from other global strains. Furthermore, microbial community profiling of the original lung tissue revealed a co-infection background involving multiple bacterial pathogens, offering an etiological context for the severe disease presentation. These results provide the first complete genomic resource for an M. ovipneumoniae strain from Inner Mongolia associated with unusual pulmonary pathology, offering insights into its genetic diversity and supporting the future development of targeted diagnostics and vaccines for regional disease control. Full article

Accurate and non-contact identification of individual sheep is important for intelligent livestock management, but remains challenging due to subtle inter-individual differences, breed-dependent facial morphology, and complex farm environments. This study proposes a lightweight sheep face detection and keypoint recognition framework based on an improved YOLO11 architecture, termed SAMS-KLA-YOLO11. The model incorporates a Sheep Adaptive Multi-Scale Convolution (SAMSConv) module to enhance feature extraction across breed-dependent facial scales, a Keypoint-Aware Lightweight Attention (KLAttention) mechanism to emphasize biologically discriminative facial landmarks, and the Efficient IoU (EIoU) loss to stabilize bounding box regression. A dataset of 3860 images from 68 individuals belonging to three breeds (Hu, Dorper, and Dorper × Hu crossbreeds) was collected under unconstrained farm conditions and annotated with five facial keypoints. On this dataset, the proposed model achieves higher precision, recall, and mAP than several mainstream YOLO-based baselines, while reducing FLOPs and parameter count compared with the original YOLO11. Additional ablation experiments confirm that each proposed module provides complementary benefits, and OKS-based evaluation shows accurate facial keypoint localization. All results are obtained on a single, site-specific dataset without external validation or on-device deployment benchmarks, so the findings should be viewed as an initial step toward practical sheep face recognition rather than definitive evidence of large-scale deployment readiness. Full article