Search Results (368)

The current study evaluated the effects of different levels of inclusion of ensiled pomegranate by-product (PS: 0, 5, 10, and 15% DM) into the diet of lactating dairy goats on production performance and metabolic status. Seventy-two Murciano-Granadina goats were used and balanced split into the four treatments (18 goats/treatment × 4 treatments) and also distributed into two homogeneous batches per treatment to record diet and water ingestion at batch level, according to individual variables (milk yield, body weight, SCC, and parity) obtained in a pre-experimental sampling, when all the variables at the individual (milk yield and composition, body weight, blood) and batch level (DM and water intake) were recorded. Later, the feeding trial was started and conducted for 8 weeks, with body weight, milk yield, and milk composition—fat, crude protein, lactose, milk urea, somatic cell count (SCC)—recorded biweekly. Water intake (WI) and dry matter intake (DMI) were registered weekly over 2 consecutive days. Physiological and oxidative status were reviewed through hemogram, serum biochemical profile, and plasma antioxidant activity at the last sampling. Individual level variables were analyzed using mixed linear models with repeated measures, including diet, sampling, and their interaction as fixed effects, the covariate in the pre-experimental sampling, and the animal and the batch nested to diet as the random effects (PROC GLIMMIX, SAS v9.4). Additionally, observed means and standard deviations of WI and DMI were recorded. The results showed that milk yield and its composition were not significantly (p > 0.05) affected by up to 15 PS inclusion. The statistical differences observed in the hematological and plasma biochemical profiles, as well as in the antioxidant activity, had no practical relevance, as all measured values remained within the established physiological reference ranges. In conclusion, PS can be added to dairy goats diet up to 15% with no evidence of negative effects on production and animal physio-metabolic response during the study period, although longer trials considering complete lactation periods are needed to corroborate these findings. Full article

This study evaluated the effects of precision dietary crude protein (CP) reduction through corn dust substitution for soybean meal on lactational performance, milk fatty acid composition, and antioxidant status in mid-lactation dairy cows. Six Holstein Friesian cows were assigned to a replicated 3 × 3 Latin square design with three 28-day periods and fed total mixed rations containing 17.40% (TMR17), 16.29% (TMR16), or 15.18% CP (TMR15). Forage was maintained at 40% of dietary dry matter. Dry matter intake and plasma metabolites were unaffected by dietary treatment (p > 0.05). However, apparent digestibility of dry matter, organic matter, and crude protein declined significantly (p < 0.05), while acid detergent fiber digestibility showed a linear downward tendency (p = 0.06). Actual milk yield, lactose yield, and solids-not-fat (SNF) yield were unaffected by treatments (p > 0.05), but milk protein percentage decreased linearly (p = 0.01) as dietary CP declined. Body weight change also tended to decline (p = 0.09), suggestive of possible increased body reserve mobilization, although this was not confirmed with body condition score or direct metabolic indicators. Milk urea nitrogen decreased linearly (p = 0.05), which suggested improved nitrogen utilization. Plasma superoxide dismutase (SOD) activity, GSH-Px activity, and total antioxidant capacity were not significantly modified (p > 0.05); however, plasma DPPH radical scavenging capacity increased linearly with higher protein levels (p = 0.01; Trt: p = 0.02). Conversely, TMR15 improved milk lipid quality by significantly increasing monounsaturated fatty acids (p = 0.03; Trt: p = 0.05), particularly oleic acid (p = 0.05), whereas total saturated fatty acids remained unchanged (p = 0.55). Overall, reducing dietary CP improved MUFA proportions and nitrogen efficiency but decreased milk protein percentage and plasma DPPH antioxidant protection, highlighting a trade-off between production performance, animal health, and milk quality. Full article

Rumen biohydrogenation is a microbial process that converts dietary unsaturated fatty acids into more saturated products and produces a range of intermediates that can affect animal products and rumen fermentation. This review summarizes current knowledge on the main biohydrogenation pathways, the microbial groups involved, and the nutritional and breeding strategies used to regulate this process. Particular attention is given to the transformation of C18 fatty acids, the formation of vaccenic acid and conjugated linoleic acid, the trans-10 shift, and the links between lipid metabolism, hydrogen use, and methane formation. Evidence indicates that diet composition, lipid source, plant secondary metabolites, rumen-protected fat technologies, microbial interventions, and host-related factors can all influence biohydrogenation outcomes. These strategies can improve the fatty acid profile of meat and milk, but their effects are context-dependent and vary with animal species, diet, and rumen microbial structure. Important gaps remain, including the identification of active microbial populations, the functions of many transient intermediates, and the extent to which changes in biohydrogenation directly contribute to methane mitigation. Clarifying these mechanisms is essential for improving the nutritional quality of ruminant products and the sustainability of production systems. Full article

Raw and fermented Astragalus membranaceus (AM) serve promising herbal additives for small ruminants, yet their integrated regulatory functions across lactating ewes and suckling lambs are insufficiently characterized. This study aimed to elucidate how dietary supplementation with raw and fermented Astragalus membranaceus modulates ruminal microbial communities, circulating metabolites, redox homeostasis, and lactation performance in postpartum Turpan black ewes, and to characterize the consequent effects on immune development and body weight gain in their offspring. The findings are intended to inform evidence-based strategies for herbal supplementation in sheep production. Forty-five postpartum Turpan black ewes were randomly allocated to three groups (n = 15): control (basal diet), AM and FAM groups. Ewe plasma, rumen fluid, milk yield, milk composition and serum antioxidant indices were sampled periodically. Lamb body weight, plasma antioxidants, immunoglobulins, growth hormone (GH) and insulin-like growth factor-1 (IGF-1) were measured every 15 days. Rumen 16S rRNA sequencing and untargeted plasma metabolomics were performed on day 45 post-partum. The group of FAM significantly increased milk yield (p < 0.05) and markedly improved total antioxidant capacity in ewes (p < 0.01). In the AM group, metabolites such as linoleic acid were significantly downregulated (p < 0.05), with enrichment in the linoleic acid metabolism pathway, while flavonoid metabolites, including quercetin 4′-isobutyrate, were strongly upregulated (p < 0.01). In the FAM group, tetradecanoic acid, palmitoleic acid, and related metabolites were significantly reduced (p < 0.05), and these differential metabolites showed significant enrichment in fatty acid biosynthesis (p < 0.05). Flavonoid compounds represented by melilotocarpan E were also significantly upregulated (p < 0.05). Rumen microbial diversity was significantly higher in the FAM group (p < 0.05). At the genus level, the FAM group showed enrichment of fiber-degrading bacteria, including Rikenellaceae_RC9_gut_group, unclassified_Muribaculaceae, and unclassified_F082. In newborn lambs, plasma GH and IGF-1 levels increased markedly in both the FAM and AM groups (p < 0.01). In the FAM group, immunoglobulin A (IgA) and immunoglobulin G (IgG) concentrations were also markedly elevated (p < 0.01). In addition, lambs in the FAM group exhibited substantially higher plasma catalase (CAT) activity and nitric oxide (NO) concentration (p < 0.01), whereas plasma total antioxidant capacity was significantly lower (p < 0.01). In conclusion, AM and FAM supplementation increased the relative abundance of Bacteroidetes, regulated fatty acid synthesis through modulation of plasma metabolites, enhanced antioxidant capacity in ewes, increased milk fat percentage, and improved immune function, antioxidant status, and growth performance in lambs. To provide a theoretical basis and data support for its application in ewes after lambing and for improving the growth and development of lambs. Overall, FAM produced superior effect. Full article

The peripartum period in prolific ewes is associated with increased metabolic demands, and dietary lipid supplementation may increase the energy density of the prepartum diet. This study evaluated the effects of prepartum supplementation with alternative lipid matrices on the physicochemical characteristics and comprehensive fatty acid (FA) profiles of mature and transitional sheep milk. Thirty-two pregnant Olkuska ewes were randomly assigned to four cohorts (n = 8/group): Control (basal diet), flaxseed oil (low n-3/high n-6 variety; FO), black soldier fly larvae oil (BSFL oil), and Mix oil (2:1 ratio of FO to BSFL oil). Dietary treatments exerted no significant effects (p > 0.05) on transitional milk composition or lipid quality indices. In contrast, in mature milk, BSFL oil supplementation significantly increased milk fat content (6.09%) compared to the Control group (4.70%; p < 0.01). Furthermore, all oil treatments significantly reduced total saturated FAs (p < 0.01), while the BSFL oil and Mix oil supplementation significantly increased the monounsaturated FA fraction (p < 0.01). The differences, particularly the increase in cis-9, trans-11 CLA concentration and the significant reduction in both the atherogenic and thrombogenic indices (p < 0.01), were observed exclusively in mature milk. These findings suggest that the combination of sustainable insect lipids with high-linoleic plant oils may represent a viable strategy to transform sheep milk into a functional food with potential cardiovascular health benefits for consumers. These findings additionally indicate that prepartum lipid supplementation may exert a persistent carry-over effect into early lactation, influencing the fatty acid composition of mature sheep milk. Full article

Background: Dietary metabolizable energy (ME) and crude protein (CP) levels are important for lactation performance and metabolic responses in dairy ruminants. This study aimed to evaluate the effects of dietary ME and CP levels on lactation performance and postprandial metabolic responses in lactating dairy goats. Methods: Goats were randomly assigned to a 4 × 4 two-factor Latin square experiment consisting of four 14 d periods. The dietary treatments were high energy, high protein (HEHCP); high energy, low protein (HELCP); low energy, high protein (LEHCP); and low energy, low protein (LELCP). Serial postprandial arterial blood samples were collected at 17 daytime time points to characterize temporal changes in plasma amino acids, biochemical parameters and hormones. Results: Increasing CP supply elevated milk yield (+6%) and lactose yield (+5%) but decreased milk fat yield (−8%; p ≤ 0.04). Increasing ME supply tended to enhance milk yield and milk fat yield and increased milk lactose content only under the high CP condition (ME × CP interaction: p = 0.04), suggesting that the response to ME supply depended partly on dietary CP level. High CP increased plasma branched chain amino acid concentrations, whereas high ME reduced Leu and Val under the high CP condition. Most plasma amino acids exhibited marked postprandial dynamics, decreasing initially and then stabilizing, with CP × time interactions observed for Leu, Met, and Phe (p ≤ 0.05). High ME decreased plasma AST activity and tended to reduce urea N concentration and also reduced ALT activity and increased glucose concentration under the high CP diet. Following morning feeding, plasma urea N showed a progressive postprandial decline (p = 0.02), with glucagon decreasing and both prolactin and growth hormone increasing, despite no dietary effects on mean plasma hormone concentrations. Conclusions: Overall, dietary ME and CP levels affected lactation performance and selected plasma metabolic indicators in lactating dairy goats. Coordinated energy and protein supply should be considered when formulating diets for lactating dairy goats. Serial postprandial sampling further revealed temporal changes in plasma metabolites and hormones, providing useful information for refining precision nutrition strategies during lactation. Full article

Gut barrier dysfunction and portal endotoxemia contribute to metabolic dysfunction-associated steatohepatitis (MASH) progression through activation of hepatic inflammatory signaling. Milk-derived extracellular vesicles (EVs) contain bioactive microRNAs and have recently attracted attention as modulators of intestinal homeostasis. This study investigated the effect of bovine milk-derived extracellular vesicles (B-mEVs) in ameliorating MASH by improving intestinal barrier function. C57BL/6J mice fed a choline-deficient amino acid-defined high-fat diet (CDA-HFD) were orally treated with B-mEVs, and therapeutic effects were evaluated. Liver histology, fibrosis, portal lipopolysaccharide (LPS) levels, intestinal permeability, and gut microbiota composition were evaluated. The direct effects of B-mEVs on intestinal barrier function were assessed using palmitic acid-stimulated Caco-2 cells. Small RNA sequencing and microRNA enrichment analyses were performed to characterize B-mEV cargo. B-mEV treatment attenuated hepatic steatosis, inflammation, and fibrosis in CDA-HFD-fed mice and reduced serum aminotransferase levels, portal LPS concentrations, hepatic macrophage accumulation, and hepatic TLR4/NF-κB signaling activation. Meanwhile, B-mEVs restored intestinal tight junction proteins, including ZO-1, occludin, and claudin-1, and improved intestinal permeability in vivo. In Caco-2 cells, B-mEVs attenuated palmitic acid-induced barrier dysfunction and suppressed myosin light chain kinase expression. Gut microbiota analysis revealed partial restoration of Akkermansia abundance after B-mEV administration. Furthermore, to explore the molecular basis of these protective effects, small RNA sequencing demonstrated enrichment of regulatory microRNAs, including let-7a-5p, and pathway analyses identified associations with intestinal barrier and inflammatory signaling pathways. B-mEVs ameliorated CDA-HFD-induced steatohepatitis by restoring intestinal barrier integrity and suppressing gut-derived LPS/TLR4 inflammatory signaling. These findings suggested that milk EVs may represent a novel gut–liver axis-targeted therapeutic strategy for MASH. Full article

(1) Background: Sunflower hulls (SFHs) are an abundant agro-industrial by-product that may serve as an alternative fiber source in sheep diets, particularly in arid production systems. This study evaluated the effects of graded levels of dietary SFH during late gestation and lactation on colostrum and milk composition, lamb growth performance, neonatal survival, and serum biochemical parameters in Naemi sheep. (2) Methods: Seventy-two primiparous Naemi ewes (initial body weight = 55.0 ± 3.8 kg) were randomly allocated to four dietary treatments containing 0, 12, 20, or 28% SFH (n = 18 ewes per treatment) from late gestation until lamb weaning at 90 days postpartum. Data were analyzed using mixed-model procedures, and treatment effects were considered significant at p ≤ 0.05. (3) Results: Dietary SFH supplementation did not affect lamb birth weight or overall survival rate (p > 0.05). However, weaning weight declined from 28.03 kg in the control group to 25.11 kg in the 20% SFH group, showing a significant linear decrease with increasing SFH inclusion (p = 0.044). Likewise, average daily gain decreased linearly by 10.4% (p = 0.044). Colostrum composition was partially affected by dietary treatment, with fat and protein concentrations at 48 h postpartum increasing quadratically by 46.6% and 33.50%, respectively, in ewes fed 20% SFH compared with the control group (p < 0.05). In contrast, milk fat and total solids contents decreased quadratically by 30.7% and 13.4%, respectively, in ewes receiving 12% SFH (p = 0.01). Most serum metabolite variables were unaffected by dietary treatment and remained within normal physiological reference ranges. However, overall serum triglyceride concentration decreased linearly with increasing SFH inclusion (p = 0.023). (4) In conclusion, SFH can be incorporated into the diets of Naemi ewes during late gestation and lactation as an alternative fiber source without adversely affecting lamb birth weight, survival, or overall metabolic health. However, increasing dietary SFH inclusion reduced pre-weaning lamb growth despite improvements in selected colostrum quality traits. Based on the productive and physiological responses observed, 12% dietary SFH appears to be the optimal inclusion level, providing the best balance between animal performance and sustainable feed utilization. Full article

Early-life dietary transition is a critical window for gut microbiota assembly and intestinal maturation in squabs. This study compared the overall artificial-feeding system using a lactic acid bacteria-fermented diet (AF) with a parent-feeding system (PF) during 18–25 days of age. Because AF differed from PF in both diet exposure and feeding ecology, including manual feeding, absence of parental feeding and crop milk, altered feeding rhythm, and potential loss of parental microbial transmission, the objective was to characterize associations between the two systems rather than to isolate the effect of fermentation alone. Squabs were assigned to AF or PF for 7 days. Microbial communities in the duodenum, jejunum, ileum, and rectum were profiled by 16S rRNA sequencing, and body size traits, organ indices, jejunal morphology, muscle histology, serum biochemical indicators, and muscle composition were assessed. The AF system, characterized by lower pH, a higher acid value, and detectable lactic acid bacteria in the feed, was associated with higher alpha diversity in multiple segments and distinct beta-diversity profiles relative to PF. Across intestinal regions, lactobacilli-related genera were enriched, with Limosilactobacillus consistently identified as the most discriminant genus and, together with Lactobacillus, occupying central positions in exploratory co-occurrence networks. AF was also associated with a greater jejunal villus height and villus height-to-crypt depth ratio, larger muscle fiber dimensions, higher intramuscular fat content with increased levels of selected polyunsaturated fatty acids, altered lipid-related serum indicators, and higher organ indices, including the bursa of Fabricius. PICRUSt2 further suggested differences in predicted functional potential related to carbohydrate, amino acid, lipid, and cofactor/vitamin metabolism, although these outputs represent inference from 16S data rather than directly measured functions. Collectively, the AF system was associated with a lactobacilli-centered, tract-wide microbial signature and coordinated intestinal, muscular, and lipid-related phenotypes in squabs, but the findings should not be interpreted as evidence for fermentation alone. Full article

This study evaluated the effects of dietary inclusion of free and protected acid protease on productive performance, milk composition, metabolic profile, nutrient digestibility, and ruminal environment in lactating Jersey cows. Fifteen multiparous cows (67 ± 7.5 days in milk; 27.5 ± 3.5 kg/day) were assigned to a 3 × 3 Latin square (5 squares) design with 21-day periods. Treatments consisted of: control (no enzyme), free protease (4.4 g/day), and protected protease (4.4 g/day). The protected form was developed using alginate-based encapsulation to enhance enzyme stability under ruminal conditions. Protease inclusion did not affect dry matter intake, milk yield, or feed efficiency (p > 0.05). However, free protease increased lactation persistency (p = 0.05) and improved fat-corrected and energy-corrected milk yields (p ≤ 0.02), with intermediate responses observed for protected protease. Milk fat and protein contents were higher in enzyme-fed cows (p ≤ 0.05), while other compositional parameters remained unchanged. Apparent crude protein digestibility was greater in cows receiving free protease (p = 0.037), with no effects on dry matter or fiber digestibility. Protease intake increased total volatile fatty acid concentrations and major fermentation products (acetate, propionate, and butyrate; p ≤ 0.01), indicating enhanced ruminal fermentation. Blood metabolites showed increased total protein and globulin levels in cows fed free protease (p ≤ 0.05), suggesting improved protein metabolism. Microbiota analysis revealed no differences in alpha or beta diversity; however, specific microbial taxa and predicted metabolic pathways were modulated by treatments, particularly in post-ruminal compartments. In conclusion, exogenous protease, especially in free form, improved protein utilization and corrected milk production without disrupting microbial stability. These findings highlight the potential of protease as a nutritional strategy to enhance efficiency in dairy systems through targeted modulation of ruminal function and nutrient metabolism. Full article

Leucine, an essential branched-chain amino acid, serves not only as a substrate for protein synthesis but also as a key regulator of placental function and fetal development. This study investigated the effects of dietary supplementation with RP-Leu during late gestation on placental development and offspring performance in Hu sheep. Sixty twin-pregnant ewes at day 80 of pregnancy were randomly assigned to either a control group (fed a basal diet) or an RP-Leu group (fed a basal diet supplemented with 19 g/day RP-Leu). The feeding trial lasted for 60 d. The ewes were slaughtered at day 140 of gestation. Maternal slaughter traits and fetal organ weights were recorded. Blood and milk samples were collected for milk composition analysis and targeted metabolomic profiling. Leucine supplementation significantly increased the percentage of milk fat content, total solid content, and the birth weight of lambs (p < 0.05). Improvements in placental morphology and antioxidant capacity were observed, including a significant increase in cotyledon density and a significant enhancement of catalase (CAT) activity (p < 0.05). Gene expression analysis indicated that the NOS3, SLC38A1 and FABP4 genes in the placental cotyledons (p < 0.05), and the VEGFA, NOS3, SLC27A1 and FABP4 genes were significantly upregulated in the maternal caruncles (p < 0.05). Plasma metabolomic profiling revealed increased L-glutamic acid levels and alterations in several amino acids, with pathway enrichment indicating involvement in amino acid metabolism and membrane transport processes. Transcriptomic analysis identified 739 differentially expressed genes, which were mainly enriched in the PI3K/Akt signaling pathway, ECM–receptor interaction pathway, and cytokine–cytokine receptor interaction pathway. Collectively, these findings suggest that RP-Leu supplementation during late gestation may enhance offspring growth by modulating amino acid metabolism, promoting placental development, and improving placental nutrient transport capacity, thereby supporting fetal growth and development. Full article

Background/Objectives: The aim of the study was to assess the metabolic response of women to a six-week consumption of full-fat sheep milk yogurt, with a focus on cardiovascular risk markers, lipid profile, and subfractions of low-density (LDL) and high-density (HDL) lipoproteins of both atherogenic and non-atherogenic nature. Methods: A total of 55 women were enrolled in the nutritional intervention after the application of inclusion criteria. Blood samples were collected at baseline and after the six-week intervention period. Lipoprotein subfractions were determined in serum using the Lipoprint System LDL/HDL Subfractions Kit in combination with the Lipoprint^® analyzer. Results: In the group of women over 40 years of age with overweight or obesity, without adjustment for total cholesterol, a significant increase was observed in selected HDL subfractions (intermediate HDL-6, HDL-7 and small HDL-8, HDL-9; p < 0.05), while the small/large HDL ratio, LDL subfractions, and mean LDL particle size remained unchanged (p > 0.05). A decrease in triglycerides, LDL/HDL ratio, TG/HDL ratio, and cardiovascular risk index was recorded, alongside a slight increase in LDL-C and HDL-C levels. After adjustment for total cholesterol (T-C), no significant deterioration in the lipid profile was observed in either the group with normal or elevated T-C levels; in the group with elevated T-C, only the intermediate HDL-7 subfraction increased significantly (p < 0.05). Despite the presence of risk-level values in some parameters already at baseline (VLDL, IDL-A, IDL-B, small HDL), no worsening was observed. Conclusions: Six-week consumption of full-fat sheep milk yogurt did not lead to deterioration of the lipid profile or lipoprotein subfractions. The results suggest a neutral to mildly beneficial effect on selected cardiovascular risk markers. Full article

Leptin (LEP) is an adipocyte-derived cytokine that integrates nutritional status, metabolism, and reproduction in cattle, with particular relevance for modern high-producing dairy cows. In ruminants, LEP and its receptors are widely expressed in metabolic and reproductive tissues, including adipose tissue, liver, hypothalamus, pituitary, ovary, uterus, and placenta, where LEP modulates energy homeostasis, neuroendocrine function, and local tissue responses. Changes in circulating LEP concentrations during the transition period reflect changes in body fat reserve, insulin and GH-IGF-1 dynamics, thyroid hormones, and inflammation and contribute to coordinated metabolic adaptations supporting the onset of lactation. At the reproductive level, LEP influences the hypothalamic–pituitary–gonadal axis, affects the pulsatility of luteinizing hormone (LH) under nutritional stress, and exerts direct effects on ovarian steroidogenesis, folliculogenesis, oocyte competence, embryo development, and uterine immune function. New evidence also links LEP profiles to major peripartum disorders, including subclinical ketosis, insulin resistance, postpartum ovarian inactivity, and uterine inflammatory diseases, and emphasises its potential as part of a panel evaluating the risk of metabolic and reproductive disorders. Furthermore, polymorphisms within the bovine LEP gene and its signalling network have been associated with milk production, feed efficiency, body condition, and fertility traits, suggesting opportunities to incorporate markers into genomic selection schemes aimed at improving robustness and reproductive performance. This review summarises current knowledge on LEP biology in cattle, with an emphasis on dairy cows, and discusses perspectives on translating this information into practical tools for nutritional management, health monitoring, and genetic improvement in bovine production systems. Full article

This study aims to investigate the effects of cysteamine zinc supplementation on milk production, composition, amino acid profile, and metabolites in mares. Building on prior experimental findings, a dose of 7 mg/kg body weight of CS-Zn was selected for the experimental group, which was compared with a control group. Milk samples were collected at various time points, and milk yield was recorded each time. Routine analysis of milk components, as well as the determination of milk metabolites and amino acids, were performed. The results indicated that, compared to the control group, the experimental group exhibited increases in milk yield and the content of milk fat, lactose, and non-fat solids (p < 0.05), with an extremely significant increase in milk protein (p < 0.01). Conversely, the levels of L-glutamine and L-proline in milk were significantly reduced (p < 0.05). Metabolomic analysis revealed that differentially expressed metabolites were enriched in pathways such as ABC transporters, D-aminoadipate metabolism, aminoacyl-tRNA biosynthesis, and protein digestion and absorption. Notably, milk metabolites including cAMp, biotin, and taurine showed a tendency to be upregulated, while oxoglutaric acid, methionine, and diacetyloxyxanthone were downregulated. Based on evidence from the literature other species, it is speculated that CS-Zn supplementation may be associated with alterations in endocrine and amino acid metabolism pathways, potentially influencing lactation performance in mares. However, because no hormones were directly measured in this study, such a mechanism remains speculative and requires direct experimental validation. Full article

Early-life nutrition is critical for the development and health of dairy calves, necessitating alternatives to in-feed antibiotics. This study investigated whether dietary glycerol monolaurate (GML) enhances growth performance, reduces diarrhea incidence, improves systemic antioxidant and immune status, and modulates hepatic immunometabolic function in calves. Twenty-four Holstein bull calves (7 ± 0.5 d of age) were randomly assigned by body weight and age to a control group or a GML-supplemented group, both fed milk replacer with starter feed provided throughout the 45-day trial. Calves in the GML group received GML at a dosage of 100 mg/kg of body weight, mixed into the milk replacer prior to feeding. Calves in the GML group had significantly greater final body weight, average daily gain, and starter intake during the latter period (d 23–45) compared with the control group. GML supplementation also significantly reduced the incidence of diarrhea and fever, alongside lower fecal scores and fewer antibiotic treatments. Plasma analysis revealed enhanced antioxidant capacity, as indicated by increased total antioxidant capacity and glutathione peroxidase, along with an improved immune profile characterized by elevated immunoglobulin G and reduced interleukin-2. Transcriptomic analysis of the liver showed that GML upregulated genes and pathways related to innate antiviral immunity, such as radical S-adenosyl methionine domain containing 2, interferon-stimulated gene 15, and MX dynamin like GTPase 1. Lipidomics further indicated that GML induced a targeted remodeling of hepatic lipids, including increased diacylglycerols and triacylglycerols and decreased specific phospholipids and sphingolipids, suggesting a metabolic shift supportive of immune activation and inflammatory control. In conclusion, dietary GML enhances growth and health in suckling calves, which is mediated through a coordinated immunometabolic reprogramming in the liver. GML represents a promising functional fat additive for sustainable calf rearing. Full article