Jiaying Ma

Large-scale dairy farms with anaerobic digestion (AD) are expanding rapidly in China, yet high-resolution assessments of N flows, N use efficiency (NUE), and N footprint remain limited. This study conducted a process-based N accounting and N footprint assessment for a large-scale commercial dairy farm with AD in China using farm-specific data on herd structure, feed intake, milk production, manure management, feed production, transportation, and on-farm energy use. Whole-farm N flows were traced from feed inputs to animal products, manure excretion, manure treatment, field application, soil deposition, and environmental losses. Total herd N intake was 3.12 × 10⁶ kg N yr⁻¹, of which 5.83 × 10⁵ kg N was exported in milk, and 2.45 × 10⁶ kg N was excreted. Lactating cow milk NUE was 28.11%, while whole-herd milk-only and product NUE were 18.70% and 19.90%, respectively. The milk-allocated N footprint was 7.21 g N kg⁻¹ fat- and protein-corrected milk (FPCM) under the cradle-to-farm-gate boundary and increased to 13.56 g N kg⁻¹ FPCM when manure land application was included. Feed production was the largest contributor under the cradle-to-farm-gate boundary, whereas manure management dominated under the expanded boundary. Scenario analysis showed that the largest simulated reductions were 30.52% for dietary mitigation under the cradle-to-farm-gate boundary and 18.77% for combined manure-management mitigation under the expanded boundary. These results highlight the need for coordinated improvements in feeding, herd management, and manure management.

Supplementation with Saccharomyces cerevisiae fermentation-derived postbiotics (SCFP) in calves can improve calf growth and health. This study evaluated the effects of SCFP supplementation in the calf diet on growth, health, rumen fermentation, and rumen microbiota during the first 70 d of life in 2 independent calf experiments conducted under different maternal dietary contexts. The dams of the calves consisted of 400 pregnant Holstein dry cows that received either a basal far-off and close-up TMR without SCFP (n = 200) or the same diets supplemented with SCFP (n = 200) beginning at dry-off. From these dams, 144 female calves were enrolled and allocated within maternal dietary background, blocked by birth date, and randomly assigned to receive SCFP or not in the calf diet, resulting in 2 independent experiments (n = 36 calves per group, 4 groups in total): experiment 1, CC (dam: -SCFP, calf: -SCFP) and CT (dam: -SCFP, calf: +SCFP); and experiment 2, TC (dam: +SCFP, calf: -SCFP) and TT (dam: +SCFP, calf: +SCFP). Growth performance, serum metabolites and antioxidant and anti-inflammatory indicators, diarrhea incidence, and rumen fermentation and microbial composition were measured. In experiment 1, CT calves showed greater weaning weight and preweaning ADG, reduced diarrhea incidence, and altered rumen microbial community structure at 70 d of age, with enrichment of Erysipelotrichaceae_UCG-002 and Sharpea. In experiment 2, TT calves tended to have greater preweaning ADG, whereas weaning weight was unaffected. In both experiments, calves supplemented with SCFP consistently reduced preweaning diarrhea risk. At 70 d of age, rumen microbial diversity was not affected, although calves in the TT group exhibited greater total volatile fatty acid and ammonia-nitrogen concentrations. In conclusion, direct SCFP supplementation to calves during the preweaning period improved growth performance and health and modified rumen fermentation and microbial composition. Differences in calf responses between experiments highlight the need for future studies with replicated maternal treatments to clarify the role of maternal supplementation.

Pasteurized colostrum has significantly contributed to improving the health and growth of newborn calves by reducing total bacterial count. However, previous research on animal responses to pasteurized colostrum has primarily focused on physiological functioning and production performance, especially during the preweaning period, with limited attention to any postweaning effects from the feeding of pasteurized colostrum at birth. We conducted a comprehensive investigation into the growth, health, blood immunity, and microbiota responses of dairy calves in these two groups from birth to 180 d of age. In this study, a total of 32 healthy female Holstein calves [mean birth weight = 39.8 ± 1.22 kg (mean ± standard deviation)] were selected and divided into two groups (n = 16; fed either pasteurized or unpasteurized colostrum at birth). The results demonstrated that calves fed pasteurized colostrum exhibited enhanced growth performance as indicated by higher body weight (BW) and average daily gain (ADG) compared to those fed unpasteurized colostrum (p < 0.05). Calves fed pasteurized colostrum displayed higher lymphocyte ratio (W-SCR) and platelet distribution width (PDW), along with lower neutrophil ratio (W-LCR) and neutrophil count (W-LCC) (p < 0.05). Additionally, substantial differences were identified in microbial richness and diversity between the pasteurized and unpasteurized colostrum-fed groups (p < 0.05). Distinct microbial communities were observed in the ruminal and fecal regions (p < 0.05), and we detected shared beneficial microbiota (Alloprevotella, Parabacteroides, and unidentified_Prevotellaceae) and metabolic functions (metabolism of energy, amino acids, and glycan) in both gut regions of the pasteurized group. Furthermore, our study revealed intricate and robust interactions among microbiota, volatile fatty acid (VFA) and blood indicators (|r| > 0.5 and p < 0.05). In conclusion, the findings in the present experiment suggest that the positive effects from d 0 pasteurized colostrum feeding may be seen up to d 180, including improved growth performance, health, and blood immunity, and these may be attributed to modifications in microbiota development induced by pasteurized colostrum.

Long‐term artificial selection and environmental shifts have driven adaptive changes in both the host genome and the intestinal microbiota. The complex symbiotic relationship between these two has become essential for maintaining intestinal homeostasis and overall health. Concurrently, advancements in sequencing technology and the functional annotation of noncoding RNAs, particularly microRNAs (miRNAs), have facilitated the exploration of mechanisms regulating intestinal homeostasis. Herein, we systematically update the role of miRNA–microbiota interactions in regulating the intestinal barrier, intestinal immunity, changes in intestinal microbiota dynamics, and maintenance of intestinal homeostasis, and we further critically discuss the role of miRNA–microbiota interactions in the maintenance of host intestinal health, metabolic regularity, brain function, and neurodegenerative disease‐related disorders. Finally, we highlight the prospects and therapeutic strategies regarding miRNA–microbiota interactions in humans and animals in the context of intestinal microbiota and gene function studies. This study provides a comprehensive overview of miRNA–microbiota interactions and their influence on intestinal homeostasis and host health and offers novel therapeutic strategies for future personalized prevention and treatment of intestinal diseases.

Mastitis (inflammation of the mammary gland) commonly occurs in dairy cattle during the periparturient period (transition period), in which dairy cattle experience physiological and hormonal changes and severe negative energy balance, followed by oxidative stress. To maintain successful lactation and combat negative energy balance (NEB), excessive fat mobilization occurs, leading to overproduction of reactive oxygen species (ROS). Excessive fat mobilization also increases the concentrations of nonesterified fatty acids (NEFA) and β-hydroxybutyric acid (BHB) during the periparturient period. In addition, the excessive utilization of oxygen by cellular respiration in the mammary causes abnormal production of oxidative stress (OS). OS impairs the immunity and anti-inflammatory efficiency of periparturient dairy cattle, increasing their susceptibility to mastitis. To alleviate oxidative stress and subsequent mastitis, antioxidants are supplemented to dairy cattle from an external source. Extensive studies have been conducted on the supplementation of selenium (Se) and vitamins E and B9 to mitigate mastitis during the transition period in dairy cattle. Altogether, in the current review, we discuss the research development on bovine mastitis and its major causes, with special emphasis on oxidative stress during the transition period. Moreover, we discuss the antioxidant, immunoregulatory, and anti-inflammatory properties of Se and vitamins E and B9 and their role in the control of bovine mastitis in periparturient dairy cattle.

This study evaluated the effects of incremental tributyrin supplementation in pasteurized waste milk on growth performance, health, and blood metabolism of dairy calves before and after weaning. Forty-eight newborn female Holstein dairy calves (39.6 ± 2.75 kg; mean ± standard deviation) were blocked by age and randomly assigned to 3 treatments: pasteurized waste milk (1) without supplementation, (2) with 1 g/L of tributyrin products (unprotected solid powder; containing 35% tributyrin), or (3) with 2 g/L of tributyrin products. The calves were weaned on d 56 and were raised until d 77. Data were analyzed for the preweaning, postweaning, and overall periods. The results showed that starter intake and hay intake were not different among treatments in any period of the trial, but the crude protein intake tended to increase linearly with tributyrin supplementation during the overall period. Although tributyrin supplementation had no effects on body weight during preweaning and overall periods, body weight increased linearly with tributyrin supplementation postweaning. The average daily gain tended to increase linearly during postweaning and overall periods. No effects were observed on feed efficiency in any period. A positive linear relationship between body length and tributyrin supplementation was observed during the postweaning period, but no differences were found for the other body structural measurements in any period. The results of diarrhea showed that tributyrin concentration had a negative linear relationship with diarrhea frequency during preweaning and overall periods. The rectal temperature did not differ among treatments in any period, but a treatment × week effect for rectal body temperature was observed. For blood metabolism, tributyrin supplementation had no effects on insulin, growth hormone, total protein, albumin, or globulin. No differences were found in serum amyloid A concentration in any of the periods, yet haptoglobin concentration decreased linearly with increasing tributyrin concentration during postweaning and overall periods. Endothelin concentration showed a tendency to decrease linearly during preweaning and postweaning periods and decreased linearly with tributyrin supplementation during the overall period. An increasing tributyrin concentration was associated with a negative linear relationship with IL-1β concentration during the preweaning period, and no differences were found in the other periods. The concentration of IL-6 and tumor necrosis factor α were not different among treatments in any of the periods. These data suggest that increasing the concentration of tributyrin in pasteurized waste milk could increase growth performance and health of dairy calves, and incremental tributyrin supplementation could linearly reduce haptoglobin, endothelin, and IL-1β concentrations, indicating a positive effect of tributyrin on alleviating oxidative stress and inflammatory status of dairy calves. Calves fed pasteurized waste milk supplemented with tributyrin products (containing 35% tributyrin) at 2 g/L compared with 1 g/L of milk had more improved growth and health.

Dairy cattle experience health risks during the periparturient period. The continuous overproduction of reactive oxygen species (ROS) during the transition from late gestation to peak lactation leads to the development of oxidative stress. Oxidative stress is usually considered the main contributor to several diseases such as retained placenta, fatty liver, ketosis, mastitis and metritis in periparturient dairy cattle. The oxidative stress is generally balanced by the naturally available antioxidant system in the body of dairy cattle. However, in some special conditions, such as the peripariparturient period, the natural antioxidant system of a body is not able to balance the ROS production. To cope with this situation, the antioxidants are supplied to the dairy cattle from external sources. Natural antioxidants such as selenium and vitamin E have been found to restore normal health by minimizing the harmful effects of excessive ROS production. The deficiencies of Se and vitamin E have been reported to be associated with various diseases in periparturient dairy cattle. Thus in the current review, we highlight the new insights into the Se and vitamin E supplementation as antioxidant agents in the health regulation of periparturient dairy cattle.

Camel milk is a rich source of vitamin C, lactic acid bacteria (LAB), beta-caseins and milk whey proteins, including lactoferrin, lysozyme, lactoperoxidase, alpha-lactalbumin and immunoglobulin. The lactoferrin plays a key role in several physiological functions, such as conferring antioxidant, anti-microbial and anti-inflammatory functions in cells. Similarly, the camel milk alpha-lactalbumin has shown greater antioxidative activity because of its higher antioxidant amino acid residues. The antioxidant properties of camel milk have also been ascribed to the structural conformation of its beta-caseins. Upon hydrolysis, the beta-caseins lead to some bioactive peptides having antioxidant activities. Consequently, the vitamin C in camel milk has a significant antioxidant effect and can be used as a source of vitamin C when the climate is harsh. Furthermore, the lysozyme and immunoglobulins in camel milk have anti-microbial and immune regulatory properties. The LAB isolated from camel milk have a protective role against both Gram-positive and -negative bacteria. Moreover, the LAB can be used as a probiotic and may restore the oxidative status caused by various pathogenic bacterial infections. Various diseases such as cancer and hepatitis have been associated with oxidative stress. Camel milk could increase antiproliferative effects and regulate antioxidant genes during cancer and hepatitis, hence ameliorating oxidative stress. In the current review, we have illustrated the anti-microbial and antioxidant properties of camel milk in detail. In addition, the anti-cancer and anti-hepatitis properties of camel milk have also been discussed.

The cytokine-activated Janus kinase (JAK)—signal transducer and activator of transcription (STAT) pathway is a sequence of communications between proteins in a cell, and it is associated with various processes such as cell division, apoptosis, mammary gland development, lactation, anti-inflammation, and immunity. The pathway is involved in transferring information from receptors on the cell surface to the cell nucleus, resulting in the regulation of genes through transcription. The Janus kinase 2 (JAK2), signal transducer and activator of transcription A and B (STAT5 A & B), STAT1, and cytokine signaling suppressor 3 (SOCS3) are the key members of the JAK-STAT pathway. Interestingly, prolactin (Prl) also uses the JAK-STAT pathway to regulate milk production traits in dairy cattle. The activation of JAK2 and STATs genes has a critical role in milk production and mastitis resistance. The upregulation of SOCS3 in bovine mammary epithelial cells inhibits the activation of JAK2 and STATs genes, which promotes mastitis development and reduces the lactational performance of dairy cattle. In the current review, we highlight the recent development in the knowledge of JAK-STAT, which will enhance our ability to devise therapeutic strategies for bovine mastitis control. Furthermore, the review also explores the role of the JAK-STAT pathway in the regulation of milk production in dairy cattle.

Mastitis is the inflammation of the mammary gland. Escherichia coli and Staphylococcus aureus are the most common bacteria responsible for mastitis. When mammary epithelial cells are infected by microorganisms, this activates an inflammatory response. The bacterial infection is recognized by innate pattern recognition receptors (PRRs) in the mammary epithelial cells, with the help of Toll-like receptors (TLRs). Upon activation by lipopolysaccharides, a virulent agent of bacteria, the TLRs further trigger nuclear factor-κB (NF-κB) signaling to accelerate its pathogenesis. The NF-κB has an essential role in many biological processes, such as cell survival, immune response, inflammation and development. Therefore, the NF-κB signaling triggered by the TLRs then regulates the transcriptional expression of specific inflammatory mediators to initiate inflammation of the mammary epithelial cells. Thus, any aberrant regulation of NF-κB signaling may lead to many inflammatory diseases, including mastitis. Hence, the inhibiting of NF-κB signaling has potential therapeutic applications in mastitis control strategies. In this review, we highlighted the regulation and function of NF-κB signaling in mastitis. Furthermore, the role of NF-κB signaling for therapeutic purposes in mastitis control has been explored in the current review.