Dairy Research Bulletin: Selected Articles from December 2024

Environmental Management and Sustainability

UC Davis-led Research: United States Dairy Farms and Global Warming. Rotz CA, Mitloehner F.J Dairy Sci. 2024 Dec 17:S0022-0302(24)01382-1.

Several metrics have developed for combining the warming effects of various greenhouse gases (GHG). The metric used can affect the life cycle assessment and comparison of dairy production systems due to the weighting placed on long- versus short-lived gases in the atmosphere.
Global warming potential with a time horizon of 100 years (GWP-100) has become the standard but metrics are also available for other time horizons. Metrics for 20-, 100- and 500-year horizons gave average farmgate emission intensities of 2.08, 0.98 and 0.50 kg CO₂e/kg of fat-and-protein-corrected-milk produced for current US dairy farms.
Compared with the use of GWP metrics, which represent energy absorption, use of global temperature-change potential (GTP), combined global temperature-change potential (CGTP) or global warming potential star (GWP*) reduced the warming effect of methane relative to other GHG. These metrics representing temperature change reduced the warming potential of US dairy farms by 17 to 49% compared with the use of GWP-100.
The metrics used also affected the comparison of individual production systems providing different life cycle assessments of management practices. Use of GWP-100 metrics indicated that warming from GHG emissions of US dairy farms increased 11-15% between 1971 and 2020, while the use of GTP, CGTP and GWP* metrics showed little or no effect on global temperature change over the 50-year period.
Use of GWP-100 metrics indicated that GHG emissions related to milk production on dairy farms represented 1.6% of all US GHG emissions in 2020 while use of other metrics ranged from 0.9 and 1.8%.
Although all approaches for representing the integrated warming impact of GHG have benefits and challenges, approaches such as CGTP and GWP* that account for the rate of methane emission relative to the oxidation rate in the atmosphere provide a more process-based assessment of the long-term impact of dairy farms on global temperature and perhaps a more scientifically sound approach for assessing strategies to mitigate the warming effect of dairy farms.

Vermicomposting significantly reduced antibiotic resistance genes in cow manure even under high tetracycline concentrations. Li Z, Yang F, Han B, Zhao R, Yang M, Zhang K. Bioresour Technol. 2024 Dec 21;419:132002.

Minimizing antibiotic resistance genes (ARGs) in livestock manure is crucial for curbing ARG dissemination. Vermicomposting can eliminate ARGs, but the effect of residual antibiotics on its reduction efficacy remains unclear.
Herein, Eisenia foetida was employed to convert cow manure with varying concentrations of tetracycline (i.e., 0, 10, 100 mg/kg), aiming to explore the impact of tetracycline on ARG fate during vermicomposting for 35 days.
Results showed that the total ARG abundance in vermicomposting (0.05 copies/16S rRNA copies) was significantly lower than that in natural composting (0.06 copies/16S rRNA copies) (p < 0.05).
Notably, exposure to tetracycline increased total ARG abundance (p < 0.05) and stimulated microbial succession during vermicomposting, with some ARGs increasing and others decreasing. But ARGs removal in vermicomposting was still higher even under tetracycline stress than that in natural composting.
Overall, vermicomposting is an effective method for reducing ARGs in cow manure even at high tetracycline levels.

Inactivation of Escherichia coli O157:H7 in Dairy Manure Compost with Alkaline Walnut Hull Biochar. Gurtler JB, Mullen CA. J Food Prot. 2024 Dec 18:100438.

Biochar has been used to accelerate heating profiles during composting by increasing oxygenation, which could also reduce microbial pathogens. However, the antimicrobial inactivation of foodborne pathogens in compost, by amending with biochar without increased heating profiles, has not been evaluated.
In this study, researchers examined the ability of biochar to inactivate E. coli O157:H7 (EC) in fresh dairy manure compost by amending with one of four types of biochar. Two slow pyrolysis biochars (high temperature walnut hull biochar [HTWHB], and walnut hull cyclone biochar [WHCB]), and two fast pyrolysis biochars were examined.
Compost with 8.1 log CFU/g of EC + 10% amended biochar was held at 22°C and analyzed for EC weekly. The control treatment sustained ca. 8.7 log CFU of EC through week 7; however, the bacterium was not detected by direct plating in WHCB compost (below the detection limit) by day 7, through the entire 49 days (which may be attributed to increased compost alkalinity).
Populations of EC in compost supplemented with 10% of the three other biochars sustained EC populations ≥ 9.2 log through the balance of the study.
The four biochars were further tested in soil at 17% moisture to determine if concentrations as low as 3.5% could inactivate EC. When 3.5% HTWHB was added to soil, populations were 5.1 log CFU lower than when 10% of the same biochar was amended into dairy compost by week 3. This may indicate that alkaline biochar, amended into lower moisture, soil may be more biocidal than when alkaline biochar is added to high moisture manure compost.
The current study demonstrates that highly alkaline walnut hull cyclone biochar is capable of reducing up to 8 log of EC in high moisture fresh compost in only 7 days, while as little as 3.5% alkaline WHCB in 17% moisture soil can reduce 6.7 log of EC in only 14 days.
These results may assist farmers in amending compost, manure, cattle feedlots, or soil with biochar to reduce EC, and potentially other pathogens (e.g., Salmonella enterica, Campylobacter jejuni, and Listeria monocytogenes), with the goal of reducing the dissemination of human bacterial pathogens to meat, poultry, and fresh produce.

Deciphering cleaner and sustainable frontiers in scientific cow waste valorization: a review. Kushwaha J, Singh Y, Dhoble AS, et al. Environ Monit Assess. 2024;196(10):988.

The forecasted global population growth is poised to create a greater exigency for livestock-derived food production, leading to a significant waste generation from the industrial-scale livestock operations, which necessitates to develop sustainable waste management solutions.
The heightened demand for livestock and dairy products has driven a surge in cow waste (CW) production. While CW is typically used as organic fertilizer or solid fuel, improper disposal poses potential environmental hazards.
Anaerobic digestion and composting transform CW into valuable products, such as biofuels and organic fertilizers, with the potential for electricity and heat generation, biochar production, and advanced friction materials.
The CW contains essential inorganic and organic compounds vital for plant functions, including lignin, cellulose, hemicellulose, nitrogen, and minerals such as potassium, sulfur, iron, magnesium, copper, cobalt, and manganese.
Additionally, the rich microbial diversity in cow dung drives the production of bioenergy carriers like biomethane and biohydrogen, promoting cost-effective energy generation and environmental sustainability. This review employs bibliometric analysis to explore the latest trends in CW applications, with a particular focus on innovative applications such as cellulose extraction, biochar production, microbial fuel cells, and nanoparticle synthesis.
It further evaluates the environmental impacts of these technologies and assesses their potential to advance sustainable and cleaner frontiers in the valorization of CW.

How does the chemical composition of dung affect nitrous oxide and methane emissions in pasture soils? Amaral Júnior FP, Souza de Sousa CE, Ruggieri AC, et al. J Environ Manage. 2024 Dec 9;373:123630.

There is an important gap in how variations in herbivore dung composition affect GHG emissions on pastures, especially due to differences in dry matter (DM) and nitrogen contents. Oversimplifications can compromise the accuracy of mitigation strategies.
This study aims to address this gap by investigating how the chemical composition of dung from different species influences GHG emissions in pasture systems.
The results showed that drier dung led to higher cumulative N₂O emissions. The highest emissions were observed from goat at 9.47 mg N-N₂O g⁻¹dry soil, followed by sheep at 5.95 mg N-N₂O g⁻¹ dry soil, beef cattle at 5.44 mg N₂O g⁻¹ dry soil, dairy cattle at 2.67 mg N₂O g⁻¹ dry soil.
It was observed that higher dung moisture content generally corresponded to increased CH₄ emissions. The highest cumulative CH₄ emission was for dairy cattle dung (8.29 mg C-CH₄ g⁻¹dry soil), followed by beef cattle (3.89 mg C-CH₄ g⁻¹ dry soil), sheep (2.32 mg C-CH₄ g⁻¹ dry soil), and goats (1.89 mg C-CH₄ g⁻¹ dry soil).
Principal Component Analysis illustrated that PC₁, named as diet quality, explained 61.9% of the variance, was positively correlated with N₂O and negatively correlated with fiber content and C/N ratio, while PC₂, named as acetrophic and hydrogenotrophic methanogenesis, explained 19.6% of the variance, linking VS to reduced CH₄ emissions.
This study establishes relationships between manure chemical composition and GHG emissions, filling a fundamental knowledge gap and supporting the development of cause-and-effect models.

Perspective: Enteric methane mitigation and its impact on livestock hydrogen emissions. Hristov AN, Solomon S.J Dairy Sci. 2025 Jan;108(1):1-5.

In a hydrogen-based economy future, hydrogen leakage is becoming an environmental concern. Ruminants naturally produce small amounts of hydrogen, which is emitted in the environment along with other fermentation gases, such as the GHG methane and carbon dioxide.
Here, for the first time, researchers estimated hydrogen emissions from the global ruminant livestock at 527 kt/yr, or about 3.5% of the global anthropogenic hydrogen emissions.
When methanogenesis is decreased by various methane-mitigation practices, hydrogen emissions increase, raising questions regarding net environmental impacts because hydrogen is an indirect greenhouse gas. Therefore, researchers estimated the potential contribution of hydrogen from ruminant livestock under 3 enteric methane reduction scenarios.
At the highest methane reduction (75%) scenario, the percentage increase in global ruminant hydrogen emissions over baseline emissions (as kilotons per year) due to the reduction in enteric methanogenesis was 5.95% and yielded a 0.48% increase in CO₂-equivalents (CO₂-eq), when the benefit of reduced methane was accounted for.
This study suggests that the net climate benefit of reduced methane emissions from ruminants is decreased by less than 1%, when expected increases in hydrogen emissions are considered as an offset to the CO₂-eq emissions avoided.

Methane production related to microbiota in dairy cattle feces. Liu J, Zhou M, Lichtfouse E, et al. Environ Res. 2024 Dec 17:120642.

Methane (CH₄) emission from livestock feces, led by ruminants, shows a profound impact on global warming. Despite this, we have almost no information on the syntrophy of the intact microbiome metabolisms, from carbohydrates to the one-carbon units, covering multiple stages of ruminant development.
In this study, syntrophic effects of polysaccharide degradation and acetate-producing bacteria, and methanogenic archaea were revealed through metagenome-assembled genomes from water saturated dairy cattle feces.
Although CH₄is thought to be produced by archaea, more edges, nodes, and balanced interaction types revealed by network analysis provided a closed bacteria-archaea network. The CH₄ production potential and pathways were further evaluated through dynamic, thermodynamic and ¹³C stable isotope analysis.
The powerful CH₄production potential benefited from the metabolic flux: classical polysaccharides, soluble sugar (glucose, galactose, lactose), acetate, and CH₄ produced via typical acetoclastic methanogenesis. In comparison, a cooperative model dominated by hydrogenotrophic methanogenic archaea presented a weak ability to generate CH₄.
These findings comprehensively link carbon and CH₄metabolism paradigm to specific microbial lineages which are shaped related to developmental stages of the dairy cattle, directing influencing global warming from livestock and waste treatment.

Animal Health and Food Safety

CDRF-Funded Research: Grape pomace supplementation reduced methane emissions and improved milk quality in lactating dairy cows. Akter A, Li X, Grey E, Wang SC, Kebreab E. J Dairy Sci. 2024 Dec 20:S0022-0302(24)01416-4.

Grape pomace (GP) is a byproduct of the viticulture industry and shows promise for feeding dairy cattle as well as reducing enteric methane (CH₄) emissions.
This study investigates the potential of using fresh GP in dairy cow feeding and its effects on CH₄
Multiparous Holstein dairy cows (n = 24, 205 ± 39 DIM) were housed in free stall barns and provided rations consisting of alfalfa hay, wheat hay, almond hulls, cottonseed, and grain mix.
After a 2-wk adaptation period, cows were randomly assigned to one of the 3 treatments: a control diet (CON) a diet with 10% grape pomace (10% GP), and a diet with 15% GP (15% GP) on a DM basis. Rations were provided twice daily and gas emissions from cows were measured using an automated GreenFeed system.
Milk production was recorded both in the morning and evening h and milk samples were collected weekly for fat, protein, lactose, SNF, MUN, and SCC analysis. For fatty acids analysis, milk samples were collected on the last 3 days of each 28-day period.
Dry matter intake was reduced in GP-fed cow, where CON had the highest DMI followed by 10% and 15% GP.
Methane and H₂emissions were reduced in GP-supplemented group compared with CON group. On the other hand, CO₂ emissions was found higher in GP-supplemented group compared with the CON group.
Milk yield was not different among different GP treatments. Although no differences were observed in fat, protein, lactose, SNF, and SCC, we did observe that MUN was lower in the 10% and 15% GP compared with CON group.
The reduction in CH₄emissions in GP-supplemented group suggests that the chemical components of GP were effective in reducing CH₄ On the other hand, lower DMI in GP supplemented groups indicates that DMI can act as an indicator of lower CH₄ production.
No effects on fat, protein percentage, and milk yield indicate that GP did not negatively affect milk production. Total PUFA and linoleic acid in milk fat, were greater in 10% and 15% GP groups compared with CON group.
In conclusion, GP supplementation helped reduce enteric CH₄emissions from cows without impacting milk production.

A meta-analysis of dietary inhibitors for reducing methane emissions via modulating rumen microbiota in ruminants. Ma G, Jing W, Chen Y, et al. J Nutr. 2024 Dec 20:S0022-3166(24)01237-9.

Rumen methane emissions (RME) significantly contribute to global greenhouse gas emissions, underscoring the essentials to identify effective inhibitors for RME mitigation. Despite various inhibitors shown potential in reducing RME by modulating rumen microbes, their impacts include considerable variations and inconsistency.
Therefore, researchers aimed to quantitively assess the impacts of various methane inhibitors on RME, rumen microbial abundance and fermentation in ruminants. Additionally, the relationships between microbial abundance and RME were also examined through the meta-regressions.
Meta-analysis and meta-regression were conducted to assess the impacts of methane inhibitions, including 3-nitrooxypropanol, ionophores, nitrate, triglycerides, phytochemicals and co-inhibitors, on RME and rumen microbiota in beef, dairy cattle and sheep.
Analyses of 922 datasets from 274 experiments revealed that inhibitors, except ionophores, significantly reduced RME, with co-inhibitors displaying the highest efficacy. Inhibitors effects were more pronounced in sheep relative to beef and dairy cattle.
Inhibitors decreased the abundance of ciliates and methanogens, with positive correlations observed between Dasytrichidae, Entodinomorphs, Methanobacteriale and fungi with RME.
Among inhibitors, triglycerides exhibited simultaneous reduction in methanogen, ciliate and fungal abundances. 3-nitrooxypropanol and triglycerides increased H₂in the rumen while reducing the acetate-propionate ratio, especially in beef. The H₂ emission negatively, and acetate-propionate ratio positively were correlated with RME, respectively.
In conclusion, microbes including Dasytrichidae, Entodinomorphs, Methanobacteriale and fungi significantly attribute to RME, and co-inhibitors have the highest efficacy in limiting RME and reducing microbial abundances.
This study underscores the roles of both host and microbiota in modulating the inhibitor efficacy in RME, informing the refinement of rumen additives to mitigate RME from meat and milk production.

Safety Leadership Training Effectiveness Evaluation on Behavior Change Among Large-Herd U.S. Dairy Farm Supervisors. Douphrate DI, Rodriguez A, Kines P, Hossein Javid A. Workplace Health Saf. 2024 Dec 13:21650799241302817.

Prior research suggests leader-based interventions are considered to have a much stronger influence on worker safety behavior and climate than worker-based interventions. However, no prior research has evaluated training effectiveness of safety-specific leadership skill development for front-line supervisors on dairy farms.
A tailored safety leadership training program targeting dairy farm supervisors was developed, delivered, and evaluated for its training effect on the supervisor’s safety leadership behavior.
A 12-module safety leadership training program was developed and delivered in an asynchronous format using e-learning methods to 73 dairy farm supervisors, representing 30 farms across five western U.S. states.
Evaluation of knowledge gained among participants revealed significant differences between pre- and post-test scores with medium to very large learning effect sizes across all training modules, particularly with training modules addressing safety culture, workplace conflict, and safety meetings.
Safety leadership behavior change evaluation revealed significant pre-post training effects across most training modules, particularly regarding safety dialogue, hazard assessment, safety modeling, and conducting safety meetings.
These findings suggest that safety leadership training can result in essential leadership behavior change among front-line dairy farm supervisors. Additional research is needed on the effectiveness and sustainability of safety leadership training in high-risk industrial sectors such as agriculture.

A single mutation in dairy cow-associated H5N1 viruses increases receptor binding breadth. Good MR, Fernández-Quintero ML, Ji W, Rodriguez AJ, Han J, Ward AB, Guthmiller JJ. Nat Commun. 2024 Dec 30;15(1):10768.

Clade 2.3.4.4b H5N1 is causing an unprecedented outbreak in dairy cows in the United States. To understand if recent H5N1 viruses are changing their receptor use, we screened recombinant hemagglutinin (HA) from historical and recent 2.3.4.4b H5N1 viruses for binding to distinct glycans bearing terminal sialic acids using a glycan microarray. We find that H5 from A/Texas/37/2024, an isolate from the dairy cow outbreak, has increased binding breadth to core glycans bearing terminal α2,3 sialic acids, the avian receptor, compared to historical and recent 2.3.4.4b H5N1 viruses. We do not observe any binding to α2,6 sialic acids, the receptor used by human seasonal influenza viruses. Using molecular dynamics and a cryo-EM structure of A/Texas/37/2024 H5, we show A/Texas/37/2024 H5 is more flexible within the receptor-binding site compared to a 2.3.4.4b H5 from 2022. We identify a single mutation outside of the receptor binding site, T199I, is responsible for increased binding breadth, as it increases receptor binding site flexibility. Together, these data show recent H5N1 viruses are evolving increased receptor binding breadth which could impact the host range and cell types infected with H5N1.

Are we cultivating the perfect storm for a human avian influenza pandemic? Perez-Acle T, Ravello C, Rosemblatt M. Biol Res. 2024 Dec 19;57(1):96.

The emergence of highly pathogenic avian influenza (HPAI) A H5N1 virus in dairy cattle marks a troubling new chapter in the ongoing battle against zoonotic diseases. Since its initial detection in 1955, the H5N1 virus has primarily been associated with poultry, posing significant threats to both animal and human health.
However, recent outbreaks in U.S. dairy herds across nine states have revealed an alarming expansion of the virus, with over 190 herds affected as of September 2024. This unprecedented spread in cattle has sparked intense concern among scientists and health officials, especially with reports indicating that up to 20% of dairy products may contain traces of the virus.
The implications of the H5N1 virus establishing itself in cattle populations are profound. This potential endemic presence could transform dairy farms into reservoirs of the virus, facilitating its evolution and increasing the risk of human transmission. Mutations enhancing viral replication in mammals have already been identified, including the notorious PB2 E627K mutation linked to increased virulence. Moreover, the detection of the virus in the central nervous system of infected animals, including cats, underscores the broad tissue tropism and severe pathogenic potential of the H5N1 virus.
Current containment efforts include stringent biosecurity measures and financial incentives for enhanced testing and personal protective equipment (PPE) for farmers. Yet, gaps in testing infrastructure and the resurgence of raw milk consumption pose significant challenges. The U.S. Department of Agriculture (USDA) and the Centers for Disease Control and Prevention (CDC) emphasize the critical need for comprehensive testing and pasteurization to mitigate the risk of human infection.
As the scientific community races to adapt existing antiviral treatments and develop effective vaccines, the concept of a One Health approach becomes increasingly vital. This holistic strategy calls for coordinated actions across human, animal, and environmental health sectors to preemptively tackle emerging zoonotic threats. Strengthening surveillance, fostering international cooperation, and investing in research are essential steps to prevent the H5N1 virus from igniting the next global health crisis.
The current avian influenza outbreak serves as a stark reminder of the delicate balance between human activities and viral evolution. Our collective ability to respond effectively and proactively will determine whether we can avert the perfect storm brewing on the horizon.

Nutrition and Health

Scientific Report of 2025 Dietary Guidelines Advisory Committee: Report to the Secretary of Health and Human Services and Secretary of Agriculture. U.S. Department of Health and Human Services. Dec 10, 2024.

The Dietary Guidelines for Americans is updated every five years and serves as the cornerstone of federal nutrition programs and policies, providing food-based recommendations to help prevent diet-related chronic diseases and promote overall health.
The guidelines provide health professionals with guidance and resources to assist the public in choosing an overall healthy diet that works for them. And they help HHS, USDA, and others in the federal government to tailor their policies to best serve the American people.
The Scientific Report, alongside public comments and federal agency input, will inform the two departments as they develop the Dietary Guidelines for Americans, 2025-2030, which is expected to be published in late 2025. This report will help to ensure that the next edition of the Dietary Guidelines is based on current scientific evidence and medical knowledge.
The 2025 Dietary Guidelines Advisory Committee’s work is notable for its intentional focus on health equity to ensure that factors such as socioeconomic position, race, ethnicity, and culture were considered to the greatest extent possible. The Committee also expanded the scope of evidence reviewed beyond recommended amounts and types of foods to also include strategies to effectively promote healthy dietary patterns across the lifespan.

Yogurt consumption and risk of accelerated aging: A population-based study from the NHANES 2003-2006. Yue X, Liu H, Guo W, Gao Y, Shi S. Front Nutr. 2024 Dec 11;11:1482980.

Yogurt consumption is beneficial to health, but its association with aging remains unclear. This study aims to explore the relationship between yogurt consumption and aging using data from the 2003-2006 National Health and Nutrition Examination Survey (NHANES).
Researchers used data from 4,056 participants to examine the relationship between yogurt consumption and aging. Phenotypic age acceleration was used as a surrogate marker for aging.
Yogurt consumption was associated with a lower risk of accelerated aging compared to non-consumers (OR = 0.544). A U-shaped relationship was observed between the frequency of yogurt intake and the risk of accelerated aging. Additionally, yogurt consumption was related to a lower risk of overweight status.
These findings suggest that yogurt consumption may reduce the risk of accelerated aging and may also be linked to a lower risk of overweight status. This could provide a promising avenue for exploring the beneficial effects of dietary factors on lifespan extension.

Associations of milk, dairy products, calcium and vitamin D intake with risk of developing Parkinsons disease within the EPIC4ND cohort. Gröninger M, Sabin J, Katzke VA, et al. Eur J Epidemiol. 2024;39(11):1251-1265.

The scientific literature indicates a potential association between dairy consumption and risk of Parkinson´s disease (PD), especially among men, yet the results remain inconclusive.
Therefore, researchers investigated this association between dairy consumption and PD in a large prospective European cohort.
Dietary and non-dietary data was collected from 183,225 participants of the EPIC-for-Neurodegenerative-Diseases (EPIC4ND) cohort, a sub-cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort.
No relationship was observed between dairy consumption (HR 1.07), individual dairy products (milk: HR 0.95; yogurt: HR 1.03; cheese: HR 1.13), or vitamin D (HR 1.08) with PD risk.
However, the researchers observed a risk-increasing association with higher calcium intakes (HR 1.33), which was more pronounced in men (HR 1.50) and in ever smokers (HR 1.64).
No compelling evidence was found for an association between dairy products or vitamin D intake and PD risk indicating a potentially limited relevance of dairy intake in PD risk than previously described.

Exploring the Effect of Cheese Intake on Cholelithiasis Through Biomarkers: A Mendelian Randomization Study. Yang W, Yang Y, Ji R. J Dairy Sci. 2024 Dec 17:S0022-0302(24)01393-6.

Cholelithiasis, or gallstone disease, is a prevalent health condition characterized by the formation of gallstones in the gallbladder. These stones, which primarily consist of cholesterol or bilirubin, can lead to a range of complications, including biliary colic, cholecystitis, and even pancreatitis.
The global burden of cholelithiasis is significant, and it is influenced by both genetic and environmental factors, with diet playing a key role. Understanding how specific dietary components affect gallstone formation is crucial for developing prevention strategies.
This study assesses the causal relationship between intake of cheese and cholelithiasis through the analysis of relevant biomarkers using Mendelian Randomization (MR). Data from the Open GWAS project and FinnGen Biobank were used, including biomarkers related to blood cells, blood biochemistry, and blood pressure.
The analysis revealed that cheese intake significantly influences biomarkers such as Apolipoprotein B, direct bilirubin, C-reactive protein, cystatin C, IGF-1, and sex hormone-binding globulin. Importantly, cheese consumption was found to have a protective effect on the risk of cholelithiasis (OR = 0.624).
A 2-step mediation analysis indicated that these biomarkers act as mediators between intake of cheese and cholelithiasis risk, with effects ranging from -2.13% to 7.22%.
These findings suggest that intake of cheese may reduce the susceptibility of gallstone formation by influencing metabolic and inflammatory pathways. Future research is needed to confirm these results in more diverse populations and explore underlying mechanisms further.

Meat-egg-dairy consumption and depressive symptoms among Chinese older adults: exploring rural/urban and gender disparities. Si B, Zhang K. Front Psychiatry. 2024 Nov 26;15:1489387.

The dietary patterns of older adults correlate with their physical and mental health condition, particularly in the context of depressive symptoms. With the global population aging, comprehending the complex interplay between dietary patterns and the depressive symptom is becoming increasingly crucial for promoting healthy aging and mitigating the burden of age-related health issues.
Therefore, this study examines the association between Meat, Egg, and Dairy (MED) product consumption and depressive symptoms among older adults in China, focusing on rural/urban and gender differences.
This study employed data from the latest wave (year 2018) of the Chinese Longitudinal Healthy Longevity Survey (CLHLS), and Ordinary Least Squares (OLS) models were applied to examine the association between MED consumption and depression levels.
The findings revealed that higher MED intake was associated with lower depression levels. Urban residents and males exhibited higher MED consumption, which correlated with less depressive symptoms.
However, the impact of MED consumption on depression varied by subgroups; urban older adults benefited more from MED consumption than their rural counterparts, and the relationship between MED intake and depression was more pronounced in males than in females.
The study highlighted the influence of socio-demographic factors, such as literacy, income, and self-rated health, on depression levels.
The results suggested that MED consumption may offer protective effects on mental health in older adults, although the association may not be causal. The study underscored the need for further research to explore the complex interplay between diet and mental health in older adults, particularly in diverse cultural contexts.

Comparison of anti-SARS-CoV-2 activity of some commercial dairy products. Hayashi Y, Arizono S, Tanikawa T.J Dairy Res. 2024 Dec 5:1-4.

The continuing emergence of new variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) could be ameliorated by infection prevention through daily diet.
In this study, researchers examined the anti-SARS-CoV-2 activity of 10 commercially available dairy products.
The dairy products did not show any cytotoxicity against VeroE6/transmembrane protease serine 2 (TMPRSS2) cells (CC₅₀> 4 mg/ml). Importantly, these cells were checked using the cytopathic effect (CPE) assay, and 4 mg/ml dairy products reduced virus-induced CPE by more than 30%.
Notably, Icreo akachan milk, an infant formula, showed the highest antiviral activity with an IC₅₀of 1.4 mg/ml.
The researchers assessed the effects of the dairy products on the entry of SARS-CoV-2 pseudovirus. R1 and Yakult, lactic acid bacterial beverages, inhibited viral entry with IC₅₀of 2.9 and 3.5 mg/ml, respectively.
Collectively, these results indicate that commercially available dairy products moderately inhibit SARS-CoV-2 infection and may reduce the incidence of viral infections.

Milk osteopontin has high iron-binding capacity and facilitates iron absorption in intestinal cells. Buhl EH, Christensen B, Pedersen FH, S Rensen ES. J Dairy Sci. 2025 Jan;108(1):90-100.

Insufficient absorption of iron and the consequent development of iron deficiency have serious health consequences. Hence, identification and development of iron delivery systems that can increase the bioavailability and uptake of dietary iron are important.
Osteopontin (OPN) is an acidic and highly phosphorylated integrin-binding protein found in milk where it exists as a full-length protein and as N-terminally derived fragments. Milk OPN can be taken up by enterocytes and transported across the intestinal barrier into the circulation. Milk OPN has previously been shown to bind calcium and magnesium.
This study investigates milk OPN as a carrier of iron and its potential to increase iron absorption in intestinal cells.
Full-length OPN and N-terminal fragments of OPN were shown to bind ∼30 and ∼10 mol of iron, respectively, and the phosphorylated residues were crucial for iron binding. Osteopontin retained iron bound after simulated gastrointestinal digestion.
Immunodetection of digested OPN and OPN-Fe complexes showed that the OPN-Fe complexes were more resistant to pepsin digestion than OPN without bound iron. The cellular uptake of iron was investigated by measuring intracellular ferritin formation and mRNA expression of divalent metal transporter 1 in Caco-2 cells.
Osteopontin increased the uptake of iron even in the presence of phytic acid, a dietary inhibitor of iron absorption.
These data indicate that OPN can function as an iron carrier for use in alternative strategies for delivering iron in a bioavailable form for intestinal uptake.

Innovation, Social Science, and Dairy Alternatives

Sensors for surveillance of RNA viruses: a One Health perspective. Chen Y, Wang P, Wang D, et al. Lancet Microbe. 2024 Dec 13:101029.

RNA viruses, especially those capable of cross-species transmission, pose a serious threat to human, animal, and environmental health, as exemplified by the 2024 outbreak of the highly pathogenic avian influenza H5N1 virus in cattle, unpasteurized milk, and workers on dairy farms in the USA.
This escalating risk of a new RNA virus pandemic highlights the urgent need to implement One Health strategies. However, the centralized virus detection systems currently in use fall short of meeting the required level of virus surveillance and infection diagnosis, particularly in resource-limited regions. In this context, the latest advancements in RNA virus-sensing technologies offer promising solutions.
Through interdisciplinary collaboration, these sensors can achieve sensitivity and reliability similar to that of standard laboratory equipment and offer several advantages, such as compact size, affordability, and operational simplicity.
In this Review, we highlight the latest advances in sensing technologies for detecting different biomarkers of viral infections (RNA, antigens, and antibodies). Researchers further compare the sensing principles and performances of these technologies and discuss the possibility of deployment of these sensors in the One Health approach and the challenges expected in this pursuit.
In conclusion, the widespread use of RNA virus sensors is expected to enhance the effectiveness of surveillance systems for infectious diseases.

Probiotic-Based Mineralized Living Materials to Produce Antimicrobial Yogurts. Ramírez-Rodríguez GB, Sabio L, Delgado-López JM, et al. Adv Healthc Mater. 2024 Dec 8:e2402793

Mineralization of living cells represents an evolutionary adaptation that enhances cellular resilience to physicochemical stress. Inspired by this strategy, researchers have here developed hybrid living materials (HLMs), incorporating probiotics into mineralized collagen 3D matrices, with the aim of protecting and promoting the successful oral delivery of the bacteria.
Collagen fibrils are simultaneously self-assembled and mineralized in the presence of the probiotics (Lactobacillus acidophilus, La, was used as model), resulting in the integration of the probiotics into the hybrid matrix (i.e., bulk encapsulation). During this process, probiotics are also coated with a nanofilm of apatite mineral (single-cell encapsulation), which provides them with extra protection and reinforces their viability and activity.
The resulting HLM is metabolically active, and maintain the capacity to ferment milk into yogurt with antibacterial activity against the two major foodborne pathogens Pseudomonas aeruginosa (Pa) and Staphylococcus aureus (Sa). Interestingly, the HLM provides probiotics an additional protection in the gastrointestinal environment (i.e., simulated gastric fluid), which is of special interest for healthcare materials for oral administration.
The results pave the way for the creation of innovative healthcare materials with enhanced functionalities and the potential to produce probiotic foods with notable antimicrobial properties.

The Holobiont concept in ruminant physiology – more of the same, or something new and meaningful to food quality, food security, and animal health? Callaway T, Perez HG, Corcionivoschi N, Bu D, Fluharty FL. J Dairy Sci. 2024 Dec 20:S0022-0302(24)01427-9.

The holobiont concept has emerged as an attempt to recognize and describe the myriad interactions and physiological signatures inherent to a host organism, as impacted by the microbial communities that colonize and/or co-inhabit the environment within which the host resides.
The field acknowledges and draws upon principles from evolution, ecology, genetics, and biology, and in many respects has been “pushed” by the advent of high throughput DNA sequencing and, to a lesser extent, other “omics”-based technologies.
Despite the explosion in data generation and analyses, much of our current understanding of the human and ruminant “holobiont” is based on compositional forms of data and thereby, restricted to describing host phenotypes via associative or correlative studies.
So, where to from here? In this article, researchers discuss some past findings arising from ruminant and human gut microbiota research and seek to evaluate the rationale, progress, and opportunities that might arise from the “holobiont” approach to the ruminant and human host.
In particular, the researchers consider what is a “good” or “bad” host gastrointestinal microbiome in different scenarios, as well as potential avenues to sustain or alter the holobiont.
While the holobiont approach might improve food quality, food security and animal health, these benefits will be most likely achieved via a judicious and pragmatic compromise in data generation, both in terms of its scale, as well as its generation in context with the “forgotten” knowledge of ruminant and human physiology.

UC ANR-Led Research Financial implications of treating nonsevere gram-negative clinical mastitis in 3 California dairies. Bruno DR, Cleale RM, Overton MW, Short T, Pedraza JR, Wallace R.JDS Commun. 2024;5(6):659-663.

Bovine mastitis is a common and costly disease that negatively affects dairy farms and can affect a cow’s ability to remain productive and increase risk of early culling. In the United States, mastitis-related economic losses are estimated at US$2 billion annually with indirect costs accounting for >70% of the total costs.
Clinical mastitis (CM) affects 25% of lactating cows per dairy farm annually, and cases are classified according to their clinical presentation.
On 3 large California dairies, 415 lactating cows with nonsevere CM and infected with gram-negative (GN) bacteria were randomly assigned to 1 of 3 treatment groups: nontreated control (CON; 135 cases), 2 days of ceftiofur HCl (SP2; 133 cases), or 5 days of ceftiofur HCl (SP5; 147 cases). Bacteriological cure, clinical cure, mastitis recurrence, culling or death, and overall treatment success differed among treatment groups.
Although duration of milk withheld due to mastitis therapy was higher for SP5 (9.4 days), there was no difference between CON (6.9 days) and SP2 (7.1 days). Culling and death rates due to GN CM were the main effects that affected partial cost calculations.
Of study cows culled across the 3 herds, a higher proportion of CON cows (25%) were culled compared with SP2 (11%) or SP5 (18%). Mastitis-related expenses were higher ($550) for CON than SP2 ($343) or SP5 ($423).
Results of this partial budget evaluation for the 3 California dairies indicated economic justification for treating cases of nonsevere GN CM with ceftiofur HCl for 2 days.

Biosecurity Strategies for Optimization of Calf Health in North American Beef and Dairy Operations. Barnhardt TR, Raabis SM.Vet Clin North Am Food Anim Pract. 2024 Dec 3:S0749-0720(24)00051-3.

Calves are the most vulnerable population on farm operations and, thus, are highly sensitive to pathogen density within their environment. Maternity pen and calving area overcrowding increases the risk of diarrhea and respiratory disease outbreaks in calves. New herd additions without quarantine and infectious disease testing protocols in place increases the risk of calfhood disease and reduced future herd productivity.
As beef and dairy operations continue to evolve, it will be essential to safeguard calf health to optimize future productivity in the beef and dairy industries. Veterinarians serve a critical role of educating producers and overseeing worker training protocols by communicating consistent messaging on the importance of biosecurity.
Managing biosecurity for calves within the beef industry will always be directly impacted by the pathogen exposure from new additions to the herd, shared grazing sites, fomites, and environmental factors. Effective quarantine strategies for new cattle and contact between cattle of various ages will be crucial for protecting future calf performance.

“The advice? Think bigger”: Community perspectives on dairy farming, including surplus calves – an Australian focus group study. Bolton SE, Vandresen B, von Keyserlingk MAG. J Dairy Sci. 2024 Dec 16:S0022-0302(24)01264-5.

Citizens are becoming increasingly disconnected from food production. Despite this, many people still hold strong values about how food is produced.
The aim of this study was to attain an in-depth understanding of Australian public attitudes toward sustainability and animal welfare in dairy production, as well as early life killing of surplus dairy calves and cow-calf separation; issues commonly identified as being out of step with public values.
The researchers conducted 3 focus group sessions, each with 8 Australians that varied in age, gender identity, income, and frequency of consumption of dairy products. Thematic analysis of the semi-structured discussions resulted in 2 key themes, each with underlying sub-themes: 1) Animal agriculture as an industry, including sustainability, farmers as people, and farming practices; and 2) Personal impacts and reflections as citizens, including ethical considerations, and consumer behaviors.
Participants varied in their attitudes toward sustainability and the consumption of animal products. This variation was influenced by the different ethical lenses through which they viewed the topics, and alignment or otherwise with their personal values.
Many participants acknowledged that farmers have a hard life and care about their animals but must also prioritize economics when making management decisions. Most participants were unaware of the common dairy industry practices of early life killing of surplus calves and cow calf separation, but once made aware, there was widespread rejection of the practices.

Understanding and correcting where food animal production practices fail to align with the evolving values of the public provides opportunities to preserve the social sustainability of animal agriculture into the future.