Dairy Research Bulletin: Selected Articles from July 2024 - California Dairy Research Foundation

Environmental Management and Sustainability

National Greenhouse Gas Emission Reduction Potential from Adopting Anaerobic Digestion on Large-Scale Dairy Farms in the United States. Greene JM, Wallace J, Williams RB, Leytem AB, Bock BR, McCully M, Kaffka SR, Rotz CA, Quinn JC. Environ Sci Technol. 2024 Jul 16;58(28):12409-12419.

Waste-to-energy systems can provide a functional demonstration of the economic and environmental benefits of circularity, innovation, and reimagining existing systems.
This study offers a robust quantification of the greenhouse gas (GHG) emission reduction potential of the adoption of anaerobic digestion (AD) technology on applicable large-scale dairy farms in the contiguous United States.
GHG reduction estimates were developed through a robust life cycle modeling framework paired with sensitivity and uncertainty analyses. Twenty dairy configurations were modeled to capture important differences in housing and manure management practices, applicable AD technologies, regional climates, storage cleanout schedules, and methods of land application.
Monte Carlo results for the 90% confidence interval illustrate the potential for AD adoption to reduce GHG emissions from the large-scale dairy industry by 2.45-3.52 MMT of CO₂-eq per year considering biogas use only in renewable natural gas programs and as much as 4.53-6.46 MMT of CO₂-eq per year with combined heat and power as an additional biogas use case.
At the farm level, AD technology may reduce GHG emissions from manure management systems by 58.1-79.8% depending on the region. Discussion focuses on regional differences in GHG emissions from manure management strategies and the challenges and opportunities surrounding AD adoption.

An integral assessment of the impact of diet and manure management on whole-farm greenhouse gas and nitrogen emissions in dairy cattle production systems using process-based models. Ouatahar L, Bannink A, Amon B, et al. Waste Manag. 2024 Jul 11;187:79-90.

Feed management decisions are crucial in mitigating greenhouse gas (GHG) and nitrogen (N) emissions from ruminant farming systems. However, assessing the downstream impact of diet on emissions in dairy production systems is complex, due to the multifunctional relationships between a variety of distinct but interconnected sources such as animals, housing, manure storage, and soil.
Therefore, there is a need for an integral assessment of the direct and indirect GHG and N emissions that considers the underlying processes of carbon (C), N and their drivers within the system.
Here, researchers show the relevance of using a cascade of process-based (PB) models, such as Dutch Tier 3 and (Manure)-DNDC (Denitrification-Decomposition) models, for capturing the downstream influence of diet on whole-farm emissions in two contrasting case study dairy farms: a confinement system in Germany and a pasture-based system in New Zealand.
Considerable variation was found in emissions on a per hectare and per head basis, and across different farm components and categories of animals. Moreover, the confinement system had a farm C emission of 1.01 kg CO₂-eq kg^-1fat and protein corrected milk (FPCM), and a farm N emission of 0.0300 kg N kg^-1
In contrast, the pasture-based system had a lower farm C and N emission averaging 0.82 kg CO₂-eq kg^-1FPCM and 0.006 kg N kg^-1 FPCM, respectively over the 4-year period.
The results demonstrate how inputs and outputs could be made compatible and exchangeable across the PB models for quantifying dietary effects on whole-farm GHG and N emissions.

Mitigation of ammonia and methane emissions with manure amendments during storage of cattle slurry. Owusu-Twum MY, Kelleghan D, Krol DJ, et al. Waste Manag Res. 2024 Jul 28:734242X241265007.

Storing livestock manure is the primary stage of manure management where microbial processes and chemical reactions result in the release of methane (CH₄), ammonia (NH₃), and other gases.
This study aimed at assessing the efficacy of manure amendments in abating NH₃ and CH₄ emissions during storage.
Two experiments were carried out.
- Experiment 1 was conducted using 20 L of slurry for 98 days. Treatments were: aluminium sulphate (alum), lactogypsum, zeolite, actiglene, ammonium thiosulphate, biochar, dairy processing waste, Digest-IT and control (without amendment).
- Experiment 2 was conducted using 660 L of slurry in underground storage tanks for 77 days. Treatments were: sulphuric acid, gypsum, biochar and control (without amendment).
NH₃measurements for experiment 1 and experiment 2 were conducted using the photoacoustic gas monitor and dynamic chamber techniques, respectively. CH₄ was measured using the static chamber technique in both experiments. The effect of amendments on slurry composition was determined at the end of the experiments.
Experiment 1 showed a significant reduction in NH₃emissions in the alum (82%), lactogypsum (46%) and zeolite (32%) treatments relative to the control (100.3% total ammoniacal nitrogen (TAN)). CH₄ was reduced significantly in the alum (87%), ammonium thiosulphate (64%) and lactogypsum (67%) relative to the control (291.9 g m^-2).
Experiment 2 showed a significant reduction (32%) in NH₃emissions in the sulphuric acid relative to the control (4.4% TAN). CH₄ was reduced significantly in the sulphuric acid (46%), gypsum (39%) and biochar (15%) treatments relative to the control (291.9 g m^-2).
In general, amendments altered slurry composition such as dry matter, volatile solids, carbon and nitrogen contents at the end of storage. Lactogypsum, alum and sulphuric acid were effective in abating both NH₃and CH₄ emissions and can contribute to improving air quality.

Optimizing application of dairy effluent with synthetic N fertilizer reduced nitrogen leaching in clay loam soil. Nartey OD, Liu D, Ding W, et al. Heliyon. 2024 Jul 1;10(13):e33900.

High application rates of dairy effluent and manure are often associated with nitrogen (N) leaching, which can affect groundwater quality.
Here, researchers used a lysimeter to examine N leaching losses and biomass yield following application of dairy effluent and manure under wheat-maize cropping.
The field experiment included seven treatments:
1. no N fertilizer (Control);
2. 200/300 kg N ha^-1synthetic N fertilizer only (wheat/maize) (CN);
3. 100/150 kg N ha^-1synthetic N fertilizer plus 100/150 kg N ha^-1 dairy effluent (DE1);
4. 100/150 kg N ha^-1synthetic N fertilizer plus 150/200 kg N ha^-1 dairy effluent (DE2);
5. 100/150 kg N ha^-1 synthetic N fertilizer plus 250/350 kg N ha^-1 dairy effluent (DE3);
6. 100/150 kg N ha^-1synthetic fertilizer plus 100/150 kg N ha^-1 dairy manure (SM1);
7. and 150/225 kg N ha^-1synthetic fertilizer plus 50/75 kg N ha^-1 dairy manure (SM2).
Compared with CN, DE1 treatment increased maize yield by 10.0 %, wheat N use efficiency (NUE) by 26.5 %, and wheat and maize N uptake by 7.7-16.3 %, while reduced N leaching by 22.4 % in wheat season and by 40.4 % in the maize season.
In contrast, DE2 and DE3 treatment increased N leaching by 27.2-241 % and reduced NUE by 26.2-55.2 %.
SM2 treatment increased yield and NUE by 8.8 % and 7.8 %, respectively, and reduced N leaching by 42.9 % during the wheat but not the maize season.
Annual N leaching losses were 37.6 kg N ha^-1under CN treatment, but decreased to 27.4 kg N ha^-1 under DE1. In contrast, N leaching increased to 52.8 and 84.1 kg N ha^-1 under DE2 and DE3 treatment, respectively (P < 0.05).
Meanwhile, under SM1 and SM2 treatment, N leaching decreased by 71.2 % and 32.0 %, respectively, compared with CN.
These results suggest that replacing 50 % and 25 % synthetic N fertilizer with dairy farm effluent and manure could reduce N leaching losses but had varied effects on crop productivity under wheat-maize cropping.

Modelling solar photovoltaic systems on dairy farms for cost savings and GHG emission reduction. Dean J, Vogel E, Murphy F. Sci Total Environ. 2024 Jul 20;948:174874.

Rising on-farm electricity demand, coupled with surges in electricity prices, has increased costs associated with milk production. Additionally, the use of grid electricity with a high carbon footprint depreciates the environmental performance of dairy farming.
Researchers assessed the potential of photovoltaic (PV) systems installed on dairy parlors under different policy incentives to reduce electricity costs and the carbon footprint of dairy farms in Ireland.
The HOMER Pro software was employed to model electricity consumption, generation and economic performance of four 15-year PV project scenarios for 11 Irish farms. Scenarios considering the targeted agricultural modernization scheme II (TAMS) and the microgeneration support scheme are assessed.
The results show that PV systems are a feasible option to power dairy farms when current energy prices and inflation rates are applied. Small systems eligible for TAMS grants presented an average discounted payback period of 5 years, making them a better option for farmers than larger projects, which had an average payback period of 8.5 years.
The deployment of PV systems reduced the GHG intensity of electricity consumed at the farms by up to 29 %.

Potential of 2 Northern European brown seaweeds (Fucus serratus and Fucus vesiculosus) as enteric methane inhibitors in dairy cows. Thorsteinsson M, Chassé É, Nielsen MO, et al. J Dairy Sci. 2024 Jul 25:S0022-0302(24)01039-7.

The 2 brown seaweeds, Fucus serratus and Fucus vesiculosus, have demonstrated anti-methanogenic properties in vitro with reductions in CH₄production ranging from 53 to 63%.
This study aimed to investigate the effects of the 2 Fucus seaweeds on enteric CH₄emissions, DMI, ECM, and nutrient digestibility when fed to dairy cows.
The experiment was conducted using 4 multi-cannulated lactating Danish Holstein dairy cows, which over 3 experimental periods received either:
- 1) basal diet (CON; diet without any seaweed)
- 2) basal diet diluted with 4% (DM basis) Fucus serratus (SER)
- 3) basal diet diluted with 4% (DM basis) Fucus vesiculosus (VES)
Each period lasted 21 days and consisted of 14 days of adaptation, followed by 3 days of digesta sampling, and 4 days of gas exchange measurements using respiration chambers.
Milk yield and feed intake were recorded daily. Blood samples were collected on day 15 and 17.
Opposite to what was expected, neither of the 2 Fucus seaweeds reduced CH₄emissions from the dairy cows as daily CH₄ production was significantly higher for both Fucus treatments compared with CON. Additionally, CH₄ yield (g CH₄/kg DMI) and intensity (g CH₄/kg ECM) were significantly higher for SER compared with CON.
Milk yield, DMI, and total-tract digestibility were unaffected by the treatments; however, SER resulted in lower milk protein yield (kg/d) and lower milk and blood plasma urea concentrations compared with CON.
In conclusion, neither Fucus serratus (SER) nor Fucus vesiculosus (VES) showed potential as methane-mitigating feed additives when fed to dairy cows at an inclusion level of 4% of DM. The inclusion of the 2 brown seaweeds had no effects on DMI, milk yield, or total-tract digestibility.

Animal Health and Food Safety

Spillover of highly pathogenic avian influenza H5N1 virus to dairy cattle. Caserta LC, Frye EA, Diel DG, et al. Nature. 2024 Jul 25.

Highly pathogenic avian influenza (HPAI) H5N1 clade 2.3.4.4b virus has caused the death of millions of domestic birds and thousands of wild birds in the U.S. since January, 2022. Throughout this outbreak, spillovers to mammals have been frequently documented.
Researchers now report spillover of HPAI H5N1 virus in dairy cattle herds across several states in the U.S. The affected cows displayed clinical signs encompassing decreased feed intake, altered fecal consistency, respiratory distress, and decreased milk production with abnormal milk.
Infectious virus and viral RNA were consistently detected in milk from affected cows. Viral distribution in tissues via immunohistochemistry and in situ hybridization revealed a distinct tropism of the virus for the epithelial cells lining the alveoli of the mammary gland in cows.
Whole viral genome sequences recovered from dairy cows, birds, domestic cats, and a raccoon from affected farms indicated multidirectional interspecies transmissions.
Epidemiologic and genomic data revealed efficient cow-to-cow transmission after apparently healthy cows from an affected farm were transported to a premise in a different state.
These results demonstrate the transmission of HPAI H5N1 clade 2.3.4.4b virus at a non-traditional interface underscoring the ability of the virus to cross species barriers.

The Bifidobacterium-dominated fecal microbiome in dairy calves shapes the characteristic growth phenotype of host. Zhuang Y, Liu S, Cao Z, et al. NPJ Biofilms Microbiomes. 2024 Jul 21;10(1):59.

The dominant bacteria in the hindgut of calves play an important role in their growth and health, which could even lead to lifelong consequences. However, the identification of core probiotics in the hindgut and its mechanism regulating host growth remain unclear.
Here, a total of 1045 fecal samples were analyzed by 16S rRNA gene sequencing from the 408 Holstein dairy calves at the age of 0, 14, 28, 42, 56, and 70 days to characterize the dynamic changes of core taxa.
Moreover, the mechanisms of nutrient metabolism of calf growth regulated by core bacteria were investigated using multi-omics analyses. Finally, fecal microbiota transplantation (FMT) in mice were conducted to illustrate the potential beneficial effects of core bacteria.
Four calf enterotypes were identified and enterotypes dominated by Bifidobacterium and Oscillospiraceae_UCG-005 were representative. The frequency of enterotype conversion shifted from variable to stable.
The close relationship observed between phenotype and enterotype, revealing a potential pro-growth effect of Bifidobacterium, might be implemented by promoting the use of carbohydrate, activating the synthesis of volatile fatty acids, amino acids and vitamin B6, and inhibiting methane production in the hindgut.
The FMT results indicated the beneficial effect of Bifidobacterium on host growth and hindgut development. These results support the notion that the Bifidobacterium-dominated fecal microbiome would be an important driving force for promoting the host growth in the early life.
These findings provide new insights into the potential probiotic mining and application strategies to promote the growth of young animals or improve their growth retardation.

Are you ready for a challenge? Personality traits influence dairy calves’ responses to disease, pain, and nutritional challenges. Setser MMW, Neave HW, Costa JHC. J Dairy Sci. 2024 Jul 19:S0022-0302(24)01013-0.

Dairy calves routinely experience disease, pain, and nutritional stressors such as diarrhea, dehorning, and weaning early in life. These stressors lead to changes in behavioral expression that varies in magnitude between individuals, where a greater magnitude change would suggest lower resilience in individuals to a stressor.
Thus, this study first aimed to quantify the individual variation in magnitude change in feeding behaviors and activity in response to a bout of diarrhea, dehorning, and weaning. The next objective was to then investigate if personality traits were related to this magnitude of behavioral response in dairy calves, and thus their resilience toward these stressors.
Calves were followed with 2 precision livestock technologies (e.g.: an automatic feeding system (AFS), and leg accelerometer) to track behavioral changes in response during the time when the stressors were present.
At 23 ± 3 days of age, Holstein dairy calves (n = 49) were subjected to a series of standardized personality tests that exposed calf to novelty and fear stimuli. Personality tests were utilized to represent personality traits: Factor 1 (‘Fearful’), Factor 2 (‘Active’) and Factor 3 (‘Explorative’).
Researchers found that calves varied in their behavioral responses to diarrhea, dehorning, and weaning stressors, despite being reared in the same environment and experiencing consistent management procedures.
Additionally, personality traits measured from standardized tests were associated to both the direction and magnitude of change in behaviors around each stressor. For instance, with diarrhea, calves that were highly ‘Fearful’ had a greater magnitude change in milk intake and drinking speed following diagnosis than the least ‘Fearful’ calves.
With dehorning, calves that were highly ‘Explorative’ had a greater magnitude change in lying time when dehorned, but a smaller magnitude change in lying bouts and drinking speed following dehorning, than the least ‘explorative’ calves.
With weaning, calves that were highly ‘Active’ had a smaller magnitude change in unrewarded visits leading up to and following weaning than calves that were the least ‘Active’.
Each of the personality traits had a significant association with change in behavior surrounding each of the stressors evaluated, although these associations depended on the type of stressor. These results have implications for how individual calves experience each stressor and therefore individual animal welfare.

Association of Dry Period Length with Automatic Milking System, Mastitis, and Reproductive Indicators in Cows. Jukna V, Meškinytė E, Antanaitis R, Juozaitienė V. Animals (Basel). 2024 Jul 14;14(14):2065.

The scientific literature highlights the importance of optimal dry period management for improving milk production, cow health, and reproductive performance. Integrating automatic milking system (AMS) data into this analysis could provide deeper insights into the multifaceted impacts of dry period management.
The objective of this study was to evaluate the association between dry period (DP) length and various indicators of productivity, reproduction, and udder health in cows managed with an automatic milking system.
Researchers analyzed records from 3,861 cows, categorizing them into three groups based on their DP duration: (1) <40 days, (2) 40-70 days, and (3) DP > 70 days.
Cows with a DP of 40-70 days had an average energy-corrected milk production that was 8.2 kg greater than that of cows with a short DP and 5.0 kg greater than that of cows with a long DP. Milk from the 40-70-day DP group exhibited the highest lactose concentration.
Additionally, cows with the longest DP had the smallest proportion of animals with a milk fat-to-protein ratio of 1.2 to 1.4. Cows with a DP of 40-70 days also showed the lowest milk electrical conductivity across all udder quarters, whereas cows with the shortest DP had the highest conductivity.
The highest conception rates were observed in the group with the shortest DP. These results suggest that a DP of 40-70 days is optimal for maximizing milk production and improving both udder health and reproductive performance under AMS.
Proper management of DP duration can be an effective strategy for sustainable dairy herd management.

Assessment of microbial communities in a dairy farm from a food safety perspective. Perdomo A, Calle A. Int J Food Microbiol. 2024 Jul 15;423:110827.

Microbial communities associated with dairy farm operations have a significant influence on food safety, dairy product quality, and animal health.
This study aimed to create a microbial mapping at a dairy farm to learn about their bacterial diversity, distribution, and potential dissemination pathways.
The investigation included the detection of key zoonotic pathogens, enumeration of Staphylococcus aureus and Escherichia coli as indicators of typical bacterial loads in a dairy production environment, and a microbiome analysis using metagenomics.
A total of 160 samples (environmental, udder swabs, feed, feces, raw milk, and water) were collected during winter (N = 80) and spring (N = 80).
In winter, Cronobacter spp. were detected in four feed and two water samples; L. monocytogenes was identified in two samples, one from feces and one from a cattle mat; E. coli O157:H7 was found in two feed samples. On the other hand, during spring, Cronobacter spp. were present in four feed samples and one hallway drain, with only one feed sample testing positive for E. coli O157:H7, while L. monocytogenes was absent during the spring season.
Regarding microbial counts, there was no significant difference between the two seasons for S. aureus; however, a significant difference was observed for E. coli.
Environmental microbiome analysis showed the presence of Proteobacteria (46.0 %) and Firmicutes (27.2 %) as the dominant phyla during both seasons. Moraxellaceae (11.8 %) and Pseudomonadaceae (10.62 %) were notable during winter, while Lactobacillaceae (13.0 %) and Enterobacteriaceae (12.6 %) were prominent during spring.
These findings offer valuable insights into microbial distribution within a dairy farm and potential risks to animal and human health through environmental cross-contamination.

Human Health and Nutrition

Effectiveness of dairy products to protect against cognitive decline in later life: a narrative review. Anderson RC, Alpass FM. Front Nutr. 2024;11:1366949.

As the world’s population ages the prevalence of age-related health concerns is increasing, including neurodegeneration disorders such as mild cognitive impairment, vascular dementia and Alzheimer’s disease.
Diet is a key modifiable risk factor for the development of neurodegeneration, likely due to gut-brain axis interactions related to neuroinflammation. Analyses of dietary patterns identified dairy as being part of a cognitively healthy diet; however, its contribution to cognitive outcomes is difficult to discern.
This narrative review evaluates the literature to determine whether there is sufficient evidence that the consumption of dairy products helps to maintain cognitive function in later life.
A search using the terms (dairy OR milk OR cheese OR yogurt OR yogurt) AND (“mild cognitive impairment” OR dementia OR “Alzheimer’s disease”) identified 796 articles. After screening and sorting, 23 observational studies and 6 intervention studies were identified.
The results of the observational studies implied that the relationship between total dairy consumption and cognitive outcomes is inverse U-shaped, with moderate consumption (1-2 servings per day) being the most beneficial.
The analysis of the intake of different types of dairy products indicated that fermented products, particularly cheese, were most likely responsible for the observed benefits. The experimental studies all used dairy-derived peptides produced during fermentation as the dietary intervention, and the results indicated that these could be an effective treatment for early-stage cognitive impairment.
Further experimental studies with whole dairy products, particularly fermented dairy, are needed to determine whether the regular consumption of these foods should be recommended to maximize the likelihood of healthy cognitive aging.

Consumption of dairy foods to achieve recommended levels for older adults has no deleterious effects on serum lipids. Iuliano S, Hare DL, Vogrin S, Poon S, Robbins J, French C, Seeman E. Nutr Metab Cardiovasc Dis. 2024 Jun 13:S0939-4753(24)00231-X.

Correction of calcium and protein undernutrition using milk, yogurt, and cheese in older adults in aged care homes is associated with reduced fractures and falls. However, these foods contain potentially atherogenic fats.
Therefore, researchers aimed to determine whether this intervention that increased dairy consumption to recommended levels adversely affects serum lipid profiles.
This was a sub-group analysis of a 2-year cluster-randomized trial involving 60 aged care homes in Australia. Thirty intervention homes provided additional milk, yogurt, and cheese on menus while 30 control homes continued with their usual menus.
A sample of 159 intervention and 86 controls residents (69% female, median age 87.8 years) had dietary intakes recorded using plate waste analysis and fasting serum lipids measured at baseline and 12 months. Diagnosis of cardiovascular disease and use of relevant medications were determined from medical records. Outcome measures were serum total, HDL and LDL cholesterol and ApoA-1 & B.
Intervention increased daily dairy servings from 1.9 ± 1.0 to 3.5 ± 1.4 while controls continued daily intakes of ≤2 servings daily. No group differences were observed for serum total cholesterol/high-density lipoprotein-C (TC/HDL-C) ratio, Apoprotein B/Apoprotein A-1 (ApoB/ApoA-1) ratio, low-density lipoprotein-C (LDL-C), non-HDL-C, or triglycerides (TGs) at 12 months.
In conclusion, among older adults in aged care homes, correcting insufficiency in intakes of calcium and protein using milk, yogurt and cheese does not alter serum lipid levels, suggesting that this is a suitable intervention for reducing the risk of falls and fractures.

Healthy Effects of Milk and Dairy Product Consumption in the Mediterranean Area and Japan. Jirillo F. Endocr Metab Immune Disord Drug Targets. 2024 Jul 11.

Milk is a food enriched in essential components for human health. Especially, in the Mediterranean area, besides cow’s milk, milk from goats, sheep, and donkeys, is largely used.
The consumption of animal milk is an important component of the Mediterranean (MED) diet, even if in moderate amounts. Milk is a complete food since it contains proteins, carbohydrates, and fats, as well as micronutrients (minerals and vitamins).
Milk-fermented products are largely consumed in the MED diet, such as cheese and yogurt, which are rich in essential metabolites, bioactive compounds, vitamins, minerals, and exopolysaccharides.
A large body of evidence suggests that consumption of milk and dairy products does not increase the risk of all-cause mortality, type 2 diabetes, and cardiovascular disease, even if some earlier studies have reported harmful effects associated with their higher consumption.
Also, in Japan, despite the lower consumption of milk than in Western countries, intake of bovine milk is associated with healthy effects.
The present review describes the effects of the various constituents of animal milk on human health, with special reference to the Mediterranean area and Japan.
Experimental data and clinical trials support the ability of milk and dairy products to lower the risk of chronic diseases.

Impact of dairy supplementation on bone acquisition in children’s limbs: a 12-month cluster-randomized controlled trial and meta-analysis. Zhao ZF, Li BY, Tang XY, et al. Arch Osteoporos. 2024 Jul 24;19(1):65.

The impact of milk on bone health in rural preschoolers is under-researched.
This study, through a clinical trial and a meta-analysis, finds that milk supplementation enhances forearm and calcaneus bone acquisition in children, supporting the benefits of daily milk consumption.
This study evaluated the impact of dairy supplementation on bone acquisition in children’s limbs through a cluster-randomized controlled trial and a meta-analysis.
The trial involved 315 children (4-6 year) from Northwest China, randomized to receive either 390 ml of milk daily (n = 215) or 20-30 g of bread (n = 100) over 12 months. Researchers primarily assessed bone mineral density (BMD) and content (BMC) changes at the limbs, alongside bone-related biomarkers, measured at baseline, the 6th and 12th months.
The meta-analysis aggregated BMD or BMC changes in the forearm/legs/calcaneus from published randomized trials involving children aged 3-18 years supplemented with dairy foods (vs. control group).
Of 278 completed the trial, intention-to-treat analysis revealed significant increases in BMD (4.05% and 7.31%) and BMC (4.69% and 7.34%) in the left forearm at the 6th and 12th months in the milk group compared to controls.
The calcaneus showed notable improvements in BMD (2.01%) and BMC (1.87%) at 6 months but not at 12 months. Additionally, milk supplementation was associated with beneficial changes in bone resorption markers, parathyroid hormone (- 12.70%), insulin-like growth factor 1 (6.69%), and the calcium-to-phosphorus ratio (2.22%).
The meta-analysis, encompassing 894 children, indicated that dairy supplementation significantly increased BMD and BMC in the arms, but not in the legs.
In conclusion, milk supplementation significantly improves bone health in children’s forearms, underscoring its potential as a strategic dietary intervention for bone development.

The effects of whey, pea, and collagen protein supplementation beyond the recommended dietary allowance on integrated myofibrillar protein synthetic rates in older males: a randomized controlled trial. McKendry J, Lowisz CV, Phillips SM, et al. Am J Clin Nutr. 2024 Jul;120(1):34-46.

Skeletal muscle mass is determined predominantly by feeding-induced and activity-induced fluctuations in muscle protein synthesis (MPS). Older individuals display a diminished MPS response to protein ingestion, referred to as age-related anabolic resistance, which contributes to the progression of age-related muscle loss known as sarcopenia.
Researchers aimed to determine the impact of consuming higher-quality compared with lower-quality protein supplements above the recommended dietary allowance (RDA) on integrated MPS rates. They hypothesized that increasing total protein intake above the RDA, regardless of the source, would support higher integrated rates of myofibrillar protein synthesis.
Thirty-one healthy older males (72 ± 4 y) consumed a controlled diet with protein intake set at the RDA: control phase (days 1-7). In a double-blind, randomized controlled fashion, participants were assigned to consume an additional 50 g (2 × 25g) of whey (n = 10), pea (n = 11), or collagen (n = 10) protein each day (25 g at breakfast and lunch) during the supplemental phase (days 8-15).
Deuterated water ingestion and muscle biopsies assessed integrated MPS and acute anabolic signaling. Postprandial blood samples were collected to determine feeding-induced aminoacidemia.
Integrated MPS was increased during supplemental with whey (1.59 ± 0.11 %/d) and pea (1.59 ± 0.14 %/d) when compared with RDA (1.46 ± 0.09 %/d for the whey group; 1.46 ± 0.10 %/d for the pea group); however, it remained unchanged with collagen.
Supplemental protein was sufficient to overcome anabolic signaling deficits (mTORC1 and rpS6), corroborating the greater postprandial aminoacidemia.
These findings demonstrate that supplemental protein provided at breakfast and lunch over the current RDA enhanced anabolic signaling and integrated MPS in older males; however, the source of additional protein may be an important consideration in overcoming age-related anabolic resistance.

Investigating the Dietary Impact on Trans-Vaccenic Acid (Trans-C18:1 n-7) and Other Beneficial Fatty Acids in Breast Milk and Infant Formulas. Sanjulian L, Lamas A, Regal P, et al. Foods. 2024 Jul 9;13(14):2164.

Maternal diet plays a significant role in the fatty acid composition of breast milk. Dietary products such as milk and meat are the primary sources of natural TFAs for humans. These peculiar fatty acids hold nutritional significance as they not only lack the detrimental effects of industrially produced transfats on the endothelium characteristic, but they also exhibit anti-inflammatory properties.
The relationship between the presence of eight fatty acids in breast milk (including natural TFAs trans-vaccenic and conjugated linoleic acid) and the maternal diet has been explored, and their abundance has been compared to that of infant formulas.
Two cohorts of lactating women, originating from a Spanish region, participated in this study; they adhered to the Southern European Atlantic diet or the Atlantic diet.
While the consumption of conventional meat or dairy products does not seem to increase the abundance of TFAsin breast milk, trans-vaccenic and oleic acid are among the most distinctive features of breast milk fat in mothers consuming naturally improved dairy products with an improved fatty acid profile.
The most significant differences between natural breastfeeding and formula feeding lie in natural TFAs, since formulas are notably deficient in natural TFAs while being overfortified in alpha-linolenic acid in comparison to breast milk.
Therefore, the researchers suggest an improvement in the formulation of these products through using cow’s milk with an optimal fatty acid profile that better mimics the fatty acid composition found in human milk.

Innovation, Economics, and Dairy Alternatives

Wisconsin Farmers Share Their Stressors and Mental Healthcare Needs Through Focus Groups. Schlesser H, Krull J, Wantoch K, Voss A, Morrill S, KirkPatrick J.J Agromedicine. 2024 Jul 24:1-10.

Dairy farmers can experience high levels of stress due to the physical labor, long hours, and external conditions of their work. Additionally, financial uncertainty, physical isolation and increasingly unpredictable crop yields are just some of the stressors that are fueling a mental health crisis among farmers.
In this study, the project team was interested in learning from Wisconsin farmers and farm families about: (1) the unique stressors farmers face, (2) the barriers that exist for farmers to seek help for mental and physical health, and (3) coping strategies that could be implemented to help farm families cope with stress.
The project team collected qualitative data utilizing standardized questions during three focus groups held via Zoom. The 10 participants were from various Wisconsin farm enterprises including dairy, beef, and produce farms. Data were coded into five codes: stressors, farmers as a unique subculture, barriers to seeking help, coping strategies, and strategies for addressing barriers to seeking help.
Participants emphasized the need for healthcare professionals to better understand farming is more than a job; it is their life. The top stressor was time pressure and the top barrier to seeking care was workload, which make it challenging to get off the farm.
Stigma and self-reliance are additional barriers in the farming community. Participants offered strategies to address these barriers, including learning how to effectively communicate with farmers and raising awareness of mental health issues in rural communities.
The insights from this study can inform rural healthcare professionals on strategies to better support the mental and physical well-being of farmers and their families in Wisconsin and rural communities in the United States.

A cross-sectional comparison of gut metagenomes between dairy workers and community controls. Trinh P, Teichman S, Roberts MC, Rabinowitz PM, Willis AD. BMC Genomics. 2024 Jul 20;25(1):708.

As a nexus of routine antibiotic use and zoonotic pathogen presence, the livestock farming environment is a potential hotspot for the emergence of zoonotic diseases and antibiotic resistant bacteria. Livestock can further facilitate disease transmission by serving as intermediary hosts for pathogens before a spillover event.
In light of this, researchers aimed to characterize the microbiomes and resistomes of dairy workers, whose exposure to the livestock farming environment places them at risk for facilitating community transmission of antibiotic resistant genes and emerging zoonotic diseases.
Using shotgun sequencing, the researchers investigated differences in the taxonomy, diversity and gene presence of 10 dairy farm workers and 6 community controls’ gut metagenomes, contextualizing these samples with additional publicly available gut metagenomes.
They found no significant differences in the prevalence of resistance genes, virulence factors, or taxonomic composition between the two groups. They did, however, observe patterns warranting further investigation including greater abundance of tetracycline resistance genes and prevalence of cephamycin resistance genes as well as lower average gene diversity (even after accounting for differential sequencing depth) in dairy workers’ metagenomes.
The researchers also found evidence of commensal organism association with tetracycline resistance genes in both groups (including Faecalibacterium prausnitzii, Ligilactobacillus animalis, and Simiaoa sunii).
This study highlights the utility of shotgun metagenomics in examining the microbiomes and resistomes of livestock workers, focusing on a cohort of dairy workers in the United States.
While this study revealed no statistically significant differences between groups in taxonomy, diversity and gene presence, researchers observed patterns in antibiotic resistance gene abundance and prevalence that align with findings from previous studies of livestock workers in China and Europe.
The results lay the groundwork for future research involving larger cohorts of dairy and non-dairy workers to better understand the impact of occupational exposure to livestock farming on the microbiomes and resistomes of workers.

Reformulating ice cream to improve postprandial glucose response: an opportunity for industry to create shared value. Al-Ozairi E, Mandani Y, Alfaleh G, Raj J, Alshammari S, Le Roux CW. Front Nutr. 2024 Jul 16;11:1349392.

Ultra-processed foods are associated with metabolic dysfunction and driving chronic diseases. The Metabolic Matrix is a tool used to reformulate products to promote positive metabolic outcomes. The Kuwait Danish Dairy Company (KDD) has used this tool to develop a no-added-sugar products.
This clinical trial tested the glycemic response of a no-added-sugar ice cream in individuals with type 2 diabetes.
The hypothesis was that the no-added-sugar ice cream would have a substantially better postprandial glycemic response than conventional ice cream in patients with type 2 diabetes.
In this randomized cross over designed study, postprandial glycemic response was measured after 300 grams of no-added-sugar ice cream or normal ice cream was consumed. Despite similar composition and palatability, the postprandial responses were better with the no-added sugar ice cream, albeit that the natural sugar in the product still resulted in a marked postprandial glycemic response.
This finding emphasizes the necessity of clearly communicating to both patients and healthcare professionals that “no-added-sugar” does not equate to “zero total sugar.”
The path to improved metabolic health involves not only product improvement but also transparent messaging to enable informed dietary choices. Reformulation resulting in palatable no-added sugar products provides an opportunity for companies to Create Shared Value by addressing the important social problems such as obesity and type 2 diabetes, by creating scalable solutions, that are profitable.

Impact of high-pressure processing on the bioactive compounds of milk – A comprehensive review. Siddiqui SA, Khan S, Bahmid NA, Nagdalian AA, Jafari SM, Castro-Muñoz R. J Food Sci Technol. 2024 Sep;61(9):1632-1651.

High-pressure processing (HPP) is a promising alternative to thermal pasteurization. Recent studies highlighted the effectivity of HPP (400-600 MPa and exposure times of 1-5 min) in reducing pathogenic microflora for up to 5 logs.
Analysis of modern scientific sources has shown that pressure affects the main components of milk including fat globules, lactose, casein micelles.
The behavior of whey proteins under HPP is very important for milk and dairy products. HPP can cause significant changes in the quaternary (> 150 MPa) and tertiary (> 200 MPa) protein structures. At pressures > 400 MPa, they dissolve in the following order: αs₂-casein, αs₁-casein, k-casein, and β-casein.
A similar trend is observed in the processing of whey proteins. HPP can affect the rate of milk fat adhering as cream with increased results at 100-250 MPa with time dependency while decreasing up to 70% at 400-600 MPa.
Some studies indicated the lactose influencing casein on HP, with 10% lactose addition in case in suspension before exposing it to 400 MPa for 40 min prevents the formation of large casein micelles.
A number of researchers have shown that moderate pressure (up to 400 MPa) and mild heating can activate or stabilize milk enzymes. Pressures of 350-400 MPa for 100 min can boost the activity of milk enzymes by up to 140%.
This comprehensive and critical review will benefit scientific researchers and industrial experts in the field of HPP treatment of milk and its effect on milk components.

Serial fermentation in milk generates functionally diverse community lineages with different degrees of structure stabilization. Gapp C, Dijamentiuk A, Borges F, et al. mSystems. 2024 Jul 23:e0044524.

Microbial communities offer considerable potential for tackling environmental challenges by improving the functioning of ecosystems. Top-down community engineering is a promising strategy that could be used to obtain communities of desired function. However, the ecological factors that control the balance between community shaping and propagation are not well understood.
Dairy backslopping, which consists of using part of the previous production to inoculate a new one, can be used as a model engineering approach to investigate community dynamics during serial propagations.
In this study, 26 raw milk samples were serially propagated 6 times each, giving rise to 26 community lineages. Bacterial community structures were analyzed by metabarcoding, and acidification was recorded by pH monitoring.
The results revealed that different types of community lineages could be obtained in terms of taxonomic composition and dynamics. Five lineages reached a repeatable community structure in a few propagation steps, with little variation between the final generations, giving rise to stable acidification kinetics.
Moreover, these stabilized communities presented a high variability of structure and diverse acidification properties between community lineages. Besides, the other lineages were characterized by different levels of dynamics leading to parallel or divergent trajectories.
The functional properties and dynamics of the communities were mainly related to the relative abundance and the taxonomic composition of lactic acid bacteria within the communities.
These findings highlight that short-term schemes of serial fermentation can produce communities with a wide range of dynamics and that the balance between community shaping and propagation is intimately linked to community structure.

Milking the Alternatives: Understanding Coffee Consumers’ Preferences for Non-Dairy Milk. Halabi N, Hristova V, Vlaev I. Behav Sci (Basel). 2024 Jul 5;14(7):569.

Consumer interest in plant-based milk alternatives is growing, despite extra charges in coffeehouses. While much research exists on non-dairy alternatives, plant-based milks in coffee drinks remain understudied.
This study examines consumer preferences and behaviors regarding milk alternatives in coffee, using the Theoretical Domains Framework (TDF) and the Behavior Change Wheel (BCW).
A survey of 200 participants from 19 countries explored demographics, coffee habits, attitudes towards non-dairy milk charges, and marketing awareness.
Market insights showed taste as the main reason for coffee choice, with a preference for cow’s milk and local cafes for quality. Many opposed the extra charges for non-dairy options, citing lactose intolerance or allergies, especially among Gen Z and Millennials.
Regional variations included stronger opposition in the UK and Germany compared to the UAE and USA. The marketing for non-dairy milk was less memorable than general coffee advertisements.
Regression analysis confirmed that viewing non-dairy milk as a dietary staple increased consumption, aligning with the TDF’s “Beliefs about Consequences” domain. Finally, within the BCW framework, the intervention strategies centered on training and coercion were discussed.
Implementing these approaches could encourage the wider adoption of non-dairy milk options in coffee shops, fostering inclusivity, health awareness, and supporting environmental sustainability efforts.