Dairy Research Bulletin Selected Articles from June 2024

Environmental Management and Sustainability

Assessment of Ammonia Emissions and Greenhouse Gases in Dairy Cattle Facilities: A Bibliometric Analysis. Ferraz PFP, Ferraz GAES, Ferreira JC, Aguiar JV, Santana LS, Norton T. Animals (Basel). 2024 Jun 7;14(12):1721.

  • A deeper understanding of gas emissions in milk production is crucial for promoting productive efficiency, sustainable resource use, and animal welfare.
  • This paper aims to analyze ammonia and greenhouse gas emissions in dairy farming using bibliometric methods.
  • A total of 187 English-language articles with experimental data from the Scopus and Web of Science databases (January 1987 to April 2024) were reviewed.
  • Research mainly focuses on ammonia and methane emissions, including quantification, volatilization, and mitigation strategies. Other gases like carbon dioxide, nitrous oxide, and hydrogen sulfide were also studied.
  • Bibliometric analysis revealed research evolution, identifying trends, gaps, and future research opportunities. Key institutions include the University of California-Davis and Aarhus University.
  • This bibliometric analysis offers insights into emissions, air quality, sustainability, and animal welfare in dairy farming, highlighting areas for innovative mitigation strategies to enhance production sustainability.
  • It is possible to conclude that this research is a valuable tool for understanding the evolution of research on gas emissions in dairy cattle facilities, providing guidance for future studies and interventions to promote more sustainable production.

Chemical characterization of volatile organic compounds emitted by animal manure. Haider KM, Focsa C, Ciuraru R, et al. J Environ Manage. 2024 Jun;364:121453.

  • Animal manure is considered a valuable organic fertilizer due to its important nutrient content enhancing soil fertility and plant growth in agriculture. Besides its beneficial role as fertilizer, animal manure represents a significant source of volatile organic compounds (VOCs), playing a significant role in atmospheric chemistry.
  • Understanding the composition of VOCs Understanding VOCs from animal manure is crucial for assessing their environmental impact, as they can cause air pollution, odors, and harm to human health and ecosystems.
  • In this context, researchers conducted an experimental study involving various animal manures (cow, horse, sheep, and goat) taken from a farm in Grignon (near Paris, France).
  • The researchers employed atmospheric simulation chambers within a controlled laboratory environment. The analysis of VOCs involved the combination of Proton Transfer Reaction-Quadrupole ion guide-Time-of-Flight Mass Spectrometry (PTR-QiTOF-MS) and Thermal Desorption-Gas Chromatography-Mass Spectrometry (TD-GC-MS). Using PTR-QiTOF-MS.
  • 368 compounds were detected and quantified within the manure samples. These findings revealed various chemical groups of VOCs, including oxygenated compounds (e.g., ethanol, cresol, acetaldehyde, etc.), nitrogenated compounds (ammonia, trimethylamine, etc.), sulfur compounds (methanethiol, dimethyl sulfide, etc.), aromatic compounds (phenols and indoles), terpenes (isoprene, D-limonene, etc.) and halogenated compounds.
  • Cow manure exhibited the highest VOC emission fluxes, followed by goat, sheep, and horse manures. Notably, oxygenated VOCs were dominant contributors to total VOC emission fluxes in all samples.
  • Statistical analysis highlighted the distinct nature of cow manure emissions, characterized by oxygenated compounds and nitrogenated compounds. In addition, goat manure was isolated from the other samples with high emissions of compounds having both oxygen and nitrogen atoms in their molecular formulas (e.g., CH3NO2).
  • The experimental dataset obtained in this study provides an inventory reference for both VOCs and their emission fluxes in animal manures. Furthermore, it highlights odorant compounds and VOCs that serve as atmospheric aerosol precursors. Future studies can explore the effectiveness of various manure treatment methods to promote sustainable agriculture practices.

Climate Change and Photochemical Ozone Creation Potential Impact Indicators of Cow Milk: A Comparison of Different Scenarios for a Diet Assessment. Froldi F, Lamastra L, Trevisan M, Moschini M. Animals (Basel). 2024 Jun 7;14(12):1725. 

  • An estimate of the environmental impact of dairy farms in Northern Italy producing milk for hard cheese (protected designation of origin) has been obtained through a comprehensive life cycle assessment.
  • The estimate focused on climate change and photochemical ozone creation potential indicators, which were evaluated according to the Intergovernmental Panel on Climate Change (IPCC) guidelines and interpreted with the aid of the feeds’ composition evaluated using near-infrared reflectance spectroscopy (Foss NIR-System 5000) as well as with a diet evaluation according to the NRC (National Research Council) or the CNCPS (Cornell Net Carbohydrate and Protein System) nutrient requirement modeling.
  • Herds were classified into high-, mid-, and low-performing based on the daily milk yield per cow.
  • A lower impact on indicators was observed as herd performance increased. The high-performing herds had a lower contribution from enteric fermentation (6.30 × 10-1kgCO2-eq), and the more milk that they produced allowed for a differentiation of climate change from land use and transformation (2.39 × 10-1 kgCO2-eq), compared to low-performing herds (3.66 × 10-1 kgCO2-eq).
  • Compared to the IPCC approach, the climate change and photochemical ozone creation potential indicator estimates were reduced when addressing the feed’s quality, particularly in mid- and high-performing herds.
  • The results could be helpful in the dairy sector as they provide an insight into how diet quality affects the environmental impact of milk.

Partial replacement of mineral fertilizers with animal manures in an apple orchard: Effects on GHG emission. Esteves C, Costa E, Fangueiro D, et al. J Environ Manage. 2024 Apr;356:120552.

  • Partial replacement of mineral fertilizers with animal manures is a good alternative to reduce MF use and increase both nutrient cycling in agriculture and soil organic matter. However, the adoption of this practice must not lead to increased environmental impacts.
  • In this two-year study conducted in an apple orchard, MF were partially replaced with various animal manures, including cattle slurry, acidified cattle slurry, solid cattle manure, or poultry manure, and their impacts on greenhouse gas emission (GHG: CO2, N2O and CH4) were examined.
  • A control receiving only mineral fertilizers served as the baseline, representing the conventional scenario in orchard fertilization.
  • Overall, replacing mineral fertilizers with manures increased GHG emissions, with the magnitude of the impacts depending on the specific characteristics of the manures and the amount of nutrients and organic matter applied. Comparing to the control, application of acidified cattle slurry and cattle slurry led to higher CH4and N2O emissions, while poultry manure application increased both N2O and CO2 In contrast, replacement with poultry manure and solid cattle manure decreased CH4 emissions.
  • Nevertheless, results varied between the two years, influenced by several factors, including soil conditions. While acidification showed potential to mitigate CH4emissions, it also led to increased N2O emissions compared to cattle slurry, particularly in 2022, suggesting the need for further investigation to avoid emission trade-offs.
  • Replacement with cattle slurry (20.49 t CO2-eqha-1) and solid cattle manure (20.30 t CO2-eq ha-1) showed comparable global warming potential (GWP) to the conventional scenario (control, 19.49 t CO2-eq ha-1), highlighting their potential as viable mineral fertilizer substitutes.

Bioconversion of cow manure through vermicomposting: effects of tylosin concentration on the weight of worms and manure quality. Ghandehari Yazdi F, Ebrahimi AA, et al. Sci Rep. 2024;14(1):12575.

  • In contrast to traditional composting, vermicomposting has a higher concentration of soluble nutrients and a higher organic matter content. This method involves a bio-oxidative mechanism in which earthworms, microorganisms, and other decomposer communities synergistically engage, expediting organic waste degradation.
  • In the vermicomposting paradigm, earthworms digest and metamorphose organic waste simultaneously, yielding compost suitable for crop cultivation. Notably, earthworm metabolic activities increase the nutrient content of the converted wastes. Finally, vermicomposting yields a surplus of available nutrients per unit weight compared with the initial organic substrate used by the earthworms.
  • In a meticulous examination of the confluence between tylosin, a notable veterinary antibiotic, and vermicomposting, researchers explore the intricate dynamics governing sustainable waste management methodologies. This study investigated batch-fed vermicomposting of cow manure, with a specific focus on assessing the effects of tylosin on the weight of earthworms and the overall quality of the resulting manure.
  • Five reactors, including three concentrations of tylosin (50, 100, and 150 mg/kg) and two control reactors, were employed. Residual tylosin concentrations were measured using high-performance liquid chromatography (HPLC). Quality parameters such as pH, temperature, volatile solids (VS), organic carbon content (OCC), electrical conductivity (EC), ash content, C/N ratio, total Kjeldahl nitrogen (TKN), and microbial content were evaluated. The toxicity and maturity of vermicompost were assessed by determining the germination index (GI). The study also monitored variations in the earthworm’s weight.
  • The results demonstrated a decreasing trend in VS, OCC, C/N, and fecal coliforms, along with increased pH, EC, ash content, and TKN during the vermicomposting process. Furthermore, investigations revealed significant reductions in the reactors with tylosin concentrations of 50, 100, and 150 mg/kg, resulting in the removal of 98%, 90.48%, and 89.38% of the initial tylosin, respectively.
  • This result confirms the faster removal of tylosin in reactors with lower concentrations. Degradation of tylosin also conforms to first-order kinetics. The findings showed a significant influence of tylosin on the weight of Eisenia fetida earthworms and the lowest antibiotic concentration led to the highest weight gain.
  • Finally, the high percentage of germination index (90-100%) showed that the quality and maturity of vermicompost is by national and international standards.

Characteristics of rumen microbiota and Prevotella isolates found in high propionate and low methane-producing dairy cows. Shinkai T, Takizawa S, Enishi O, Higuchi K, Ohmori H, Mitsumori M. Front Microbiol. 2024 Jun 3;15:1404991.

  • Ruminal methane production is the main sink for metabolic hydrogen generated during rumen fermentation, and is a major contributor to greenhouse gas (GHG) emission. Individual ruminants exhibit varying methane production efficiency; therefore, understanding the microbial characteristics of low-methane-emitting animals could offer opportunities for mitigating enteric methane.
  • Here, researchers investigated the association between rumen fermentation and rumen microbiota, focusing on methane production, and elucidated the physiological characteristics of bacteria found in low methane-producing cows.
  • Thirteen Holstein cows in the late lactation stage were fed a corn silage-based total mixed ration (TMR), and feed digestion, milk production, rumen fermentation products, methane production, and rumen microbial composition were examined.
  • Cows were classified into two ruminal fermentation groups using Principal component analysis: low and high methane-producing cows (36.9 vs. 43.2 L/DMI digested) with different ruminal short chain fatty acid ratio [(C2+C4)/C3] (3.54 vs. 5.03) and dry matter (DM) digestibility (67.7% vs. 65.3%).
  • However, there were no significant differences in dry matter intake (DMI) and milk production between both groups.
  • Additionally, there were differences in the abundance of OTUs assigned to uncultured PrevotellaSuccinivibrio, and other 12 bacterial phylotypes between both groups. Specifically, a previously uncultured novel Prevotellasp. with lactate-producing phenotype was detected, with higher abundance in low methane-producing cows.
  • These findings provide evidence that Prevotellamay be associated with low methane and high propionate production. However, further research is required to improve the understanding of microbial relationships and metabolic processes involved in the mitigation of enteric methane.

Invited review: Advances in nutrition and feed additives to mitigate enteric methane emissions. Hristov AN. J Dairy Sci. 2024;107(7):4129-4146.

  • Methane, both enteric and from manure management, is the most important greenhouse gas from ruminant livestock, and its mitigation can deliver substantial decreases in the carbon footprint of animal products and potentially contribute to climate change mitigation.
  • Although choices may be limited, certain feeding-related practices can substantially decrease livestock enteric CH4 These practices can be generally classified into 2 categories: diet manipulation and feed additives. Within the first category, selection of forages and increasing forage digestibility are likely to decrease enteric CH4emission, but the size of the effect, relative to current forage practices in the United States dairy industry, is likely to be minimal to moderate.
  • An opportunity also exists to decrease enteric CH4emissions by increasing dietary starch concentration, but interventions have to be weighed against potential decreases in milk fat yield and farm profitability. A similar conclusion can be made about dietary lipids and oilseeds, which are proven to decrease CH4 emission but can also have a negative effect on rumen fermentation, feed intake, and milk production and composition.
  • Sufficient and robust scientific evidence indicates that some feed additives, specifically the CH4inhibitor 3-nitrooxypropanol, can substantially reduce CH4 emissions from dairy and beef cattle. However, the long-term effects and external factors affecting the efficacy of the inhibitor need to be further studied. The practicality of mass-application of other mitigation practices with proven short-term efficacy (i.e., macroalgae) is currently unknown.
  • One area that needs more research is how nutritional mitigation practices (both diet manipulation and feed additives) interact with each other and whether there is synergism among feed additives with different mode of action.
  • Further, effects of diet on manure composition and greenhouse gas emissions during storage (e.g., emission trade-offs) have not been adequately studied. Overall, if currently available mitigation practices prove to deliver consistent results and novel, potent, and safe strategies are discovered and are practical, nutrition alone can deliver up to 60% reduction in enteric CH4emissions from dairy farms in the United States.

The impact of twice daily 3-nitroxypropanol supplementation on enteric methane emissions in grazing dairy cows. Costigan H, Shalloo L, Lahart B, et a. J Dairy Sci. 2024 Jun 6:S0022.

  • Although 3-NOP has been proven to reduce enteric methane (CH4) by ∼30% in indoor systems of dairying when the additive is mixed throughout a total mixed ration (TMR), there has been very limited research to date in grazing systems in which the most convenient method of additive supplementation is at milking twice daily.
  • To investigate the effect of twice daily 3-NOP supplementation on enteric CH4emissions, a 12-week study was undertaken in which treatment cows (n = 26) were supplemented with 3-NOP (80 mg per kg dry matter intake; DMI) twice daily at morning and evening milking, while control cows (n = 26) received no additive supplementation.
  • Enteric CH4, hydrogen (H2) and carbon dioxide (CO2) were measured using GreenFeed units, while milk production, body weight (BW), body condition score (BCS) and DMI were monitored to determine the effect of 3-NOP supplementation on productivity.
  • There was no significant effect of 3-NOP supplementation on any of the aforementioned parameters with the exception of CH4and H2 production, respectively. Cows supplemented with 3-NOP produced ∼36% more H2 across a 24-h period, with reductions in CH4 production of 28.5% recorded in the 3 h after additive consumption, however, levels of CH4 production returned to that of the control group thereafter.
  • When CH4production was considered across the entire 24-h period, the cows offered 3-NOP produced ∼5% less CH4 than the control. Future research should focus on methods to increase the efficacy of the additive throughout the day which would include the deployment of a slow-release form or an out of parlor feeding system that allows animals consume the product at additional time points.


Animal Health and Food Safety

Heat stress has divergent effects on the milk microbiota of Holstein and Brown Swiss cows. Ceciliani F, Maggiolino A, Biscarini F, et al. J Dairy Sci. 2024 Jun 20:S0022-0302(24)00957-3.

  • Heat stress (HS) is one of the pivotal causes of economic losses in dairy industries and affects welfare and performance, but its effect on milk microbiota remains elusive. It is also unclear if and how different breeds may cope with HS in sustaining productive performance.
  • The objectives of this study were to compare a) the performance of 2 dairy breeds, namely Holstein and Brown Swiss, subjected to HS and b) the different effects of HS on the milk microbiota of the 2 breeds in thermal comfort conditions and HS. The study was carried out on 36 dairy cows, 18 per breed.
  • The HS was induced by switching off the cooling system during a natural heat wave for 4 days. Besides the Temperature Humidity Index (THI), the animal stress was confirmed by measuring respiratory frequency and rectal temperature twice daily at 4 a.m. and 3 p.m.
  • The HS differently impacted the 2 breeds. Rectal temperatures were higher in Holstein cows, while no changes in rectal temperature were found in Brown Swiss. Milk yield recording and sampling were performed during the morning milking of day 1 (at 4.00 a.m.) and afternoon milking of day 4 (at 5.00 p.m.).
  • Productive parameters were also different: milk yield, fat-corrected milk, energy-corrected milk, protein and casein content, and renneting parameters were decreased in Holstein but remained unaffected in Brown Swiss.
  • The HS also modified the milk microbiota of the 2 breeds differently. During HS, the Brown Swiss milk microbiota was richer (α diversity) than the Holstein one. Comparing the time points before and during HS within breeds showed that Brown Swiss milk microbiota was less affected by HS than Holstein’s. Under the same thermal comfort condition, milk microbiota did not discriminate between Brown Swiss and Holstein.
  • Consistently with α and β diversity, the number of operational taxonomic units (OTUs) at the genus level that changed their abundance during HS was higher in Holstein (74 OTUs) than in Brown Swiss (only 20 OTUs). The most significant changes in abundance affected Acinetobacter, Chryseobacterium, Cutibacterium, Enterococcus, Lactococcus, Prevotella-9, Serratia, and Streptococcus.
  • In conclusion, the present report confirms and extends previous studies by demonstrating that Brown Swiss cows regulate their body temperature better than the Holstein breed. The relative thermal tolerance to HS compared with Holstein is also confirmed by changes in milk uncultured microbiota, which were more evident in Holstein than in Brown Swiss.

Calf Management: Individual or Paired Housing Affects Dairy Calf Health and Welfare. McFarland DS, McFarland LM, Shaw DJ, Macrae AI. Animals (Basel). 2024 May 23;14(11):1540.

  • Previous research has indicated that preweaned dairy calves reared in pairs compared with individually have improved performance and indicators of animal welfare.
  • One hundred and thirty Holstein female calves completed the trial, with eighty-five being allocated to paired housing and forty-five calves being allocated to individual housing.
  • Daily live weight gain (DLWG), treatments and mortality were recorded throughout the preweaning period. Salivary cortisol, latency to feed and latency to approach a novel object were assessed at batching.
  • There were no significant differences in DLWG, mortality and disease treatments between the average of the pair and the individually housed calves, although the pair-reared calves were quicker to approach the milk feed after batching and interacted more quickly with a novel object.
  • The heaviest born calves within the pair had the highest DLWG from birth to weaning, with a higher percentage of calves approaching the novel object, compared with the lightest born calf within the pair.
  • This study shows that calves within a pair may have significantly different performance and welfare during the preweaning period, with the heavier calf outperforming and displaying less fear and more exploratory behavior than the lighter calf within a pair.

Stable flies are bona fide carriers of mastitis-associated bacteria. Sommer AJ, Kettner JE, Coon KL. mSphere. 2024 Jun 26:e0033624.

  • Disease prevention on dairy farms has significant implications for cattle health, food security, and zoonosis. Of particular importance is the control of bovine mastitis, which can be caused by diverse bacteria, including KlebsiellaEscherichia coliStreptococcus, and Staphylococcus Despite being one of the most significant and costly cattle diseases worldwide, the epidemiology of bovine mastitis is not well understood.
  • Hematophagous Stomoxys(stable) fly populations in dairy barns are sustained by a constant availability of cattle hosts and manure, which serve as major reservoirs of both zoonotic and opportunistic bacterial pathogens. However, the composition of the Stomoxys fly microbiota, the mechanisms by which flies acquire their microbiome, and the ability of potentially pathogenic bacteria to colonize and persist in fly hosts remain to be investigated.
  • Here, researchers longitudinally collected fly and manure samples from two connected dairy facilities.
  • High throughput 16S rRNA gene amplicon sequencing was then used to characterize and compare bacterial communities present on or within flies and in manure collected from the same facility, while culture-dependent methods were used to verify the viability of clinically relevant bacteria.
  • Bacterial alpha diversity was overall higher in manure samples as compared to fly samples, with manure-associated bacterial communities being dominated by members of the Bacteroidales, Eubacteriales, and Oscillospirales. In contrast, flies harbored relatively low-complexity communities dominated by members of the Enterobacterales, Staphylococcales, and Lactobacillales.
  • Clinically relevant bacterial strains, including Escherichia and other taxa associated with mastitic cows housed in the same facilities, were detected in paired fly and manure samples but exhibited dramatically elevated abundances in fly samples as compared to manure samples. Viable colonies of EscherichiaKlebsiella, and Staphylococcusspp. were also readily isolated from fly samples, confirming that flies harbor culturable mastitis-associated bacteria.
  • This study identifies biting flies as bona fide carriers of opportunistically pathogenic bacterial taxa on dairy farms. The researchers further show that the fly microbiota is enriched in clinically relevant taxa-the vast majority of which can be traced to the manure habitats in which flies breed.
  • Altogether, these results identify biting flies as underrecognized carriers of bacterial taxa associated with environmental bovine mastitis and other opportunistic infections in vertebrates and offer important insights into mechanisms of microbial acquisition by these and other medically important insects.

Prevalence of Listeria monocytogenes in Milk and Dairy Product Supply Chains: A Global Systematic Review and Meta-analysis. Li X, Zheng J, Zhao W, Wu Y. Foodborne Pathog Dis. 2024 Jun 21.

  • Listeria monocytogenes, one of the main foodborne pathogens, is commonly found in milk and dairy products.
  • This study aimed to estimate the presence of  monocytogenesin milk and dairy product supply chains using a meta-analysis based on PubMed, Embase, Web of Science, and Scopus databases.
  • A total of 173 studies were included in this meta-analysis. The pooled prevalence in the supply chain environment was 8.69%, which was higher than that in dairy products (4.60%) and milk products (2.93%).
  • Subgroup analysis showed that  monocytogenesprevalence in raw milk (3.44%) was significantly higher than in pasteurized milk (0.60%). The highest prevalence of L. monocytogenes in milk and dairy products was observed in North America (5.27%) and South America (13.54%).
  • In addition, studies using culture and molecular methods (5.17%) had higher prevalence than other detection methods. Serogroup 1/2a and 3a (45.34%), serogroup 1/2b and 3b (14.23%), and serogroup 4b/4e (13.71%) were dominant in these studies.
  • The results of this study provide a better understanding of the prevalence of  monocytogenesin milk and dairy product supply chains and suggest a potential foodborne pathogen burden.

Identification and Characterization of Microorganisms Isolated from Non-compliant and/or Atypical Dairy Products in Canada. Sanschagrin L, Paniconi T, Jean J, et al. J Dairy Sci. 2024 Jun 20.

  • Despite good manufacturing practices and rigorous cleaning and sanitizing procedures established in dairy processing plants, microbiological contamination remains the main cause of products being non-compliant and/or atypical and hence not fit for human consumption.
  • The objective of this study was to isolate, identify and characterize bacteria, yeasts and molds associated with substandard dairy products in Canada and to create a collection of reference isolates.
  • In addition to conventional microbiological characterization, each isolate was tested for biofilm-forming ability and susceptibility to heat, antimicrobial agents, and common industrial disinfectants.
  • Among the 105 microbial strains isolated from pasteurized milk, cream, and cheese samples, 24 bacterial isolates, belonging mainly to the genus Pseudomonas, were shown to be moderate or strong biofilm producers in 96-well plates and highly resistant to peracetic acid (100 ppm, 5 min contact time) and sodium hypochlorite (70 ppm, 5 min contact time).
  • In addition, 56 bacterial isolates, including Acinetobacter baumannii, Enterobacter bugandensis, Klebsiella pneumoniae and Pseudomonas spp., were found resistant to ampicillin, fosfomycin and/or ceftriaxone, while 14 others, such as Bacillus spp. and Macrococcus spp., withstood a heat treatment equivalent to low-temperature long-time pasteurization (63°C for 30 min).
  • This descriptive study provides new information on potential problematic microorganisms in dairies and will guide the development of novel control strategies intended to prevent and reduce microbiological contamination and the associated economic losses.


Human Health and Nutrition

Milk protein concentrate supplementation improved appetite, metabolic parameters, adipocytokines, and body composition in dieting women with obesity: a randomized controlled trial. Elahikhah M, Haidari F, Khalesi S, et al. BMC Nutr. 2024 Jun 3;10(1):80.

  • Dairy consumption is associated with many health benefits. However, no clinical trials have examined the effects of milk protein concentrate (MPC) on metabolic health in overweight and obese adults.
  • This study investigated the effect of supplementation with MPC on glycemic status, lipid profile, biomarkers of inflammation, and anthropometric measurements in women with obesity under a weight loss diet.
  • This was a single-blind, open-labelled, parallel-group, randomized trial. Forty-four healthy women with obesity were randomized into a control (n = 22) or MPC (n = 22) group. Participants in the MPC group were supplemented with 30 g of MPC per day for 8 weeks.
  • Both groups were on a calorie-restricted diet plan with 800 Kcal lower intakes than their needs. Blood samples, dietary intake, and body composition were assessed before and after the intervention.
  • The MPC group had a significantly lower body mass index, waist circumference, fat mass, appetite score, fasting blood sugar, insulin, low-density lipoprotein cholesterol, and leptin levels and higher high-density lipoprotein cholesterol and adiponectin compared to the control group after supplementation.
  • Lean body mass, total cholesterol, and triglyceride did not differ significantly.
  • In conclusion, daily intake of 30g of MPC for 8 weeks may improve several anthropometric and metabolic markers in women with obesity under a hypocaloric diet.

Effects of high-quality protein supplementation on cardiovascular risk factors in individuals with metabolic diseases: A systematic review and meta-analysis of randomized controlled trials. Zhou S, Cheng F, He J, et al. Clin Nutr. 2024 Jun 15;43(8):1740-1750.

  • Uncertainties still exist about the effect of high-quality protein supplementation on cardiovascular disease (CVD) risk factors, although high-quality proteins such as soy and milk proteins have proposed to be beneficial for cardiometabolic health.
  • A systematic search in PubMed, Web of Science, Cochrane Library, Scopus, and Embase was conducted to quantify the impact of high-quality protein on CVD risk factors.
  • 63 RCTs on 4 types of high-quality protein including soy protein, milk protein, whey, and casein were evaluated.
    • Soy protein supplementation decreased systolic blood pressure (SBP, -1.42 mmHg), total cholesterol (TC, -0.18 mmol/L), and low-density lipoprotein cholesterol (LDL-C, -0.16 mmol/L).
    • Milk protein supplementation decreased SBP (-2.30 mmHg) and total cholesterol (-0.27 mmol/L).
    • Whey supplementation decreased SBP (-2.20 mmHg), diastolic blood pressure (DBP, -1.07 mmHg), triglycerides (-0.10 mmol/L), TC (-0.18 mmol/L), LDL-C (-0.09 mmol/L) and fasting blood insulin (FBI, -2.02 pmol/L).
    • Casein supplementation decreased SBP (-4.10 mmHg).
  • In the pooled analysis of four high-quality proteins, differential effects were seen in individuals with different health status.
    • In hypertensive individuals, high-quality proteins decreased both SBP (-2.69 mmHg) and DBP (-1.34 mmHg).
    • In overweight/obese individuals, high-quality proteins improved SBP (-1.40 mmHg), DBP (-2.59 mmHg), triglycerides (-0.09 mmol/L), TC (-0.14 mmol/L), LDL-C (-0.12 mmol/L), and HDL-C levels (0.02 mmol/L).
  • According to the benefits on CVD risks factors, whey ranked top for improving cardiometabolic health in hypertensive or overweight/obese individuals. This study supports a beneficial role of high-quality protein supplementation to reduce CVD risk factors.

Increased calcium intake from skimmed milk in energy-restricted diets reduces glycation markers in adults with type 2 diabetes and overweight: A secondary analysis of a randomized clinical trial. Oliveira JSE, Gomes JMG, Costa JA, Oliveira LL, Alfenas RCG. Nutr Res. 2024 May 2;127:40-52.

  • The effect of calcium (Ca) on glycation markers is unknown.
  • Researchers hypothesized that increased Ca intake from skimmed milk associated with an energy-restricted diet intake will reduce glycation markers and this reduction will be associated with a greater improvement in markers of metabolic control in adults with type 2 diabetes, and overweight.
  • In this secondary data analysis based on a crossover clinical trial, 14 adults were allocated into 2 groups: high calcium (shake containing 700 mg Ca/day) or low calcium (shake with 6.4 mg Ca/day), for 12 consecutive weeks per session.
  • Energy-restricted diets were also prescribed (-500 kcal/d, 800 mg of dietary Ca/d) to all participants. Advanced glycation end products (AGEs), soluble receptor for AGEs (sRAGE), glycemic control, and lipid profile were assessed at baseline and after 12 weeks.
  • High-calcium serum AGE concentrations and AGE/sRAGE ratio were lower at the end of the study. ΔAGE and ΔAGE/sRAGE ratio were both positively associated with Δtriglycerides, Δtotal cholesterol, Δtriglyceride-glucose index and variations, and Δvisceral adiposity index.
  • Consumption of approximately 1200 mg/day of calcium (3 servings of skim milk) reduced serum AGEs concentrations and the AGE/sRAGE ratio in individuals with diabetes. In general, positive changes in glycation markers are associated with lipid profile, insulin resistance, and adiposity markers worsening. ΔAGEs/ΔsRAGE ratio seems to be a better marker of metabolic status than ΔAGEs and ΔsRAGE alone.

Association between milk consumption in middle age and frailty in later life: The Aichi Workers’ cohort study. Hong YJ, Otsuka R, Yatsuya H, et al. Geriatr Gerontol Int. 2024 Jul;24(7):700-705.

  • Several studies have shown that dairy consumption in old age is effective in preventing frailty. However, there is a lack of evidence regarding the association between milk consumption during middle age and the development of frailty in old age.
  • Therefore, researchers carried out an investigation to explore the association between milk consumption during middle age and development of frailty examined after over 15 years of follow up in a long-term cohort study in Japan.
  • The researchers studied 265 participants aged 60-79 years (212 men and 53 women) in 2018, who participated in both the baseline survey in 2002 and the frailty assessment in 2018. The amount of milk consumption (g/day) at baseline was age- and energy-adjusted, and classified into three categories (no, low and high consumption: 0 g/day, ≤135.86 g/day, >135.86 g/day in men and 0 g/day, ≤126.44 g/day, >126.44 g/day in women).
  • Odds ratios (OR) and 95% confidence intervals (CI) for prefrailty/frailty after adjusting for lifestyles at baseline, stratified by sex, were estimated using logistic regression analysis.
  • The prevalence of prefrailty/frailty in 2018 was 37.7% and 28.3% in men and women, respectively. Milk consumption categories were inversely associated with the prevalence of prefrailty/frailty in men (OR 0.34 in low consumption; OR 0.31 in high consumption), but not in women (OR 0.53).
  • In this study, milk intake in middle-aged men was inversely associated with the prevalence of prefrailty/frailty later in life.

Prospective, Randomized, Double-Blind Parallel Group Nutritional Study to Evaluate the Effects of Routine Intake of Fresh vs. Pasteurized Yogurt on the Immune System in Healthy Adults. Rivero-Pino F, Casquete M, Corell A, et al. Nutrients. 2024 Jun 20;16(12):1969.

  • The immune system is affected by the dietary products humans intake. Immune system regulation by nutrition has uses in the clinical context, but it can also benefit healthy populations by delaying or preventing the emergence of immune-mediated chronic illnesses.
  • In this study, the purpose was to describe and compare the modulator effects on the immune system of the routine ingestion of fresh vs. pasteurized yogurt.
  • A unicentral, prospective, randomized, double-blind, parallel group 8-week nutritional study was carried out comparing the ingestion of 125 g of the products in healthy adults three times a day. A complete battery of in vitro tests on the activity of the immune system, processes and phenomena was performed.
  • Exclusive immune-modulatory effects of fresh yogurt with respect to base line were found in terms of increased systemic IgM (primary immune responses), increased synthesis of IFN-gamma upon stimulation (Th1) and increased peripheral T cells (mainly “naive” CD4s).
  • In the three interventions, researchers observed an increased phagocytic activity and burst test in granulocytes, together with increased secretion of IL-6, IL-1 β and IL-8 (pro-inflammatory) and increased CD16 expression (FcR favoring phagocytosis) in granulocytes.
  • Overall, it is concluded that regardless of bacteria being alive or thermally inactivated, yogurt has common effects on the innate system, but the presence of live bacteria is necessary to achieve a potentiating effect on the specific immune response.

Gut microbiome composition and functionality impact the responsiveness to a dairy-based product containing galacto-oligosaccharides for improving sleep quality in adults. Kortman GAM, Hester ER, Schaafsma A, Mulder J, Mallee L, Nauta A. Benef Microbes. 2024 Jun 20:1-13.

  • Sleep quality and duration can be impacted by diet and has been linked to gut microbiota composition and function as the result of communication via the microbiota-gut-brain axis. One strategy to improve sleep quality could be through the modulation of the gut microbiome.
  • Therefore, researchers assessed the effects of a dairy-based product containing whey protein, galacto-oligosaccharides, tryptophan, vitamins and minerals after a 3 weeks intervention on gut microbiota composition and (gut-brain related) functions on basis of 67 healthy subjects with moderate sleep disturbances.
  • Associations of the gut microbiota with sleep quality and with response/non-response to the treatment were revealed by shotgun metagenomics sequencing of fecal DNA samples, and subsequent analyses of microbiota taxonomy and generic functionality.
  • A database of manually curated Gut-Brain Modules (GBMs) was applied to analyze specific microbial functions/pathways that have the potential to interact with the brain.
  • A moderate discriminating effect of the dairy-based product treatment on gut microbiota composition was revealed which could be mainly attributed to a decrease in Pseudomonas resinovorans, Flintibacter sp. KGM00164, Intestinimonas butyriciproducens, and Flavonifractor plautii.
  • As interindividual variance in microbiota composition could have given rise to a heterogenous responsiveness of the subjects in the intervention group, researchers zoomed in on the differences between responders and non-responders.
  • A significant difference in baseline microbiota composition between responders and non-responders was apparent, showing lower Bifidobacterium longum and Bifidobacterium adolescentis, and higher Faecalibacterium prausnitzii relative abundances in responders.
  • The findings provide leads with respect to the effectiveness and potential underlying mechanisms of mode of action in sleep improvement that could support future nutritional interventions to aid sleep improvement.

Relationship between maternal consumption of fermented foods and the development of the offspring at the age of 3 years: The Japan Environment and Children’s Study. Hirai H, Tanaka T, , Inadera H, et al; Japan Environment and Children’s Study Group. PLoS One. 2024 Jun 21;19(6):e0305535.

  • It is well known that maternal diet affects the development of offspring. Herein, the relationship between maternal intake of fermented foods during pregnancy and offspring development was investigated.
  • The diet of 103,060 pregnant women at >4 months of gestation who were enrolled in the Japan Environment and Children’s Study was analyzed. Their intake levels of fermented soybeans (miso and natto), yogurt, and cheese were investigated.
  • The developmental status of the offspring at 3 years of age was assessed using the Ages and Stages Questionnaires (ASQ-3). Multivariable logistic regression analysis was performed to determine the risk of maternal intake levels of the fermented foods associated with subsequent developmental delay in the offspring.
  • Intake of cheese was associated with a reduced risk of child developmental delay in all intake level groups from the second quartile onward. Intakes of miso and yogurt were associated with a reduced risk of developmental delay in communication skills in the fourth quartile. There was no association between intake of natto and developmental delay.
  • Maternal consumption of fermented foods during pregnancy may reduce the risk of later developmental delay in offspring. It is therefore important to review the mother’s diet for fermented foods during pregnancy.

A combination of phospholipids and long chain polyunsaturated fatty acids supports neurodevelopmental outcomes in infants: a randomized, double-blind, controlled clinical trial. Ren Q, Zhu X, Pan J, Li K, Zhou Y, Lyu Y, Xie Q, Xu Y. Front Nutr. 2024 Jun 13;11:1358651.

  • Phospholipids (PLs) and long-chain polyunsaturated fatty acids (LCPUFAs) are naturally present in breast milk and play important roles in promoting the growth of the infant.
  • Several studies have investigated the effects of the combination of PLs and LCPUFAs on neurodevelopment. However, data on the effectiveness of infant formula containing both PLs and LCPUFAs on the neurodevelopment of infants is still scarce.
  • This randomized, double-blind, controlled clinical study was designed to evaluate the effect of an infant formula enriched with PLs and LCPUFAs on growth parameters and neurodevelopmental outcomes in term infants up to 365 days of age.
  • Infants were enrolled within 30 days of birth who were then randomly assigned to either a control group (n= 150) or an investigational group (n = 150). Both groups consist of cow’s milk-based formula which were generally identical in terms of composition, except that the investigational formula was additionally supplemented with PLs and LCPUFAs.
  • The infants were followed for the first year of life. In addition, Ages and Stages Questionnaires (ASQ) were also conducted at 120, 180, and 275 days of age.
  • Compared to breastfeeding, both infant formulas were well-tolerated and provided adequate growth, with no adverse events being reported throughout the study. Infants of the investigational group showed higher mean scores in cognitive performance, language, and motor skills compared the control group.
  • Notably, the test scores of infants fed the investigational formula were similar to those who were breastfed. These results indicate that PL and LCPUFA supplementation may be beneficial for neurodevelopment of infants throughout the first year of life. Further studies are needed to investigation long-term effects PL and LCPUFA on neurodevelopment in early life.

Long-term adherence and risk of allergic reactions in patients who attained milk oral immunotherapy maintenance. Mulé P, Zhang X, Ben-Shoshan M, et al .J  Allergy Clin Immunol Pract. 2024 Jun 27:S2213-2198(24)00668-8.

  • Oral immunotherapy (OIT) has emerged as the most popular therapy for food allergy. However, data on the long-term adherence and efficacy of this approach are sparse.
  • Researchers aimed to assess the long-term adherence rates to OIT protocol and the associated risk of allergic reactions.
  • Patients who completed milk OIT and reached a maintenance dose of 200 ml of milk were surveyed biannually on their dairy consumption and occurrence of allergic reactions. A survival analysis was performed to evaluate the association between the risk of reaction and adherence to OIT maintenance protocol.
  • The cohort consisted of 50 patients. Only 56% of the cohort adhered to protocol, which consisted of ingesting a minimum of 200 ml of milk at least 3 times per week. Adherent patients had a significantly reduced risk of allergic reactions, as well as a reduced incidence of anaphylaxis, healthcare/ER visits, and epinephrine/antihistamine administration.
  • The findings demonstrate the importance of consistent maintenance dose consumption in the management of food allergies, with regular milk consumption contributing to the maintenance of unresponsiveness and decreased risk of allergic symptoms.

Lactose malabsorption and intolerance in older adults. Gallo A, Marzetti E, Pellegrino S, Montalto M. Curr Opin Clin Nutr Metab Care. 2024;27(4):333-337.

  • Lactose malabsorption and intolerance are very common conditions. However, their optimal approach, including the diagnostic assessment, remains a matter of debate, especially in advanced age.
  • In this brief review, researchers focused on current knowledge, concerns, and impact in clinical practice of lactose malabsorption and intolerance in elderly.
  • Older adults are at high risk of malnutrition, owing to frequent occurrence of cognitive impairment, loss of appetite, dysphagia, and poor oral health. A significant decrease in the consumption of dairy products may lead to inadequate intake of high-quality protein and minerals, with a consequent impact on muscle and bone health.
  • Testing for lactose malabsorption may be challenging in older adults. Instead, a detailed clinical evaluation should always be pursued to identify both lactose intolerance and all confounding factors mimicking the same clinical picture.
  • Overall, the management of lactose malabsorption and intolerance in older adults deserves a personalized approach. Because of the importance of maintaining an adequate nutritional status in this age group, efforts should be put forth to avoid excessively restrictive diets.


Innovation, Economics, and Dairy Alternatives

Potential consumer response to the healthy symbol proposed by the U.S. food and Drug Administration. Hyink J, McFadden BR, Ellison B. Heliyon. 2024;10(10):e30863.

  • The U.S. Food and Drug Administration (FDA) has proposed updates to the definition of “healthy,” including distinctions between types of sugar and fats and limits on added sugar, saturated fat, and sodium. To communicate the updated standards, the FDA is developing a Healthy symbol to display on food packages, which could reduce knowledge gaps by assisting U.S. consumers in meeting recommended nutritional guidelines.
  • This study aimed to explore the potential for the label to increase consumers’ ability to correctly identify a food product that met the FDA’s criteria for a healthy symbol.
  • To complete the study objective, 1018 adults were recruited to represent the U.S. population regarding gender, age, income, and geographic region, and a randomized group experiment was used to determine the potential communication value of an FDA Healthy symbol.
  • Respondents were randomized to a group shown either a healthy yogurt with the FDA symbol, a healthy yogurt without the symbol, or an unhealthy yogurt. Respondents were then asked whether they considered the yogurt shown to be healthy, a question examining the desired criteria for the Healthy symbol, willingness to accept various costs to implement the symbol, and questions to measure objective dietary knowledge.
  • Adding the symbol to yogurt that already met the healthy criteria only yielded about a 4 percentage point increase in the proportion of respondents identifying it as healthy. However, 53 % of participants still identified a yogurt too high in added sugars as healthy.
  • For the desired label criteria, 64 % of respondents selected limits on added sugars, 57 % selected limits on sodium, and 54 % selected limits on saturated fats, which all align with the proposed updates to the definition of healthy.
  • Over half of the participants supported the implementation of the label, even at a cost of $40 annually, and 86 % supported implementation at no cost.

Sustainable packaging materials for fermented probiotic dairy or non-dairy food and beverage products: challenges and innovations. Francis DV, Dahiya D, Gokhale T, Nigam PS. AIMS Microbiol. 2024 May 8;10(2):320-339.

  • The food and beverage packaging industry has experienced remarkable growth in recent years. Particularly the requirement for appropriate packaging materials used for the sale of fermented products is boosted due to the rising acceptance of economical functional foods available to consumers on the shelves of their local supermarkets.
  • The most popular nutraceutical foods with increased sales include natural yogurts, probiotic-rich milk, kefir, and other fermented food and beverage products. These items have mainly been produced from dairy-based or non-dairy raw materials to provide several product options for most consumers, including vegan and lactose-intolerant populations.
  • Therefore, there is a need for an evaluation of the potential developments and prospects that characterize the growth of the food packaging industry in the global market.
  • The article is based on a review of information from published research, encompassing current trends, emerging technologies, challenges, innovations, and sustainability initiatives for food industry packaging.

Emerging Parameters Justifying a Revised Quality Concept for Cow Milk. Mezzetti M, Passamonti MM, Dall’Asta M, Bertoni G, Trevisi E, Ajmone Marsan P.Foods. 2024 May 25;13(11):1650.

  • Milk has become a staple food product globally. Traditionally, milk quality assessment has been primarily focused on hygiene and composition to ensure its safety for consumption and processing. However, in recent years, the concept of milk quality has expanded to encompass a broader range of factors.
  • Consumers now also consider animal welfare, environmental impact, and the presence of additional beneficial components in milk when assessing its quality. This shifting consumer demand has led to increased attention on the overall production and sourcing practices of milk.
  • Reflecting on this trend, this review critically explores such novel quality parameters, offering insights into how such practices meet the modern consumer’s holistic expectations. The multifaceted aspects of milk quality are examined, revealing the intertwined relationship between milk safety, compositional integrity, and the additional health benefits provided by milk’s bioactive properties.
  • By embracing sustainable farming practices, dairy farmers and processors are encouraged not only to fulfill but to anticipate consumer standards for premium milk quality. This comprehensive approach to milk quality underscores the necessity of adapting dairy production to address the evolving nutritional landscape and consumption patterns.

A discussion on A1-free milk: Nuances and comments beyond implications to the health. Dantas A, Pierezan MD, Camelo-Silva C, Zanetti V, Pimentel TC, da Cruz AG, Verruck S. Adv Food Nutr Res. 2024;110:197-241.

  • This chapter provides an overarching view of the multifaceted aspects of milk β-casein, focusing on its genetic variants A1 and A2. The work examines the current landscape of A1-free milk versus regular milk, delving into health considerations, protein detection methods, technological impacts on dairy production, non-bovine protein, and potential avenues for future research.
  • Firstly, it discussed ongoing debates surrounding categorizing milk based on A1 and A2 β-casein variants, highlighting challenges in establishing clear regulatory standards and quality control methods. The chapter also addressed the molecular distinction between A1 and A2 variants at position 67 of the amino acid chain.
  • This trait affects protein conformation, casein micelle properties, and enzymatic susceptibility. Variations in β-casein across animal species are acknowledged, casting doubt on non-bovine claims of “A2-like” milk due to terminology and genetic differences. Lastly, this work explores the burgeoning field of biotechnology in milk production.

Milk Odd- and Branched-Chain Fatty Acids as Biomarkers of Rumen Fermentation. Kupczyński R, Pacyga K, Lewandowska K, Bednarski M, Szumny A. Animals (Basel). 2024 Jun 6;14(11):1706.

  • Cow’s milk and dairy products are the primary sources of OBCFAs, which have beneficial health properties.
  • The goal of this study was to identify the factors that influence the content of OBCFAs in cow’s milk and to indicate which OBCFAs can serve as biomarkers for fermentation processes.
  • The content of OBCFAs in milk depends on the species of ruminants, with studies showing that this varies between 3.33% (in goat’s milk) and 5.02% (in buffalo’s milk). These differences also stem from the animals’ energy balance, lactation phases, forage-to-concentrate ratio, and the presence of bioactive compounds in feeds, as well as management practices and environmental conditions.
  • The OBCFAs in milk fat mainly come from rumen bacteria, but can also be synthesized de novo in the mammary gland, making them potentially useful noninvasive indicators of rumen fermentation.
  • The concentration of BCFA is lower in colostrum and transitional milk than in full lactation milk. The proportions of total OBCFAs are higher in first- and second-parity cows. The most effective predictors of the biohydrogenation of fatty acids in the rumen are likely C18:2 cis-9, trans-11, iso-C16:0, and iso-C13:0. OBCFAs have been identified as potential biomarkers for rumen function, because their synthesis depends on specific bacteria.
  • Strong predictors of subclinical ruminal acidosis include iso-C14:0, iso-C13:0, and C15:0. The concentration of ∑ OBCFA >C16 in milk is associated with fat mobilization and serves as a significant marker of the energy balance in cows.

Comparing Nutritional Values and Bioactivity of Kefir from Different Types of Animal Milk. La Torre C, Caputo P, Cione E, Fazio A. Molecules. 2024 Jun 6;29(11):2710.

  • The growing interest in fermented dairy products is due to their health-promoting properties. The use of milk kefir grains as a starter culture made it possible to obtain a product with a better nutritional and biological profile depending on the type of milk.
  • Cow, buffalo, camel, donkey, goat, and sheep milk kefirs were prepared, and the changes in sugar, protein, and phenol content, fatty acid composition, including conjugated linoleic acids (CLAs), as well as antioxidant activity, determined by ABTS and FRAP assays, were evaluated and compared.
  • The protein content of cow, buffalo, donkey, and sheep milk increased after 24 hours of fermentation.
  • The fatty acid profile showed a better concentration of saturated and unsaturated lipids in all fermented milks, except buffalo milk. The highest content of beneficial fatty acids, such as oleic, linoleic, and C18:2 conjugated linoleic acid, was found in the cow and sheep samples.
  • All samples showed a better antioxidant capacity, goat milk having the highest value, with no correlation to the total phenolic content, which was highest in the buffalo sample (260.40 ± 5.50 μg GAE/mL).
  • These findings suggested that microorganisms living symbiotically in kefir grains utilize nutrients from different types of milk with varying efficiency.

Assessing the nutrient content of plant-based milk alternative products available in the U.S. Johnson AJ, Stevenson J, Pettit J, Jasthi B, Byhre T, Harnack L.J Acad Nutr Diet. 2024 Jun 11:S2212-2672(24)00269-7.

  • Consumption of plant-based milk alternatives is increasing. Current dietary guidance primarily relies on dairy milk as a source of key nutrients of public health concern including calcium and vitamin D.
  • The objective of this research was to compare the nutritional content of plant-based milk alternatives between categories (e.g., soy, almond, and oat) and with dairy milk.
  • This study presents an evaluation of the nutritional content of 219 plant-based milk alternatives from 21 brands available in the US marketplace using data from the University of Minnesota Nutrition Coordinating Center’s (NCC) database.
  • Nutrients of focus include those identified as nutrients of public health concern in the Dietary Guidelines for American’s (DGA) or used by the United States Department of Agriculture (USDA) as criteria for determining whether a plant-based milk is a suitable substitute for dairy milk.
  • Fortified soy-based products most closely mimic the nutrient content of dairy milk. High variability was present in all the nutrients and food components. Plant-based milk alternatives were generally lower in protein and saturated fatty acids than dairy milk, with high variability in added sugars content. Approximately 70% were fortified with both calcium and vitamin D.
  • These results indicate that most plant-based milk alternative products are not nutritionally equivalent to dairy milk, and there is high nutritional variability between and within product types. These findings highlight the importance of communicating the nutritional differences between plant-based milk alternatives and dairy milk to consumers.

Current status and challenges for cell-cultured milk technology: a systematic review. Kwon HC, Jung HS, Kothuri V, Han SG. J Anim Sci Biotechnol. 2024 Jun 8;15(1):81.

  • Cellular agriculture is an innovative technology for manufacturing sustainable agricultural products as an alternative to traditional agriculture. While most cellular agriculture is predominantly centered on the production of cultured meat, there is a growing demand for an understanding of the production techniques involved in dairy products within cellular agriculture.
  • This review focuses on the current status of cellular agriculture in the dairy sector and technical challenges for cell-cultured milk production.
  • Cellular agriculture technology in the dairy sector has been classified into fermentation-based and animal cell culture-based cellular agriculture. Currently, various companies synthesize milk components through precision fermentation technology. Nevertheless, several startup companies are pursuing animal cell-based technology, driven by public concerns regarding genetically modified organisms in precision fermentation technology.
  • Hence, this review offers an up-to-date exploration of animal cell-based cellular agriculture to produce milk components, specifically emphasizing the structural, functional, and productive aspects of mammary epithelial cells, providing new information for industry and academia.