Dairy Research Bulletin – February 2021

Welcome to the February 2021 Dairy Research Bulletin. The Dairy Research Bulletin delivers a brief synopsis of the most current Human, Animal, and Environmental dairy research that is going on in the World, and also that which is of special interest to California dairy producers and consumers alike.

If you would like to peruse the most pertinent dairy research from months past, then visit the Dairy Research Bulletin Archive.

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Selected Articles on Social Responsibility, Environmental Management, and Sustainability

Agriculture’s Contribution to Climate Change and Role in Mitigation Is Distinct From Predominantly Fossil CO(2)-Emitting Sectors. Lynch J, Cain M, Frame D, Pierrehumbert R. Front Sustain Food Syst. 2021 Feb 3;4:518039.

  • Agriculture is a significant contributor to anthropogenic global warming, and reducing agricultural emissions-largely methane and nitrous oxide-could play a significant role in climate change mitigation.
  • However, there are important differences between carbon dioxide (CO2), which is a stock pollutant, and methane (CH4), which is predominantly a flow pollutant. These dynamics mean that conventional reporting of aggregated CO2-equivalent emission rates is highly ambiguous and does not straightforwardly reflect historical or anticipated contributions to global temperature change.
  • As a result, the roles and responsibilities of different sectors emitting different gases are similarly obscured by the common means of communicating emission reduction scenarios using CO2-equivalence.
  • This paper argues for a shift in how we report agricultural greenhouse gas emissions and think about their mitigation to better reflect the distinct roles of different greenhouse gases.
  • Policy-makers, stakeholders, and society at large should also be reminded that the role of agriculture in climate mitigation is a much broader topic than climate science alone can inform, including considerations of economic and technical feasibility, preferences for food supply and land-use, and notions of fairness and justice.
  • A more nuanced perspective on the impacts of different emissions could aid these conversations.

Methane emissions from the storage of liquid dairy manure: Influences of season, temperature and storage duration. Cárdenas A, Ammon C, Schumacher B, Stinner W, Herrmann C, Schneider M, Weinrich S, Fischer P, Amon T, Amon B.Waste Manag. 2021 Feb 15;121:393-402.

  • Methane emissions from livestock manure are primary contributors to GHG emissions from agriculture and options for their mitigation must be found.
  • This paper presents the results of a study on methane emissions from stored liquid dairy cow manure during summer and winter storage periods.
  • Manure from the summer and winter season was stored under controlled conditions in barrels at ambient temperature to simulate manure storage conditions. Methane emissions from the manure samples from the winter season were measured in two time periods: 0 to 69 and 0 to 139 days. For the summer storage period, the experiments covered four time periods: from 0 to 70, 0 to 138, 0 to 209, and 0 to 279 continuous days, with probing every 10 weeks.
  • The experiment showed that the methane emissions from manure stored in summer were considerably higher than those from manure stored in winter. CH4production started after approximately one month, reaching values of 0.061 kg CH4 kg-1 Volatile Solid (VS) and achieving high total emissions of 0.148 kg CH4 kg-1 VS (40 weeks). In winter, the highest emissions level was 0.0011 kg CH4 kg-1 VS (20 weeks).
  • The outcomes of these experimental measurements can be used to suggest strategies for mitigating methane emissions from manure storage.

Strategies to boost anaerobic digestion performance of cow manure: Laboratory achievements and their full-scale application potential. Li Y, Zhao J, Krooneman J, Euverink GJW.Sci Total Environ. 2021 Feb 10;755(Pt 1):142940.

  • Cow manure represents a surplus manure waste in agricultural food sectors, which requires proper disposal. Anaerobic digestion, in this regard, has raised global interest owing to its apparent environmental benefits, including simultaneous waste diminishment and renewable energy generation. However, dedicated intensifications are necessary to promote the degradation of recalcitrant lignocellulosic components of cow manure.
  • Hence, this manuscript presents a review of how to exploit cow manure in anaerobic digestion through different incentives extensively at lab-scale and full-scale. These strategies comprise 1) co-digestion; 2) pretreatment; 3) introduction of additives (trace metals, carbon-based materials, low-cost composites, nanomaterials, and microbial cultures); 4) innovative systems (bio-electrochemical fields and laser irradiation).
  • Results imply that co-digestion and pretreatment approaches gain the predominance on promoting the digestion performance of cow manure. Particularly, for the co-digestion scenario, the selection of lignin-poor co-substrate is highlighted to produce maximum synergy and pronounced removal of lignocellulosic compounds of cow manure.
  • Mechanical, thermal, and biological (composting) pretreatments generate mild improvement at laboratory-scale and are proved applicable in full-scale facilities. It is noteworthy that the introduction of additives (Fe-based nanomaterials, carbon-based materials, and composites) is acquiring more attention and shows promising full-scale application potential.
  • Finally, bio-electrochemical fields stand out in laboratory trials and may serve as future reactor modules in agricultural anaerobic digestion installations treating cow manure.

Mycoplasma species isolated from bovine milk collected from US dairy herds between 2016 and 2019. Gioia G, Addis MF, Santisteban C, Gross B, Nydam DV, Sipka AS, Virkler PD, Watters RD, Wieland M, Zurakowski MJ, Moroni P.J Dairy Sci. 2021 Feb 18:S0022-0302(21)00148-X.

  • Determining the species of mycoplasma isolated from culture-positive milk samples is important for understanding the clinical significance of their detection.
  • Between August 2016 and December 2019, 214,518 milk samples from 2,757 dairy herds were submitted to Quality Milk Production Services (QMPS) at Cornell University for mycoplasma culture.
  • From these samples, 3,728 collected from 204 herds were culture positive. Based on the request of herd managers, owners, or veterinarians, 889 isolates from 98 herds were subjected to molecular identification by PCR and amplicon sequencing.
  • The largest proportion of the identified isolates were from New York State (78.1%), while the others came from the eastern United States (17.8%), Texas (2.0%), and New Mexico (2.1%). As expected, Mycoplasma spp. were the most common (855 isolates, 96.2%) and Acholeplasma spp. accounted for the remainder (34 isolates, 3.8%).
  • Mycoplasma bovis was the most prevalent Mycoplasma species (75.1%), followed by M. bovigenitalium (6.5%), M. canadense (5.9%), M. alkalescens (5%), M. arginini (1.7%), M. californicum (0.1%), and M. primatum (0.1%).
  • Mycoplasma bovis was the only species identified in 59 of the 98 herds. However, more than 1 Mycoplasma sp. was identified in 29 herds, suggesting that herd infection with 2 or more mycoplasmas is not uncommon.
  • From the subset of 889 mycoplasma culture-positive isolates from 98 herds, the researchers determined that over a third of the herds had either more than 1 Mycoplasma sp. or a Mycoplasma sp. other than M. bovis detected in their milk samples.
  • In conclusion, it was observed that M. bovis is the most common pathogenic Mycoplasma species found in mastitic milk, but other Mycoplasma species are not uncommon. These results suggest that it is critical to test milk samples for mycoplasmas using diagnostic tests able to identify both the genus and the species.

Trends in somatic cell count deteriorations in Dutch dairy herds transitioning to an automatic milking system. van den Borne BHP, van Grinsven NJM, Hogeveen H.J Dairy Sci. 2021 Feb 18:S0022-0302(21)00172-7.

  • Udder health is at risk when herds transition from a conventional milking system (CMS) to an automatic milking system (AMS). Somatic cell counts (SCC) are generally elevated for several months following a transition. However, such observations were made in studies conducted in the early 2000s. Technical improvements to AMS have likely been made since then, and farm management may have improved, learning from past experiences.
  • This longitudinal observational study quantified national trends in SCC deteriorations in dairy herds that transitioned from a CMS to an AMS.
  • Census data from the Dutch test day recording was used to determine these trends. It consisted of all cow-level SCC measurements conducted in the Netherlands from January 1, 2007 to December 31, 2019.
  • Decreasing SCC deteriorations were observed during the study period for all 3 udder health indicators. Udder health deteriorations around the transition to an AMS were still observed, but they decreased in magnitude over the course of the study period. Bulk-milk SCC deteriorations were, for instance, 2.5 times lower in 2019 compared with those observed in 2007.
  • Therefore, the effect of transitioning to an AMS on udder health became less severe in more recent years. However, deteriorations in the proportion of new SCC elevations were still evident toward the end of the study period.
  • Efforts to lower udder health deteriorations in herds that transition to an AMS should therefore be continued and should intensify on factors lowering the proportion of cows having a new elevated SCC.

Intergenerational cycle of disease: Maternal mastitis is associated with poorer daughter performance in dairy cattle. Swartz TH, Bradford BJ, Clay JS.J Dairy Sci. 2021 Feb 18:S0022-0302(21)00153-3.

  • Adverse prenatal environments, such as maternal stress and infections, can influence the health and performance of offspring. Mastitis is the most common disease in dairy cattle, yet the intergenerational effects have not been specifically investigated.
  • Therefore, researchers examined the associations between the dam’s mammary gland health and daughter performance using somatic cell score (SCS) as a proxy for mammary health. Using data obtained from Dairy Records Management Systems (Raleigh, NC), the researchers linked daughter records with their dam’s records for the lactation in which the daughter was conceived.
  • The researchers uncovered a phenomenon similar to those found in human and mouse models examining prenatal inflammation effects, whereby daughters born from dams with elevated SCS had poorer performance. For every 1-unit increase in dam mean SCS, daughter’s first- and second-lactation mature equivalent fat yield declined by 0.34% and 0.91%, respectively, although no effect was found on first- or second-lactation milk or milk protein yield.
  • When accounting for genetics, daughter SCS, and dam mean SCS was associated with reduced second-lactation milk fat yield, and a tendency was found for first-lactation milk fat yield.
  • Taken together, the association of greater dam mean SCS with lesser daughter milk fat yield is likely due to a few underlying mechanisms, in particular, a predisposition for mastitis and alterations in the epigenome controlling milk fat synthesis. As such, future studies should examine epigenetic mechanisms as a potential underpinning of this phenomenon.

Outbreaks of Foodborne Salmonella Enteritidis in The United States 1990-2015: Epidemiologic and Spatial-temporal Trends Analyses. Sher AA, Mustafa BE, Grady SC, Gardiner JC, Saeed AM.Int J Infect Dis. 2021 Feb 9:S1201-9712(21)00108-9.

  • Foodborne infections have become a severe public health issue in both developing and developed countries. Non-typhoidal Salmonella serotypes are a major cause of foodborne infection outbreaks worldwide. It has been estimated that 93.8 million cases of non-typhoidal Salmonellosis and 155,000 deaths occur every year in the world and that 86% of these illnesses were due to the consumption of Salmonella-contaminated food items.
  • To assess the roles of eggs and other food vehicles as risk factors associated with Salmonella Enteritidis (SE) outbreaks aiming to address the endemicity of SE infection in the USA.
  • Researchers retrieved and analyzed the data of all SE outbreaks reported to the Centers for Disease Control and Prevention (CDC) from 1990 to 2015.
  • The study found that egg-based dishes were the most common food vehicle reported in SE outbreaks; 273 (24%) followed by other implicated food items; meat 130 (11%), vegetables 96 (8%), chicken items 95 (8%), dairy products 55 (5%), and bakery items 8 (1%) in the country.
  • Of 1144 SE outbreaks, 402 (35%) occurred in the Northeast region, followed by the South region; 253 (22%), West region; 250 (22%), and Midwestern region; 239 (21%).
  • Epidemiologic and spatiotemporal trends analyses in this study attributed significant proportions of the foodborne Salmonella Enteritidis outbreaks to food vehicles other than eggs. Results of this study can be used to plan effective strategies to mitigate the increasing occurrence of foodborne SE outbreaks.

The carbon footprint of dietary guidelines around the world: a seven country modeling study. Kovacs B, Miller L, Heller MC, Rose D.Nutr J. 2021 Mar 1;20(1):15.

  • Do the environmental impacts inherent in national food-based dietary guidelines (FBDG) vary around the world, and, if so, how? Most previous studies that consider this question focus on a single country or compare countries’ guidelines without controlling for differences in country-level consumption patterns.
  • To address this gap, researchers modeled the carbon footprint of the dietary guidelines from seven different countries, examine the key contributors to this, and control for consumption differences between countries.
  • In this purposive sample, the researchers obtained FBDG from national sources for Germany, India, the Netherlands, Oman, Thailand, Uruguay, and the United States. These were used to structure recommended diets using 6 food groups: protein foods, dairy, grains, fruits, vegetables, and oils/fats. All guidelines were scaled to a 2000-kcal diet.
  • Daily recommended amounts of dairy foods ranged from a low of 118 ml/d for Oman to a high of 710 ml/d for the US. The GHGE associated with these two recommendations were 0.17 and 1.10 kg CO2-eq/d, respectively.
  • The GHGE associated with the protein food recommendations ranged from 0.03 kg CO2-eq/d in India to 1.84 kg CO2-eq/d in the US, for recommended amounts of 75 g/d and 156 g/d, respectively.
  • Overall, US recommendations had the highest carbon footprint at 3.83 kg CO2-eq/d, 4.5 times that of the recommended diet for India, which had the smallest footprint. After controlling for country-level consumption patterns by applying the US consumption pattern to all countries, US recommendations were still the highest, 19% and 47% higher than those of the Netherlands and Germany, respectively.
  • Despite our common human biology, FBDG vary tremendously from one country to the next, as do the associated carbon footprints of these guidelines. Understanding the carbon footprints of different recommendations can assist in future decision-making to incorporate environmental sustainability in dietary guidance.

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Selected Articles on Dairy Intake and Human Health

Association of Major Dietary Protein Sources With All-Cause and Cause-Specific Mortality: Prospective Cohort Study. Sun Y, Liu B, Snetselaar LG, Wallace RB, Shadyab AH, Kroenke CH, Haring B, Howard BV, Shikany JM, Valdiviezo C, Bao W.J Am Heart Assoc. 2021 Feb 24:e015553.

  • Background Dietary recommendations regarding protein intake have been focused on the amount of protein. However, such recommendations without considering specific protein sources may be simplistic and insufficient.
  • Researchers investigated 102,521 postmenopausal women enrolled in the Women’s Health Initiative between 1993 and 1998, and followed them through February 2017. During 1,876,205 person-years of follow-up, 25,976 deaths occurred.
  • Comparing the highest with the lowest quintile, plant protein intake was inversely associated with all-cause mortality (hazard ratio [HR], 0.91), cardiovascular disease mortality (HR, 0.88), and dementia mortality (HR, 0.79).
  • Among major protein sources, comparing the highest with the lowest quintile of consumption, processed red meat (HR, 1.06) or eggs (HR, 1.14) was associated with higher risk of all-cause mortality.
  • Unprocessed red meat (HR, 1.12), eggs (HR, 1.24), or dairy products (HR, 1.11) was associated with higher risk of cardiovascular disease mortality.
  • Egg consumption was associated with higher risk of cancer mortality (HR, 1.10).
  • Processed red meat consumption was associated with higher risk of dementia mortality (HR, 1.20), while consumption of poultry (HR, 0.85) or eggs (HR, 0.86) was associated with lower risk of dementia mortality.
  • In substitution analysis, substituting of animal protein with plant protein was associated with a lower risk of all-cause mortality, cardiovascular disease mortality, and dementia mortality, and substitution of total red meat, eggs, or dairy products with nuts was associated with a lower risk of all-cause mortality.
  • Different dietary protein sources have varying associations with all-cause mortality, cardiovascular disease mortality, and dementia mortality. These findings support the need for consideration of protein sources in future dietary guidelines.

Role of Diet in Colorectal Cancer Incidence: Umbrella Review of Meta-analyses of Prospective Observational Studies. Veettil SK, Wong TY, Loo YS, Playdon MC, Lai NM, Giovannucci EL, Chaiyakunapruk N. JAMA Netw Open. 2021 Feb 1;4(2):e2037341.

  • Several meta-analyses have summarized evidence for the association between dietary factors and the incidence of colorectal cancer (CRC). However, to date, there has been little synthesis of the strength, precision, and quality of this evidence in aggregate.
  • To grade the evidence from published meta-analyses of prospective observational studies that assessed the association of dietary patterns, specific foods, food groups, beverages (including alcohol), macronutrients, and micronutrients with the incidence of CRC.
  • From 9954 publications, 222 full-text articles (2.2%) were evaluated for eligibility, and 45 meta-analyses (20.3%) that described 109 associations between dietary factors and CRC incidence were selected.
  • There was convincing evidence of an association of intake of red meat (high vs low) and alcohol (≥4 drinks/d vs 0 or occasional drinks) with the incidence of CRC and an inverse association of higher vs lower intakes of dietary fiber, calcium, and yogurt with CRC risk.
  • This umbrella review found convincing evidence of an association between lower CRC risk and higher intakes of dietary fiber, dietary calcium, and yogurt and lower intakes of alcohol and red meat. More research is needed on specific foods for which evidence remains suggestive, including other dairy products, whole grains, processed meat, and specific dietary patterns.

Yogurt Consumption Is Associated with Lower Levels of Chronic Inflammation in the Framingham Offspring Study. Yuan M, Singer MR, Moore LL.Nutrients. 2021 Feb 4;13(2):506.

  • Some studies suggest that dairy foods may be linked with less chronic inflammation. However, few studies have investigated the separate effects of different types of dairy on inflammation.
  • Therefore, the current study aims to examine the separate prospective impacts of milk, yogurt and cheese on biomarkers of chronic inflammation in 1753 community-dwelling participants of the Framingham Offspring Study (FOS).
  • Mean intakes of dairy foods were derived from two sets of three-day diet records. Six inflammatory biomarkers were assessed approximately seven years later at exam 7.
  • Results showed that those who consumed yogurt (vs. those who did not) had statistically significantly lower levels of interleukin-6 (IL-6) and fibrin. The inverse association between IL-6 and yogurt consumption was similar in participants who were of normal weight and those who were overweight. For fibrin, the effects were stronger in overweight individuals.
  • No statistically significant associations were observed between any of these inflammation biomarkers and milk or cheese intakes. Overall, this study compared the separate impacts of three types of dairy foods on chronic inflammation and found that only yogurt intake was linked with lower levels of chronic inflammation.

Invited review: Potential antiobesity effect of fermented dairy products. Manzanarez-Quín CG, Beltrán-Barrientos LM, Hernández-Mendoza A, González-Córdova AF, Vallejo-Cordoba B.J Dairy Sci. 2021 Feb 4:S0022-0302(21)00109-0.

  • The growing prevalence of obesity affects millions of people around the world and has gained increased attention over the years because it is associated with the development of other chronic degenerative diseases.
  • Different organizations recommend lifestyle changes to treat obesity; nevertheless, other strategies in addition to lifestyle changes have recently been suggested. One of these strategies is the use of probiotics in fermented dairy products; however, a need exists to review the different studies available related to the potential antiobesity effect of these products.
  • Because probiotic fermented dairy products that support weight management are not available in the market, there is a great opportunity for the development of functional dairy products with new lactic acid bacteria that may present this added health benefit.
  • Thus, the purpose of this overview is to highlight the importance of probiotic fermented dairy products as potential antiobesogenic functional foods and present in vitro and in vivo studies required before this kind of product may be introduced to the market.
  • Overall, most studies attributed the antiobesity effect of fermented dairy foods to the probiotic strains present; however, bioactive peptides released during milk fermentation may also be responsible for this effect.

Comparative effects of probiotic and paraprobiotic addition on microbiological, biochemical and physical properties of yogurt. Molaee Parvarei M, Fazeli MR, Mortazavian AM, Sarem Nezhad S, Mortazavi SA, Golabchifar AA, Khorshidian N.Food Res Int. 2021 Feb;140:110030.

  • Paraprobiotics are inactivated probiotics that exert various health and technological benefits making them suitable for production of functional yogurt.
  • In the present study, probiotic yogurt containing Lactobacillus acidophilus ATCC SD 5221 and Bifidobacterium lactis BB-12 and paraprobiotic yogurt containing inactivated form of the mentioned bacteria were produced and were compared regarding microbiological, biochemical, and physical properties during 28 days of storage at refrigerated temperature.
  • Results revealed that the greatest mean pH drop rate, mean acidity increase rate, mean redox potential increase rate, final acidity and final redox potential were observed in yogurt containing inactivated L. acidophilus added before fermentation.
  • The highest lactic acid after 28 days of storage was obtained in samples prepared by addition of paraprobiotic form of L. acidophilus after fermentation.
  • Yogurt samples with B. lactis and L. acidophilus added after fermentation showed the highest and lowest acetic acid level, respectively after 28 days of storage.
  • Addition of paraprobiotics increased viability of starter cultures. In addition, incorporation of inactivated probiotic cells into yogurt resulted in lower syneresis and the higher WHC compared to probiotic yogurt samples.
  • Overall, it can be concluded that incorporation of paraprobiotics into yogurt involves less technological challenges and can be considered as a suitable appropriate alternative for probiotics in development of functional yogurt.

Probiotic Yogurt Fortified with Vitamin D Can Improve Glycemic Status in Non-Alcoholic Fatty Liver Disease Patients: a Randomized Clinical Trial. Morvaridzadeh M, Nachvak SM, Mohammadi R, Moradi S, Mostafai R, Pizarro AB, Abdollahzad H.Clin Nutr Res. 2021;10(1):36-47.

  • Non-alcoholic fatty liver disease (NAFLD) is a significant public health problem globally and the most notable chronic liver disease in Asian countries. Various dietary supplements have been assessed as potential methods to alleviate the metabolic damages related to NAFLD, but the results of these works have been equivocal.
  • This study aimed to evaluate the effects of probiotic yogurt fortified with vitamin D on glycemic and anthropometric indices in patients with NAFLD.
  • One hundred and four NAFLD patients of both sexes were randomly allocated to 2 groups: (Vit D fortified) and (unfortified yogurt). The intervention period was 3 months. Fasting blood samples were obtained for measuring fasting blood sugar and insulin level.
  • Eighty-eight patients completed the study. The mean serum level of Vit D was elevated significantly (p < 0.001), while insulin level decreased significantly (p < 0.003) in the fortified yogurt group at the end of the study. Fasting blood sugar levels showed no significant differences between the groups at the end of the trial.
  • Vit D fortified yogurt in the diets of patients with NAFLD may attenuate insulin resistance and improve serum level of Vit D.

Improving Human Health with Milk Fat Globule Membrane, Lactic Acid Bacteria, and Bifidobacteria. Kosmerl E, Rocha-Mendoza D, Ortega-Anaya J, Jiménez-Flores R, García-Cano I.Microorganisms. 2021 Feb 9;9(2):341.

  • The milk fat globule membrane (MFGM), the component that surrounds fat globules in milk, and its constituents have gained significant attention for their gut function, immune-boosting properties, and cognitive-development roles.
  • The MFGM can directly interact with probiotic bacteria, such as bifidobacteria and lactic acid bacteria (LAB), through interactions with bacterial surface proteins. With these interactions in mind, increasing evidence supports a synergistic effect between MFGM and probiotics to benefit human health at all ages.
  • This important synergy affects the survival and adhesion of probiotic bacteria through gastrointestinal transit, mucosal immunity, and neurocognitive behavior in developing infants.
  • In this review, researchers highlight the current understanding of the co-supplementation of MFGM and probiotics with a specific emphasis on their interactions and colocalization in dairy foods, supporting in vivo and clinical evidence, and current and future potential applications.