Welcome to the January 2020 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


Selected Articles on Social Responsibility, Environmental Management, and Sustainability

Can greenhouse gases in breath be used to genetically improve feed efficiency of dairy cows? Difford GF, Løvendahl P, Veerkamp RF, Bovenhuis H, Visker MHPW, Lassen J, de Haas Y. J Dairy Sci. 2020 Jan 15.

  • There is considerable interest in improving feed utilization of dairy cattle while limiting losses to the environment (i.e., greenhouse gases, GHG). Reducing dry matter take (DMI) requirements while maintaining production has high economic value to farmers, but DMI is costly to record and thus limited to small research or nucleus herds.
  • Conversely, enteric methane (CH4) currently has no economic value, is also costly to record, and is limited to small experimental trials. However, breath gas concentrations of methane (CH4c) and carbon dioxide (CO2c) are relatively cheap to measure at high throughput under commercial conditions by installing sniffers in automated milking stations.
  • The objective of this study was to assess the genetic correlations between DMI, body weight (BW), fat- and protein-corrected milk yield (FPCM), and GHG-related traits: CH4c and CO2c from Denmark (DNK) and the Netherlands (NLD). A second objective was to assess the genetic potential for improving feed efficiency and the added benefits of using CH4c and CO2c as indicators.
  • Feed intake data were available on 703 primiparous cows in DNK and 524 in NLD; CH4c and CO2c records were available on 434 primiparous cows in DNK and 656 in NLD.
  • The GHG-related traits were heritable (e.g., CH4c h2: DNK = 0.26, NLD = 0.15) but were differentially genetically correlated with DMI and feed efficiency in both magnitude and sign, depending on the population and the definition of feed efficiency. Across feed efficiency traits and DMI, having bulls with 100 daughters with FPCM, BW, and GHG traits resulted in sufficiently high accuracy to almost negate the need for DMI records.
  • Despite differences in genetic correlation structure, the relatively cheap GHG-related traits showed considerable potential for improving the accuracy of breeding values of highly valuable feed intake and feed efficiency traits.

Carbohydrate-rich supplements can improve nitrogen use efficiency and mitigate nitrogenous gas emissions from the excreta of dairy cows grazing temperate grass. Almeida JGR, Dall-Orsoletta AC, Oziemblowski MM, Michelon GM, Bayer C, Edouard N, Ribeiro-Filho HMN. Animal. 2020 Jan 7:1-12.

  • Temperate pasture species constitute a source of protein for dairy cattle. On the other hand, from an environmental perspective, their high N content can increase N excretion and nitrogenous gas emissions by livestock.
  • This work explores the effect of energy supplementation on N use efficiency (NUE) and nitrogenous gas emissions from the excreta of dairy cows grazing a pasture of oat and ryegrass.
  • The study was divided into two experiments: an evaluation of NUE in grazing dairy cows, and an evaluation of N-NH3 and N-N2O volatilizations from dairy cow excreta. In the first experiment, 12 lactating Holstein × Jersey F1 cows were allocated to a double 3 × 3 Latin square (three experimental periods of 17 days each) and subjected to three treatments: cows without supplementation (WS), cows supplemented at 4.2 kg DM of corn silage (CS) per day, and cows supplemented at 3.6 kg DM of ground corn (GC) per day.
  • In the second experiment, samples of excreta were collected from the cows distributed among the treatments. Aliquots of dung and urine of each treatment plus one blank (control – no excreta) were allotted to a randomized block design to evaluate N-NH3 and N-N2O volatilization. Measurements were performed until day 25 for N-NH3 and until day 94 for N-N2O.
  • Dietary N content in the supplemented cows was reduced by 20% compared with WS cows, regardless of the supplement. Corn silage cows had lower N intake than WS and GC cows (366 v. 426 g/day, respectively). Ground corn supplementation allowed cows to partition more N towards milk protein compared with the average milk protein of WS cows or those supplemented with corn silage (117 v. 108 g/day, respectively).
  • Thus, even though they were in different forms, both supplements were able to increase NUE from 27% in WS cows to 32% in supplemented cows. Supplementation was also effective in reducing N excretion (761 v. 694 g/kg of Nintake), N-NH3 emission (478 v. 374 g/kg of Nmilk) and N-N2O emission (11 v. 8 g/kg of Nmilk).
  • Corn silage and ground corn can be strategically used as feed supplements to improve NUE, and they have the potential to mitigate N-NH3 and N-N2O emissions from the excreta of dairy cows grazing high-protein pastures.

Effects of the vat pasteurization process and refrigerated storage on the bovine milk metabolome. Zhu D, Kebede B, Chen G, McComb K, Frew R. J Dairy Sci. 2020 Jan 21. pii: S0022-0302(20)30052-7.

  • Milk metabolomics are affected by complex matrices, animal species, cow status, farming systems and thermal treatment.
  • This study is the first to investigate the evolution of cow milk metabolites throughout the vat pasteurization process and storage using untargeted metabolomics based on a multiplatform approach.
  • Nuclear magnetic resonance and ultraperformance liquid chromatography-quadrupole time-of-flight mass spectrometry were used for fingerprinting water-soluble nutritional compounds, and headspace gas chromatography-mass spectrometry was used to fingerprint the volatile organic compounds.
  • This study demonstrated that vat pasteurization was an efficient and mild means of milk preservation resulting in only minor changes to the metabolites.
  • The pasteurized milk samples exhibited a stable metabolome during the first 8 d of refrigerated storage. However, at the latter stage of storage, the concentrations of pantothenic acid and butyrylcarnitine decreased, whereas some fatty acids, organic acids, α-AA, peptides, and ketones increased.
  • These selected metabolites that changed during milk storage could be used as potential biomarkers to track the storage conditions of pasteurized cow milk.

Role of Bacillus species in biofilm persistence and emerging antibiofilm strategies in the dairy industry. Shemesh M, Ostrov I. J Sci Food Agric. 2020 Jan 23

  • Biofilm-forming Bacillus species are often involved in persistent contamination and spoilage of dairy products. Therefore, they present a major microbiological challenge in the field of dairy food quality and safety.
  • Due to a vast physiological versatility, Bacillus species can survive in various sections of dairy manufacturing plants, leading to high risk in product spoilage and potential dissemination of foodborne diseases. Furthermore, biofilm and heat-resistant spore formation make these bacteria challenging to eliminate.
  • Thus, some strategies have been employed to remove, prevent, or delay the formation of Bacillus biofilms in the dairy industry, but with limited success. Lack of understanding in the Bacillus biofilm structure and behavior in conditions relevant to dairy-associated environments could partially account for this situation.
  • Current paper reviews dairy-associated biofilm formation by Bacillus species, with particular attention to the role of biofilm in Bacillus species adaptation and survival in a dairy processing environment. Besides, relevant model systems are discussed for developing novel antimicrobial approaches to improve the quality of dairy food.

Dairy manure acidification reduces CH4 emissions over short and long-term. Sokolov VK, VanderZaag A, Habtewold J, Dunfield K, Wagner-Riddle C, Venkiteswaran JJ, Crolla A, Gordon R. Environ Technol. 2020 Jan 10:1-21.

  • Acidification with sulphuric acid and cleaning residual manure in tanks are promising practices for reducing methane (CH4), which is a potent greenhouse gas. To date, no data is available on CH4reductions from acidifying only residual manure (rather than all manure). Moreover, long-term effects of manure acidification (i.e. inoculating ability of previously acidified residual manure in the subsequent storages) is not known.
  • To address these gaps, fresh manure (150 mL) combined with treated or untreated inoculum (30 mL) were anaerobically incubated at 17, 20, and 23°C for 116 days. Acidified fresh manure, regardless of location of acid addition, reduced CH4production by 80% at 17°C, 90% at 20°C, and 19% at 23°C compared to the control (untreated fresh manure and untreated inoculum).
  • To test long-term acidification effects, fresh manure was inoculated with manure that had been acidified 6-months prior. This created comparable CH4production to fresh manure with no inoculum and reduced CH4 production by 99% at 17°C and 20°C, and 49% at 23°C compared to the control.
  • The results indicate that residual slurries of acidified manure become poor inoculants in subsequent storage, hence manure acidification has a long-term treatment effects in reducing CH4 This could reduce how often acidification is needed in dairy manure tanks and also increasing its cost-effectiveness for farmers.

Short communication: Increasing temperature and pH can facilitate reductions of cephapirin and antibiotic resistance genes in dairy manure slurries. Li MM, Ray P, Teets C, Pruden A, Xia K, Knowlton KF. J Dairy Sci. 2020 Jan 15.

  • Quantifying antibiotics and antibiotic resistance genes in manure exposed to various temperature and pH treatments could guide the development of cost-effective manure handling methods to minimize the spread of antibiotic resistance following land application of manure.
  • This study aimed to investigate the effect of various temperatures and initial pH shocks on the persistence of a cephalosporin antibiotic and antibiotic resistance genes in dairy manure slurries.
  • Feces and urine were collected from 5 healthy dairy cows administered with cephapirin (cephalosporin antibiotic) at dry-off via intramammary infusion and were mixed with sterile water to generate manure slurries. In a 28-d incubation study, dairy manure slurries either were continuously exposed to 1 of 3 temperatures (10, 35, and 55°C) or received various initial pH (5, 7, 9, and 12) shocks.
  • Cephapirin was detected in the initial samples and on day 1 following all treatments, but it was undetectable thereafter. This indicates that cephapirin can be rapidly degraded irrespective of temperature and pH treatments. However, degradation was greater on day 1 with the mesophilic (35°C) and thermophilic (55°C) environments compared with the psychrophilic environment (10°C).
  • Increasing pH beyond neutral also accelerated degradation as cephapirin concentrations were lower on day 1 after initial alkaline adjustments (pH 9 and 12) than after neutral and acidic adjustments (pH 7 and 5).
  • Abundances of macrolide antibiotic resistance genes, mefA, were decreased in the psychrophilic and thermophilic environments and also following exposure to a strong alkaline shock (pH 12).
  • These results suggest that increasing temperature or pH during storage of dairy manure slurries could be used together with other on-farm practices that are tailored to reduce the transfer of antibiotic resistance genes from manure to the environment following land application.


Selected Articles on Dairy Intake and Human Health

Health Care Costs and Savings Associated with Increased Dairy Consumption among Adults in the United States. Scrafford CG, Bi X, Multani JK, Murphy MM, Schmier JK, Barraj LM. Nutrients. 2020 Jan 16;12(1).

  • The 2015–2020 Dietary Guidelines for Americans (DGA) encourages all Americans to consume 3 cup-equivalents (c-eq) of dairy products daily. However, the majority of Americans fall short of meeting recommended intakes of dairy products. Only 14% of Americans one year and older consume the recommended intake of dairy.
  • The purpose of this study is to estimate the impact on health care costs if United States (US) adults increased their dairy consumption to meet Dietary Guidelines for Americans (DGA) recommendations.
  • Risk estimates from recent meta-analyses quantifying the association between dairy consumption and health outcomes were combined with the increase in dairy consumption under two scenarios where population mean dairy intakes from the 2015-2016 What We Eat in America were increased to meet the DGA recommendations: (1) according to proportions by type as specified in US Department of Agriculture Food Intake Patterns and (2) assuming the consumption of a single dairy type.
  • The resulting change in risk was combined with published data on annual health care costs to estimate impact on costs. Health care costs were adjusted to account for potential double counting due to overlapping comorbidities of the health outcomes included.
  • Total dairy consumption among adults in the US was 1.49 cup-equivalents per day (c-eq/day), requiring an increase of 1.51 c-eq/day to meet the DGA recommendation. Annual cost savings of $12.5 billion (B) (range of $2.0B to $25.6B) were estimated based on total dairy consumption resulting from a reduction in stroke, hypertension, type 2 diabetes, and colorectal cancer and an increased risk of Parkinson’s disease and prostate cancer.
  • Similar annual cost savings were estimated for an increase in low-fat dairy consumption ($14.1B; range of $0.8B to $27.9B). Among dairy sub-types, an increase of approximately 0.5 c-eq/day of yogurt consumption alone to help meet the DGA recommendations resulted in the highest annual cost savings of $32.5B (range of $16.5B to $52.8B), mostly driven by a reduction in type 2 diabetes.
  • In conclusion, the adoption of a dietary pattern with increased dairy consumption among adults in the US to meet DGA recommendations has the potential to provide billions of dollars in savings.

Re-examination of dairy as a single commodity in US dietary guidance. Jacobs ET, Foote JA, Kohler LN, Skiba MB, Thomson CA. Nutr Rev. 2020 Jan 6. pii: nuz093.

  • Dairy products have been a key component of dietary guidance in the United States for more than 100  As noted in the 2015 Dietary Guidelines Advisory Committee (DGAC) report, research also shows that the consumption of dairy products at levels consistent with dietary guidance is associated with reduced risks for many chronic health conditions, including but not limited to obesity, cardiovascular disease, type 2 diabetes, and metabolic syndrome.
  • In light of major advances in the understanding of dietary intake and metabolism, the aim of this review was to examine whetherdairy should remain a single commodity in federal guidance.
  • Considerations include recognizing that a substantial proportion of the world’s adult population (65%-70%) exhibits lactase nonpersistence, a reduced ability to metabolize lactose to glucose and galactose. Shifts in the US population, including a greater proportion of African Americans and Asians, are of key importance because several studies have shown a markedly higher prevalence of lactase nonpersistence and, consequently, a lower dairy intake among these groups.
  • While cow’s milk alternatives are available, families who use them will pay up to an additional $1400 per year compared with those who are able to consume dairy products. Dietary guidance also contains downstream effects for government assistance, such as the US Department of Agriculture’s National School Lunch Program and School Breakfast Program.
  • The results of the present review suggest that consideration of these issues when developing population-level guidelines in the United States is warranted.

Potential Cardiometabolic Health Benefits of Full-Fat Dairy: The Evidence Base. Hirahatake KM, Astrup A, Hill JO, Slavin JL, Allison DB, Maki KC. Adv Nutr. 2020 Jan 6. pii: nmz132.

  • Since their inception in 1980, the Dietary Guidelines for Americans have promoted low- or fat-free dairy foods.
  • Removing fat from dairy does not reduce putatively beneficial nutrients per serving, including calcium, vitamin D, and potassium. Additionally, links between saturated fat and dietary cholesterol intakes with cardiovascular disease risk have helped to sustain the view that low-fat dairy foods should be recommended.
  • Emerging evidence shows that the consumption of full-fat dairy foods has a neutral or inverse association with adverse cardiometabolic health outcomes, including atherosclerotic cardiovascular disease, type 2 diabetes, and associated risk factors.
  • Thus, although low-fat dairy is a practical, practice-based recommendation, its superiority compared with full-fat dairy is not obviously supported by results from recent prospective cohort studies or intervention trials.
  • To evaluate the emerging science on full-fat dairy, a group of nutrition experts convened to summarize and discuss the scientific evidence regarding the health effects of consuming full-fat dairy foods.
  • Future studies should focus on full-fat dairy foods (milk, yogurt, and cheese) in the context of recommended dietary patterns and consider meal composition and metabolic phenotype in assessing the relation between full-fat dairy consumption and cardiometabolic health.

Substitution of Milk with Whole-Fat Yogurt Products or Cheese Is Associated with a Lower Risk of Myocardial Infarction: The Danish Diet, Cancer and Health cohort. Kvist K, Laursen ASD, Overvad K, Jakobsen MU. J Nutr. 2020 Jan 9. pii: nxz337.

  • Food-based dietary guidelines recommend replacement of whole-fat dairy products with low-fat variants based on data suggesting that diets high in saturated fat are associated with a higher risk of ischemic heart disease. However, the health effects of saturated fat may depend on the source.
  • The aim of this study was to investigate substitutions between different subgroups of dairy products and the risk of myocardial infarction.
  • Data were from the Danish Diet, Cancer and Health cohort and included 54,903 men and women aged 50-64 years at enrollment and without a myocardial infarction diagnosis.
  • During a median follow-up of 15.9 years, 3033 cases were identified. Whole-fat yogurt products in place of low-fat or whole-fat milk were associated with a lower risk of myocardial infarction (HR: 0.89 per 200 g/d replaced; and HR: 0.87 per 200 g/d replaced, respectively).
  • Substitution of 20 g/d of cheese for 200 g/d of low-fat or whole-fat milk was also associated with a lower risk of myocardial infarction (HR: 0.96 and HR: 0.95, respectively).
  • In conclusion, among middle-aged Danish men and women, intake of whole-fat yogurt products or cheese in place of milk, regardless of fat content, was associated with a lower risk of development of myocardial infarction.

Yogurt Intake Reduces All-Cause and Cardiovascular Disease Mortality: A Meta-Analysis of Eight Prospective Cohort Studies. Gao X, Jia HY, Chen GC, Li CY, Hao M. Chin J Integr Med. 2020 Jan 22.

  • Yogurt intake has been associated with overall better dietary quality, and recent studies have reported positive effects of yogurt intake on health outcomes, such as the lower incidence of type 2 diabetes mellitus.
  • The aim of this meta-analysis was to assess the relationship between yogurt intake and mortality risk from 8 prospective cohort studies.
  • The results of the highest and lowest categories of yogurt intake in each study were collected. The dose-response analysis was calculated.
  • Compared with the lowest category, the highest category of yogurt intake was not significantly related with all-cause mortality (HR =0.93), CVD mortality (HR=0.92) and cancer mortality (HR=0.97).
  • However, yogurt intake ⩾200 g/d was significantly associated with a lower all-cause mortality (HR=0.88) and CVD mortality (HR=0.87) in the subgroup analysis. The dose-response analysis showed that yogurt intake of 200 g/d was inversely associated with all-cause mortality (HR=0.95) and CVD mortality (HR=0.92).
  • This review provided the evidence regarding yogurt intake can reduce all-cause and CVD mortality. Although some positive findings were identified, more high-quality cohort studies and randomized controlled trials are warranted on a possible protective effect of yogurt on health.

Trimethylamine-N-Oxide Postprandial Response in Plasma and Urine Is Lower After Fermented Compared to Non-Fermented Dairy Consumption in Healthy Adults. Burton KJ, Krüger R, Scherz V, Münger LH, Picone G, Vionnet N, Bertelli C, Greub G, Capozzi F, Vergères G. Nutrients. 2020 Jan 16;12(1).

  • Trimethylamine-N-oxide (TMAO) can be produced by the gut microbiota from dietary substrates and is associated with cardiovascular disease. While dairy products contain TMAO precursors, the effect of fermented dairy on TMAO metabolism remains unclear.
  • In this study, the researchers used plasma and urine samples collected from two randomized cross-over studies to evaluate the effects of fermented dairy consumption on TMAO metabolism.
  • In Study 1, thirteen healthy young men tested a yogurt and an acidified milk during postprandial tests and a two-week daily intervention. In Study 2, ten healthy adults tested milk and cheese during postprandial tests.
  • Fermented milk products were associated with lower postprandial TMAO responses than non-fermented milks in urine and in plasma, comparing yogurt and acidified milk. Daily consumption of dairy products did not differentially affect fasting TMAO metabolites. Significant correlations were observed between microbiota taxa and circulating or urinary TMAO concentrations.
  • In conclusion, fermentation of dairy products appear, at least transiently, to affect associations between dairy products and circulating TMAO levels.

Whey protein but not collagen peptides stimulate acute and longer-term muscle protein synthesis with and without resistance exercise in healthy older women: a randomized controlled trial. Oikawa SY, Kamal MJ, Webb EK, McGlory C, Baker SK, Phillips SM. Am J Clin Nutr. 2020 Jan 9. pii: nqz332.

  • Aging appears to attenuate the response of skeletal muscle protein synthesis to anabolic stimuli such as protein ingestion and resistance exercise.
  • The purpose of this study was to determine the effects of protein quality on feeding- and feeding plus resistance exercise-induced increases of acute and longer-term muscle protein synthesis after ingestion of whey protein and collagen protein.
  • In a double-blind parallel-group design, 22 healthy older women were randomly assigned to consume a 30-gram supplement of either whey protein or collagen protein twice daily for 6 days. Participants performed unilateral resistance exercise twice during the 6-day period .
  • Acutely, whey protein increased muscle protein synthesis in the feeding-only leg (Rest) and in the feeding plus exercise leg (Exercise), whereas collagen protein increased muscle protein synthesis only in the exercise leg.
  • Muscle protein synthesis was greater in whey protein than collagen in both the Rest and Exercise legs. Longer-term muscle protein synthesis increased in Rest and in Exercise with whey protein; however, muscle protein synthesis was not significantly elevated above baseline in Rest or Exercise with collagen protein. Longer-term muscle protein synthesis was greater in whey protein than in collagen protein in both Rest and Exercise.
  • In conclusion, supplementation with whey protein elicited greater increases in both acute and longer-term muscle protein synthesis than collagen protein supplementation, which is suggestive that whey protein is a more effective supplement to support skeletal muscle retention in older women than collagen protein.