Dairy Research Bulletin – August 2020

Welcome to the August 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.

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Selected Articles on Social Responsibility, Environmental Management, and Sustainability

Analysis of closed versus operating dairies in the southeastern United States. Ellis J, DeLong KL, Lambert DM, Schexnayder S, Krawczel P, Oliver S.J Dairy Sci. 2020;103(6):5148-5161.

  • Significant changes have occurred in the US dairy industry in the last decade, involving the number of dairy farms, herd size, milk quality, and management practices, yet the dairy industry remains the fourth leading agricultural sector in the United States, with $38 billion of milk sales in 2017.
  • Although the number of dairy cows in the United States has remained relatively constant over the past decade, at approximately 9 million head, the number of dairy operations has decreased by 30%, resulting in larger dairies. This trend is even more prevalent in the southeastern United States, where the number of dairies has decreased by 39% from 5,315 in 2008 to only 3,235 in 2017.
  • Additionally, downward pressure on bulk tank somatic cell count, which is used as a milk quality metric and has implications regarding animal health, intensified with US processors’ introduction of incentive and penalty systems for quality milk production, necessitating better management of mastitis in dairy herds.
  • In this context, this study examines factors that affect southeastern US dairy farms’ persistence in the industry by using primary survey data collected in 2013 through a mail survey of Grade A dairies in Georgia, Mississippi, Kentucky, North Carolina, South Carolina, Tennessee, and Virginia. Dairies that were no longer operational had exited the industry from 2007 through 2014. This study analyzed differences between dairies that have closed compared with dairies still operating in the southeastern United States.
  • Dairy farms with more cows and higher average milk production per cow were more likely to be operational. For an additional 10 kg/day of milk production per cow, the dairy was 1.5% more likely to be operational. For each 100 additional cows a dairy had, it was 4% more likely to be operational.
  • The analysis also identifies nonpecuniary determinants of operational status for southeastern US dairies, such as mastitis management practices. Findings suggest that operations capable of leveraging scale effects are more likely to remain operational, with results affirming the consolidation of the US dairy industry and demonstrating that more productive farms are more likely to stay in operation. Results also suggest that factors other than farm size affect a dairy’s operational status.

The dairy biorefinery: Integrating treatment processes for cheese whey valorisation. Asunis F, De Gioannis G, Dessì P, Isipato M, Lens PNL, Muntoni A, Polettini A, Pomi R, Rossi A, Spiga D.J Environ Manage. 2020 Aug 28;276:111240.

  • With an estimated worldwide production of 190 billion kg per year, and due to its high organic load, cheese whey represents a huge opportunity for bioenergy and biochemicals production.
  • Several physical, chemical and biological processes have been proposed to valorise cheese whey by producing biofuels (methane, hydrogen, and ethanol), electric energy, and/or chemical commodities (carboxylic acids, proteins, and biopolymers).
  • A biorefinery concept, in which several value-added products are obtained from cheese whey through a cascade of biotechnological processes, is an opportunity for increasing the product spectrum of dairy industries while allowing for sustainable management of the residual streams and reducing disposal costs for the final residues.
  • This review critically analyses the different treatment options available for energy and materials recovery from cheese whey, their combinations and perspectives for implementation.
  • Thus, instead of focusing on a specific valorisation platform, in the present review the most relevant aspects of each strategy are analysed to support the integration of different routes, in order to identify the most appropriate treatment train.

A comparative study on milk composition of Jersey and Holstein dairy cows during the early lactation. Lim DH, Mayakrishnan V, Lee HJ, Ki KS, Kim TI, Kim Y.J Anim Sci Technol. 2020 Jul;62(4):565-576.

  • Recently, Jersey cattle was introduced and produced by embryo transfer to Korea. This study was conducted to investigate the differences of milk compositions between Jersey and Holstein cows and the relationship between days in milk (DIM) and milk compositions during early lactation.
  • Data were collected from twelve lactating cows from Department of Animal Resources Development at National Institute of Animal Science. Cows in parity 1 were used, and calved at spring from April to March of 2017. All cows were housed in two sections within a free-stall barn, which divided into six from each breed, and received a basal total mixed ration.
  • Milk samples of each cow were collected at 3 DIM and 30 DIM for analyzing the milk compositions, including fatty acids (FA), amino acids and minerals.
  • Total solids, citrate, and milk urea nitrogen level differed between the breeds. As DIM went from 3 to 30, milk protein, total solids, and somatic cell count decreased, but lactose increased in all breed milk.
  • Citrate and free fatty acid (FFA) elevated in Jersey milk, whereas reduced in Holstein milk.
  • Proportions of some individual FA varied from the breeds. Myristic (C14:0), palmitic (C16:0), and arachidonic acid (C20:4) in milk from all cows were higher at 3 DIM than at 30 DIM. Also, stearic (C18:0) and oleic acid (C18:1) were lower at 3 DIM than at 30 DIM, and the C18:1 to C18:0 ratio was significantly differed in DIM × breed interactions.
  • The contents of the individual amino acids did not differ from the breeds. Calcium, phosphorous, magnesium, and zinc (Zn) contents was significantly increased in Holstein milk than Jersey milk at 3 DIM. Also, K and Zn concentrations were higher in Holstein milk than in Jersey milk at 30 DIM.
  • It was concluded that Jersey cows would produce more effective milk in processing dairy products and more proper energy status compared with Holstein cows in early lactation under the same environmental and nutritional conditions.

Review: Climate Finance readiness of the animal protein sector: overview of experience in linking the sector to Climate Finance, and options to address bottlenecks. Massé J, Gerber PJ, Halpern C, Baedeker T.Animal. 2020 Aug 19:1-9.

  • Despite the importance of the role of Climate Finance to comply with the United Nations Framework Convention on Climate Change 1.5°C objective, there is no consensus on the definition of Climate Finance and the estimated assessment of its aggregated flows and effects remains challenging.
  • Despite being a major emitter and having a significant and cost-effective mitigation potential, the livestock sector has so far only received a marginal share of Climate Finance. As demand for animal protein products continues to increase (68% between 2010 and 2050), there is a compelling case for channeling more Climate Finance investments into the sector to incentivize greenhouse gas emissions reduction at scale.
  • Bottlenecks in linking the livestock sector to Climate Finance include the insufficient capacity to assess the cost-benefit of projects, high upfront cost and risk perception of investors, the informality of the sector, non-existence of Climate Finance instruments dedicated to the livestock sector and lack of cost-efficient Monitoring, Reporting and Verification systems.
  • Nevertheless, recent developments provide avenues to increase the access of the animal protein sector to Climate Finance.

Fossil energy use, climate change impacts, and air quality-related human health damages of conventional and diversified cropping systems in Iowa, USA. Hunt ND, Liebman M, Thakrar SK, Hill JD.Environ Sci Technol. 2020 Aug 10.

  • Cropping system diversification can reduce the negative environmental impacts of agricultural production, including soil erosion and nutrient discharge. Less is known about how diversification affects energy use, climate change, and air quality, when considering farm operations and supply-chain activities.
  • Researchers conducted a life cycle study using measurements from a nine-year Iowa field experiment to estimate fossil energy use, greenhouse gas (GHG) emissions, PM2.5-related emissions, human health impacts, and other agronomic and economic metrics of contrasting crop rotation systems and herbicide regimes.
  • Rotation systems comprised a 2-year corn-soybean system, a 3-year corn-soybean-oat/clover system, and a 4-year corn-soybean-oat/alfalfa-alfalfa system. Each was managed with conventional and low-herbicide treatments.
  • GHG and PM2.5-related emissions damages were 42%-57% lower in the 3-year and 4-year rotations than the 2-year rotation. Diversification reduced GHG emissions by 56%-65% and lowered fossil energy consumption by 58%-65%. Herbicide treatment had no significant impact on environmental outcomes, while corn and soybean yields and whole-rotation economic returns improved significantly under diversification.
  • Results suggest that diversification via shifting from conventional corn-soybean rotations to longer rotations with small grain and forage crops substantially reduced fossil energy use, and GHG emissions, and air quality damages, but did not compromise economic or agronomic performance.

Emergence of livestock-associated MRSA ST398 from bulk tank milk, China. Cui M, Li J, Ali T, Kalim K, Wang H, Song L, Li Z, Ren X, Ma F, Zou M, Shen S, Xu S.J Antimicrob Chemother. 2020 Aug 14:dkaa367.

  • Staphylococcus aureusis a common facultative pathogenic bacterium that has been recognized as a serious public health risk, especially considering the emergence of MRSA. Since the discovery of clonal complex (CC) 398, particularly livestock-associated MRSA (LA-MRSA) ST398 among livestock, ST398 has been found to be associated with human infections, representing a great public health concern.
  • The objective of this study was todetect livestock-associated MRSA (LA-MRSA) ST398 from bulk tank milk in China and to determine the phenotypic and genomic characteristics of the strains.
  • LA-MRSA ST398 strains were isolated from bulk tank milk samples in Shanghai and their susceptibilities to antimicrobials were determined using the broth dilution method. Genomic characterization of MRSA ST398 strains was performed by WGS and their evolutionary relationships were assessed by phylogenetic analysis.
  • Two LA-MRSA ST398 isolates were recovered from bulk tank milk samples in two geographically distant farms in China. Whole-genome analysis strongly suggested that the LA-MRSA ST398 strains were closely related to the highly virulent hospital-associated MRSA (HA-MRSA) ST398 strains in China.
  • The presence of LA-MRSA ST398 in bulk tank milk might be a serious threat to public health, highlighting the need for active surveillance of LA-MRSA in healthy cattle in China.

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Selected Articles on Dairy Intake and Human Health


Invited review: Maintaining and growing fluid milk consumption by children in school lunch programs in the United States.
Sipple LR, Barbano DM, Drake M.J Dairy Sci. 2020 Sep;103(9):7639-7654.

  • Fluid milk consumption among children has declined for decades. Adequate consumption of milk and dairy products, especially during childhood, has beneficial health outcomes for growth, development, and reduced risk of osteoporosis, hypertension, obesity, and cancer during adulthood.
  • Satisfaction with milk flavor, perceived health benefits derived from milk, and habit are primary drivers of lifelong milk consumption. Child preferences and attitudes for milk may differ from those of adults, and as such, understanding and fulfilling the needs of children is crucial to reverse the decline in milk consumption.
  • School meal programs make fluid milk accessible to millions of children each day; however, regulations and school lunch procurement systems in the United States sometimes make it difficult to provide novel or value-added milk products in these programs.
  • Total consumption of all milk types in US schools declined by 14.2% from 2008 to 2017, and the percentage of children participating in the school lunch program has also declined. This decline has also been driven by declining average daily participation in the school meal program and may also reflect children’s dissatisfaction with the sensory characteristics and the form of milk offered in schools.
  • The change in form of milk offered in schools to lower fat and lower added sugar content in the United States has been driven by government-mandated school lunch calorie and fat requirements.
  • This review describes the current milk consumption trends among children; the structure and basic requirements of the school lunch program in total and for milk; and the intrinsic, extrinsic, and environmental factors that influence child perception, preference, and consumption of fluid milk in the US school system.

Community-based interventions to increase dairy intake in healthy populations: a systematic review. Nikniaz Z, Tabrizi JS, Ghojazadeh M, Farhangi MA, Hosseini MS, Allameh M, Norouzi S, Nikniaz L.Public Health Rev. 2020 Aug 4;41:18.

  • Considering the low frequency of dairy intake in the population, interventions aiming to increase its consumption can be a priority for any health system.
  • This study aims to summarize community-based interventions for improving dairy consumption and their effectiveness to help policy-makers in designing coherent public health strategies.
  • This study was conducted in 2019, using PubMed/MEDLINE, Scopus, EMBASE, Cochrane Library, Web of Science, ProQuest, and Google Scholar.
  • Out of 521 initially identified articles, 25 studies were included. These results from these articles showed that:
    • Interventions reported in 19 of 25 studies were effective in increasing dairy consumption.
    • Interventions in high-income countries were more effective than those in middle- and low-income countries.
    • Interventions in health centers and supermarkets were more effective than the community and school-level interventions.
    • Interventions in supermarkets and adolescents as target groups were more effective than children, middle-aged people, and the elderly.
    • Education interventions and changing buying/selling pattern were more effective than multiple interventions.
    • Interventions longer than 24 and 48 weeks were more effective than shorter interventions.
  • In conclusion,three policy options including educational interventions, multiple interventions, and changing the purchase pattern are suggested. It seems that applying all of the interventions together can be more effective. Also, long-term and well-designed future studies in different settings are recommended to confirm these results.

Dairy consumption and risk of type-2 diabetes: the untold story. Gudi SK.Ann Pediatr Endocrinol Metab. 2020 Jul 31.

  • The role of dairy products in human health has been extensively studied for decades; however, evidence regarding dairy consumption and risk of type 2 diabetes (T2D) remains controversial and uncertain. Furthermore, study results are misinterpreted to a remarkable extent.
  • The aim of this review is to critically appraise the association between intake of dairy foods and risk of T2D. A thorough search was conducted using electronic databases of PubMed, Scopus, and Web of Science. Related studies that addressed this research question between 2004 to 2019 were considered.
  • Although most of the existing evidence suggests a beneficial role of dairy consumption on risk of T2D, only low-fat dairy foods and yogurt have shown a significant and consistent role, while other dairy products showed no association with prevention of T2D.
  • Researchers, readers, and the public should maintain caution when reporting and interpreting findings and consider aspects such as heterogeneity, generalizability, and clinical and statistical significance.
  • After considering all available evidence, dairy products as part of a healthy diet plan do not show harmful effects on glycemic control. However, the potential benefits of dairy consumption on plasma glucose level, insulin sensitivity, and other T2D-related outcomes warrant future investigations with long-term, well-designed clinical trials.

Traditional plain yogurt: a therapeutic food for metabolic syndrome? Baspinar B, Güldaş M.Crit Rev Food Sci Nutr. 2020 Aug 4:1-15.

  • Dairy products have an important role in a healthy diet due to their high-quality protein and rich micronutrients. Yogurt, a fermented milk product, has a similar composition to milk but is a more concentrated product in terms of group B vitamins, minerals, and proteins. It is known that bioactive metabolites and live enzymes that occur by fermentation and digestion, affect the health positively by improving gut microbiota.
  • In recent years, the prevalence of metabolic syndrome, which threatens public health, is increasing rapidly. As with other noninfectious diseases, the diet has an important effect on the prevention and treatment of metabolic syndrome.
  • It has been demonstrated that yogurt has a high-quality amino acid pattern, reduces energy intake by stimulating satiety, and regulates blood glucose level. In addition to the rich protein variety, yogurt also contains peptides that positively affect blood pressure.
  • Unlike milk, increased acidity during the fermentation of yogurt positively affects calcium absorption. Calcium plays an important role in the control of blood glucose and energy metabolism through insulin-dependent and non-insulin-dependent routes. In addition to reducing inflammation, calcium has a positive effect on the regulation of the blood lipid profile by increasing fecal fat excretion.
  • There are many lipid and lipoid nutrients such as saturated fatty acids, phospholipids, sphingolipids, and conjugated linoleic acid that may affect the blood lipid profile in yogurt positively or negatively.
  • There are seen very few randomized controlled studies that are focused on the relationship between yogurt and metabolic syndrome, and these are based on contradictory results. In this review, based on the clinical studies conducted to date, and the nutrient content of yogurt, possible mechanisms of these contradictory results are investigated.

Dairy consumption and risks of colorectal cancer incidence and mortality: a meta-analysis of prospective cohort studies. Jin S, Kim Y, Je Y. Cancer Epidemiol Biomarkers Prev. 2020 Aug 27:cebp.0127.2020.

  • Previous studies of dairy consumption and colorectal cancer incidence have shown inconsistent results, and there was no meta-analysis of dairy consumption with colorectal cancer mortality.
  • Researchers conducted a comprehensive analysis of prospective cohort studies to investigate these associations. PubMed and Web of Science databases were searched for eligible studies published up to July 2019, and random effects model was used to estimate pooled RR.
  • The researchers identified 31 prospective cohort studies, which included 24,964 and 2,302 cases for colorectal cancer incidence and mortality, respectively. The pooled RR of colorectal cancer incidence for the highest versus lowest categories of total dairy consumption was 0.79. For milk consumption, there was also a significant inverse association.
  • For cheese and fermented milk consumption, overall no association was found, but studies conducted in Europe showed a significant inverse association of cheese and fermented milk consumption.
  • For colorectal cancer mortality, the researchers found a 29% lower risk of death from colorectal cancer in subjects with high dairy consumption compared to those with low intakes of dairy products, but each type of dairy consumption did not show a significant association.
  • These findings suggest that high dairy consumption may be associated with lower colorectal cancer incidence and mortality, but further studies are warranted.

High prevalence of low dairy calcium intake and association with insomnia, anxiety, depression and musculoskeletal pain in university students from Jordan. Alkhatatbeh MJ, Khwaileh HN, Abdul-Razzak KK.Public Health Nutr. 2020 Aug 24:1-9.

  • There is evidence to suggest that increased dietary Ca intake, which is mainly obtained from dairy products(6), is associated with improved quality of sleep and reduced insomnia.
  • The objective of this study was to assess dairy Ca intake and investigate its relationship with insomnia and other common co-morbidities including anxiety, depression and musculoskeletal pain (MSP) among university students.
  • This cross-sectional study conducted at a University in Irbid, Jordan used a population of 1,000 young adults.
  • Low dairy Ca intake (<1000 mg/d) was reported by 96.5 % of participants, and moderate to severe insomnia reported by 15.6 % of participants. Abnormal anxiety and depression scores were reported by 26.2 and 18.0 % of participants, respectively. MSP was reported by 42.9 % of participants.
  • Participants with moderate to severe insomnia had lower dairy Ca, higher anxiety and depression scores and higher measures of MSP compared to participants with no insomnia.
  • Dairy Ca was weakly inversely correlated with Insomnia Severity Index (ISI) score, depression score and measures of MSP. Regression analysis indicated that insomnia was predicted by low dairy Ca, anxiety, depression, MSP, and smoking. Both anxiety and depression were predicted by increased ISI score, while depression alone was predicted by low dairy Ca.
  • In conclusion, low dairy Ca was highly prevalent and associated with insomnia and depression among university students. Individuals should be advised to increase dietary Ca intake to achieve the recommended daily amount. Further research is required to investigate a potential causal relationship between low Ca and both insomnia and its related co-morbidities.

Effect of Dairy Protein Intake on Muscle Mass among Korean Adults: A Prospective Cohort Study. So E, Joung H.Nutrients. 2020 Aug 21;12(9):E2537.

  • Although sarcopenia is largely attributed to aging, the condition can be accelerated by modifiable lifestyle factors such as physical inactivity, alcohol consumption, smoking, and malnutrition. Among dietary factors, it is generally accepted that adequate dietary protein is required for the maintenance of muscle mass in older adults.
  • Especially, increasing attention has focused on dairy foods, with evidence that essential amino acids play the predominant role in promoting positive muscle protein balance.
  • This cohort study aimed to identify the associations of dairy protein intake with the risk of developing a low muscle mass during a 12-year follow-up period, using data from 4412 middle-aged Korean Genome and Epidemiology Study participants with a normal baseline muscle mass.
  • Overall, 395 subjects developed a low Skeletal muscle mass index (SMI%) during an average follow-up of 141 months. The average consumption of milk and other dairy products was 73.6 and 104.1 g/day, respectively.
  • In men, a higher dairy protein intake was associated with a decreased risk of developing a low SMI. In a stratified analysis according to a total protein intake, this association was stronger in the lower-protein intake group, but not detected in the higher-protein intake group. Men who consumed milk ≥1 time/day had a significantly lower risk of developing a low SMI. No significant associations were observed in women.
  • In summary, dairy consumption appears to be beneficial for decreasing the risk of developing a low muscle mass in middle-aged Korean men.