Dairy Research Bulleting – April 2021

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

Environmental Management and Sustainability

Defining and validating regenerative farm systems using a composite of ranked agricultural practices. Fenster TLD, LaCanne CE, Pecenka JR, et al. F1000 Res. 2021;10:115.

• Ongoing efforts attempt to define farms as regenerative to aid marketers, policymakers, farmers, etc. The approach needs to balance precision with function, and must be transparent, simple, scalable, transferable, incorruptible, and replicable.
• Researchers have developed practice-based scoring systems to distinguish regenerative cropland and rangeland, and to validate them based on whether these scores scaled with regenerative goals on actual farm operations.
• Study systems included cornfields of the Upper Midwest, almond orchards of California, and rangeland systems of the Northern Plains. Response variables included soil carbon and organic matter, soil micronutrients, water infiltration rates, soil microbial communities, plant community structure, invertebrate community structure, pest populations, yields, and profit.
• The results showed that soil organic matter, fine particulate organic matter, total soil carbon, total soil nitrogen, phosphorous, calcium and sulfur all increased alongside regenerative matrix scores in one or both of the cropping systems. Water infiltration rates were significantly faster in more regenerative almond orchards. Soil bacterial biomass and soil health test scores were higher as cropland incorporated more regenerative practices.
• Plant species diversity and biomass increased significantly with the number of regenerative practices employed on almonds and rangelands. Invertebrate species diversity and richness were positively associated with regenerative practices in corn, almonds, and rangelands, whereas pest populations and almond yields were unaffected by the number of regenerative practices.
• Corn yields were negatively associated with more regenerative practices, while almond yields were unaffected by the number of regenerative practices. Profit was significantly higher on more regenerative corn and almond operations.
• In conclusion, this scoring system scaled positively with desired regenerative outcomes, and provides the basis for predicting ecosystem responses with minimal information about the farming operation. Natural clusters in the number of regenerative practices used can be used to distinguish regenerative and conventional operations.

Effect of winter cover crops on the soil microbiome: a systematic literature review. Morales ME, Iocoli GA, Villamil MB, Zabaloy MC. Rev Argent Microbiol. 2021 Apr 30:S0325-7541(21)00042-0.

• The inclusion of winter cover crops in no-till systems in replacement of bare fallow is a promising alternative to improve soil health and consequently, contribute to environmental sustainability of agricultural systems.
• This review provides a comprehensive evaluation of the effects of the use of winter cover crops in rotation with summer cash crops under no-till systems on the soil microbiome versus bare fallows.
• A systematic literature search was conducted to evaluate the impact of winter cover crops on microbial parameters indicative of abundance, activity and diversity.
• Twenty-two papers were selected based on seven combined criteria. The results of this review show that enzyme activities in soil are enhanced with the inclusion of winter cover crops in the rotation, particularly those that include legumes and mix of species.
• In general, more than half of the analyzed papers report higher microbial biomass in soils with winter cover crops than in bare fallow.

Integrating Dairy Manure for Enhanced Resource Recovery at a WRRF: Environmental Life Cycle and Pilot-scale Analyses. Bryant C, Coats ER. Water Environ Res. 2021 Apr 20. doi: 10.1002/wer.1574.

• The Twin Falls, Idaho wastewater treatment plant currently operates solely to achieve regulatory permit compliance.
• Research was conducted to evaluate conversion of the wastewater treatment plant to a water resource recovery facility and to assess the water resource recovery facility environmental sustainability.
• Process configurations were evaluated to produce five resources – reclaimed water, biosolids, struvite, biogas, and bioplastics (polyhydroxyalkanoates, PHA) which occurred using fermented dairy manure.
• Results indicate that electricity production via combined heat and power was most important in achieving environmental sustainability; energy offset ranged from 43-60%, thereby reducing demand for external fossil fuel-based energy.
• Integrating dairy manure to produce bioplastics diversifies the resource recovery portfolio while maintaining water resource recovery facility environmental sustainability; pilot scale evaluations demonstrated that water resource recovery facility effluent quality was not affected by the addition of effluent from PHA production.
• Collectively, results show that a water resource recovery facility integrating dairy manure can yield a diverse portfolio of products while operating in an environmentally sustainable manner.

Novel use of Kombucha consortium to reduce Escherichia coli in dairy shed effluent. Laurenson S, Villamizar L, Ritchie W, Scott S, Mackay M. J Sci Food Agric. 2021 Apr 11.

• Fecal contamination from dairy farm effluent is a major risk to water quality in New Zealand.
• In this study researchers tested the efficacy of Kombucha SCOBY (symbiotic culture of bacteria and yeast), to reduce the concentration of Escherichia coli in dairy shed effluent (DSE).
• The results showed thatKombucha SCOBY was highly effective in lowering the number of E. coli colony forming units (CFUs) to levels that were undetectable. The decrease in CFUs occurred rapidly within 48 h of Kombucha SCOBY being inoculated to the effluent matrix and was accompanied by a corresponding decline in pH.
• In conclusions, the researchers concluded that Kombucha SCOBY was effective in reducing the abundance of E. coli in DSE due to its effect on solution pH. Further work is required to assess the practicality of treating DSE with Kombucha SCOBY within a farm environment where effluent management and climatic complexities are important.

Animal Health and Food Safety

On-Farm Anaerobic Digestion of Dairy Manure Reduces the Abundance of Antibiotic Resistance-Associated Gene Targets, and the Potential for Plasmid Transfer. Tran TT, Scott A, Tien YC, et al. Appl Environ Microbiol. 2021 Apr 30:AEM.02980-20.

• Using livestock manure for fertilization can entrain antibiotic resistant bacteria into soil. Although lab-scale anaerobic treatments have showed potential of reducing antibiotic resistance genes, there are very few data from commercial farms.
• The present study investigated the impact of on-farm anaerobic digestion on the abundance of enteric bacteria, antibiotic resistance-associated gene targets and the horizontal transfer potential of extended-spectrum β-lactamase (ESBL) genes.
• Samples of raw and digested manure were obtained from six commercial dairy farms in Ontario, Canada.
• Digestion significantly abated populations of viable coliforms in all six farms. Digestion significantly decreased the frequency of the horizontal transfer potential of ESBL genes.
• Ten gene targets were quantified by quantitative PCR on a subset of 18 raw and 18 digested samples. Most targets were significantly more abundant in raw manure, however two targets (ermBand ermF) targets were more abundant in digested samples.
• Overall, anaerobic digestion abated coliform bacteria, the genes that they carry and the potential for ESBL-carrying plasmid transfer.

Views of American animal and dairy science students on the future of dairy farms and public expectations for dairy cattle care: A focus group study. Ritter C, Russell ER, Weary DM, von Keyserlingk MAG. J Dairy Sci. 2021 Apr 22:S0022-0302(21)00538-5.

• Students completing advanced degrees in dairy or animal science may go on to have a major impact on the food animal agriculture industries.
• The aim of this study was to better understand student views of the future of dairying, including changes in practices affecting animal care on farms as well as perceived public perceptions.
• Researchers conducted 6 focus group sessions with undergraduate students enrolled in the 2019 US Dairy Education and Training Consortium held in Clovis, New Mexico, and used explorative key word analysis of written notes and thematic analysis of the semi-structured discussions.
• Some “must-haves” of future animal care on dairy farms included increased use of technology, group housing of calves, and adequate facilities, including enrichment.
• Although the influence of the public was highlighted by the students, they were not always certain what specific values the public holds and doubted the feasibility and practicality of some expectations, such as providing pasture access or keeping the calf and cow together. They further demonstrated uncertainty about how best to align the directions of the industry with public expectations.
• Although the students felt that public education could be used to demonstrate the legitimacy of dairy practices, they also believed that the industry should strive to find compromises and work toward meeting public expectations.
• Deciding what animal welfare considerations (e.g., naturalness, affective states, or animal health) were most relevant was a challenge for the students, perhaps reflecting diverging messages received during their own education.

Benchmarking of farms with automated milking systems in Canada and associations with milk production and quality. Matson RD, King MTM,  DeVries TJ, et al. J Dairy Sci. 2021 Apr 22:S0022-0302(21)00553-1.

• The objective of this study was to benchmark the herd-level housing and management strategies of automated milking system (AMS) farms across Canada and assess the associations of these herd-level housing factors and management practices with milk production and quality.
• Canadian AMS farms (n = 197; Western Canada: n = 50, Ontario: n = 77, Quebec: n = 59, Atlantic Canada: n = 11) were each visited once from April to September 2019, and details were collected related to barn design and herd management practices. Milk-recording data for the 6 months before farm visits were collected.
• Farms averaged (± standard deviation) 110 ± 102 lactating cows, 2.4 ± 1.9 AMS units/farm, 47.5 ± 14.9 cows/AMS, 36.7 ± 5.0 kg/d of milk, 4.13 ± 0.34% fat, 3.40 ± 0.16% protein, and a herd-average somatic cell count of 186,400 ± 80,800 cells/mL.
• Farms mainly used freestall housing systems (92.5%), organic bedding substrates (73.6%), and free flow cow traffic systems (87.8%); farms predominantly milked Holsteins (90.4%).
• At the herd level, feed push-up frequency and feed bunk space were positively associated with milk yield. Greater milk yield was associated with herds using inorganic (sand) versus organic bedding, milking Holsteins versus non-Holsteins, and using a form of mechanical ventilation versus natural ventilation alone.
• Milk fat and milk protein content were only associated with breed. Herds with lower somatic cell counts had more frequent alley cleaning, wider lying alleys, and sand bedding.
• The results highlight the importance of using sand bedding, using mechanical ventilation, keeping feed pushed up, ensuring alleys are clean, and ensuring adequate space at the feed bunk for maintaining herd-level productivity and milk quality in farms with AMS.

Consumer trust in the dairy value chain in China: The role of trustworthiness, melamine scandal, and media. Li S, Wang Y, Tacken GML, Liu Y, Sijtsema SJ. J Dairy Sci. 2021 Apr 22:S0022-0302(21)00539-7.

• This study provides a deep insight into Chinese consumer trust in the Chinese dairy value chain, as a lack of trust due to the 2008 melamine scandal has been widely recognized as a barrier to the development of the domestic dairy industry in China.
• Based on face-to-face interviews with 954 Chinese consumers in Beijing, Shanghai, and Shijiazhuang, this study measured consumer trust in farmers, manufacturers, retailers, the government, and third parties. Consumer trust was studied by measuring the effect of beliefs on the trustworthiness of actors (i.e., competence, benevolence, integrity, credibility, and openness), and current experiences regarding the melamine scandal and the media. The results showed that the level of trust in dairy chain actors varied.
• The government and third parties were relatively highly trusted, whereas retailers were considered less trustworthy. The importance of consumer beliefs about trustworthiness are different among actors. Consumer belief of competence determines trust in farmers and manufacturers.
• For retailers, the government, and third parties, respectively, benevolence, credibility, and openness are the most important factors.
• Trust in dairy chain actors is still strongly negatively affected by current experiences regarding the melamine scandal, even though it occurred more than 10 years ago. Using social media to directly provide more information and establish continuous daily communication with consumers could help manufacturers and third parties to strengthen consumer trust.

Human Nutrition and Health

Consumption of dairy products and cardiovascular disease risk: results from the French prospective cohort NutriNet-Sante. Sellem L, Srour B, Jackson KG, et al. Br J Nutr. 2021 Apr 29:1-37.

• In France, dairy products contribute to dietary saturated fat intake, of which reduced consumption is often recommended for cardiovascular disease (CVD) prevention. Epidemiological evidence on the association between dairy consumption and CVD risk remains unclear, suggesting either null or inverse associations.
• This study aimed to investigate the associations between dairy consumption (overall and specific foods) and CVD risk in a large cohort of French adults.
• This prospective analysis included 104,805 participants aged ≥ 18 years from the NutriNet-Santé cohort (2009-2019) with a mean follow-up 5.5 years. Total dairy, milk, cheese, yogurts, fermented and reduced-fat dairy intakes were investigated. CVD cases (n=1,952) included cerebrovascular (n=878 cases) and coronary heart diseases (CHD, n=1,219 cases).
• There were no significant associations between dairy intakes and total CVD or CHD risks. However, the consumption of at least 160 g/d of fermented dairy (e.g. cheese and yogurts) was associated with a 19% reduced risk of cerebrovascular diseases compared to intakes below 57 g/d.
• Despite being a major dietary source of saturated fats, dairy consumption was not associated with CVD or CHD risks in this study. However, fermented dairy was associated with a lower cerebrovascular disease risk.

Dairy consumption and mortality after myocardial infarction: a prospective analysis in the Alpha Omega Cohort. Cruijsen E, Jacobo Cejudo MG, Küpers LK, Busstra MC, Geleijnse JM. Am J Clin Nutr. 2021 Apr 7:nqab026.

• Population-based studies generally show neutral associations between dairy consumption and ischemic heart disease (IHD) mortality, whereas weak inverse associations were found for cardiovascular disease (CVD) and stroke mortality. Whether dairy consumption affects long-term survival after myocardial infarction is unknown.
• The objective of this study was to investigate different types of dairy and long-term mortality risk in drug-treated post-MI patients.
• The study included 4,365 Dutch patients from the Alpha Omega Cohort aged 60-80 y (21% women) with a myocardial infarction ≤10 year before enrollment.
• The results showed that most patients were Dutch, 24% were obese, 20% had diabetes, and 97% used cardiovascular medication.
• Median intakes were 39 g/d for plain yogurt, 88 g/d for total nonfermented milk, and 17 g/d for hard cheeses. Of the cohort, 10% consumed high-fat milk.
• During ∼12 y of follow-up, 2035 deaths occurred, including 903 from CVD, 558 from IHD, and 170 from stroke. Yogurt was linearly inversely associated with CVD mortality (4% reduced risk per 25 g/d) and nonlinearly inversely associated with all-cause mortality. Milk was not associated with any of the outcomes, except for a 30% higher mortality risk in high-fat milk consumers. Other dairy groups were not associated with mortality risk.
• In Dutch post- myocardial infarction patients, yogurt consumption was inversely associated with CVD mortality and all-cause mortality. Associations for milk and other dairy products were neutral or inconsistent.

Associations of Dairy Intake with Circulating Biomarkers of Inflammation, Insulin Response, and Dyslipidemia among Postmenopausal Women. Shi N, Olivo-Marston S, Jin Q, et al. J Acad Nutr Diet. 2021 Apr 13:S2212-2672(21)00151-9.

• Cardiometabolic diseases are prevalent in aging Americans. Although some studies have implicated greater intake of dairy products, it is not clear how dairy intake is related to biomarkers of cardiometabolic health.
• The study’s aim was to test the hypothesis that associations of dairy foods with biomarkers of lipid metabolism, insulin-like growth factor signaling, and chronic inflammation may provide clues to understanding how dairy can influence cardiometabolic health.
• This was a cross-sectional study in the Women’s Health Initiative using baseline food frequency questionnaire data to calculate dairy intake. Participants were 35,352 postmenopausal women aged 50 to 79 years at 40 clinical centers in the United States.
• The results showed that lower triglyceride concentrations were associated with greater intake of total dairy (-0.8%), mainly driven by full-fat varieties. Individual dairy foods had specific associations with circulating lipid components. For example, greater total milk intake was associated with lower concentrations of total cholesterol (-0.4%) and high-density lipoprotein cholesterol (-0.5%), whereas greater butter intake was associated with higher total cholesterol (0.6%) and high-density lipoprotein cholesterol (1.6%) concentrations.
• In contrast, higher total yogurt intake was associated with lower total cholesterol (-1.1%) and higher high-density lipoprotein cholesterol (1.8%).
• Greater total dairy intake (regardless of fat content), total cheese, full-fat cheese, and yogurt were consistently associated with lower concentrations of glucose, insulin, and C-reactive protein. However, milk and butter were not associated with these biomarkers.
• Higher dairy intake, except butter, was associated with a favorable profile of lipids, insulin response, and inflammatory biomarkers, regardless of fat content.

Food and Food Groups in Inflammatory Bowel Disease (IBD): The Design of the Groningen Anti-Inflammatory Diet (GrAID). Campmans-Kuijpers MJE, Dijkstra G. Nutrients. 2021;13(4):1067.

• Diet plays a pivotal role in the onset and course of inflammatory bowel disease (IBD). Patients are keen to know what to eat to reduce symptoms and flares, but dietary guidelines are lacking. To advice patients, an overview of the current evidence on food (group) level is needed.
• This narrative review studies the effects of food (groups) on the onset and course of IBD and if not available the effects in healthy subjects or animal and in vitro IBD models. Based on this evidence the Groningen anti-inflammatory diet (GrAID) was designed and compared on food (group) level to other existing IBD diets.
• Although on several foods conflicting results were found, this review provides patients a good overview. Based on this evidence, the GrAID consists of lean meat, eggs, fish, plain dairy (such as milk, yoghurt, kefir and hard cheeses), fruit, vegetables, legumes, wheat, coffee, tea and honey.
• Red meat, other dairy products (such as ice cream) and sugar should be limited. Canned and processed foods, alcohol and sweetened beverages should be avoided.
• This comprehensive review focuses on anti-inflammatory properties of foods providing IBD patients with the best evidence on which foods they should eat or avoid to reduce flares.

Invited review: Milk fat globule membrane-A possible panacea for neurodevelopment, infections, cardiometabolic diseases, and frailty. Raza GS, Herzig KH, Leppäluoto J. J Dairy Sci. 2021 Apr 22:S0022-0302(21)00535-X

• Milk is an evolutionary benefit for humans. For infants, it offers optimal nutrients for normal growth, neural development, and protection from harmful microbes. Humans are the only mammals who drink milk throughout their life.
• Lipids in colostrum originate mostly from milk fat globule membrane (MFGM) droplets extruded from the mammary gland. The MFGM gained much interest as a potential nutraceutical, due to their high phospholipid (PL), ganglioside (GD), and protein contents.
• In this review, we focused on health effects of MFGM ingredients and dairy food across the life span, especially on neurodevelopment, cardiometabolic health, and frailty in older adults.
• The MFGM supplements to infants and children reduced gastrointestinal and respiratory tract infections and improved neurodevelopment due to the higher content of protein, PL, and GD in MFGM.
• The MFGM formulas containing PL and GD improved brain myelination and fastened nerve conduction speed, resulting in improved behavioral developments. Administration of MFGM-rich ingredients improved insulin sensitivity and decreased inflammatory markers, LDL-cholesterol, and triglycerides by lowering intestinal absorption of cholesterol and increasing its fecal excretion.
• The MFGM supplements, together with exercise, improved ambulatory activities, leg muscle mass, and muscle fiber velocity in older adults. There are great variations in the composition of lipids and proteins in MFGM products, which make comparisons of the different studies impossible.
• Although we are currently only beginning to understand the possible health effects of MFGM products, the current MFGM supplementation trials as presented in this review have shown significant clinical health benefits across the human life span, which are worth further investigation.

The Potential Nutrition-, Physical- and Health-Related Benefits of Cow’s Milk for Primary-School Aged Children. Rumbold P, McCullogh N, Boldon R, et al. Nutr Res Rev. 2021 Apr 27:1-42.

• Cow’s milk is a naturally nutrient-dense foodstuff. A significant source of many essential nutrients, its inclusion as a component of a healthy balanced diet has been long recommended. Beyond milk’s nutritional value, an increasing body of evidence illustrates cow’s milk may confer numerous benefits related to health.
• Evidence from adult populations suggests that cow’s milk may have a role in overall dietary quality, appetite control, hydration and cognitive function. Although evidence is limited compared to the adult literature, these benefits may be echoed in recent paediatric studies.
• This article, therefore, reviews the scientific literature to provide an evidence-based evaluation of the associated health benefits of cow’s milk consumption in primary-school aged children (4-11 years). We focus on seven key areas related to nutrition and health comprising nutritional status, hydration, dental and bone health, physical stature, cognitive function, and appetite control. The evidence consistently demonstrates cow’s milk (plain and flavoured) improves nutritional status in primary-school aged children.
• With some confidence, cow’s milk also appears beneficial for hydration, dental and bone health and beneficial to neutral concerning physical stature and appetite. Due to conflicting studies, reaching a conclusion has proven difficult concerning cow’s milk and cognitive function therefore a level of caution should be exercised when interpreting these results.
• Nonetheless, when the nutritional-, physical- and health-related impact of cow’s milk avoidance is considered, the evidence highlights the importance of increasing cow’s milk consumption.

Associations between dairy consumption and constipation in adults: A cross-sectional study. Aslam H, Mohebbi M, Ruusunen A, Dawson SL, et al. Nutr Health. 2021 Apr 8:2601060211004784.

• Increasing the fiber and fluid content of the diet is recommended to improve symptoms of constipation. On the other hand, there are some data suggesting that elimination of dairy, in particular milk, may abate constipation symptoms.
• The current study aimed to assess the association between dairy consumption and constipation in the general adult population.
• Data from the Geelong Osteoporosis Study were used to assess the association between dairy consumption and constipation in women (n=632) and men (n=609). Information on milk, yogurt and cheese, and constipation were self-reported.
• Total dairy was calculated by summing the intake of milk, yogurt and cheese and expressed as servings per day.
• In women, consumption of 1-2 servings/d of total dairy was associated with reduced odds for constipation (OR: 0.49) compared to consuming <1 serving/d of total dairy. Also, consumption of 1-4 servings/d of milk was associated with marginally reduced odds for constipation (OR: 0.63) compared to women who consumed <1 serving/d of milk after adjusting for covariates.
• There were no significant associations detected between other types of dairy consumption and constipation in women, and none in men.
• In conclusion, in women, consumption of moderate amounts of dairy is associated with reduced odds for constipation whereas in men no associations were detected between dairy consumption and constipation.

Innovation, Economics, and Dairy Alternatives

Public attitudes toward dairy farm practices and technology related to milk production. Ly LH, Ryan EB, Weary DM. PLoS One. 2021 Apr 30;16(4):e0250850.

• Dairy farm systems have intensified to meet growing demands for animal products, but public opposition to this intensification has also grown due, in part, to concerns about animal welfare. One approach to addressing challenges in agricultural systems has been through the addition of new technologies, including genetic modification.
• Previous studies have reported some public resistance towards the use of these technologies in agriculture, but this research has assessed public attitudes toward individual practices and technologies and few studies have examined a range of practices on dairy farms.
• In the present study, we presented participants with four scenarios describing dairy practices (cow-calf separation, the fate of excess dairy calves, pasture access and disbudding). Citizens from Canada and the United States (n = 650) indicated their support (on a 7-point scale) toward five approaches (maintaining standard farm practice, using a naturalistic approach, using a technological approach, or switching to plant-based or yeast-based milk production) aimed at addressing the welfare issues associated with the four dairy practices. Respondents also provided a text-based rationale for their responses and answered a series of demographic questions including age, gender, and diet.
• Participant diet affected attitudes toward milk alternatives, with vegetarians and vegans showing more support for the plant-based and yeast-based milk production. Regardless of diet, most participants opposed genetic modification technologies and supported more naturalistic practices.
• Qualitative responses provided insight into participants’ values and concerns and illustrated a variety of perceived benefits and concerns related to the options presented. Common themes included animal welfare, ethics of animal use, and opposition toward technology.
• The researchers concluded that Canadian and US citizens consider multiple aspects of farm systems when contemplating animal welfare concerns, and tend to favor naturalistic approaches over technological solutions, especially when the latter are based on genetic modification.

Effects of the circadian rhythm on milk composition in dairy cows: Does day-milk differ from night-milk? Teng ZW, Yang GQ, Wang LF, et al. J Dairy Sci. 2021 Apr 14:S0022-0302(21)00514-2.

• Metabolism in most organisms can show variations between the day and night. These variations may also affect the composition of products derived from livestock.
• The aim of the present study was to investigate the difference in composition between the day-milk and night-milk of dairy cows.
• Ten multiparous Holstein cows (milk yield = 25.2 ± 5.00 kg/d) were randomly selected during mid lactation. Milk samples were collected at 0500 h (“night-milk”) and 1500 h (“day-milk”) and analyzed to determine their composition.
• Though milk fat, protein, lactose, and total milk solids were not different between day-milk and night-milk, small molecules, metabolites and lipids, and hormones and cytokines differed between day-milk and night-milk.
• Regarding biochemical and immune-related indicators, the concentrations of malondialdehyde, HSP70, and HSP90 in night-milk were lower than that in day-milk. However, interferon-γ levels were higher in night-milk. Additionally, night-milk was naturally rich in melatonin.
• Lipidomics analyses showed that the levels of some lipids in night-milk were higher than those in day-milk. Metabolomics analyses identified 36 different metabolites between day-milk and night-milk. Higher concentrations of N-acetyl-d-glucosamine, cis-aconitate, and d-sorbitol were observed in day-milk. However, the other 33 metabolites analyzed, including carbohydrates, lipids, AA, and aromatic compounds, showed lower concentrations in day-milk than in night-milk.
• The present findings show that the composition of night-milk differs considerably from that of day-milk. Notable changes in the circadian rhythm also altered milk composition. These results provide evidence to support the strategic use and classification of day-milk and night-milk.

Shifting toward a healthier dietary pattern through nudging and pricing strategies: A secondary analysis of a randomized virtual supermarket experiment. Stuber JM, Hoenink JC, Beulens JWJ, Mackenbach JD, Lakerveld J. Am J Clin Nutr. 2021 Apr 7:nqab057.

• Nudging and salient pricing are promising strategies to promote healthy food purchases, but it is possible their effects differ across food groups.
• To investigate in which food groups nudging and/or pricing strategies most effectively changed product purchases and resulted in within-food groups substitutions or spillover effects.
• In total, 318 participants successfully completed a web-based virtual supermarket experiment in the Netherlands. Researchers conducted a secondary analysis to investigate the single and combined effects of nudging (e.g., making healthy products salient), taxes (25% price increase), and/or subsidies (25% price decrease) across food groups (fruit and vegetables, grains, dairy, protein products, fats, beverages, snacks, and other foods).
• Compared with the control condition, the combination of subsidies on healthy products and taxes on unhealthy products in the nudging and price salience condition was overall the most effective, as the number of healthy purchases from fruit and vegetables increased by 9%, grains by 16%, and dairy by 58%, whereas the protein and beverage purchases did not significantly change.
• Regarding unhealthy purchases, grains decreased by 39% and dairy by 30%, whereas beverage and snack purchases did not significantly change. The groups of grains and dairy showed within-food group substitution patterns toward healthier products.
• In conclusion,nudging and salient pricing strategies have a differential effect on purchases of a variety of food groups. The largest effects were found for dairy and grains, which may therefore be the most promising food groups to target in order to achieve healthier purchases.

Antibiotic use and potential economic impact of implementing selective dry cow therapy in large US dairies. Hommels NMC, Ferreira FC, van den Borne BHP, Hogeveen HT.J Dairy Sci. 2021 Apr 29:S0022-0302(21)00570-1.

• Mastitis in dairy cows is financially taxing. It leads to treatment costs, milk production losses, and premature culling of cows .
• In this study, the objectives were to evaluate the economic feasibility of implementing selective dry cow therapy in large US herds and to estimate the potential reduction in antibiotic use around the dry period if selective dry cow therapy management is adopted.
• Cow-level data were obtained from the Dairy Herd Improvement Association (AgriTech, Visalia, CA) and individual dairy herds in California. Logistic regression models were used to predict the incidence risk of subclinical and clinical mastitis in the subsequent lactation for 96 last test-day somatic cell score categories. Linear programming was used to optimize the costs of dry cow therapy in 3 simulated large US dairy herds with different bulk tank somatic cell counts.
• The objective function was aimed at minimization of the total cost of mastitis around the dry period (TCMD), under a varying constraint of the maximum percentage of cows dried off with antibiotics. A sensitivity analysis was performed on milk price, dry-off antibiotic price, and risk ratio of mastitis in the subsequent lactation when no antibiotics and only teat sealant was used at dry-off.
• For all situations, blanket dry cow therapy was more expensive than selective dry cow therapy. In a herd with medium bulk tank somatic cell counts, the TCMD was $54.7 per primiparous dry cow and $58.5 per multiparous dry cow annually. In the optimal economic situation where SDCT was used, only 30% of primiparous cows received antibiotics, leading to a TCMD of $52.4 per primiparous dry cow, whereas 88% of multiparous cows received antibiotics, at a cost of $58.2 per multiparous dry cow. This corresponded with an overall reduction of 29% in the use of antibiotics around the dry period in a conservative scenario.
• This study showed that it is economically feasible to reduce antibiotic use associated with dry cow therapy in large US dairy herds. This contributes to the efforts of reducing antibiotic use worldwide.