Dairy Research Bulletin: Selected Articles from September 2021

Environmental Management and Sustainability

Current state of enteric methane and the carbon footprint of beef and dairy cattle in the United States. Dillon JA, Stackhouse-Lawson KR, Thoma GJ, Gunter SA, Rotz CA, Kebreab E, Riley DG, Tedeschi LO, Villalba J, Mitloehner F, Hristov AN, Archibeque SL, Ritten JP, Mueller ND. Anim Front. 2021 Sep 6;11(4):57-68.

Livestock is an integral part of societies worldwide and contributes to a host of human activities beyond food production, including income, heritage, insurance, labor, and culture. Livestock’s positive contributions to society are contrasted by environmental impacts, which include greenhouse gas emissions, biodiversity loss, and natural resource depletion, among others.
Though environmental impacts of ruminant livestock production extend beyond GHG emissions, considerable effort has been dedicated specifically to quantifying and mitigating enteric methane (CH₄) emissions from beef and dairy cattle, which is the focus of this review.
Technological interventions for reducing enteric CH₄from beef and dairy systems abound. Respiration chambers enable researchers to obtain highly accurate enteric CH₄measurements from controlled environments, whereas SF₆ and GreenFeed systems present opportunities for measuring emissions in open-air environments.
Currently, 3-NOP appears to be a promising inhibitor for enteric CH₄production, with seaweed garnering additional interest. Evaluation of the practicality, feasibility, long-term mitigation potential, and long-term effects on productivity, reproduction, and animal health of feed additives is critical to identifying commercially relevant CH₄ mitigation options.
Beyond the animal, soil carbon sequestration presents a potential opportunity for reducing the carbon footprint of ruminant livestock production systems, at least in the short term.

Environmental advantages of coproducing beef meat in dairy systems. Laca A, Laca A, Díaz M. Environ Technol. 2021 Sep 10:1-20.

Beef meat, one of the more environmentally costly animal-based foods, can be produced in two general ways, as the main product on specialized farms or as a co-product on dairy farms.
In this study, two cases (a semi-confinement dairy farm (A) and a pasture-based dairy farm (B)) have been analyzed by means of LCA to evaluate the environmental impacts associated with the coproduction of beef meat.
In both cases, purchased feed production was found to be the main cause of environmental impacts in most of the categories considered. Additionally, cow emissions to air were the main contributor for the global warming category.
Comparing the two dairy systems, notably lower environmental impacts were obtained for pasture-based dairy farms in 13 of the 18 categories analyzed. Regarding carbon footprint, 8.10 and 8.88 kg CO₂eq/kg live weight were obtained for A and B, respectively. These carbon footprint values were within the wide range found in the literature for beef meat (1.2-42.6 kg CO₂eq/kg live weight).
Beef calves and cull cows are an important output of dairy farming, so that co-production enables milk and meat with lower carbon footprint and associated environmental impacts to be obtained. In addition, the variability of the data found in literature and the lack of LCA studies based on real data for beef meat coproduced on dairy farms evidence the importance of in-depth study of this interesting topic.

Milk metabolome reveals variations on enteric methane emissions from dairy cows fed a specific inhibitor of the methanogenesis pathway. Yanibada B, Hohenester U, Pétéra M, Canlet C, Durand S, Jourdan F, Ferlay A, Morgavi DP, Boudra H. J Dairy Sci. 2021 Sep 13:S0022-0302(21)00872-9

Metabolome profiling in biological fluids is an interesting approach for exploring markers of methane emissions in ruminants.
In this study, a multiplatform metabolomics approach was used for investigating changes in milk metabolic profiles related to methanogenesis in dairy cows.
For this purpose, 25 primiparous Holstein cows at similar lactation stage were fed the same diet supplemented with (treated, n = 12) or without (control, n = 13) a specific anti-methanogenic additive that reduced enteric methane production by 23% with no changes in intake, milk production, and health status. The study lasted 6 weeks, with sampling and measures performed in week 5 and 6.
Overall, 38 discriminant metabolites were identified, which affected 10 metabolic pathways including methane metabolism. Some of these metabolites such as dimethylsulfoxide, dimethylsulfone, and citramalic acid, originated from the rumen microbiota or had a microbial-host animal co-metabolism that could be associated with methanogenesis.
Also, discriminant milk fatty acids were mostly of ruminal microbial origin. Other metabolites and metabolic pathways significantly affected were associated with amino acid metabolism. These findings provide new insight on the potential role of milk metabolites as indicators of enteric methane modifications in dairy cows.

Performance of full-scale aerobic composting and anaerobic digestion on the changes of antibiotic resistance genes in dairy manure. Zhang Q, Xu J, Wang X, Zhu T, Liu J, Qin S. Bioresour Technol. 2021 Sep 8;342:125898.

Understanding the different performances of full-scale active composting and anaerobic digestion on the changes of antibiotic resistance genes in dairy manure is crucial to uncover the dissemination risks of ARGs in post-biotreated manure.
In this regard, metagenomic sequencing was deployed to reveal the variations of antibiotic resistance genes in dairy manure in an intensive dairy farm.
Results showed that the total abundance of antibiotic resistance genes increased from 150.64 reads/ng DNA to 204.06 reads/ng DNA in dairy manure, and it is mainly attributed to the contributions of active composting (85.49%) rather than anaerobic digestion (14.51%).
In active composting, more antibiotic resistance genes subtypes were induced, and the dominant antibiotic resistance gene subtypes were shifted completely, probably due to the enrichment of Proteobacteria and Actinobacteria which could be the hosts of multiple antibiotic resistance genes.
These results inspire us to further evaluate the dissemination risks of antibiotic resistance genes along the route from composted manure to soil and to plants.

The Complementary Roles for Plant-Source and Animal-Source Foods in Sustainable Healthy Diets. Comerford K, Miller G, Kapsak W, Brown, K. Nutri. 2021. Sept 28;13(10), 3469.

There are approximately 100 countries with food-based dietary guidelines throughout the world, each of which aims to encompass the cultural, geographical, and health considerations unique to their country of origin. Common themes throughout these guides emphasize diverse and balanced intake of food groups from both plant- and animal-sources. With the globally recognized need to shift to more sustainable food systems, several countries and international food and health organizations have begun to incorporate sustainability recommendations into their dietary guidance. These sustainability recommendations are often based on food source (i.e., eat more plant-source and fewer animal-source foods), yet food source may not be the only useful or informative comparator for assessing healthy and sustainable diets. The purpose of this narrative review is to examine the roles of plant-source foods and animal-source foods in the context of sustainable healthy diets – with an emphasis on the contributions of the most commonly recommended food groups from global food-based dietary guidelines (i.e., fruits, vegetables, and dairy foods). Overall, plant and animal agriculture have complementary and symbiotic roles in healthy and sustainable food systems, and these abilities are largely dependent on various contextual factors (e.g., geography, production practices, processing methods, consumption patterns) – not just on whether the food originated from the plant or animal kingdom.

The Role of Food and Beverage Companies in Transforming Food Systems: Building Resilience at Multiple Scales. Bezares N, Fretes G, Martinez EM. Curr Dev Nutr. 2021 Aug;5(9):nzab110.

Food and beverage companies are increasingly aware of the risks posed by climate change and many are interested in addressing them by building resilience along their supply chains.
Financial incentives for environmental, social, and governance criteria further motivate mitigation action by firms.
To achieve sustainable outcomes, human and ecological systems must be managed for resilience. The scientific community and food and beverage firms must collaborate in the development of measurable and verifiable indicators that support adaptation and mitigation action along food supply chains.
This article identifies 3 areas in which a synergistic progress would set a resilient trajectory toward sustainability:
- 1) incentives for sustainable intensification
- 2) expanded reporting standards
- 3) pre-competitive collaborations
Incremental, clear, and measurable steps can be taken to adapt food supply chains to the pressing challenges imposed by climate change, mitigate further emissions, and bring producers and consumers along in the journey towards planetary health.

Insects as Novel Ruminant Feed and a Potential Mitigation Strategy for Methane Emissions. Ahmed E, Fukuma N, Hanada M, Nishida T. Animals (Basel). 2021 Sep 9;11(9):2648.

Typically, soybean meals are the major protein source and are commonly used in ruminant diets due to their high contents of protein and essential amino acids. However, soybean production is also associated with high environmental impacts, and its price has been increasing with some fluctuations. To meet the increasing demand for animal products in the near future, innovative solutions and alternative sustainable ingredients to replace the conventional protein in animal diets with a reduced impact on the environment are urgently required.
This study is the first to evaluate the chemical composition and impacts of four different edible insects, Acheta domesticus, Brachytrupes portentosus, Gryllus bimaculatus, and Bombyx mori, on the digestibility, rumen fermentation, and methane production when used as a substitute for 25% of the soybean meal in a ruminant diet through in vitro incubation.
The dietary treatments were:
- 100% grass hay, 60% grass hay + 40% soybean meal
- 60% grass hay + 30% soybean meal + 10% Acheta domesticus
- 60% grass hay + 30% soybean meal + 10% Brachytrupes portentosus
- 60% grass hay + 30% soybean meal + 10% Gryllus bimaculatus
- 60% grass hay + 30% soybean meal + 10% Bombyx mori
Chemical analysis of the insects showed that they were rich in fat (14-26%) with a high proportion of unsaturated fatty acids (60-70%). Additionally, the insects were rich in protein (48-61%) containing all essential amino acids and the amino acid profiles of the insects were almost the same as that of soybean meal.
The inclusion of insects did not affect nutrient digestibility or the production of volatile fatty acids but did increase the production of ammonia-nitrogen.
The addition of Gryllus bimaculatus and Bombyx mori led to decrease in methane production by up to 18% and 16%, respectively. These results reveal that substitution of 25% soybean meal in the diet with the tested insects had no negative impacts, and their potential to reduce methane production is an environmental benefit.

Animal Health and Food Safety

Antibiotic Resistance Genes and Associated Phenotypes in Escherichia coli and Enterococcus from Cattle at Different Production Stages on a Dairy Farm in Central California. Jeamsripong S, Li X, Aly SS, Su Z, Pereira RV, Atwill ER. Antibiotics (Basel). 2021. 10(9):1042.

Antimicrobial resistance is a growing concern for food safety and public health globally. Both humans and animals share similar antimicrobial drugs; hence, the judicious use of antimicrobials by both veterinary and human medicine is important to reduce the risk of antimicrobial resistance in enteric bacteria
The objectives of this study were to characterize overall genomic antibiotic resistance profiles of fecal Escherichia coliand Enterococcus from dairy cattle at different production stages using whole-genome sequencing and to determine the association between antimicrobial resistance phenotypes and their corresponding genotypes.
The Comprehensive Antibiotic Resistance Database (CARD) and ResFinder, two publicly available databases of antimicrobial resistance genes, were used to annotate isolates. Based on the findings 27.5% and 20.0% of tested coliisolates (n = 40) harbored single and ≥3 antimicrobial resistance genes, respectively; for Enterococcus spp., we observed 87.8% and 8.2%, respectively.
The highest prevalence of antimicrobial resistance genes in coliwas for resistance to tetracycline (27.5%), followed by sulphonamide (22.5%) and aminoglycoside (20.0%); the predominant antimicrobial resistance genes in Enterococcus spp. targeted macrolide drugs (77.6%).
Resistance to ≥3 antimicrobial classes was observed in all coliand 77.6% in Enterococcus spp. isolates. A high degree of agreement existed between the resistance phenotype and the presence of resistance genes for various antimicrobial classes for E. coli but much less so for isolates of Enterococcus.
Consistent with prior work, fecal coliand Enterococcus spp. isolates from calves harbored a wide spectrum of resistance genes, compared to those from cattle at other production stages, based on the cross-sectional samples from the studied farm.

Treatment practices after calving-related events on 45 dairy farms in California. Silva-Del-Río N, Valldecabres A, Espadamala A, García-Muñoz A, Pallares P, Lago A, Lima FS, Pereira RV. J Dairy Sci. 2021 Sep 2:S0022-0302(21)00858-4.

Retained fetal membranes, dystocia, and twinning are common postpartum events that increase the risk of metritis, impair reproductive performance, and contribute to antimicrobial use on dairies.
The overall objective of this study was to describe treatment decisions after retained fetal membranes, severe dystocia (cesarean section and fetotomy), non-severe dystocia (nonmechanical and mechanical assistance to extract the calf), and twinning.
A total of 44 dairies from California’s San Joaquin Valley (39 Holstein and 6 Jersey or crossbreed herds) with 450 to 9,500 lactating cows were enrolled in this study.
Researchers visited each dairy once to observe cow-side fresh cow health evaluations and to interview health evaluators and maternity workers, using a standardized survey tool. The survey included questions about antimicrobial (class, dose, and duration) and nonantimicrobial therapies for calving-related events.
Antimicrobial therapy was used in all 44 dairies to treat retained fetal membranes at 24 (n = 23), 48 (n = 10), or 72 h (n = 5) after calving, or when puerperal metritis signs were observed (n = 6). Antimicrobial therapy was used after all severe dystocia cases, and after non-severe dystocia (n = 27) and twinning (n = 15).
Ceftiofur products were the most common antimicrobial class; they were used to treat retained fetal membranes cases (n = 29), non-severe dystocia (n = 13), and twinning (n = 10). Supportive therapy for calving-related events included nonantimicrobial intrauterine treatments, nonsteroidal anti-inflammatory drugs, oxytocin, i.v. calcium, or oral drenches.
This study highlights opportunities to reduce extra-label use of antimicrobials in postpartum cows affected with retained fetal membranes, and the need for education and outreach efforts on judicious use of antimicrobials. Furthermore, antimicrobial treatment choices differed largely across dairies, indicating a need to reach consensus and promote standardized practices within the industry.

A dataset of human-inedible byproduct feeds consumed by dairy cows in the United States.de Ondarza MB, Tricarico JM.Data Brief. 2021 Sep 8;38:107358.

Dairy cows convert human-indigestible forages and byproducts nutrients into edible food for humans. Because of microbiota located in their rumen, dairy cows can digest fibrous forages and feeds which are not exploited by humans and monogastric animals like pigs.
Dairy cows in the U.S. have been fed byproduct feeds as part of their diet for decades. Dairy nutritionists use complex nutrition models to develop economical and nutritious diets composed of grains, byproduct feeds, and forages.
Accurate, complete, up-to-date information on byproduct feed consumption by dairy cows would be useful for both public and private researchers seeking to understand the type and extent of byproduct usage on US dairies.
In collaboration with the American Feed Industry Association (AFIA), a survey was sent to US feed company representatives inquiring about the types and amounts of byproducts sold as dairy cow feed during the last year, the number of lactating cows serviced, the amount of milk produced by these lactating cows, and the states where these cows were located. A similar survey was sent to practicing US dairy nutritionists inquiring about their typical daily feeding rates of byproduct feeds by type, the number of cows consuming these byproducts, the amount of milk produced by the lactating cows, and the states where these cows were located.
Survey data are representative of 33.5% of US lactating cows and 35.7% of US milk production in 2019. Amounts of each type of byproduct feed consumed per US milking cow (including replacement heifers and dry cows) and per kg of milk produced were calculated for the US and its four regions. Total 2019 regional and US byproduct consumption by type was calculated. Nutrient compositions of each byproduct feed were reported.
This survey data on byproduct feed consumption by US dairy cows could be used by environmental scientists who require inputs for life-cycle assessment models to evaluate the carbon footprint of US dairies, by economists working to assess and improve farm profitability, by milk processors seeking to understand sources of dairy cow nutrients, and by those responsible for valuating and disposing agricultural and agro-industrial byproducts.
Byproduct data found in supplementary tables: TABLE 1, TABLE 2, TABLE 3, TABLE 4.

Broad phenotypic impact of the effects of transgenerational heat stress in dairy cattle: a study of four consecutive generations. Weller JI, Ezra E, Gershoni M. Genet Sel Evol. 2021 Sep 6;53(1):69.

Global warming has increased the frequency of heat stress in livestock. Although heat stress directly leads to negative effects on production and reproduction traits in dairy cattle, the transgenerational transition of these changes is poorly understood.
Researchers hypothesized that heat stress in pregnant cows might induce epigenetic modifications in the developing embryo germ cells, which, in turn, might lead to phenotypic effects in the offspring. Here, they examined whether transgenerational effects of heat stress contribute to the phenotypic expression of economic traits in Israel dairy cattle.
The researchers found a significant association of the month of birth, season of pregnancy, and heat stress index of mothers, with the performance of their 2^nd and 3^rd generation progenies, which suggests a true transgenerational effect.
The most significant transgenerational effects were on fat yield and concentration, dystocia, still-birth, and maturation.
These findings suggest that heat stress during pregnancy affects the performance of offspring, regardless of life circumstances in at least the last three generations. Therefore, heat stress can reduce selection efficiency in breeding programs and may have economic significance in livestock.

Human Nutrition and Health

Dairy Product Consumption and Cardiovascular Health: a Systematic Review and Meta-Analysis of Prospective Cohort Studies. Chen Z, Ahmed M, Ha V, Jefferson K, Malik V, Ribeiro PAB, Zuchinali P, Drouin-Chartier JP. Adv Nutr. 2021 Sep 22:nmab118.

The association between dairy product consumption and cardiovascular health remains highly debated.
For this study, researchers quantitatively synthesized prospective cohort evidence on the associations between dairy consumption and risk of hypertension (HTN), coronary heart disease (CHD) and stroke.
Fifty-five studies were included in this analysis.
Total dairy consumption was associated with a 9% lower risk of hypertension (highest vs lowest level of intake. Each 1 serving/day increase in intake was associated with a 4% lower risk of hypertension. For coronary heart disease, total dairy intake was associated with a 4% lower risk (highest vs lowest level of intake), and a 2% lower risk for each 1 serving/day increase. For stroke, total dairy intake was associated with a 10% lower risk (highest vs lowest level of intake), and a 4% lower risk for each 1 serving/day increase.
Despite moderate to considerable heterogeneity, these associations remained consistent across multiple subgroups. Evidence on the relationship between total dairy and risk of hypertension and coronary heart disease were of moderate quality and of low quality for stroke.
Low-fat dairy consumption was associated with lower risk of hypertension and stroke, and high-fat dairy with a lower risk of stroke. Milk, cheese, or yogurt consumption showed inconsistent associations with the cardiovascular outcomes in high vs. low intake and dose-response meta-analyses.
Total dairy consumption was associated with a modestly lower risk of hypertension, coronary and stroke.

Biomarkers of dairy fat intake, incident cardiovascular disease, and all-cause mortality: A cohort study, systematic review, and meta-analysis. Trieu K, Bhat S, Dai Z, Leander K, Gigante B, Qian F, Korat AVA, Sun Q, Pan XF, Laguzzi F, Cederholm T, de Faire U, Hellénius ML, Wu JHY, Risérus U, Marklund M. PLoS Med. 2021 Sep 21;18(9):e1003763.

Researchers aimed to investigate the association of serum pentadecanoic acid (15:0), a biomarker of dairy fat intake, with incident cardiovascular disease (CVD) and all-cause mortality in a Swedish cohort study.
The researchers also systematically reviewed studies of the association of dairy fat biomarkers (circulating or adipose tissue levels of 15:0, heptadecanoic acid [17:0], and trans-palmitoleic acid [t16:1n-7]) with CVD outcomes or all-cause mortality.
For the study, researchers measured 15:0 in serum cholesterol esters at baseline in 4,150 Swedish adults (51% female, median age 60.5 years). During a median follow-up of 16.6 years, 578 incident CVD events and 676 deaths were identified using Swedish registers.
Higher 15:0 was associated with lower incident CVD risk in a linear dose-response manner. In meta-analyses including the Swedish cohort and 17 cohort, case-cohort, or nested case-control studies, higher 15:0 and 17:0 but not t16:1n-7 were inversely associated with total CVD, with the relative risk of highest versus lowest tertile being 88%, 86%, and 101% respectively.
Dairy fat biomarkers were not associated with all-cause mortality in meta-analyses. Study limitations include the inability of the biomarkers to distinguish different types of dairy foods and that most studies in the meta-analyses (including our novel cohort study) only assessed biomarkers at baseline, which may increase the risk of misclassification of exposure levels.
In conclusion,in a meta-analysis of 18 observational studies including this new cohort study, higher levels of 15:0 and 17:0 were associated with lower CVD risk. These findings support the need for clinical and experimental studies to elucidate the causality of these relationships and relevant biological mechanisms.

No adverse effects of dairy products on lipid profile: A systematic review and meta-analysis of randomized controlled clinical trials. Derakhshandeh-Rishehri SM, Ghobadi S, Akhlaghi M, Faghih S. Diabetes Metab Syndr. 2021 Sep 13;15(6):102279.

Current dietary recommendations to limit consumption of saturated fat are largely based on early nutrition studies demonstrating a direct link between dietary saturated fat, elevated blood cholesterol levels, and increased risk of cardiovascular disease. As full-fat dairy products are rich in saturated fat, these dietary guidelines recommend consumption of fat-free or low-fat dairy products in place of full-fat dairy
The current study aimed to review the effects of dairy foods on lipid profile in randomized controlled clinical trials.
Researchers searched PubMed, Scopus, Embase, and Central. Only randomized controlled trials that assess the effects of dairy foods on lipid profile were included.
The overall effects of dairy foods on lipid profile were non-significant. Dairy foods were associated with a non-significant reduction in triacylglycerol level, and a non-significant increase in total cholesterol, low density lipoprotein cholesterol, and high-density lipoprotein cholesterol level.
The researchers concluded that dairy foods do not have any unfavorable effects on lipids.

Dairy protein intake is inversely related to development of non-alcoholic fatty liver disease. Lee JH, Lee HS, Ahn SB, Kwon YJ. Clin Nutr. 2021 Aug 25;40(10):5252-5260.

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease and is closely related to metabolic dysfunction, including insulin resistance, obesity, and metabolic syndrome. Dairy protein, rich in casein and whey protein, could help to reduce metabolic diseases.
Researchers investigated the relationship between dairy protein intake and incident NAFLD.
The researchers analyzed data for 5,171 adults aged 40-69 years from the Korean Genome and Epidemiology Study (KoGES). Participants were separated as men, women aged ≥50 years, and women aged <50 years and then divided into tertiles based on dairy protein intake. NAFLD was defined as NAFLD liver fat score >-0.640.
The results revealed an inverse linear relationship between dairy protein intake and incident NAFLD. The cumulative incidence of NAFLD significantly decreased with increasing tertiles of dairy protein intake in men and women aged ≥50 years. After adjusting for confounding factors, the hazard ratios for NAFLD in the middle and highest tertiles, compared to the lowest tertile, were 0.80 and 0.71 in men, 0.89 and 0.72 in women aged ≥50 years, and 1.01 and 0.91 in women aged <50 years, respectively.
In conclusion, the researchers found that higher dairy protein intake was significantly and inversely associated with the risk of incident NAFLD in men and women aged ≥50 years. Consumption of milk and other dairy products could help prevent the development of NAFLD.

Role of Exposure to Lactic Acid Bacteria from Foods of Animal Origin in Human Health. Miranda C, Contente D, Igrejas G, Câmara SPA, Dapkevicius MLE, Poeta P. Foods. 2021 Sep 4;10(9):2092.

Animal products, in particular dairy and fermented products, are major natural sources of lactic acid bacteria. These are known for their antimicrobial properties, as well as for their roles in organoleptic changes, antioxidant activity, nutrient digestibility, the release of peptides and polysaccharides, amino acid decarboxylation, and biogenic amine production and degradation.
Due to their antimicrobial properties, lactic acid bacteria are used in humans and in animals, with beneficial effects, as probiotics or in the treatment of a variety of diseases. In livestock production, lactic acid bacteria contribute to animal performance, health, and productivity. In the food industry, lactic acid bacteria are applied as bioprotective and biopreservation agents, contributing to improve food safety and quality.
However, some studies have described resistance to relevant antibiotics in lactic acid bacteria, with the concomitant risks associated with the transfer of antibiotic resistance genes to foodborne pathogens and their potential dissemination throughout the food chain and the environment.
In this research paper, researchers summarize the application of lactic acid bacteria in livestock and animal products, as well as the health impact of lactic acid bacteria in animal food products.
In general, the beneficial effects of lactic acid bacteria on the human food chain seem to outweigh the potential risks associated with their consumption as part of animal and human diets. However, further studies and continuous monitorization efforts are needed to ensure their safe application in animal products and in the control of pathogenic microorganisms, preventing the possible risks associated with antibiotic resistance and, thus, protecting public health.

The association between dairy products and psychological disorders in a large sample of Iranian adults. Mahdavifar B, Hosseinzadeh M, Salehi-Abargouei A, Mirzaei M, Vafa M. Nutr Neurosci. 2021 Sep 11:1-11.

Dairy products contain certain nutrients that are useful in mental disorders.
This study aimed to assess the associations between dairy products and psychological disorders in a large sample of Iran, a Middle Eastern country.
This cross-sectional study was undertaken on 7,387 adults. Data on dietary intakes were obtained using a validated Food Frequency Questionnaire. Psychological health was assessed by the Iranian validated version of depression, anxiety, and stress scale 21. Odds ratio (OR) were assessed.
After adjustment for potential confounders, total milk consumption (OR for the highest vs. lowest tertile: 0.73) and total yogurt consumption (OR = 0.78) were associated with decreased odds of depression.
An inverse relationship was found between total dairy (OR = 0.73), total milk (OR = 0.72), and yogurt drink (OR = 0.80) consumption and anxiety symptoms. Higher intake of cheese was related to greater odds of stress (OR = 1.52). No association was found between the consumption of high-fat dairy, low-fat dairy, low-fat milk, low-fat yogurt, high-fat yogurt, cheese, yogurt drink, and depression. Also, there was no association between dairy products and stress symptoms. This association was significant among men and women and high-fat and low-fat products in the total adjusted stratified analysis models.
In conclusion, the findings of this study revealed that both high-fat and low-fat dairy products are associated with a reduced prevalence of psychological disorders. Still, more prospective studies are required to confirm these associations.

Role of whey protein in vascular function: a systematic review and meta-analysis of human intervention studies. Hajizadeh-Sharafabad F, Sharifi Zahabi E, Tarighat-Esfanjani A. Br J Nutr. 2021 Sep 13:1-34.

Whey protein has been heavily appreciated as a rich source of bioactive peptides, with potential benefits for cardiovascular health.
This study constitutes a systematic review and meta-analysis summarizing the effects of whey protein consumption on vascular reactivity, arterial stiffness, and circulatory biomarkers of vascular function.
The pooled analysis of 6 studies showed a significant increase in flow-mediated dilation after whey protein consumption. Meta-analysis of available data didn’t show any significant reduction in arterial stiffness measures including augmentation index and pulse wave velocity. Moreover, the pooled analysis of 6 effect sizes showed no significant effects on plasma levels of nitric oxide following whey protein supplementation.
The overall results provided evidence supporting a protective effect of whey protein on endothelial function measured by flow-mediated dilation, but not for arterial stiffness measures and circulatory biomarker of vascular function. Further research is required to substantiate the benefits of whey protein on vascular function.

Innovation, Economics, and Dairy Alternatives

Integration of statistical inferences and machine learning algorithms for prediction of metritis cure in dairy cows. de Oliveira EB, Ferreira FC, Galvão KN, Youn J, Tagkopoulos I, Silva-Del-Rio N, Pereira RVV, Machado VS, Lima FS. J Dairy Sci. 2021 Sep 15:S0022-0302(21)00882-1.

Metritis, an acute inflammatory disease with systemic implications, affects 20 to 40% of the postpartum dairy cows in the first 21 ‘days in milk’.
The study’s objectives were to identify cow-level and environmental factors associated with metritis cure to predict metritis cure using traditional statistics and machine learning algorithms.
The data set used was from a previous study comparing the efficacy of different therapies and self-cure for metritis. Metritis was defined as fetid, watery, reddish-brownish discharge, with or without fever. Cure was defined as an absence of metritis signs 12 days after diagnosis.
Cows were randomly allocated to receive a subcutaneous injection of 6.6 mg/kg of ceftiofur crystalline-free acid (Excede, Zoetis) at the day of diagnosis and 3 days later (n = 275); and no treatment at the time of metritis diagnosis (n = 275).
The variables ‘days in milk’ at metritis diagnosis, treatment, season of the metritis diagnosis, month of metritis diagnostic, number of lactation, parity, calving score, dystocia, retained fetal membranes, body condition score at day 5 postpartum, vulvovaginal laceration score, the rectal temperature at the metritis diagnosis, fever at diagnosis, milk production from the day before to metritis diagnosis, and milk production slope up to 5, 7, and 9 ‘days in milk’ were offered to univariate logistic regression.
Cows without vulvovaginal laceration had 1.91 higher odds of curing of metritis than cows with vulvovaginal laceration. Cows that developed metritis at >7 ‘days in milk’ had 2.09 higher odds of being cured than cows that developed metritis at ≤7 ‘days in milk’. For rectal temperature, each degree Celsius above 39.4°C led to lower odds to be cured than cows with rectal temperature ≤39.4°C.
Furthermore, milk production slope and milk production difference from the day before to the metritis diagnosis were essential variables to predict metritis cure. Cows that had reduced milk production from the day before to the metritis diagnosis had lower odds to be cured than cows with moderate milk production increase.
The results from the multivariable logistic regression and receiver operating characteristic analysis indicated that cows developing metritis at >7 ‘days in milk’, with increase in milk production, and with a rectal temperature ≤39.40°C had increased likelihood of cure of metritis with an accuracy of 75%.
The machine learning analysis showed that in addition to these variables, calving-related disorders, season, and month of metritis event were needed to predict whether the cow will be cured or not from metritis with an accuracy ≥70% and F1 score (harmonic mean between precision and recall) ≥0.78.

Educational interventions to address misconceptions about antibiotic residues in milk can alter consumer perceptions and may affect purchasing habits. Redding LE, Parsons B, Bender JS.J Dairy Sci. 2021 Sep 2:S0022-0302(21)00859-6.

The industrialization of the agri-food industry and resultant decrease in the number of people employed on farms has contributed to a knowledge gap among consumers about food production processes. A commonly reported concern of dairy consumers is the use of antibiotics in dairy animals, even though these drugs are an important tool for promoting animal health and welfare and food safety.
The extent to which consumers are aware of antibiotic residue avoidance practices in dairy production is unknown, and it is unclear whether acquisition of such knowledge could affect purchasing behavior and perceptions of dairy farming.
The objectives of this study were to assess consumers’ perceptions about the quality and production of dairy products in the United States and determine whether educational materials on processes that limit the occurrence of antibiotic residues in milk can change consumers’ perceptions of dairy products and purchasing behaviors.
Researchers surveyed 804 consumers and assigned them to 1 of 3 interventions:
1. a control arm (reading the content of the Dairy page of the USDA’s myplate.gov website)
2. an educational brochure on the processes that prevent antibiotic residues in milk
3. a video on the same processes
The researchers found that a majority (86.1%) of participants believe that the quality of dairy products in the United States is high, although many had concerns about the treatment of dairy animals and chemicals (pesticides, antibiotics, hormones) in dairy products.
Compared with the control intervention, the brochure was associated with a significant decrease in the level of concern consumers had about chemicals in their milk [-0.20 points on a Likert scale] and a significantly increased comfort in purchasing conventional dairy products (odds ratio = 2.43).
The video was associated with even stronger effects: a 0.29-unit decrease in the level of concern about chemicals in milk and 2.94 times greater odds of purchasing conventional dairy products.
Although consumer food decision making is complex and driven by multiple factors, it appears that education about the processes that promote food safety can reassure consumers about their concerns and potentially affect purchasing habits.

Consumer perception of dried dairy ingredients: Healthy, natural, and sustainable? Schiano AN, Gerard PD, Drake MA.J Dairy Sci. 2021 Sep 27:S0022-0302(21)00903-6.

Conscious consumerism is growing, along with consumer demand for socially conscious dairy products or dairy alternatives. To successfully position dairy products (especially conventional dairy) in this changing marketplace, dairy producers and processors must understand how to strategically use both on- and off-package messaging aligned with consumer perceptions.
However, consumer perception of attributes such as sustainable, natural, and healthy is complex, and varies between product categories as well as among products within a category.
The objective of this study was to characterize consumer definitions of the terms sustainable, natural, and healthy as they pertain to dried dairy ingredients.
To meet this objective, researchers conducted an online survey with 3 maximum difference scaling exercises to determine the importance of 63 label claims to consumer definitions of the terms sustainable, natural, and healthy.
The role of priming with dried ingredient processing information on consumer perception of these terms was also explored. Within the dried dairy ingredients category, there is extensive cognitive overlap between the terms sustainable, natural, and healthy.
Priming did not affect consumer definitions of any of these terms. Certification-related claims were considered among the least important claims for consumer definitions of sustainable, natural, and healthy, whereas claims that were simple to read and visualize were considered among the most important.
Claims related to animal welfare and happiness or simple, minimal ingredients and processing were considered by consumers to be important for all 3 terms. For each of these terms, there was a cluster of consumers who defined the term primarily by simple ingredients and minimal processing, and another cluster who defined the term primarily by happy cows and conscious farming practices.
The terms sustainable and healthy each had a third, unique consumer cluster. This third definition cluster defined sustainability primarily by environmental effects, whereas this cluster defined healthy primarily in fitness and nutrition terms.
Age and to a lesser extent, gender, affected importance placed on these 3 terms and also affected definition of the term. Understanding these consumer definitions provides insight on how to formulate marketing and educational messaging to speak to each consumer segment.

Intention to Purchase Milk Packaged in Biodegradable Packaging: Evidence from Italian Consumers. Cammarelle A, Viscecchia R, Bimbo F. Foods. 2021 Sep 2;10(9):2068.

The dairy industry generates large volumes of liquid waste that can be used to produce biopolymers, potentially employable for the creation of milk biodegradable bottles.
In that regard, this paper aims to explore the consumers’ intention to purchase sustainable packages, as well as to assess the willingness to pay for it considering renewable packages made using organic waste feedstocks from the dairy industry (e.g., whey) and plant-based material (e.g., corn, sugarcane, etc.).
To reach the stated objectives, researchers collected individual-level information (e.g., age, gender, education, income) from a convenient sample of 260 Italian consumers and a modified version of the ‘Theory of Planned Behavior’ estimated using a structural equation model.
Findings show that attitudes and perceived behavioral control are the most important drivers of the consumers’ intention to purchase sustainable packages. Finally, statistics show that respondents slightly prefer to purchase products packaged using plant-based biodegradable material, as well as most of the respondents show a low willingness to pay for milk offered in biodegradable packaging, regardless of the raw material used.
Then, policymakers and companies should invest in educational/informational campaigns pointing out the beneficial effects on the environment from the purchase of foods in sustainable packaging. This may potentially increase the consumers’ intention to purchase, as well as their willingness to pay for plant-based and dairy whey-based packages by increasing the sustainability of the dairy supply chain.

Nutritional Quality of Plant-Based Cheese Available in Spanish Supermarkets: How Do They Compare to Dairy Cheese? Fresán U, Rippin H. Nutrients. 2021 Sep 21;13(9):3291.

Plant-based cheese is one of the most increasingly consumed dairy alternatives. Evidence is lacking on their nutritional quality.
Researchers aimed to evaluate the nutritional composition of the plant-based cheese options available in Spanish supermarkets, and how they compare with dairy cheese.
An audit of plant-based cheese alternatives was conducted in seven of the most common supermarkets. For each product, the nutritional content per 100 g and ingredients were collected. Data on generic dairy cheese were retrieved from the BEDCA website. Descriptive statistics (median, minimum and maximum) were used to characterize the plant-based cheese products, for both all the products and grouped by main ingredients (i.e., coconut oil, cashew nuts and tofu).
The results showed that coconut oil-based products (the large majority of plant-based cheese products, n = 34) could not be considered as healthy foods. Their major ingredients were refined coconut oil and starches and were high in saturated fats and salt. The other smaller groups, cashew nut- (n = 4) and tofu-based (n = 2), showed a healthier nutritional profile.
Replacing dairy cheese with these groups could be nutritionally beneficial. Future investigations should address the health effects of substituting dairy cheese with these products.

Legume dreams: The contested futures of sustainable plant-based food systems in Europe. Cusworth G, Garnett T, Lorimer J. Glob Environ Change. 2021;69:102321.

With the intensification of agriculture, the simplification of crop rotations, and the rise in demand for meat, dairy and cereal products, legume production and consumption are at an historic low in Europe.
But as the environmental consequences of agriculture (biodiversity loss, high greenhouse gas emissions, water pollution) and the health outcomes of modern diets (heart disease, cancer, diabetes, obesity) become better known, so great and varied hopes are being expressed about the future role of legumes in the food system.
This paper catalogues and scrutinizes these hopes, mapping the promissory narratives now orbiting around legumes. It identifies six food futures, each of which is made possible through the greater use of legumes in various production, processing, marketing and consumption contexts.
These promissory narratives are theorized as contrasting responses to three major areas of contestation in the food systems literature. Namely:
1. the sustainability of livestock management
2. the role of technology in different visions of the ‘good diet’
3. the merits of different models for how to make agricultural management more sustainable
It identifies the promiscuity of legumes – in terms of the range of food futures they permit – before distilling three points of consensus amongst advocates of the potential of legumes.
These points of consensus relate to their nitrogen fixing capacity, their high protein content, and their long-standing historical role in the context of European food and farming. This map of legume dreams serves to guide deliberations amongst researchers, policymakers, and industry stakeholders about the futures of plant-based food in Europe.