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.

Environmental Management and Sustainability

The Ruminant Farm Systems Animal Module: A Biophysical Description of Animal Management. Hansen TL, Li M, Li J, Vankerhove CJ, Sotirova MA, Tricarico JM, Cabrera VE, Kebreab E, Reed KF. Animals (Basel). 2021 May 12;11(5):1373. 

  • Dairy production is an important source of nutrients in the global food supply, but environmental impacts are increasingly a concern of consumers, scientists, and policy-makers. Many decisions must be integrated to support sustainable production-which can be achieved using a simulation model.
  • The publication provides an example of the Ruminant Farm Systems (RuFaS) model to assess changes in the dairy system related to altered animal feed efficiency. RuFaS is a whole-system farm simulation model that simulates the individual animal life cycle, production, and environmental impacts.
  • The researchers added a stochastic animal-level parameter to represent individual animal feed efficiency as a result of reduced residual feed intake and compared High (intake = 94% of expected) and Very High (intake = 88% of expected) efficiency levels with a Baseline scenario (intake = 100% of expected).
  • As expected, the simulated total feed intake was reduced by 6 and 12% for the High and Very High efficiency scenarios, and the expected impact of these improved efficiencies on the greenhouse gas emissions from enteric methane and manure storage was a decrease of 4.6 and 9.3%, respectively.

Protein nanofibrils for next generation sustainable water purification. Peydayesh M, Mezzenga R. Nat Commun. 2021 May 31;12(1):3248.

  • Water scarcity is rapidly spreading across the planet, threatening the population across the five continents and calling for global sustainable solutions. Water reclamation is the most ecological approach for supplying clean drinking water. However, current water purification technologies are seldom sustainable, due to high-energy consumption and negative environmental footprint.
  • In this publication, researchers review the cutting-edge technologies based on protein nanofibrils as water purification agents and they highlight the benefits of this green, efficient and affordable solution to alleviate the global water crisis.
  • The researchers discuss the different protein nanofibrils agents available and analyze them in terms of performance, range of applicability and sustainability. They underline the unique opportunity of designing protein nanofibrils for efficient water purification starting from food waste, as well as cattle, agricultural or dairy industry byproducts, allowing simultaneous environmental, economic and social benefits.
  • The researchers also present a case analysis, including a detailed life cycle assessment, to establish their sustainable footprint against other common natural-based adsorbents, anticipating a bright future for this water purification approach.

Integrated eco-strategies towards sustainable carbon and nitrogen cycling in agriculture. Harindintwali JD, Zhou J, Muhoza B, Wang F, Herzberger A, Yu X. J Environ Manage. 2021 May 26;293:112856.

  • To meet the ever-growing human demands for food, fuel, and fiber, agricultural activities have dramatically altered the global carbon (C) and nitrogen (N) cycles. These biogeochemical cycles along with water, phosphorus, and sulfur cycles are fundamental features of life on Earth. To efficiently feed a growing population, crop-livestock production systems have been developed, however, these systems also contribute significantly to environmental pollution and global climate change.
  • Management of agricultural waste and the application of N fertilizers are central to the issues of greenhouse gas (GHG) emissions and nutrient runoff that contributes to the eutrophication of water bodies. If managed properly, agricultural waste can provide nutrients for plants and contribute to the conservation of soil health.
  • In order to achieve the long-term conservation of agricultural production systems, it is important to promote the proper recycling of agricultural waste in agroecosystems and to minimize the reliance on chemical N fertilizers. Composting is one of the sustainable and effective approaches for recycling agricultural waste in agriculture.
  • However, the conventional composting process is dilatory and produces compost with low N content compared to chemical N fertilizers. For this reason, comprehensive research is required to improve the composting process and the N content of the soil organic amendments.
  • This work aims to explore the beneficial effects of the integrated application of biochar and specific C and N cycling microorganisms to the composting process and the quality of the composted products. In pursuit of replacing chemical N fertilizers with bio/organic fertilizers, the researchers further discussed the power of the combined application of compost, biochar, and N-fixing bacteria in agricultural production systems.
  • The knowledge of smart integration of agricultural waste and microorganisms in agriculture could solve the main agricultural and environmental problems associated with human-induced flows of C and N.

Canola Meal versus Soybean Meal as Protein Supplements in the Diets of Lactating Dairy Cows Affects the Greenhouse Gas Intensity of Milk. Holtshausen L, Benchaar C, Kröbel R, Beauchemin KA. Animals (Basel). 2021 May 31;11(6):1636.

  • Soybean meal and canola meal are protein supplements used in lactating dairy cow diets and, recently, an enteric methane-mitigating effect was reported for canola meal. Before recommending canola meal as a greenhouse gas (GHG) mitigation strategy, it is necessary to examine the net impact on total GHG emissions from milk production.
  • The objective of this study was to determine whether using canola meal rather than soybean meal in lactating dairy cow diets decreases GHG per kilogram of fat and protein corrected milk, and whether the decrease depends upon where the meals are produced.
  • Cradle to farm-gate life cycle assessments were conducted for a simulated dairy farm in eastern (Quebec) and western (Alberta) Canada. Scenarios examined the source of protein meal, location where meals were produced, and the methane-mitigating effect of canola meal. The Holos model was used to estimate GHG emissions from animals, manure, crop production, imported feeds, and energy use.
  • GHG intensities (CO2e/kg FPCM) were 0.85-1.02 in the east and 1.07-1.11 in the west for the various scenarios, with enteric methane comprising 34 to 40% of total emissions. Canola meal produced in western Canada with a low up-stream emission factor reduced CO2e/kg of fat and protein corrected milk by 3% (western farm) to 6.6% (eastern farm) compared with SBM.
  • The researchers conclude that using canola meal rather than soybean meal in the diet of lactating dairy cows can be a GHG mitigation strategy depending upon where it is produced and whether it decreases enteric methane emissions.

Are dairy cows with a more reactive temperament less efficient in energetic metabolism and do they produce more enteric methane? Marçal-Pedroza MG, Campos MM, et al. Sant’Anna AC. Animal. 2021 May 25;15(6):100224.

  • It remains unknown whether dairy cows with more reactive temperament produce more enteric methane (CH4) and are less bioenergetically efficient than the calmer ones.
  • The objectives of this study were (a) to evaluate the relationship between cattle temperament assessed by traditionally used tests with energetic metabolism and enteric CH4emissions by crossbred dairy cows; (b) to assess how cows’ restlessness in respiration chambers affects energetic metabolism and enteric CH4
  • Temperament indicators were evaluated for 28 primiparous F1 Holstein-Gyr cows tested singly in the handling corral (entrance time, crush score, flight speed, and flight distance) and during milking (steps, kicks, defecation, rumination, and kick the milking cluster off). Cows’ behaviors within respiration chambers were also recorded for each individual kept singly.
  • Cows with more reactive temperament in milking (the ones that kicked the milking cluster off more frequently) spent 25% less net energy on lactation and emitted 37% more enteric CH4/kg of milk. Furthermore, cows that showed a higher frequency of rumination at milking parlor allocated 57.93% more net energy for milk production, spent 50% more metabolizable energy for milk production and 37% less CH4/kg of milk.
  • Regarding the handling temperament, most reactive cows according to flight speed, lost 29% less energy as urine and tended to have 14% more enteric CH4production, as well as cows with a lower entrance time (most reactive) that also lost 13% more energy as enteric CH4.
  • In conclusion, temperament and restless behavior of Holstein-Gyr cows were related to metabolic efficiency and enteric CH4 Cows’ reactivity and rumination in the milking parlor, in addition to flight speed and entrance time in the squeeze chute during handling in the corral, could be useful measures to predict animals more prone to metabolic inefficiency, which could negatively affect the sustainability of dairy systems.

Breeding for reduced methane emission and feed-efficient Holstein cows: An international response. Manzanilla-Pech CIV, L Vendahl P, Lassen J, et al. J Dairy Sci. 2021 May 14:S0022-0302(21)00597-X.

  • Selecting for lower methane (CH4) emitting animals is one of the best approaches to reduce CH4given that genetic progress is permanent and cumulative over generations. As genetic selection requires a large number of animals with records and few countries actively record CH4, combining data from different countries could help to expedite accurate genetic parameters for CH4 traits and build a future genomic reference population. Additionally, if we want to include CH4 in the breeding goal, it is important to know the genetic correlations of CH4 traits with other economically important traits.
  • Therefore, the aim of this study was first to estimate genetic parameters of 7 suggested methane traits, as well as genetic correlations between methane traits and production, maintenance, and efficiency traits using a multicountry database. The second aim was to estimate genetic correlations within parities and stages of lactation for CH4. The third aim was to evaluate the expected response of economically important traits by including CH4traits in the breeding goal.
  • A total of 15,320 methane production (MeP, g/d) records from 2,990 cows belonging to 4 countries (Canada, Australia, Switzerland, and Denmark) were analyzed. Records on dry matter intake (DMI), body weight (BW), body condition score, and milk yield (MY) were also available. Additional traits such as methane yield (MeY; g/kg DMI), methane intensity (MeI; g/kg energy-corrected milk), a genetic standardized methane production, and 3 definitions of residual methane production (g/d), residual feed intake, metabolic BW (MBW), BW change, and energy-corrected milk were calculated.
  • The estimated heritability of MeP was 0.21, whereas heritability estimates for MeY and MeI were 0.30 and 0.38, and for the residual methane traits heritability ranged from 0.13 to 0.16. Genetic correlations between different methane traits were moderate to high (0.41 to 0.97). Genetic correlations between MeP and economically important traits ranged from 0.29 (MY) to 0.65 (BW and MBW), being 0.41 for DMI.
  • Selection index calculations showed that residual methane had the most potential for inclusion in the breeding goal when compared with MeP, MeY, and MeI, as residual methane allows for selection of low methane emitting animals without compromising other economically important traits.
  • Inclusion of residual feed intake in the breeding goal could further reduce methane, as the correlation with residual methane is moderate and elicits a favorable correlated response. Adding a negative economic value for methane could facilitate a substantial reduction in methane emissions while maintaining an increase in milk production.

Animal Health and Food Safety

Epidemiology of antimicrobial resistance (AMR) on California dairies: descriptive and cluster analyses of AMR phenotype of fecal commensal bacteria isolated from adult cows. Abdelfattah EM, Ekong PS, Aly SS, et al. PeerJ. 2021. 20;9:e11108.

  • This study describes the occurrence of antimicrobial resistance in commensal Escherichia coliand Enterococcus/Streptococcus isolated from fecal samples of dairy cows and assesses the variation of antimicrobial resistance profiles across regions and seasons following the implementation of the Food and Agricultural Code Sections 14400-14408 (formerly known as Senate Bill, SB 27) in California.
  • The study was conducted on ten dairies distributed across California’s three milk sheds: Northern California (NCA), Northern San Joaquin Valley (NSJV), and the Greater Southern California (GSCA). Each cohort comprised of 12 cows per dairy. The fecal samples were collected at enrollment before calving (close-up stage) and then monthly thereafter for four consecutive time points up to 120 days in milk. A total of 2,171  coliand 2,158 Enterococcus/Streptococcus isolates were tested for antimicrobial susceptibility against a select panel of antimicrobials.
  • The results showed that the  coliisolates had high resistance to florfenicol (83.31%) and sulphadimethoxine (32.45%), while resistance to ampicillin (1.10%), ceftiofur (1.93%), danofloxacin (4.01%), enrofloxacin (3.31%), gentamicin (0.32%) and neomycin (1.61%) had low resistance proportions.
  • The Enterococcus/Streptococcus isolates were highly resistant to tildipirosin (50.18%), tilmicosin (48%), tiamulin (42%) and florfenicol (46%), but were minimally resistant to ampicillin (0.23%) and penicillin (0.20%).
  • Multidrug resistance (resistance to at least 1 drug in ≥3 antimicrobial classes) was observed in 14.14% of  coliisolates and 39% of Enterococcus/Streptococcus isolates. E. coli isolates recovered during winter showed higher multidrug resistance prevalence compared to summer isolates (20.33% vs. 8.04%). A higher prevalence of multidrug resistance was observed in NSJV (17.29%) and GSCA (15.34%) compared with NCA (10.10%).
  • In conclusion, these findings showed high rates of antimicrobial resistance to several drugs that are not labeled for use in lactating dairy cattle 20 months of age or older. Conversely, very low resistance was observed for drugs labeled for use in adult dairy cows, such as cephalosporins and penicillin. Overall, our findings identified important differences in antimicrobial resistance by antimicrobial class, region and season.

Feeding high amounts of almond hulls to lactating cows. Swanson KL, Bill HM, Asmus J, Heguy JM, DePeters EJ. J Dairy Sci. 2021 May 10:S0022-0302(21)00576-2.

  • California is the leading state for the production of almonds, with more than 400,000 bearing hectares of orchards that produced approximately 1 billion kg of shelled nuts in 2017. Almond hulls (AH) are a regional by-product feedstuff fed predominately to dairy cattle in California.
  • A 2012 study surveyed 40 dairy farms in California and found that 39 out of 104 total mixed rations contained AH, with a mean daily feeding rate of 1.45 kg/cow. In 2017, approximately 2 billion kg of AH was produced. At a feeding rate of 1.45 kg/cow daily, even if all 1.7 million lactating cows in California are consuming AH, there will be a surplus of AH on the market as the approximately 130,000 nonbearing hectares come into nut production.
  • Therefore, the potential of feeding varying amounts of AH to lactating dairy cows was investigated using 12 Holstein cows with 4 primiparous and 8 multiparous cows.
  • The dietary treatments were 4 total mixed rations containing 0, 7, 13, or 20% AH. The AH used contained 12.8% crude fiber (as-is basis), which was below the 15% legal limit set by state feed regulations. Diets were formulated so that as the inclusion rate of AH increased, the amount of steam-flaked corn and soyhull pellets decreased and soybean meal inclusion increased.
  • Diet had a cubic effect on actual milk yield, energy-corrected milk yield, and dry matter intake, with the 7% AH diet having the highest values and the 13% AH diet having the lowest. The percent and yield of total solids and the yields of lactose and fat did not differ with diet, but percent and yield of protein declined linearly with increased AH inclusion, and fat percent increased linearly. Total percentage of the day spent ruminating increased linearly with higher amounts of AH.
  • Overall, this work demonstrated that AH can be fed at varying amounts, up to 20% of the diet, to lactating dairy cows to support high levels of milk production and that increasing amounts of AH (up to 20%) in the diet could lead to improved digestibility and milk fat percentage but decreased milk protein production.

ADSA Foundation Scholar Award: New frontiers in calf and heifer nutrition-From conception to puberty. van Niekerk JK, Fischer-Tlustos AJ, Steele MA, et al. J Dairy Sci. 2021 May 27:S0022-0302(21)00623-8.

  • Dairy calf nutrition is traditionally one of the most overlooked aspects of dairy management, despite its large effect on the efficiency and profitability of dairy operations. Unfortunately, among all animals on the dairy farm, calves suffer from the highest rates of morbidity and mortality. These challenges have catalyzed calf nutrition research over the past decade to mitigate high incidences of disease and death, and improve animal health, growth, welfare, and industry sustainability. However, major knowledge gaps remain in several crucial stages of development.
  • The purpose of this review is to summarize the key concepts of nutritional physiology and programming from conception to puberty and their subsequent effects on development of the calf, and ultimately, future performance.
  • During fetal development, developmental plasticity is highest. At this time, maternal energy and protein consumption can influence fetal development, likely playing a critical role in calf and heifer development and, importantly, future production. After birth, the calf’s first meal of colostrum is crucial for the transfer of immunoglobulin to support calf health and survival.
  • However, colostrum also contains numerous bioactive proteins, lipids, and carbohydrates that may play key roles in calf growth and health. Extending the delivery of these bioactive compounds to the calf through a gradual transition from colostrum to milk (i.e., extended colostrum or transition milk feeding) may confer benefits in the first days and weeks of life to prepare the calf for the preweaning period.
  • Throughout the world, the majority of dairy calves rely on milk replacer to supply adequate nutrition. Recent research has started to re-evaluate traditional formulations of milk replacers, which can differ significantly in composition compared with whole milk.
  • Transitioning from a milk-based diet to solid feed is critical in the development of mature ruminants. Delaying weaning age and providing long and gradual step-down protocols have become common to avoid production and health challenges. Yet, determining how to appropriately balance the amount of energy and protein supplied in both liquid and solid feeds based on preweaning milk allowances, and further acknowledging their interactions, shows great promise in improving growth and health during weaning.
  • After weaning and during the onset of puberty, heifers are traditionally offered high-forage diets. However, recent work suggests that an early switch to a high-forage diet will depress intake and development during the time when solid feed efficiency is greatest.
  • It has become increasingly clear that there are great opportunities to advance our knowledge of calf nutrition; yet, a more concentrated and rigorous approach to research that encompasses the long-term consequences of nutritional regimens at each stage of life is required to ensure the sustainability and efficiency of the global dairy industry

Effects of Pre-Parturient Iodine Teat Dip Applications on Modulating Aversive Behaviors and Mastitis in Primiparous Cows. Phillips HN, Sorge US, Heins BJ. Animals (Basel). 2021 May 31;11(6):1623.

  • Heifers and their human handlers are at risk for decreased welfare during the early lactation period.
  • This experiment investigated pre-parturient teat dipping and parlor acclimation to reduce mastitis and aversive behaviors in early lactation heifers.
  • Three weeks prior to calving, heifers were randomly assigned to receive either: (1) a weekly 1.0% iodine-based teat dip in the parlor (trained; n= 37) or (2) no treatment (control; n = 30).
  • For the first 3 days of lactation, heifers were milked twice daily, and treatment-blinded handlers assessed behaviors and clinical mastitis. Aseptic quarter milk samples were collected within 36 h of calving and analyzed for pathogens.
  • Control heifers had 2.2 ± 0.6 times greater odds of kicking during milking. Trained heifers had 1.7 ± 0.4 times greater odds of being very calm during milking, while control heifers had 2.2 ± 0.8 and 3.8 ± 2.1 times greater odds of being restless and very restless or hostile during milking, respectively.
  • Quarters of control heifers had 5.4 ± 3.4 greater odds of intramammary Staphylococcus aureus infection, yet clinical mastitis was similar among treatments.
  • The results indicate that teat dipping in the parlor weekly for 3 weeks before calving may alleviate some aversive milking behaviors and protect against early lactation  aureus intramammary infections.

Prevalence, antibiotic resistance, virulence and genetic diversity of Staphylococcus aureus isolated from bulk tank milk samples of U.S. dairy herds. Patel K, Godden SM, Royster EE, Crooker BA, Johnson TJ, Smith EA, Sreevatsan S. BMC Genomics. 2021 May 20;22(1):367.

  • Colonization of dairy cows by Staphylococcus aureus (S. aureus), especially those which are multi-drug resistant and toxin producing, is a concern for animal health and well-being as well as public health.
  • The objective of this study was to investigate the prevalence, antibiotic resistance, gene content and virulence determinants of S. aureus in bulk tank milk samples from U.S. dairy herds.
  • Bulk milk tank samples were collected, once in winter and once in summer, from 189 U.S. dairy herds.
  • Of 365 BTM samples cultured, the sample and herd prevalence of S. aureus in BTM was 46.6% (170 of 365 samples) and 62.4% (118 of 189 herds), respectively. Among a subset of 138 S. aureus isolates that were stored for further analysis, 124 were genome sequenced after being confirmed as S. aureus using phenotypic tests.
  • The most commonly identified antimicrobial resistance-associated gene was norA (99.2%) and mecA gene responsible for methicillin resistance (MRSA) was identified in one isolate (0.8%). The most frequently detected putative virulence genes were aur (100%), hlgB (100%), hlgA, hlgC, hlb (99.2%), lukE (95.9%) and lukD (94.3%).
  • In the 53 staphylococcal enterotoxin positive isolates, sen (37.9%), sem (35.5%), sei (35.5%) and seg (33.1%) were the most frequently detected enterotoxin genes. Among the 14 sequence types and 18 spa types identified, the most common was ST2187 (20.9%) and t529 (28.2%), respectively. The most predominant clone was CC97 (47.6%) followed by CC unknown (36.3%). The single MRSA isolate belonged to sequence type 72-CC8, spa type t126 and was negative for the tst gene but harbored all the other virulence genes investigated.
  • These findings indicated a high prevalence of S. aureus in bulk tank milk of U.S. dairy herds, with isolates showing little evidence of resistance to antibiotics commonly used to treat mastitis. However, isolates often carried genes for the various enterotoxins. Despite lower prevalence, the presence of MRSA and multi-drug resistant strains in bulk tank milk poses a significant risk to animal and public health if their number were to increase in dairy environment. Therefore, it is necessary to continuously monitor the use of antibiotics in dairy cows.

Human Nutrition and Health

Global Review of Dairy Recommendations in Food-Based Dietary Guidelines. Comerford K, Miller G, Boileau A, Massiello Schuette S, Giddens J, Brown K. Front. Nutr. 2021 May 25.

  • At present, there are ~100 countries with national food-based dietary guidelines. While the intent of these guidelines is to inform national-level dietary recommendations, they also tie into global health and sustainable development initiatives, since diet and nutrition are linked to outcomes for all 17 United Nations Sustainable Development Goals.
  • Therefore, key messaging in food-based dietary guidelines plays an important role in both national and global health efforts. However, this type of national-level dietary guidance is not standardized and varies considerably from country to country, and from food group to food group.
  • The main objective of this review is to provide a novel look at dairy food group messaging within global food-based dietary guidelines, focusing specifically on nutrient-based and health-based messaging.
  • Dairy-based messaging from 94 national food-based dietary guidelines was reviewed and grouped by region, with an emphasis on messaging regarding dairy’s contribution to nutrients of public health concern for both underconsumption and overconsumption.
  • The results showed that most nutrient-based dairy messaging relating to underconsumption was focused on calcium, followed by vitamin D, iodine, potassium, and protein; whereas messaging related to overconsumption was focused on saturated fat, added sugars, and salt.
  • Health-based messaging specific to dairy food intake typically coalesced around three types of health outcomes: (1) bone, teeth, and muscle, (2) cardiometabolic, and (3) gut and immune.
  • Although a fundamental concept of food-based dietary guidelines is to provide dietary guidance in a manner that is both “food-based,” and in the context of “dietary” patterns, most food-based dietary guidelines still express the health value of dairy foods (and potentially other foods groups) solely in terms of their nutrient content – and often times only in the context of a single nutrient (e.g., calcium).

Effect of Early Childhood Cow’s Milk Elimination Diet on Eating Behaviors, Nutrition, and Growth Status at age 2-6 years. Ercan N, Tel Adıgüzel K. J Hum Nutr Diet. 2021 May 11.

  • Cow’s milk allergy (CMA) is the most common Food Allergy (FA) in children, and the essential strategy in prevention is avoiding the allergens that may cause potentially life-threatening reactions.
  • The purpose of this study was to investigate the eating behavior, nutritional status, and growth of Caucasian children in ages 2-6 years who had a diet due to Cow’s Milk Protein Allergy (Ig E-mediated and/or non-Ig E-mediated) in early childhood.
  • In this cross-sectional, case-control study, the CME (Cow’s Milk Elimination) group was constituted of children (n=62) aged 0-2 who received a CME diet due to cow’s milk allergy. The control group never had a restricted diet. A three-day food record was taken to determine the macronutrient and micronutrient intake of the children.
  • Weight-for-age and height-for-age were statistically lower in the CME group than the control group (p<0.001). In the CME group, the current frequency of adequate energy, vitamin B1, folic acid, vitamin C, and calcium intake was significantly lower than the control group (p<0.05).
  • In conclusion, dietary interventions due to cow’s milk allergy in ages 0-2 can negatively affect children’s nutritional habits and parental-reported assessment of children’s eating behaviors and result in growth restriction with insufficient micro/macronutrients and/or dairy products at the age of 2-6 years.

Age and Sex Interact to Determine the Effects of Commonly Consumed Dairy Products on Postmeal Glycemia, Satiety, and Later Meal Food Intake in Adults. Vien S, Fard S, El Khoury D, Luhovyy B, Fabek H, Anderson GH. J Nutr. 2021 May 24:nxab122.

  • Dairy consumption reduces postprandial glycemia and appetite when consumed with carbohydrates.
  • The objective was to test the effects of frequently consumed dairy products, age, and sex on glycemia, appetite, and food intake.
  • In a randomized, unblinded, crossover design, 30 older (60-70 years) and 28 young (20-30 years) adults consumed 500 mL of a calorie-free control (water), skim milk and whole milk, 350 g Greek yogurt, and 60 g cheddar cheese. Food intake at an ad libitum meal was measured 120 min later. Glycemia, appetite, and gastric hormone responses were measured premeal (15-120 min), within-meal (120-140 min), and postmeal (140-170 min).
  • The results showed thatall forms of dairy, compared with water, decreased postmeal glycemia, premeal appetite, and meal intake. Premeal glucose, insulin, and glucagon-like peptide 1 increased, and ghrelin decreased, but effects of dairy differed with age and sex.
  • Older adults had 10% higher pre- and postmeal glucose. Premeal appetite suppression per 100 kcal of treatments was more after yogurt than other dairy, but overall appetite suppression was less in older adults than in young adults and in males than in females.
  • Pizza intake was reduced by 175 kcal after yogurt and cheese and by 82 kcal after milks compared to water. Mealtime reduction for treatment calories averaged 62% after yogurt and cheese but was less at 33% after milks. Compensation was less in older (33%) than in young (63%) adults.
  • In conclusion, dairy products consumed in usual forms before a meal stimulate metabolic responses leading to reduced premeal appetite, later food intake, and post-meal glycemia, but their effects differ in magnitude and with the sex and age of adults.

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. 2021 May;24(7):1778-1786.

  • There is evidence to suggest that increased dietary calcium intake, which is mainly obtained from dairy products, is associated with improved quality of sleep and reduced insomnia. In addition, brain calcium is proposed to have a role in regulating the duration of sleep in mammals. The effect of dairy products on sleep could also be due to their content of tryptophan, as calcium is involved in producing melatonin, the sleep-inducing neurosecretory hormone, from tryptophan in the brain.
  • The objective of this study was to assess dairy calcium intake and investigate its relationship with insomnia and other common co-morbidities including anxiety, depression and musculoskeletal pain among university students.
  • 1,000 young adults from the University of Irbid, Jordan participated in this cross-sectional study.
  • The results showed that low dairy calcium 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 and 18% of participants, respectively. Musculoskeletal pain was reported by 43% of participants.
  • Participants with moderate to severe insomnia had lower dairy calcium, higher anxiety and depression scores and higher measures of musculoskeletal pain compared to participants with no insomnia. Dairy calcium was weakly inversely correlated with Insomnia Severity Index (ISI) score, depression score, and measures of musculoskeletal pain.
  • Regression analysis indicated that insomnia was predicted by low dairy calcium, anxiety, depression, musculoskeletal pain and smoking. Both anxiety and depression were predicted by increased ISI score, while depression alone was predicted by low dairy calcium.
  • For this study population of university students, low dairy calcium was highly prevalent and associated with insomnia and depression. Individuals should be advised to increase dietary calcium intake to achieve the recommended daily amount.

Consumption of OLL1073R-1 yogurt improves psychological quality of life in women healthcare workers: secondary analysis of a randomized controlled trial. Kinoshita T, Maruyama K, Suyama K, Nishijima M, Akamatsu K, Jogamoto A, Katakami K, Saito I. BMC Gastroenterol. 2021 May 24;21(1):237.

  • It has been established that yogurt, a fermented dairy product, has beneficial effects on certain gastrointestinal conditions including lactose intolerance, constipation, inflammatory bowel diseases, and Helicobacter pylori infection. Recent studies have investigated the role of yogurt in enhancing human immune function by changing the balance of the intestinal microbiota and stimulating the intestinal immune system via lactic acid-producing bacteria or substances produced by the bacteria.
  • Furthermore, some studies have attempted to demonstrate the beneficial effects of probiotics on mental health, i.e., ameliorating depression, anxiety, fatigue, and sleep disturbance. The reported results have however been inconsistent.
  • Researchers conducted a randomized controlled trial to investigate the effects of consumption of yogurt fermented with Lactobacillus delbrueckii ssp. bulgaricus OLL1073R-1 in women healthcare workers.
  • The participants (961 women; mainly nurses, aged 20-71 years) were randomly allocated to either the yogurt group (n = 479) or the control group (n = 482). Participants in the yogurt group drank 112 mL of OLL1073R-1 yogurt for 16 weeks, while those in the control group did not consume any yogurt. The participants answered the Pittsburgh Sleep Quality Index (PSQI), Short Form-8 Health Survey (SF-8), and Gastrointestinal Symptom Rating Scale (GSRS) questionnaires at baseline and after 16 weeks.
  • The PSQI score showed significant improvement after the intake of yogurt. SF-8 results showed significant intervention effects in the General Health and Vitality scores. In other subscales of SF-8, the researchers did not observe significant effects of the yogurt. In the GSRS, daily intake of yogurt exerted a preventive effect on constipation.
  • In conclusion, the consumption of yogurt fermented with Lactobacillus delbrueckii ssp. bulgaricus OLL1073R-1 may enhance subjective psychological quality of life by improving quality of sleep and gastrointestinal condition among women healthcare workers.

Dietary yogurt is distinct from other dairy foods in its association with circulating lipid profile: Findings from the Million Veteran Program. Ivey KL, Nguyen XT, Tobias DK, Song R, Rogers GB, Ho YL, Li R, Wilson PW, Cho K, Gaziano JM, Willett WC, Djoussé L. Clin Nutr ESPEN. 2021 Jun;43:456-463.

  • Dyslipidemia is a major cardiovascular disease risk factor. Research has proposed mechanisms whereby yogurt may improve circulating lipid concentrations. However, at the population level, the association of yogurt, as distinct from other dairy foods, with these important risk factors is poorly understood.
  • This study aimed to determine whether the circulating lipid profile associated with yogurt is different to the circulating lipid profile that is associated with non-yogurt dairy products, specifically milk and cheese.
  • The current study included the 192,564 US Veterans enrolled in the Million Veteran Program who reported frequency of yogurt consumption (assessed via food frequency questionnaire) and had lipid concentrations assessed. Mean age was 65 years.
  • The study found that a one serving/day higher yogurt consumption was positively associated with the concentration of high-density lipoprotein cholesterol (HDL-C; “good cholesterol”) for individuals who regardless of whether they were using cholesterol-lower medications or not. Furthermore, higher yogurt consumption was inversely associated with the concentration of triglycerides, but only in individuals who were not using cholesterol-lower medications.
  • These apparent beneficial associations of a higher frequency of yogurt consumption with improved HDL-C and triglycerides were independent of consumption of non-yogurt dairy foods and were not observed for consumption of either milk or cheese.

Dairy Consumption and Risk of Metabolic Syndrome: Results from Korean Population and Meta-Analysis. Jin S, Je Y. Nutrients. 2021 May 8;13(5):1574.

  • Dairy consumption has been associated with decreased risk of metabolic syndrome (MetS) in previous studies, but the association may be different according to each type of dairy products and its subgroups.
  • Thus, researchers conducted an updated meta-analysis of observational studies to examine the association between various dairy products and risk of MetS.
  • A total of 35 studies (12 cohort studies and 25 cross-sectional studies) with 398,877 subjects were included in the meta-analysis. The pooled relative risks (RR) of MetS for the highest versus lowest categories of dairy consumption was 0.80. For the type of dairy products, there were also significant inverse associations with milk (RR=0.83) and yogurt consumption (RR=0.89). For cheese consumption, however, no significant association was found (RR= 0.98).
  • These findings suggest that milk and yogurt consumption is inversely associated with the risk of MetS, but not cheese consumption.

Effect of fermented milk on upper respiratory tract infection in adults who lived in the haze area of Northern China: a randomized clinical trial. Zhang H, Miao J, Su M, Liu BY, Liu Z. Pharm Biol. 2021;59(1):647-652.

  • Upper respiratory tract infection (URTI) is the most common illness in humans. Fermented milk containing probiotics can mitigate URTI symptoms.
  • This study tested the effect of fermented milk (Qingrun), a yogurt supplemented with Bifidobacterium animalislactis Bl-04, on adults with URTIs who live in a haze-covered area in a randomized clinical trial.
  • A total of 136 subjects were enrolled in the study at the baseline and randomized to consume either control yogurt or Qingrun yogurt (250 g) once daily for 12 weeks. The duration and severity of URTI were evaluated by the Wisconsin Upper Respiratory Symptom Survey-24. Blood and fecal samples were collected at the baseline and post-intervention, to determine the changes of immune biomarkers.
  • Qingrun yogurt significantly reduced the incidence of the common cold by 62% and influenza-like illness by 68%. Compared to the control yogurt, Qingrun yogurt significantly reduced the duration and severity score of URTI. In addition, the post-intervention levels of interferon-γ and secretory immunoglobulin A significantly increased in the Qingrun group, compared with those in the control group.
  • In conclusions,Qingrun yogurt showed a protective effect against URTI in adults, suggesting that the use of yogurt with probiotics could be a promising dietary supplement for mitigating URTI.

Innovation, Economics, and Dairy Alternatives

Dairy By-Products: A Review on the Valorization of Whey and Second Cheese Whey. Pires AF, Marnotes NG, Rubio OD, Garcia AC, Pereira CD.Foods. 2021 May 12;10(5):1067.

  • The search for new food products that promote consumers health has always been of great interest. The dairy industry is perhaps the best example regarding the emergence of new products with claimed health benefits.
  • Cheese whey (CW), the by-product resulting from cheese production, and second cheese whey (SCW), which is the by-product of whey cheese manufacture, have proven to contain potential ingredients for the development of food products with improved nutritional characteristics and other functionalities.
  • Nowadays, due to their nutritional quality, whey products have gained a prominent position among healthy food products. However, for a long time, CW and SCW were usually treated as waste or as animal feed. Due to their high organic content, these by-products can cause serious environmental problems if discarded without appropriate treatment.
  • Small and medium size dairy companies do not have the equipment and structure to process whey and second cheese whey. In these cases, generally, they are used for animal feed or discarded without an appropriate treatment, being the cause of several constraints.
  • There are several studies regarding CW valorization and there is a wide range of whey products in the market. However, in the case of SCW, there remains a lack of studies regarding its nutritional and functional properties, as well as ways to reuse this by-product in order to create economic value and reduce environmental impacts associated to its disposal.

Probiotics in the dairy industry-Advances and opportunities. Gao J, Li X, Zhang G,  Sang Y ,et al. Compr Rev Food Sci Food Saf. 2021 May 3.

  • The past two decades have witnessed a global surge in the application of probiotics as functional ingredients in food, animal feed, and pharmaceutical products. Among food industries, the dairy industry is the largest sector where probiotics are employed in a number of dairy products including sour/fermented milk, yogurt, cheese, butter/cream, ice cream, and infant formula.
  • These probiotics are either used as starter culture alone or in combination with traditional starters, or incorporated into dairy products following fermentation, where their presence imparts many functional characteristics to the product (for instance, improved aroma, taste, and textural characteristics), in addition to conferring many health-promoting properties.
  • However, there are still many challenges related to the stability and functionality of probiotics in dairy products. This review highlights the advances, opportunities, and challenges of application of probiotics in dairy industries. Benefits imparted by probiotics to dairy products including their role in physicochemical characteristics and nutritional properties (clinical and functional perspective) are also discussed.
  • In this publication, the researchers transcend the traditional concept of the application of probiotics in dairy products and discuss paraprobiotics and postbiotics as a newly emerged concept in the field of probiotics in a particular relation to the dairy industry. Some potential applications of paraprobiotics and postbiotics in dairy products as functional ingredients for the development of functional dairy products with health-promoting properties are briefly elucidated.

Trends in the consumption of conventional dairy milk and plant-based beverages and their contribution to nutrient intake among Canadians. Islam N, Shafiee M, Vatanparast H. J Hum Nutr Diet. 2021 May 1.

  • Current evidence suggests a shift from conventional dairy milk to plant-based beverages (PBBs) due to a number of lifestyles and perceived health-related reasons.
  • Using nationally representative cross-sectional data from the 2004 and 2015 Canadian Community Healthy Surveys, the main objectives of this study were to 1) examine the trend in the proportion of Canadians (≥2 years) consuming plain milk and PBBs, and 2) determine the percent contribution of plain milk and PBBs to daily energy and nutrient intakes.
  • From 2004 to 2015, the percentage of Canadians consuming plain milk significantly decreased from 70.2% to 56.1%, while the percentage of PBBs consumers significantly increased from 1.8% to 3.0%. In 2015, plain milk provided near 50% of the daily vitamin D intake, over 30% of calcium and vitamin B12, and over 20% of vitamin A and riboflavin among plain milk consumers.
  • The top five nutrients provided by PBBs among PBBs consumers were vitamin D, calcium, vitamin B12, vitamin A, and riboflavin. While plain milk was a major contributor to saturated fat (14.5%) and protein (12.5%) intake among plain milk consumers, PBBs provided only 0.2% of saturated fat and 1.4% of protein intake in the diet of PBBs consumers.
  • Canadians’ consumption of plain milk has declined and the consumption of PBBs has increased, which may differentially affect the nutritional profile of the diet.

Safety of Alternative Proteins: Technological, Environmental and Regulatory Aspects of Cultured Meat, Plant-Based Meat, Insect Protein and Single-Cell Protein. Hadi J, Brightwell G. Foods. 2021 May 28;10(6):1226.

  • Food security and environmental issues have become global crises that need transformative solutions. As livestock production is becoming less sustainable, alternative sources of proteins are urgently required. These include cultured meat, plant-based meat, insect protein and single-cell protein.
  • Herein, researchers describe the food safety aspects of these novel protein sources, in terms of their technological backgrounds, environmental impacts and the necessary regulatory framework for future mass-scale production.
  • Briefly, cultured meat grown in fetal bovine serum-based media can be exposed to viruses or infectious prion, in addition to other safety risks associated with the use of genetic engineering.
  • Plant-based meat may contain allergens, anti-nutrients and thermally induced carcinogens.
  • Microbiological risks and allergens are the primary concerns associated with insect protein.
  • Single-cell protein sources are divided into microalgae, fungi and bacteria, all of which have specific food safety risks that include toxins, allergens and high ribonucleic acid (RNA) contents.
  • The environmental impacts of these alternative proteins can mainly be attributed to the production of growth substrates or during cultivation. Legislations related to novel food or genetic modification are the relevant regulatory framework to ensure the safety of alternative proteins.
  • Lastly, additional studies on the food safety aspects of alternative proteins are urgently needed for providing relevant food governing authorities with sufficient data to oversee that the technological progress in this area is balanced with robust safety standards.

The science of plant-based foods: Constructing next-generation meat, fish, milk, and egg analogs. McClements DJ, Grossmann L. Compr Rev Food Sci Food Saf. 2021 May 30.

  • Consumers are increasingly demanding foods that are more ethical, sustainable and nutritious to improve the health of themselves and the planet. The food industry is currently undergoing a revolution, as both small and large companies pivot toward the creation of a new generation of plant-based products to meet this consumer demand.
  • In particular, there is an emphasis on the production of plant-based foods that mimic those that omnivores are familiar with, such as meat, fish, egg, milk, and their products.
  • The main challenge in this area is to simulate the desirable appearance, texture, flavor, mouthfeel, and functionality of these products using ingredients that are isolated entirely from botanical sources, such as proteins, carbohydrates, and lipids.
  • The molecular, chemical, and physical properties of plant-derived ingredients are usually very different from those of animal-derived ones. It is therefore critical to understand the fundamental properties of plant-derived ingredients and how they can be assembled into structures resembling those found in animal products.
  • This review article provides an overview of the current status of the scientific understanding of plant-based foods and highlights areas where further research is required. In particular, it focuses on the chemical, physical, and functional properties of plant-derived ingredients; the processing operations that can be used to convert these ingredients into food products; and, the science behind the formulation of vegan meat, fish, eggs, and milk alternatives.