Welcome to the July 2020 Dairy Research Bulletin. The Dairy Research Bulletin delivers a brief synopsis of the most current Human, Animal, and Environmental dairy research that is going on in the World, and also that which is of special interest to California dairy producers and consumers alike.

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


Selected Articles on Social Responsibility, Environmental Management, and Sustainability

Short communication: Relationship of dry matter intake with enteric methane emission measured with the GreenFeed system in dairy cows receiving a diet without or with 3-nitrooxypropanol. Hristov AN, Melgar A.Animal. 2020 Jul 28:1-7.

  • The relationship between dry matter intake (DMI) and enteric methane emission is well established in ruminant animals but may depend on measurement technique (e.g. spot v. continuous gas sampling) and rumen environment (e.g. use of fermentation modifiers). A previous meta-analysis has shown a poor overall (i.e. 24-hour) relationship of DMI with enteric methane emission in lactating dairy cows when measured using the GreenFeed system (GF).
  • Therefore, researchers examined this relationship in a 15-week experiment with lactating dairy cows receiving a control diet or a diet containing the investigational product 3-nitrooxypropanol (3-NOP), an enteric methane inhibitor, applied at 60 mg/kg feed DM.
  • Daily methane emission, measured using GF, and DMI were clustered into 12 feed-intake timeslots of 2 hours each. Methane emission and DMI were the lowest 2 hours before feeding and the highest within 6 hours after feed provision.
  • The overall (24-hour) relationship between methane emission and DMI was poor. The relationship for the control (but not 3-NOP) cows was improved when DMI was allocated to timeslots and was strongest 8 to 10 hours after feed provision. Analysis of the 3-NOP emission data showed marked differences in the mitigation effect over time.
  • There was a lack of effect in the 2-hour timeslot before feeding, the mitigation effect was highest (45%) immediately after feed provision, persisted at around 32% to 39% within 10 hours after feed provision, and decreased to 13%, 4 hours before feeding. These trends were clearly related to DMI (i.e. 3-NOP intake) by the cows.
  • The current analysis showed that the relationship of enteric methane emission, as measured using GF, and DMI in dairy cows depends on the time of measurement relative to time of feeding. The implication of this finding is that a sufficient number of observations, covering the entire 24-hour feeding cycle, have to be collected to have representative emission estimates using the GF system. This analysis also revealed that the methane mitigation effect of 3-NOP is highest immediately after feed provision and lowest before feeding.

Life Cycle Assessment of Struvite Precipitation from Anaerobically Digested Dairy Manure: A Wisconsin Perspective. Temizel-Sekeryan S, Wu F, Hicks AL.Integr Environ Assess Manag. 2020 Jul 27.

  • Recovering valuable nutrients (e.g. phosphorus and nitrogen) from waste materials has been extensively investigated at the laboratory scale. Although it has been shown that struvite precipitation from several manure sources contribute to nutrient management practices by recovering valuable nutrients and preventing them from reaching water bodies, it has not been widely applied in commercial (i.e. farm) scales.
  • The purpose of this study is to evaluate the potential environmental impacts of the struvite recovery process from the liquid portion of the anaerobically digested dairy cow manure generated in Wisconsin dairy farms using life cycle assessment methodology for both bench and farm scale scenarios.
  • The struvite precipitation process involves the use of additional chemicals and energy, therefore, investigating upstream impacts are crucial to evaluate the environmental costs and benefits of this additional treatment process.
  • Results indicate that up to a 78% impact decrease in eutrophication potential can be achieved when phosphorus and nitrogen are recovered in the form of struvite and are applied in lieu of conventional fertilizers, rather than using the liquid portion of the anaerobically digested dairy manure as a fertilizer.
  • Additionally, significant differences are identified in the majority of environmental impact categories when the struvite precipitation process is modeled and evaluated in a farm scale setting.
  • Future work should expand to evaluate the overall environmental impacts and tradeoffs of struvite recovery application including the anaerobic digestion system itself at the farm scale.

Economic Viability of Adoption of Automated Oestrus Detection Technologies on Dairy Farms: A Review. Adenuga AH, Jack C, Olagunju KO, Ashfield A.Animals (Basel). 2020 Jul 21;10(7):E1241.

  • The decision for dairy farmers to invest in automated oestrus detection (AOD) technologies involves the weighing up of the costs and benefits of implementation.
  • In this paper, through a review of the existing literature, researchers examine the impacts of investment in AOD technologies in relation to the profitability and technical performance of dairy farms.
  • Peer-reviewed articles published between 1970 and 2019 on the investment viability of AOD technologies were collated and analyzed.
  • The researchers capture the different measures used in assessing the economic performance of investment in AOD technologies over time which include net present value (NPV), milk production, Benefit-Cost Ratio (BCR), internal rate of return (IRR) and payback period (PBP).
  • The study concludes that investment in AOD technologies is not only worthwhile but also contributes to farm profitability.

Youth and adult public views of dairy calf housing options. Perttu RK, Ventura BA, Endres MI.J Dairy Sci. 2020 Jul 1:S0022-0302(20)30496-3.

  • Welfare and management of calves is of increasing interest to the public.
  • The objective of this study was to explore views on dairy calf housing options among American youth and adults. Youth views were of interest because they are future consumers, yet their influence on livestock production practices is often overlooked.
  • Participants 5 to 17 years of age (n = 463) and 18 years or older (n = 1,310) completed an in-person survey at the Minnesota State Fair (St. Paul, MN) in summer 2018. The survey was administered via Qualtrics survey software and presented 3 images of calf housing options (individual, pair, or group) and asked participants to select their preferred option and indicate their reasoning for selection (youth), or acceptance for each option and reasoning for selection (adult).
  • The median age of youth participants was 11 years, 61% were female, 82% were urban residents, and 63% did not have prior experience handling agricultural animals, but 83% had visited a farm in the past.
  • Median age range of adult participants was 45 to 54 years, 65% were female, 82% urban residents, 41% completed a bachelor’s degree, and 81% did not have prior experience handling agricultural animals, but 63% had visited a farm in the past.
  • Overall, group housing was overwhelmingly preferred by youth participants (80.1%), followed by pair (14.3%) and individual housing (5.6%). Youth who chose group housing most commonly cited reasons related to increased socialization (71.4%) and space allowance (58.5%). Housing preference of youth was not associated with age, gender, or prior visits to a farm. However, rural youth more frequently preferred individual housing compared with urban youth.
  • Similarly, adult participants were most accepting of group housing for dairy calves (75.8% of participants), with reasons focused on calves’ ability to socialize and access to increased space allowance. Adult males, rural residents, and individuals with previous livestock handling experience more frequently accepted individual calf housing compared with females, urban residents, and individuals without previous livestock handling experience.
  • These findings suggest that housing systems that enable greater degrees of behavioral freedom for calves may be more socially sustainable for the dairy sector.

Antimicrobial Resistance at Two United States Cull Cow Processing Establishments. Schmidt JW, Vikram A, Arthur TM, Belk KE, Morley PS, Weinroth MD, Wheeler TL.J Food Prot. 2020 Jul 30.

  • Culled beef cows (cows from cow-calf operations that have reached the end of productive life span) and culled dairy cows amount to approximately 18% of the cattle harvested in the U.S. annually, but data on antimicrobial resistance (AMR) levels in U.S. cull cattle is extremely limited.
  • To address this data gap, colon contents were obtained from 180 culled beef cows (conventional beef), 179 culled dairy cows (conventional dairy), and 176 culled organic dairy cows produced without using antimicrobials (organic dairy).
  • Also, 181 conventional beef, 173 conventional dairy, and 180 organic dairy carcasses were sponge sampled. These samples were obtained on 6 days (3 each at two beef harvest and processing establishments). At one establishment 30 samples of beef manufacturing trimmings (trim) from conventional cows and 30 samples of trim from organic dairy cows were acquired.
  • All 1,129 samples were cultured for Escherichia coli, tetracycline-resistant (TETr) E. coli, third-generation cephalosporin-resistant (3GCr) E. coli, Salmonella, and 3GCrSalmonella. Metagenomic DNA was isolated from 535 colon content samples and quantitative PCR was performed to assess the abundances of 10 antimicrobial resistance genes: aac(6′)-Ie-aph(2″)-Ia, aadA1, blaCMY-2,blaCTX-M,blaKPC-2, erm(B),mecA, tet(A),tet(B), and tet(M).
  • For colon contents only TETrE. coli, 3GCrE. coli, and erm(B) levels were higher in conventional than organic cows. Sampling day also significantly affected each of these levels. Production system did not affect the levels of any measured antimicrobial resistance on carcasses or trim.
  • The human health impact of the few statistically significant AMR differences are undefinable due to the lack of standards for normal, background, safe, or basal levels. Study results provide key heretofore unavailable data that may inform quantitative microbial risk assessments to address these gaps.

Diurnal Flight Activity of House Flies (Musca domestica) is Influenced by Sex, Time of Day, and Environmental Conditions. Zahn LK, Gerry AC.Insects. 2020 Jun 23;11(6):391.

  • House flies (Musca domestica) are common synanthropic pests associated with confined animal operations, including dairy farms. House flies can cause substantial nuisance and may transmit human and animal pathogens. Surprisingly little is known about the daily flight activity of house flies.
  • This study examined diurnal house fly flight activity on two southern California dairies using clear sticky traps to capture flies over hourly intervals.
  • Flight activity for both males and females combined started near dawn and generally increased to a single broad activity peak during mid to late morning. Male flight activity peaked earlier than female flight activity and this separation in peak activity widened as mean daytime temperature increased.
  • Flight activity for both sexes increased rapidly during early morning in response to the combined effects of increasing light intensity and temperature, with decreasing flight activity late in the day as temperature decreased.
  • During midday, flight activity was slightly negatively associated with light intensity and temperature.
  • Collection period (time of day) was a useful predictor of house fly activity on southern California dairies and the diurnal pattern of flight activity should be considered when developing house fly monitoring and control programs.


Selected Articles on Dairy Intake and Human Health

Plant-based food and protein trend from a business perspective: markets, consumers, and the challenges and opportunities in the future. Aschemann-Witzel J, Gantriis RF, Fraga P, Perez-Cueto FJA.Crit Rev Food Sci Nutr. 2020 Jul 13:1-10.

  • The food sector is increasingly turning toward sustainability issues. A sustainable food system should provide sufficient, nutritious food for all within limited natural resources.
  • Plant-based food and proteins are a recent, growing trend setting out to contribute to this challenge. However, food industry stakeholders need to be aware of the challenges and opportunities.
  • This paper reviews the trend from a business perspective. It outlines the global drivers, market trends, market data observations, and consumer behavior factors of relevance, and pinpoints the strengths, weaknesses, opportunities and threats (SWOT) for food sector companies.
  • Findings suggest that the policy and market context is favorable in the near future, but that consumer beliefs, perception and understanding has to change further for the business opportunity to grow on a larger scale.
  • More innovations are needed, in particular in the direction of meat-replacements that are healthy as well as clean label.

Replacing the nutrients in dairy foods with non-dairy foods will increase cost, energy intake and require large amounts of food: National Health and Nutrition Examination Survey 2011-2014. Cifelli CJ, Auestad N, Fulgoni VL.Public Health Nutr. 2020 Jul 27:1-12.

  • The 2015 US Dietary Guidelines for Americans recommends increased consumption of the dairy group to three daily servings for ages 9+ years to help achieve adequate intakes of prominent shortfall nutrients. Identifying affordable, consumer-acceptable foods to replace dairy’s shortfall nutrients is important especially for people who avoid dairy.
  • Researchers used the National Health and Nutrition Examination Survey (2011-2014) to examine cost, energy and dietary Implications of replacing dairy with food combinations optimized for lowest cost, fewest kJ or the smallest amount of food by weight.
  • Phase 1 (only dairy foods excluded): when optimized for lowest cost or fewest kJ, all non-dairy food replacements required large amounts (2.5-10 cups) of bottled/tap water.
  • Phase 2 (dairy and unreasonable non-dairy foods excluded (e.g. baby foods; tap/bottled water): when intake of non-dairy foods was constrained to <90th percentile of current intake.
  • The lowest cost food combination replacements for dairy cost 0.5 times more and provide 5·7 times more energy; the lowest energy food combinations cost 5.9 times more, provide 2.5 times more energy and require twice the amount of food by weight; and food combinations providing the smallest amount of food by weight cost 3.5 times more and provide five times more energy than dairy.
  • Identifying affordable, consumer-acceptable foods that can replace dairy’s shortfall nutrients at both current and recommended dairy intakes remains a challenge.

Effect of High versus Low Dairy Consumption on the Gut Microbiome: Results of a Randomized, Cross-Over Study. Swarte JC, Eelderink C, Douwes RM, Said MY, Hu S, Post A, Westerhuis R, Bakker SJL, Harmsen HJM.Nutrients. 2020 Jul 17;12(7):E2129.

  • The influence of dairy on the gut microbiome has not been studied extensively.
  • Researchers performed a randomized cross-over study to analyze the effect of high dairy intake on the gut microbiome.
  • Subjects were randomly assigned to a high-dairy diet (HDD) (5-6 dairy portions per day) and a low-dairy diet (LDD) (≤1 dairy portion per day) for 6 weeks with a washout period of 4 weeks in between both diets. In total, 46 healthy overweight subjects (BMI range 25-30 kg/m2) completed both intervention periods.
  • During the HDD, there was a significantly higher abundance of the genera Streptococcus, Leuconostoc, and Lactococcus, and the species Streptococcus thermophilus, Erysipelatoclostridium ramosum and Leuconostoc mesenteroides.
  • Furthermore, during the HDD, there was a significantly lower abundance of the genera Faecalibacterium and Bilophila, and the species Faecalibacterium prausnitzii, Clostridium aldenense, Acetivibrio ethanolgignens, Bilophila wadsworthia and Lactococcus lactis.
  • There were eight subjects who became constipated during the HDD and these subjects all had a lower abundance of F. prausnitzii.
  • An HDD led to a significantly different composition of the gut microbiome, with a particularly lower abundance of F. prausnitzii and a higher abundance of S. thermophilus. Constipation was observed in several subjects during the HDD. Predicted metabolic pathways were not significantly altered due to an HDD.

Randomised Controlled Trial: Partial Hydrolysation of Casein Protein in Milk Decreases Gastrointestinal Symptoms in Subjects with Functional Gastrointestinal Disorders. Laatikainen R, Salmenkari H, Sibakov T, Vapaatalo H, Turpeinen A.Nutrients. 2020 Jul 18;12(7):E2140.

  • Unspecific gastrointestinal symptoms associated with milk consumption are common. In addition to lactose, also other components of milk may be involved.
  • Researchers studied whether the partial hydrolysation of milk proteins would affect gastrointestinal symptoms in subjects with functional gastrointestinal disorders.
  • In a randomised, placebo-controlled crossover intervention, subjects (n= 41) were given ordinary or hydrolysed high-protein, lactose-free milkshakes (500 mL, 50 g protein) to be consumed daily for ten days. After a washout period of ten days, the other product was consumed for another ten days. Blood and urine samples were analysed for markers of inflammation, intestinal permeability and immune activation.
  • Both the Irritable Bowel Syndrome score and total symptom score reported daily were significantly reduced when participants consumed the hydrolysed product. Less bloating was reported during both study periods when compared with the baseline for both groups.
  • Flatulence and heartburn decreased when consuming the hydrolysed product but not when drinking the control product. No significant differences in the levels of inflammatory markers (tumor necrosis factor alpha, TNF-α and interleukin 6, IL-6), intestinal permeability (fatty acid binding protein 2, FABP2) or immune activation (1-methylhistamine) were detected between the treatment periods.
  • The results suggest that the partial hydrolysation of milk proteins (mainly casein) reduces subjective symptoms to some extent in subjects with functional gastrointestinal disorders. The mechanism remains to be resolved.

An Infant Formula with Partially Hydrolyzed Whey Protein Supports Adequate Growth and Is Safe and Well-Tolerated in Healthy, Term Infants: A Randomized, Double-Blind, Equivalence Trial. Picaud JC, Pajek B, Arciszewska M, Tarczón I, Escribano J, Porcel R, Adelt T, Hassink E, Rijnierse A, Abrahamse-Berkeveld M, Korczowski B, On Behalf Of The Tenuto Study Group.Nutrients. 2020 Jul 13;12(7):E2072.

  • Allergies and food reactions are common and may be associated with foods including adapted cow’s milk formula. Formulas containing hydrolyzed proteins have been used to treat infants with allergy or food intolerance.
  • The current study evaluates the safety and tolerance of a partially hydrolyzed whey protein-based infant formula (PHF) versus an in intact cow’s milk protein formula (IPF). Breastfed infants were included as a reference group.
  • In a multi-country, multicenter, randomized, double-blinded, controlled clinical trial, infants whose mothers intended to fully formula feed were randomized to PHF (n= 134) or IPF (n = 134) from ≤14 days to 17 weeks of age.
  • Equivalence of weight gain per day from enrolment until 17 weeks of age was demonstrated in the PHF group compared to the IPF group, with estimated means of 30.2 grams/day and 31.4 grams/day, respectively.
  • No significant differences in growth outcomes, the number, severity or type of (serious) adverse events and tolerance outcomes, were observed between the two formula groups.
  • A partially hydrolyzed whey protein-based infant formula supports adequate infant growth, with a daily weight gain equivalent to a standard intact protein-based formula; it is also safe for use and well-tolerated in healthy term infants.

Effects of Prolonged Whey Protein Supplementation and Resistance Training on Biomarkers of Vitamin B12 Status: A 1-Year Randomized Intervention in Healthy Older Adults (the CALM Study). Greibe E, Reitelseder S, Bechshøft RL, Bülow J, Højfeldt GW, Schacht SR, Knudsen ML, Tetens I, Ostenfeld MS, Mikkelsen UR, Heegaard CW, Nexo E, Holm L.Nutrients. 2020 Jul 7;12(7):E2015.

  • Whey protein isolate contains vitamin B12. However, the efficacy of whey protein as a bioavailable source of this vitamin in the elderly has not been previously tested.
  • Researchers investigated the effect of long-term whey supplementation on biomarkers of B12 status in healthy older adults subjected to different schemes of supplements and exercise.
  • The total study population examined at baseline consisted of 167 healthy older adults (age ≥ 65 year) who were randomized to 1-year intervention with two daily supplements of:
    • whey protein (3.1 µg B12/day) (WHEY-ALL)
    • collagen (1.3 µg B12/day) (COLL)
    • maltodextrin (0.3 µg B12/day) (CARB).
  • WHEY-ALL was comprised of three groups, who performed heavy resistance training (HRTW), light resistance training (LITW), or no training (WHEY).
  • Dietary intake was assessed through 3-day dietary records. For the longitudinal part of the study, researchers included only the participants (n= 110), who met the criteria of ≥ 50% compliance to the nutritional intervention and ≥ 66% and ≥ 75% compliance to the heavy and light training, respectively.
  • At baseline, the study population (n= 167) had an overall adequate dietary B12 intake of median (range) 5.3 (0.7-65) µg/day and median B12 biomarker values within reference intervals.
  • The whey intervention (WHEY-ALL) caused an increase in B12 and holotranscobalamin. In addition, methylmalonic acid decreased in the LITW group. No change in B12 biomarkers was observed during the intervention with collagen or carbohydrate, and the training schedules induced no changes.
  • In conclusion, longer-term daily whey intake increased plasma B12 and holotranscobalamin in older individuals. No effect of intervention with collagen or carbohydrate or different training regimes was observed.

Varying roles of glucoregulatory function measures in postprandial cognition following milk consumption. Anderson JR, Maki KC, Palacios OM, Edirisinghe I, Burton-Freeman B, Spitznagel MB.Eur J Nutr. 2020 Jul 31.

  • Past work suggests milk consumption may facilitate cognition in children and college students with higher fasting glucose compared to other beverages (e.g., fruit juice). However, no studies have evaluated this phenomenon in adults, or considered other measures of glucoregulatory function.
  • This open-label study assessed the role of glucoregulatory function in postprandial cognition after milk intake in adults. The researchers hypothesized participants with lower fasting or post-consumption plasma glucose following a glucose excursion challenge (glucose response) would demonstrate better cognition following beverages of higher (juice) versus lower (milk) or no (water) glycemic content.
  • Forty-four nondiabetic, overnight-fasted adults attended three laboratory visits, ingesting 237 mL of 2% fat milk, apple juice, or water at each visit in a randomized, counterbalanced, crossover design. Participants completed cognitive testing (CNS Vital Signs) at baseline and 30, 90, and 150 min post-ingestion; primary outcomes were CNS Vital Signs composite scores. Fasting and post-consumption plasma glucose levels were assessed, with glucose response indexed as the change in plasma glucose from baseline to 30 min after juice (ΔGlucose).
  • Mixed modeling revealed participants with higher fasting glucose demonstrated better complex attention after water versus juice at 30 min, but better performance after juice versus water at 150 min (p = 0.02). Participants with a larger ΔGlucose demonstrated better processing speed (p = 0.01) 30 min after milk versus water; this effect also reversed at 150 min.
  • Different methods of measuring glucoregulatory function reveal its differing roles in postprandial cognition. Time since ingestion may also determine which beverages best optimize cognition.

Myoprotective Whole Foods, Muscle Health and Sarcopenia: A Systematic Review of Observational and Intervention Studies in Older Adults. Granic A, Dismore L, Hurst C, Robinson SM, Sayer AA.Nutrients. 2020 Jul 28;12(8):E2257.

  • Decline in skeletal muscle strength and mass (sarcopenia) accelerates with age, leading to adverse health outcomes and poor quality of life. Diet plays a crucial role in muscle ageing being an important element of a healthy lifestyle. However, unlike single nutrients, such as dietary protein, or dietary patterns, such as the Mediterranean diet, the relationship between individual whole foods and muscle health has not been systematically evaluated.
  • Therefore, researchers aimed to investigate which whole foods (meat, fish, eggs, fruit and vegetables, and non-liquid dairy) may be beneficial (myoprotective) for ageing muscle and sarcopenia in adults aged ≥ 50 years.
  • Nineteen observational and nine intervention studies were identified through systematic searches of the four electronic databases (last search: March 2020).
  • The synthesis of findings showed strong and consistent evidence for a beneficial effect of lean red meat on muscle mass or lean tissue mass in both observational and intervention studies.
  • Higher intake of fruit and vegetables was associated with better muscle function in observational studies, but the evidence from intervention studies was scarce.
  • Non-liquid dairy foods were beneficial for muscle mass in both observational and intervention studies. There was moderate evidence for the role of these foods in muscle strength and sarcopenia, and limited or inconclusive evidence for the benefits of other whole foods (e.g., fish, eggs) for muscle health in older adults.
  • Although current nutritional recommendations are often based on a single nutrient approach, further research about the role of protein-rich and other foods in muscle health will allow for the development of guidelines that are based on whole foods, also highlighting the potential importance of non-protein nutrients within these foods for myoprotection in older adults.