Dairy Research Bulletin – January 2021

Welcome to the January 2021 Dairy Research Bulletin. The Dairy Research Bulletin delivers a brief synopsis of the most current Human, Animal, and Environmental dairy research that is going on in the World, and also that which is of special interest to California dairy producers and consumers alike.

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

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Selected Articles on Social Responsibility, Environmental Management, and Sustainability

The Impact of Plant-Based Non-Dairy Alternative Milk on the Dairy Industry. Park YW. Food Sci Anim Resour. 2021 Jan;41(1):8-15.

  • Vegetarians have claimed and actively promoted the advantages of plant-based alternative milks as the best option for human nutrition and health, compared to the natural dairy milk. However, numerous scientific reports have demonstrated that the natural milk possesses more beneficial nutrients and bioactive components than artificially manufactured plant-derived milks.
  • The biochemical and nutritional advantages and functionalities of natural dairy milk cannot be replaced by man-made or crafted plant-based beverage products. On the other hand, the tremendous increase in production and consumption of the plant-based alternative milks in recent years has led a serious business downturn in traditional roles and stability of the dairy industry, especially in the major dairy producing Western countries.
  • Although plant-based milk alternatives may have some benefits on nutrition and health of certain consumers, the plant-derived alternative milks may not overshadow the true values of natural milk. Milk is not a high fat and high cholesterol food as animal meat products. Unlike plant-based alternative milks, natural milk contains many bioactive as well as anti-appetizing peptides, which can reduce body weight.
  • It has proven that taking low-fat, cultured and lactase treated milk and dairy products with other diversified nutritionally balanced diets have been shown to be healthier dietary option than plant-based milk/foods alone.

Describing motivation for health and treatment decisions and communication choices of calf-care workers on western United States dairies. Moore DA, Blackburn CC, Afema JA, Kinder DR, Sischo WM.J Dairy Sci. 2021 Jan 14:S0022-0302(21)00008-4.

  • On large dairy farms, animal health assessments and treatments are made by farm employees. Little is known about how employees make decisions about illness detection or treatment, information critical to improving antimicrobial stewardship.
  • The objectives of this study were to describe calf-care employee motivations for decisions associated with pre-weaned calf health and treatments, describe on-farm worker communication networks, and determine information sources used by these employees to support their decisions.
  • Personal interviews were conducted with 103 calf-care employees on 28 farms in the western United States. The interview consisted of 10 motivation source type (MST) questions and questions about training, communication, and educational opportunities.
  • Forty-three percent of calf-care employees fell into a class where responses were a combination of internal and intrinsic (personal beliefs or values and task fulfillment, respectively) and 23% were a combination of internal and goal internal (aligned with organizational goals). This latter class aligned health decisions with internal motivation and treatment decisions with goal internal.
  • A network analysis summarized dominant communication relationships and established that feeders and treaters perceived more communication with supervisors than was reciprocated by supervisors, and that there was less communication between workers and management for tasks relative to daily work.
  • Employee training was primarily done by herdsman, calf manager, or coworkers, and information for skill improvement and problem solving was sought from these individuals.
  • Although veterinarians were not often involved in employee training, when they were involved, employees were likely to use them as an information source for skill improvement and problem solving.
  • Few participants had ever used social media, but almost all had a device that could access the internet; more than 60% indicated interest in a social media platform for work-related information.
  • Work motivation for many calf caretakers appeared to be sourced from personal beliefs, values, and job fulfillment, particularly when deciding to treat a sick calf. Investigation and incorporation of beliefs and values in training programs could help with alignment of protocols with actual treatment and further efforts to implement judicious use of antimicrobials.

Public perceptions of antibiotic use on dairy farms in the United States. Wemette M, Greiner Safi A, Wolverton AK, Beauvais W, Shapiro M, Moroni P, Welcome FL, Ivanek R.J Dairy Sci. 2021 Jan 14:S0022-0302(21)00003-5.

  • There has been a global push for improved antimicrobial stewardship, including in animal agriculture, due to growing concerns about antimicrobial resistance. However, little is known about the general public’s perceptions of antimicrobial use in animal agriculture.
  • The aim of this study was to explore the US public’s perceptions of antibiotic use in dairy farming and how these perceptions influence purchasing decisions.
  • Data from the 2017 Cornell National Social Survey developed in collaboration with the Cornell Survey Research Institute were used to assess the public’s perceptions. The Survey Research Institute of Cornell University (Ithaca, NY) administered the survey by telephone to a random sample of 1,000 adults in the continental United States.
  • The survey collected information about perceptions of threat to human health posed by antibiotic use in cows on dairy farms and willingness to pay more for milk from cows raised without antibiotics, as well as several presumed explanatory variables, including respondents’ knowledge of antibiotics, beliefs regarding cattle treatment in dairy farming, and 18 sociodemographic characteristics.
  • Among respondents, 90.7% (n = 892/983) reported that antibiotic use on dairy farms posed some level of threat to human health and 71.5% (n = 580/811) indicated they would be willing to pay more for milk produced from cows raised without antibiotics. Respondents who believed that antibiotic use in dairy farming posed a moderate to high threat to human health were more likely to be female and report willingness to pay more for milk or not purchase milk.
  • Additionally, consumers’ willingness to pay more for milk from cattle raised without antibiotics was associated with the belief that antibiotic use posed some threat to human health, the belief that cows are treated better on organic dairy farms, an annual household income of $50,000 or greater, being born outside the United States, having a liberal social ideology, and being currently or formerly married.
  • These results suggest that the general public’s decisions as consumers of dairy products are associated with demographic factors in addition to perceptions of antibiotic use and cattle treatment in dairy farming. The rationale behind such perceptions should be further explored to facilitate consumers’ informed decision making about antibiotic use in agriculture, links to cattle treatment, and associated willingness-to-pay attitudes.

Survey of perceptions and attitudes of an international group of veterinarians regarding antibiotic use and resistance on dairy cattle farms. Llanos-Soto SG, Vezeau N, Wemette M, Bulut E, Greiner Safi A, Moroni P, Shapiro MA, Ivanek R.Prev Vet Med. 2021 Jan 15;188:105253.

  • Veterinarians are the main source of information for farmers regarding the responsible use of antibiotics in farm animals and how to reduce the risk of antibiotic resistance. Consequently, understanding how veterinarians perceive their clients’ and colleagues’ antibiotic use and their own beliefs about the development of antibiotic resistance is essential to determining areas in which antibiotic use practices can be improved to minimize the emergence of antibiotic resistance.
  • An international cross-sectional study was carried out using a questionnaire designed to elucidate perceptions, attitudes, and concerns of dairy veterinarians regarding antibiotic use and the emergence of antibiotic resistance in dairy farming.
  • A total of 71 participants from 21 countries participated in the survey, the majority were from the United States and member countries of the European.
  • Participants perceived that nearly half of their clients overuse or inappropriately use antibiotics, and nearly half of their colleagues overprescribe or inappropriately prescribe antibiotics.
  • Participants concerned about antibiotic resistance on clients’ dairy farms were also more likely to consider better adherence to drug labelling as important for reducing farmers’ antibiotic use.
  • Thematic analysis revealed four themes surrounding the perceived reasons for veterinarians’ overprescribing of antibiotics: (i) knowledge, (ii) attitudes, (iii) barriers, and (iv) rules and regulations. The study findings will aid in the development of strategies to improve antibiotic use in dairy farming and educational initiatives looking to enhance the communication between veterinarians and farmers about judicious use of antibiotics.

Characterization of Listeria monocytogenes isolates from lactating dairy cows in a Wisconsin farm: Antibiotic resistance, mammalian cell infection, and effects on the fecal microbiota. Chow JTH, Gall AR, Johnson AK, Huynh TN.J Dairy Sci. 2021 Jan 27:S0022-0302(21)00081-3.

  • Listeria monocytogenes is an invasive foodborne pathogen that is ubiquitously present in the dairy farm environment. Although cattle are a reservoir of L. monocytogenes, most adult animals do not exhibit clinical symptoms, suggesting a homeostasis between this pathogen and the bovine gastrointestinal ecosystem.
  • Nevertheless, substantial prevalence of L. monocytogenes fecal shedding by dairy cattle has been reported in many studies, posing threats of transmission within the herd and contamination of the human food supply. Accordingly, understanding the L. monocytogenes ecology within the bovine gastrointestinal tract is important to prevent clinical illness in the animal host, reduce transmission, and guide intervention strategies.
  • In this study, researchers conducted a longitudinal sampling of fecal samples from 20 lactating dairy cows in one Wisconsin farm over a 29-day period and found a strikingly high incidence of L. monocytogenes shedding, in 90% of sampled animals. The L. monocytogenes isolates were genetically diverse, representing all common serotypes previously identified from cattle.
  • Additionally, most tested isolates were resistant to ampicillin, and a few were also resistant to gentamicin or trimethoprim/sulfamethoxazole. Most isolates effectively infected human epithelial cells (Caco-2) and murine fibroblasts (L2), suggesting that they are all capable of causing systemic infection if the intestinal barrier is breached.
  • Overall, these findings highlight the threat of antibiotic resistance among some L. monocytogenes isolates, emphasize the need for a strain-specific approach in listeriosis treatment, and suggest the potential negative influence of subclinical L. monocytogenes carriage on animal gut health.

Methane emissions from the storage of liquid dairy manure: Influences of season, temperature and storage duration. Cárdenas A, Ammon C, Schumacher B, Stinner W, Herrmann C, Schneider M, Weinrich S, Fischer P, Amon T, Amon B.Waste Manag. 2021 Feb 15;121:393-402.

  • Methane emissions from livestock manure are primary contributors to GHG emissions from agriculture and options for their mitigation must be found.
  • This paper presents the results of a study on methane emissions from stored liquid dairy cow manure during summer and winter storage periods.
  • Manure from the summer and winter season was stored under controlled conditions in barrels at ambient temperature to simulate manure storage conditions. Methane emissions from the manure samples from the winter season were measured in two time periods: 0 to 69 and 0 to 139 days. For the summer storage period, the experiments covered four time periods: from 0 to 70, 0 to 138, 0 to 209, and 0 to 279 continuous days, with probing every 10 weeks.
  • The experiment showed that the methane emissions from manure stored in summer were considerably higher than those from manure stored in winter. CH4production started after approximately one month, reaching values of 0.061 kg CH4 kg-1 Volatile Solid (VS) and achieving high total emissions of 0.148 kg CH4 kg-1 VS (40 weeks). In winter, the highest emissions level was 0.0011 kg CH4 kg-1 VS (20 weeks).
  • The outcomes of these experimental measurements can be used to suggest strategies for mitigating methane emissions from manure storage.

Integrated Crop-Livestock Systems for Nitrogen Management: A Multi-Scale Spatial Analysis. Ghimire S, Wang J, Fleck JR.Animals (Basel). 2021 Jan 6;11(1):100.

  • The size and productivity of the livestock operations have increased over the past several decades, serving the needs of the growing human population. This growth however has come at the expense of broken connection between croplands and livestock operations. As a result, there is a huge disconnect between the nutrient needs of croplands and the availability of nutrients from livestock operations, leading to a range of environmental and public health issues.
  • This study develops a theoretical framework for multi-scale spatial analysis of integrated crop-livestock systems. Using New Mexico, USA as a case study, the researchers quantify the amount of nitrogen produced by dairy farms in the state and examine if the available nitrogen can be assimilated by the croplands and grasslands across spatial scales.
  • The farm-level assessment identifies that all the farms under study do not have adequate onsite croplands to assimilate the nitrogen produced therein. The successive assessments at county and watershed levels suggest that the among-farm integration across operations could be an effective mechanism to assimilate the excess nitrogen.
  • This study hints towards the multi-spatial characteristic of the problem that can be pivotal in designing successful policy instruments.

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Selected Articles on Dairy Intake and Human Health

Milk consumption and multiple health outcomes: umbrella review of systematic reviews and meta-analyses in humans. Zhang X, Chen X, Xu Y, Yang J, Du L, Li K, Zhou Y.Nutr Metab (Lond). 2021 Jan 7;18(1):7.

  • In order to recapitulate the best available evidence of milk consumption and multiple health-related outcomes, we performed an umbrella review of meta-analyses and systematic reviews in humans.
  • 41 meta-analyses with 45 unique health outcomes were included in the review.
  • Milk consumption was more often related to benefits than harm to a sequence of health-related outcomes. Dose-response analyses indicated that an increment of 200 ml (approximately 1 cup) milk intake per day was associated with a lower risk of cardiovascular disease, stroke, hypertension, colorectal cancer, metabolic syndrome, obesity and osteoporosis.
  • Beneficial associations were also found for type 2 diabetes mellitus and Alzheimer’s disease. Conversely, milk intake might be associated with higher risk of prostate cancer, Parkinson’s disease, acne and Fe-deficiency anaemia in infancy. Potential allergy or lactose intolerance need for caution.
  • Overall, milk consumption does more good than harm for human health in this umbrella review. Our results support milk consumption as part of a healthy diet.

Kefir: A protective dietary supplementation against viral infection. Hamida RS, Shami A, Ali MA, Almohawes ZN, Mohammed AE, Bin-Meferij MM.Biomed Pharmacother. 2021 Jan;133:110974.

  • Coronavirus disease 2019 (COVID-19) is an infectious disease caused by a recently discovered coronavirus termed ‘severe acute respiratory syndrome coronavirus 2’ (SARS-CoV-2). Several scholars have tested antiviral drugs and compounds to overcome COVID-19.
  • ‘Kefir’ is a fermented milk drink similar to a thin yogurt that is made from kefir grains. Kefir and its probiotic contents can modulate the immune system to suppress infections from viruses (e.g., Zika, hepatitis C, influenza, rotaviruses).
  • The antiviral mechanisms of kefir involve enhancement of macrophage production, increasing phagocytosis, boosting production of cluster of differentiation-positive (CD4+), CD8+, immunoglobulin (Ig)G+and IgA+ B cells, T cells, neutrophils, as well as cytokines (e.g., interleukin (IL)-2, IL-12, interferon gamma-γ).
  • Kefir can act as an anti-inflammatory agent by reducing expression of IL-6, IL-1, TNF-α, and interferon-γ. Hence, kefir might be a significant inhibitor of the ‘cytokine storm’ that contributes to COVID-19.
  • In this paper, researchers review several studies with a particular emphasis on the effect of kefir consumption and their microbial composition against viral infection, as well as discussing the further development of kefir as a protective supplementary dietary against SARS-CoV-2 infection via modulating the immune response.

Intake of dairy products and associations with major atherosclerotic cardiovascular diseases: a systematic review and meta-analysis of cohort studies. Jakobsen MU, Trolle E, Outzen M, Mejborn H, Grønberg MG, Lyndgaard CB, Stockmarr A, Venø SK, Bysted A.Sci Rep. 2021 Jan 14;11(1):1303.

  • Specific types of dairy products may be differentially associated with atherosclerotic cardiovascular disease (CVD).
  • Researchers conducted a systematic review and meta-analysis of cohort studies to summarize findings on the associations between total dairy product intake and intake of dairy product subgroups and the risk of major atherosclerotic CVDs in the general adult population.
  • There were 13 cohort studies included for coronary heart disease (CHD), 7 for ischemic stroke and none for peripheral artery disease.
  • High-fat milk was positively associated with CHD (RR 1.08) per 200 g higher intake/day, and cheese was inversely associated with CHD (RR 0.96) per 20 g higher intake/day.
  • Heterogeneity, however, was observed in high versus low meta-analyses. Milk was inversely associated with ischemic stroke in high versus low meta-analysis only.
  • In conclusion, this systematic review indicates a positive association of high-fat milk and an inverse association of cheese with CHD risk. The findings should be interpreted in the context of the observed heterogeneity.

The impact of type of dietary protein, animal versus vegetable, in modifying cardiometabolic risk factors: A position paper from the International Lipid Expert Panel (ILEP). Zhubi-Bakija F, Bajraktari G, Bytyçi I, Mikhailidis DP, Henein MY, Latkovskis G, Rexhaj Z, Zhubi E, Banach M; International Lipid Expert Panel (ILEP).Clin Nutr. 2021 Jan;40(1):255-276.

  • Proteins play a crucial role in metabolism, in maintaining fluid and acid-base balance and antibody synthesis. Dietary proteins are important nutrients and are classified into: 1) animal proteins (meat, fish, poultry, eggs and dairy), and, 2) plant proteins (legumes, nuts and soy).
  • Dietary modification is one of the most important lifestyle changes that has been shown to significantly decrease the risk of cardiovascular (CV) disease (CVD) by attenuating related risk factors. The CVD burden is reduced by optimum diet through replacement of unprocessed meat with low saturated fat, animal proteins and plant proteins.
  • The aim of this expert opinion recommendation was to elucidate the different impact of animal vs vegetable protein on modifying cardiometabolic risk factors.
  • Many observational and interventional studies confirmed that increasing protein intake, especially plant-based proteins and certain animal-based proteins (poultry, fish, unprocessed red meat low in saturated fats and low-fat dairy products) have a positive effect in modifying cardiometabolic risk factors.
  • Red meat intake correlates with increased CVD risk, mainly because of its non-protein ingredients (saturated fats).
  • Apart from meat, other animal-source proteins, like those found in dairy products (especially whey protein) are inversely correlated to hypertension, obesity and insulin resistance.

High vs. low-fat dairy and milk differently affects the risk of all-cause, CVD, and cancer death: A systematic review and dose-response meta-analysis of prospective cohort studies. Naghshi S, Sadeghi O, Larijani B, Esmaillzadeh A.Crit Rev Food Sci Nutr. 2021 Jan 5:1-15.

  • Considerable controversy exists regarding the association between milk and dairy consumption and mortality risk.
  • The present systematic review and meta-analysis of prospective studies was undertaken to examine the association of high vs. low-fat dairy and milk consumption with mortality.
  • The authors searched PubMed/Medline, ISI Web of Science, and Scopus databases through February 2020 for prospective cohort studies that reported the association between milk and dairy consumption and mortality risk.
  • High-fat milk consumption was significantly associated with a greater risk of all-cause, CVD, and cancer mortality. However, total dairy consumption was associated with a lower risk of CVD mortality.
  • Dose-response analysis revealed a significant non-linear association of total dairy consumption with all-cause and CVD mortality. Moreover, high-fat milk consumption was significantly associated with risk of cancer mortality in linear and non-linear dose-response analysis.
  • In conclusion, we found high-fat milk consumption was associated with a higher risk of all-cause, CVD, and cancer mortality. However, total dairy consumption was associated with a lower risk of CVD mortality.

Effect of Yogurt Consumption on Metabolic Syndrome Risk Factors: a Narrative Review. Khorraminezhad L, Rudkowska I.Curr Nutr Rep. 2021 Jan 6.

  • Metabolic syndrome (MetS) comprises risk factors such as obesity, hypertriglyceridemia, hypertension, and hyperglycemia.
  • In this article, the researchers described the outcome of various yogurt consumption, either conventional, low-fat, high-fat, Greek, or enriched with nutrients or probiotics: (1) on the parameters of MetS risk factors and (2) on the mechanisms of action of the MetS risk factors.
  • The majority (25 studies) of clinical trials and meta-analyses of clinical trials reported a beneficial effect of yogurt consumption in the prevention of MetS risk. Yogurt components, such as calcium, vitamin D, proteins, and probiotics, were associated with the multiple beneficial effects on the prevention of MetS.
  • In general, yogurt consumption may be promoted within healthy dietary patterns to prevent MetS. More studies are needed to determine what type of yogurt has the greatest benefits for specific MetS risk factor prevention.

Associations of dairy intake with risk of incident metabolic syndrome in children and adolescents: Tehran Lipid and Glucose Study. Yuzbashian E, Nosrati-Oskouie M, Asghari G, Chan CB, Mirmiran P, Azizi F.Acta Diabetol. 2021 Jan 2.

  • This cohort study examined the association of total and individual dairy products with the risk of incident Metabolic Syndrome (MetS) and its components in children and adolescents.
  • Researchers prospectively assessed 531 participants aged 6-18 years without the MetS at baseline during an average 6.6-year follow-up period.
  • The incidence of MetS was 9.8% after an average 6.6-year follow-up. After adjusting for potential confounders, odds ratio (OR) for incident MetS was 0.48 for total dairy, 0.44 for low-fat dairy, 0.46 for low-fat milk, and 0.45 for low-fat yogurt when comparing participants in the highest versus lowest tertile.
  • A moderate intake of regular cheese was associated with decreased risk of MetS (OR = 0.43). Replacing one serving/day of total dairy with nuts was associated with a lower (OR: 0.63), whereas replacement by red and processed meat was associated with higher (OR: 1.55) MetS risk. No significant association was found between high-fat dairy and MetS risk.
  • Higher consumption of dairy products, particularly low-fat milk and yogurt, was associated with reduced risk of incident MetS, suggesting the capability of low-fat dairy products in the primary prevention of MetS in children and adolescents.

Dairy intake during adolescence and risk of colorectal adenoma later in life. Nimptsch K, Lee DH, Zhang X, Song M, Farvid MS, Rezende LFM, Cao Y, Chan AT, Fuchs C, Meyerhardt J, Nowak JA, Willett WC, Ogino S, Giovannucci E, Pischon T, Wu K.Br J Cancer. 2021 Jan 4.

  • Higher dairy intake during adulthood has been associated with lower colorectal cancer risk.
  • As colorectal carcinogenesis spans several decades, researchers hypothesized that higher dairy intake during adolescence is associated with lower risk of colorectal adenoma, a colorectal cancer precursor.
  • In 27,196 females from the Nurses’ Health Study 2, aged 25-42 years at recruitment (1989), who had completed a validated high school diet questionnaire in 1998 and undergone at least one lower bowel endoscopy between 1998 and 2011.
  • Colorectal adenomas were diagnosed in 2239 women. Dairy consumption during adolescence was not associated with colorectal adenoma risk. By anatomical site, higher adolescent dairy intake was associated with lower rectal, but not proximal or distal colon adenoma risk.
  • An inverse association was observed with histologically advanced, but not non-advanced adenoma.
  • In this large cohort of younger women, higher adolescent dairy intake was associated with lower rectal and advanced adenoma risk later in life.

Foods implicated in U.S. outbreaks differ from the types most commonly consumed. Richardson LC, Cole D, Hoekstra RM, Rajasingham A, Johnson SD, Bruce B.J Food Prot. 2021 Jan 7.

  • Foodborne disease outbreak investigations identify foods responsible for illnesses. However, it is not known the degree to which foods implicated in outbreaks reflect the distribution of food consumption in the U.S. population or the risk associated with their consumption.
  • To examine this, we compared the distribution of foods in 24 categories implicated in outbreaks to the distribution of foods consumed by the U.S. population.
  • Beef, chicken, eggs, fish, herbs, mollusks, pork, sprouts, seeded vegetables, and turkey were implicated in outbreaks significantly more often than expected based on the frequency of their consumption in the general population, suggesting a higher risk of contamination or mishandling from foods in these categories than in others.
  • In contrast, pasteurized dairy, fruits, grains-beans, oils and sugars, and root/underground vegetables were less frequently implicated in outbreaks than they were consumed in the general population, suggesting a lower risk for these food categories.