Dairy Research Bulletin – November 2020

Welcome to the November 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

Identifying climate change impacts on surface water supply in the southern Central Valley, California. Liu Z, Herman JD, Huang G, Kadir T, Dahlke HE.Sci Total Environ. 2020 Nov 1:143429.

  • Mountain regions in arid and semi-arid climates, such as California, are considered particularly sensitive to climate change because global warming is expected to alter snowpack storage and related surface water supply. It is therefore important to accurately capture snowmelt processes in watershed models for climate change impact assessment.
  • In this study we use the Soil and Water Assessment Tool (SWAT) to estimate projected changes in snowpack and streamflow in four alpine tributaries to the agriculturally important but less studied southern Central Valley, California. Watershed responses are evaluated for four CMIP5 climate models (HadGEM_ES, CNRM-CM5, CanESM2 and MIROC5) and two emission scenarios (RCP 4.5 and RCP 8.5) for 2020-2099.
  • Results indicate that under a warming climate, peak streamflow is expected to increase 0.5-4 times in magnitude in the coming decades and to arrive 2-4 months earlier in the year because of earlier snowmelt. In the foreseeable future, snow cover will reduce gradually in the lower elevations and diminish at higher rates at higher elevation towards the end of the 21st century.
  • Surface water supply is predicted to increase in the southern Central Valley under the evaluated scenarios but increased temporal variability (wetter wet seasons and drier dry seasons) will create new challenges for managing supply.
  • The study further highlights that the use of remote sensing based, reconstructed SWE data could fill the current gap of limited in-situ SWE observations to improve the snow calibration of SWAT to better predict climate change impacts in semi-arid, snow-dominated watersheds.

Contributions of dairy products to environmental impacts and nutritional supplies from United States agriculture. Liebe DL, Hall MB, White RR.J Dairy Sci. 2020 Nov;103(11):10867-10881.

  • Questions regarding the balance between the contribution to human nutrition and the environmental impact of livestock food products rarely evaluate specific species or how to accomplish the recommended depopulation.
  • The objective of this study was to assess current contributions of the US dairy industry to the supply of nutrients and environmental impact, characterize potential impacts of alternative land use for land previously used for crops for dairy cattle, and evaluate the impacts of these approaches on US dairy herd depopulation.
  • Researchers modeled 3 scenarios to reflect different sets of assumptions for how and why to remove dairy cattle from the US food production system coupled with 4 land-use strategies for the potential newly available land previously cropped for dairy feed. Scenarios also differed in assumptions of how to repurpose land previously used to grow grain for dairy cows.
  • The current system provides sufficient fluid milk to meet the annual energy, protein, and calcium requirements of 71.2, 169, and 254 million people, respectively. Vitamins supplied by dairy products also make up a high proportion of total domestic supplies from foods, with dairy providing 39% of the vitamin A, 54% of the vitamin D, 47% of the riboflavin, 57% of the vitamin B12, and 29% of the choline available for human consumption in the United States.
  • Retiring (maintaining animals without milk harvesting) dairy cattle under their current management resulted in no change in absolute greenhouse gas emissions (GHGE) relative to the current production system. Both depopulation and retirement to pasture resulted in modest reductions (6.8-12.0%) in GHGE relative to the current agricultural system.
  • Most dairy cow removal scenarios reduced availability of essential micronutrients such as α-linolenic acid, Ca, and vitamins A, D, B12, and choline. Those removal scenarios that did not reduce micronutrient availability also did not improve GHGE relative to the current production system.
  • These results suggest that removal of dairy cattle to reduce GHGE without reducing the supply of the most limiting nutrients to the population would be difficult.

The fate of antibiotic resistance genes in cow manure composting: shaped by temperature-controlled composting stages. Sardar MF, Zhu C, Geng B, Ahmad HR, Song T, Li H.Bioresour Technol. 2020 Nov 12;320(Pt B):124403.

  • Current work for animal manure processing is not up to the required standards and hence are not supposed to reflect the actual performance in antibiotic resistance control.
  • As a result, this study carried out temperature-controlled aerobic composting, with sulfamethoxazole (SMX) as a typical antibiotic.
  • The results of four different treatments demonstrated that temperature, water content, C/N ratio, EC, and pH showed no significant (p > 0.05) difference.
  • Antibiotic resistance genes (ARGs) significantly decreased in the initial 10 days of the thermophilic phase, but the abundance of sul1 and sul2 increased greatly after 30 days. Moreover, ARGs were closely related with each other during the late stages of composting.
  • A noteworthy effect of composting properties, especially temperature on bacterial community, which then had a positive effect on ARGs abundances. These findings provided evidence that the standard composting was still insufficient to control antibiotic resistance.

Agricultural diversification promotes multiple ecosystem services without compromising yield. Tamburini G, Bommarco R, Wanger TC, Kremen C, van der Heijden MGA, Liebman M, Hallin S. Sci Adv. 2020 Nov 4;6(45):eaba1715.

  • Enhancing biodiversity in cropping systems is suggested to promote ecosystem services, thereby reducing dependency on agronomic inputs while maintaining high crop yields.
  • The objective of this study was to assess the impact of several diversification practices in cropping systems on above- and belowground biodiversity and ecosystem services by reviewing 98 meta-analyses and performing a second-order meta-analysis based on 5,160 original studies comprising 41,946 comparisons between diversified and simplified practices.
  • Overall, diversification enhances biodiversity, pollination, pest control, nutrient cycling, soil fertility, and water regulation without compromising crop yields. Practices targeting above ground biodiversity boosted pest control and water regulation, while those targeting below ground biodiversity enhanced nutrient cycling, soil fertility, and water regulation.
  • Most often, diversification practices resulted in win-win support of services and crop yields. Variability in responses and occurrence of trade-offs highlight the context dependency of outcomes.
  • Widespread adoption of diversification practices shows promise to contribute to biodiversity conservation and food security from local to global scales.

Factors influencing water intake in dairy cows: a review. Golher DM, Patel BHM, Bhoite SH, Syed MI, Panchbhai GJ, Thirumurugan P.Int J Biometeorol. 2020 Nov 3.

  • Water is a very critical nutrient in the diet of lactating animals as it performs several functions, viz., transfer of nutrients and excretions of waste products produced during metabolism, digestion, and body temperature regulation of all living organisms.
  • Besides growth, other parameters like milk production, reproduction, adaptive potential, and feed consumption are also influenced by water status in feed and body reserves.
  • Water intake in dairy cows is influenced directly or indirectly by several factors; direct factors include animal-related factors such as breed, body size, physiological stage, age, health, stress, and ecological adaptations and environmental factors, viz., season of the year, environmental temperature, humidity, wind speed, and precipitation. These factors significantly influence the drinking water intake of dairy cows.
  • Nonetheless, different managemental practices such as rearing type, feeding practices, housing, water availability, and its quality can also affect water intake indirectly.
  • However, overall understanding of these factors affecting water intake in dairy cows could help to improve the dairy husbandry practices and subsequently health, production, and welfare of dairy cows.

Role of Secondary Plant Metabolites on Enteric Methane Mitigation in Ruminants. Ku-Vera JC, Jiménez-Ocampo R, Valencia-Salazar SS, Montoya-Flores MD, Molina-Botero IC, Arango J, Gómez-Bravo CA, Aguilar-Pérez CF, Solorio-Sánchez FJ.Front Vet Sci. 2020 Aug 27;7:584.

  • The rumen microbiome plays a fundamental role in all ruminant species, it is involved in health, nutrient utilization, detoxification, and methane emissions.
  • Methane is a greenhouse gas which is eructated in large volumes by ruminants grazing extensive grasslands in the tropical regions of the world. Enteric methane is the largest contributor to the emissions of greenhouse gases originating from animal agriculture.
  • A large variety of plants containing secondary metabolites (essential oils/terpenoids, tannins, saponins, and flavonoids) have been evaluated as cattle feedstuffs and changes in volatile fatty acid proportions and methane synthesis in the rumen have been assessed.
  • Alterations to the rumen microbiome may lead to changes in diversity, composition, and structure of the methanogen community. Legumes containing condensed tannins have shown a good methane mitigating effect when fed at levels of up to 30-35% of ration dry matter in cattle as a result of the effect of condensed tannins on rumen bacteria and methanogens.
  • It has been shown that saponins disrupt the membrane of rumen protozoa, thus decreasing the numbers of both protozoa and methanogenic archaea. Trials carried out with cattle housed in respiration chambers have demonstrated the enteric methane mitigation effect in cattle and sheep of tropical legumes such as Enterolobium cyclocarpumand Samanea saman which contain saponins.
  • Essential oils are volatile constituents of terpenoid or non-terpenoid origin which impair energy metabolism of archaea and have shown reductions of up to 26% in enteric methane emissions in ruminants.
  • There is emerging evidence showing the potential of flavonoids as methane mitigating compounds, but more work is required in vivoto confirm preliminary findings.
  • From the information hereby presented, it is clear that plant secondary metabolites can be a rational approach to modulate the rumen microbiome and modify its function, some species of rumen microbes improve protein and fiber degradation and reduce feed energy loss as methane in ruminants fed tropical plant species.

Recycling of Nutrients from Dairy Wastewater by Extremophilic Microalgae with High Ammonia Tolerance. Pang N, Bergeron AD, Gu X, Fu X, Dong T, Yao Y, Chen S.Environ Sci Technol. 2020 Nov 15.

  • This study explored the possibility of incorporating extremophilic algal cultivation into dairy wastewater treatment by characterizing a unique algal strain.
  • Results showed that extremophilic microalgae Chlorella vulgarisCA1 newly isolated from dairy wastewater tolerated a high level of ammonia nitrogen (2.7 g/L), which was over 20 times the ammonia nitrogen that regular Chlorella could tolerate.
  • The isolate was mixotrophically cultured in dairy effluent treated by anaerobic digestion for recycling nutrients and polishing the wastewater. The highest biomass content of 13.3 g/L and protein content of 43.4% were achieved in the culture in anaerobic digestion effluent.
  • Up to 96% of the total nitrogen and 79% of the total phosphorus were removed from the dairy anaerobic digestion effluent.
  • The ability of the algae to tolerate a high level of ammonia nitrogen suggests the potential for direct nutrient recycling from dairy wastewater while producing algal biomass and high value bioproducts.

Opportunities for improving the safety of dairy parlor workers. Edwards JP, Kuhn-Sherlock B.J Dairy Sci. 2020 Nov 11:S0022-0302(20)30954-1.

  • One aspect of a successful dairy business is attracting and retaining skilled staff. The ability to do this is influenced by workplace attractiveness, one aspect of which is worker comfort and safety. Working with heavy machinery and animals makes dairy farming a dangerous occupation relative to many other sectors.
  • Milking is the most time-consuming task on pasture-based dairy farms, and the parlor is the logical site of a number of injuries, although little is known about their causes or their relationship to parlor design and management.
  • To investigate worker safety further, we conducted an on-farm survey on New Zealand dairy farms between December 2018 and March 2019. The survey had 3 objectives: to identify common causes of injuries relating to milking; to describe variations in milking parlor design and management practices on dairy farms; and to identify management and parlor factors that contribute to milking injuries. Analysis of accident compensation data from the state-run accident insurer for a 5-yr period from July 2013 to June 2018 was a fourth objective.
  • A total of 136 injuries were reported on 99 of the 560 farms surveyed, and accident insurance claims were made for 53 of these injuries. The survey found that 48% of injuries occurred while workers were attaching clusters: typically soft-tissue and fracture injuries to fingers, hands, wrists, and arms. Injuries to these body parts represented the greatest cost (51% of the annual insurance cost) and identified safe cluster attachment as an area of focus for reducing milking injuries. Potential low-cost solutions include improved cluster design and a hand-arm guard.
  • The researchers identified a clear seasonal trend that coincided with busy periods in a seasonal block calving system, suggesting that options to reduce fatigue in spring may be beneficial; however, the number of hours worked or number of consecutive days worked were not associated with the number of milking injuries.
  • Those aged 20-29 yr had more injuries relative to their proportion of the workforce, indicating that more training may be beneficial (e.g., setting ergonomic milking routines). Female workers were at greater risk of injury than males; this finding may have been related to the height of the animal relative to the height of the milker.

Relationships among bedding materials, bedding bacterial composition and lameness in dairy cows. Li H, Wang X, Wu Y, Zhang D, Xu H, Xu H, Xing X, Qi Z.Asian-Australas J Anim Sci. 2020 Nov 3.

  • Bedding materials directly contact hooves of dairy cows and they may serve as environmental sources of lameness-associated pathogen. However, the specific composition of bacteria hidden in bedding materials is still not clear.
  • The aim of this study was to determine the effect bedding material and its bacterial composition has on lameness of Holstein heifers.
  • Forty-eight Holstein heifers with similar body weights were randomly assigned into three groups including sand bedding, concrete floor, and compost bedding. Hock injuries severity and gait performance of dairy cows were scored individually once a week. Blood samples were collected at the end of the experiment and bedding material samples were collected once a week for Illumina sequencing.
  • The concrete floor increased visible hock injuries severity and serum biomarkers of joint damage in comparison to sand bedding and compost bedding groups. Analysis showed that the bacterial community of compost bedding samples had higher similarity to that of sand bedding samples than to concrete floor samples. Bacteria in three bedding materials were dominated by gastrointestinal bacteria and organic matter-degrading bacteria, such as Actinobacteria, Firmicutes and norank JG30-KF-cM45.
  • The bacterial communities differed among bedding materials. However, the treponemes pathogens involved in the pathogenesis of lameness may not be a part of microbiota in bedding materials of dairy cows.

Palatable disruption: the politics of plant milk. Clay N, Sexton AE, Garnett T, Lorimer J.Agric Human Values. 2020;37(4):945-962.

  • Plant-based milk alternatives-or mylks-have surged in popularity over the past ten years. The authors consider the politics and consumer subjectivities fostered by mylks as part of the broader trend towards ‘plant-based’ food.
  • The authors demonstrate how mylk companies inherit and strategically deploy positive framings of milk as wholesome and convenient, as well as negative framings of dairy as environmentally damaging and cruel, to position plant-based as the ‘better’ alternative.
  • By navigating this affective landscape, brands attempt to (re)make mylk as simultaneously palatable and disruptive to the status quo.
  • The authors examine the politics of mylks through the concept of palatable disruption, where people are encouraged to care about the environment, health, and animal welfare enough to adopt mylks but to ultimately remain consumers of a commodity food.
  • By encouraging consumers to reach for “plant-based” as a way to cope with environmental catastrophe and a life out of balance, mylks promote a neoliberal ethic: they individualize systemic problems and further entrench market mechanisms as solutions, thereby reinforcing the political economy of industrial agriculture.
  • In conclusion, the authors reflect on the limits of the current plant-based trend for transitioning to more just and sustainable food production and consumption.


Selected Articles on Dairy Intake and Human Health

Growth and Development of Preschool Children (12-60 Months): A Review of the Effect of Dairy Intake. Clark DC, Cifelli CJ, Pikosky MA. Nutrients. 2020 Nov 20;12(11):3556.

  • Undernutrition in young children is a global health issue. The ability to meet energy and nutrient needs during this critical stage of development is necessary, not only to achieve physical and mental potential but also socio-economic achievement later in life.
  • Given ongoing discussions regarding optimization of dietary patterns to support achievement of the Sustainable Development Goals established by the United Nations, it is important to identify foods/food groups that have shown efficacy in reducing the negative impacts of undernutrition in young children.
  • This narrative review addresses the impact of dairy intake, with a focus on linear growth, cognitive development and weight gain in early childhood (12-60 months). The impact of country economic status is also examined, to help elucidate regional specific recommendations and/or future research needs.
  • Overall, the body of research addressing this age group is somewhat limited. Based on the data available, there is a positive association between dairy intake and linear growth. The impact of milk or dairy products on cognitive development is less clear due to a lack of evidence and is a gap in the literature that should be addressed.
  • Regarding the impact on body weight, the majority of evidence suggests there is either no association or an inverse association between milk intake by preschool children on overweight and obesity later in life. This evidence is exclusively in high income countries, however, so additional work in lower income countries may be warranted.

Modeling the Impact of Fat Flexibility With Dairy Food Servings in the 2015-2020 Dietary Guidelines for Americans Healthy U.S.-Style Eating Pattern. Hess JM, Cifelli CJ, Fulgoni VL 3rd. Front Nutr. 2020 Oct 22;7:595880.

  • The 2015-2020 Dietary Guidelines for Americans (DGA) recommends consuming low-fat or fat-free dairy foods due to concerns about energy and saturated fat intake. It also recommends consuming no more than 10% of daily calories from saturated fat.
  • The objective was to assess the impact of replacing one serving of fat-free dairy foods in the Healthy U.S.-Style Eating Pattern (HUSEP) from the DGA with one serving of whole- or reduced-fat dairy foods. We hypothesized that this replacement would keep the HUSEP within calorie, saturated fat, and sodium limits.
  • Utilizing the same modeling procedures as the 2015-2020 DGA, we assessed the nutrient composition of seven alternative models of the 2000-calorie HUSEP. These models replaced all three servings of dairy foods in the HUSEP with an updated fat-free dairy composite (Model 1) or one of three fat-free dairy servings in the HUSEP with: a whole-fat dairy food composite, a reduced-fat/low-fat dairy food composite, whole milk, reduced-fat milk, whole-fat cheese, or reduced-fat cheese (Models 2-7).
  • In all models, the amount of saturated fat did not exceed 10% of total calories, but the amount of energy increased by 45-94 calories. While still lower than current average intake (3,440 mg/d), sodium amounts in four of the seven models exceeded the 2,300 mg/d recommended intake level.
  • Some reduced- and whole-fat dairy foods, especially milk, can fit into calorie-balanced healthy eating patterns that also align with saturated fat recommendations. Allowing some flexibility in fat level of dairy food servings aligns with the recommendations that calories from solid fats and added sugars are best used to increase the palatability of nutrient-dense foods.

Association of Yogurt Consumption with Nutrient Intakes, Nutrient Adequacy, and Diet Quality in American Children and Adults. Cifelli CJ, Agarwal S, Fulgoni VL 3rd. Nutrients. 2020 Nov 9;12(11):E3435.

  • The popularity of yogurt has increased among consumers due to its perceived health benefits.
  • This study examined the cross-sectional association between yogurt consumption and nutrient intake/adequacy, dietary quality, and body weight in children and adults. National Health and Nutrition Examination Survey 2001-2016 data (n= 65,799) were used and yogurt consumers were defined as those having any amount of yogurt during in-person 24-h diet recall.
  • Usual intakes of nutrients were determined using the National Cancer Institute method and diet quality was calculated using the Healthy Eating Index-2015 (HEI-2015) scores after adjusting data for demographic and lifestyle factors.
  • The data show that approximately 6.4% children and 5.5% adults consume yogurt, with a mean intake of yogurt of 150 ± 3 and 182 ± 3 g/d, respectively. Yogurt consumers had higher diet quality (10.3% and 15.2% higher HEI-2015 scores for children and adults, respectively); higher intakes of fiber, calcium, magnesium, potassium, and vitamin D; and higher percent of the population meeting recommended intakes for calcium, magnesium, and potassium than non-consumers.
  • Consumption of yogurt was also associated with lower body weight, body mass index (BMI), and 23% showed a lower risk of being overweight/obese among adults only.
  • In conclusion, yogurt consumption was associated with higher nutrient intake, nutrient adequacy, and diet quality in both children and adults.

The role of yoghurt consumption in the management of type II diabetes. Yanni AE, Kartsioti K, Karathanos VT.Food Funct. 2020 Nov 19.

  • Enrichment of yoghurt with specific ingredients beneficially affects the management of Type II Diabetes Mellitus (DMII).
  • As far as the role of yoghurt in the management of DMII is concerned, the limited number of randomized clinical trials (RCTs) which have been conducted suggest that daily intake of yoghurt enriched with vitamin D and/or calcium as well as probiotics positively influences glycemic regulation and may contribute to more effective control of the disease.
  • It is argued that the various ingredients which are already contained in the complex matrix of food, such as bioactive peptides, calcium, B-complex vitamins and beneficial microbes, as well as the fact that it can be used as a vehicle for the inclusion of other effective ingredients can have an impact on the metabolic control of diabetic patients.
  • The aim of this review is to present the RCTs which have been conducted in the last decade in patients with DMII in an attempt to highlight the positive effects of yoghurt in the management of the disease.

Dietary management of cardiovascular risk including type 2 diabetes. Nestel PJ, Sullivan DR, Mori TA. Curr Opin Endocrinol Diabetes Obes. 2020 Nov 12.

  • Recently published guidance for dietary management of cardiovascular risk and type 2 diabetes have mostly common features.
  • Major findings include a trend to replace strict quantitative advice on nutrients with qualitative advice on food consumption with exceptions for diabetes, global advice to:
    • increase intake of plant foods
    • substitute mono and polyunsaturated oils for saturated and trans fats
    • supplemental omega-3 intake
    • less limitation on dairy foods and fermented dairy foods
    • reduced emphasis on specific cholesterol-rich foods allowing greater consumption of eggs
    • processed meat consumption limited allowing modest intake of lean red meat
    • distinguishing between ‘healthy’ and ‘unhealthy’ carbohydrates including sugars
    • maintaining advice on healthy bodyweight
    • reducing salt intake and encouraging water as preferred beverage.
  • The new guidance for healthier patterns of food consumption supported by evidence is more readily understood by health practitioners and translatable to consumers and patients.