We hope you enjoy the December 2018 Dairy Research Bulletin! The 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 Publications on Animal Health, Food Safety, and Sustainability

Perspectives of Microbial Inoculation for Sustainable Development and Environmental Management. Ahmad M, Pataczek L, Hilger TH, Zahir ZA, Hussain A, Rasche F, Schafleitner R, Solberg SØ. Front Microbiol. 2018 Dec 5;9:2992.

  • How to sustainably feed a growing global population is a question still without an answer. Particularly farmers, to increase production, tend to apply more fertilizers and pesticides, a trend especially predominant in developing countries.
  • Another challenge is that industrialization and other human activities produce pollutants, which accumulate in soils or aquatic environments, contaminating them. Not only is human well-being at risk, but also environmental health.
  • Currently, recycling, land-filling, incineration and pyrolysis are being used to reduce the concentration of toxic pollutants from contaminated sites, but too have adverse effects on the environment, producing even more resistant and highly toxic intermediate compounds. Moreover, these methods are expensive, and are difficult to execute for soil, water, and air decontamination.
  • Alternatively, green technologies are currently being developed to degrade toxic pollutants. This review provides an overview of current research on microbial inoculation as a way to either replace or reduce the use of agrochemicals and clean environments heavily affected by pollution.
  • Microorganism-based inoculants that enhance nutrient uptake, promote crop growth, or protect plants from pests and diseases can replace agrochemicals in food production. Several examples of how biofertilizers and biopesticides enhance crop production are discussed. Plant roots can be colonized by a variety of favorable species and genera that promote plant growth.
  • Microbial interventions can also be used to clean contaminated sites from accumulated pesticides, heavy metals, polyaromatic hydrocarbons, and other industrial effluents. The potential of and key processes used by microorganisms for sustainable development and environmental management are discussed in this review, followed by their future prospects.

Review: Make ruminants green again – how can sustainable intensification and agroecology converge for a better future? Dumont B, Groot JCJ, Tichit M. Animal. 2018 Dec;12(s2):s210-s219.

  • Livestock farming systems provide multiple benefits to humans: protein-rich diets that contribute to food security, employment and rural economies, capital stock and draught power in many developing countries and cultural landscape all around the world. Despite these positive contributions to society, livestock is also the center of many controversies as regards to its environmental impacts, animal welfare and health outcomes related to excessive meat consumption.
  • This article reviews the potentials of sustainable intensification and agroecology in the design of sustainable ruminant farming systems. The researchers analyze the two frameworks in a historical perspective and show that they are underpinned by different values and worldviews about food consumption patterns, the role of technology and our relationship with nature.
  • Proponents of sustainable intensification see the increase in animal protein demand as inevitable and therefore aim at increasing production from existing farmland to limit further encroachment into remaining natural ecosystems. Sustainable intensification can thus be seen as an efficiency-oriented framework that benefits from all forms of technological development.
  • Proponents of agroecology appear more open to dietary shifts towards less animal protein consumption to rebalance the whole food system. Agroecology promotes system redesign, benefits from functional diversity and aims at providing regulating and cultural services.
  • The researchers conclude that sustainable intensification and agroecology could converge for a better future by adopting transformative approaches in the search for ecologically benign, socially fair and economically viable ruminant farming systems.

Views of dairy farmers, agricultural advisors, and lay citizens on the ideal dairy farm. Cardoso CS, von Keyserlingk MAG, Hötzel MJ. J Dairy Sci. 2018 Dec 20. pii: S0022-0302(18)31090-7

  • The aim of this qualitative study was to explore the shared and divergent views among Brazilian dairy farmers, agricultural advisors, and lay citizens on what characteristics they viewed were most important on an ideal dairy farm.
  • Responses from 107 dairy farmers, 170 agricultural advisors (including veterinarians), and 280 lay citizens were subjected to thematic analyses. Five themes were identified: milk quality, animal welfare, economics, society, and the environment. Although all 3 groups made reference to each of the 5 themes, they emphasized different characteristics.
  • The lay citizens placed the most emphasis on milk quality. In contrast, both the farmers and the advisors highlighted economics as the most important characteristic of an ideal dairy farm.
  • When considering only animal welfare, the researchers noted differences in the use of the constructs of animal welfare: farmers and advisors referred mostly to aspects related to biological functioning, whereas lay citizens emphasized affective states and naturalness.
  • All 3 stakeholder groups referred to the use of pasture as being an important component of an ideal dairy farm but again differed in their reasons; citizens referred to pasture in the context of naturalness, whereas the other 2 stakeholder groups almost always referred to pasture using economic terms.
  • Technology was highlighted by all 3 groups as an important characteristic of an ideal dairy farm but differences were noted in their justification for this view. For example, lay citizens viewed technology as a tool to improve milk quality, whereas farmers and advisors both referred to technology as an important vehicle to improve quality of life for those working in the industry.
  • Lay citizens raised several concerns associated with the overuse of antibiotics and other chemicals, but farmers and advisors rarely mentioned these types of concerns. The latter 2 stakeholders placed considerable emphasis on the quality of life of dairy farmers and workers, an issue rarely discussed by lay citizens.
  • Overall, these findings highlight several disconnects between the expectations of the lay citizens, and farmers and their advisors. The reseatchers suggest that dairy farmers and agricultural advisors should both reflect on the desires of the lay public in what they view to be an ideal dairy farm, as this may help bridge some of the current disconnects.

Chicken or the Egg: The Reciprocal Association Between Feeding Behavior and Animal Welfare and Their Impact on Productivity in Dairy Cows. Llonch P, Mainau E, Ipharraguerre IR, Bargo F, Tedó G, Blanch M, Manteca X. Front Vet Sci. 2018 Dec 5;5:305.

  • Feeding behavior in dairy cattle has a significant impact on feed efficiency, which is important for increasing the profitability of livestock and, at the same time, reducing the environmental impact.
  • Feeding behavior can be measured by feeding time, meal duration, meal frequency, feeding rate, and rumination time. Higher feed intake is related to lower feed efficiency; whereas, an increase in feeding time facilitates chewing, reduces feed particle size and increases its digestibility. More frequent and shorter meals are usually associated with a more efficient use of feed due to improvement of feed digestibility. Rumination time is positively associated with milk production.
  • Impaired health is associated with variations in feeding behavior, which can be used to identify and predict some diseases such as ketosis, mastitis, or lameness. Changes in rumination time are also a reliable indicator of mastitis, lameness, ketosis, and the onset of calving.
  • Feeding behavior is regulated by internal and external factors and some of them are relevant for animal welfare. The main welfare-associated factors influencing feeding behavior are social behavior and temperament, and environmental effects. Cattle are social animals and hierarchy has a notable impact on feeding behavior, especially when access to feed is limited.
  • Competition for feed causes a reduction in the average feeding time but increases feeding rate. Excitable animals visit the feeder more often and spend less time per meal. High environmental temperature affects feeding behavior, as heat-stressed cattle change their feeding pattern by concentrating the feeding events in crepuscular hours, leading to an increased risk of sub-acute ruminal acidosis.
  • In conclusion, feeding behavior is a determinant feature for improving efficiency, productivity and welfare of dairy cattle. Routine assessment of feeding behavior allows monitoring of health and production status of dairy cattle at the individual and farm level, which is a useful tool to optimize the management of livestock.

Age-Associated Distribution of Antimicrobial-Resistant Salmonella enterica and Escherichia coli Isolated from Dairy Herds in Pennsylvania, 2013-2015. Cao H, Pradhan AK, Karns JS, Hovingh E, Wolfgang DR, Vinyard BT, Kim SW, Salaheen S, Haley BJ, Van Kessel JAS. Foodborne Pathog Dis. 2018 Dec 31.

  • Antimicrobial resistance has become a major global public health concern, and agricultural operations are often implicated as a source of resistant bacteria.
  • This study characterized the prevalence of antimicrobial-resistant Salmonella enterica and Escherichia coli from a total of 443 manure composite samples from preweaned calves, postweaned calves, dry cows, and lactating cows from 80 dairy operations in Pennsylvania.
  • Salmonellae were isolated from 67% of dairy operations, and 99% of the isolates were susceptible to multiple antibiotics. Salmonella were isolated more frequently from lactating and dry cow samples than from pre- and postweaned calf samples.
  • coli were isolated from all the manure composite samples, and isolates were commonly resistant to tetracyclines, sulfonamides, and aminoglycosides. Resistance was detected more frequently in the E. coli isolates from pre- and postweaned calf samples than in isolates from dry and lactating cow samples. Multidrug-resistant E. coli (i.e., resistant to >3 antimicrobial classes) were isolated from 66 farms (83%) with significantly greater prevalence in preweaned calves than in the older age groups.
  • These findings indicate that dairy animals, especially the calf population, serve as significant reservoirs for antimicrobial-resistant bacteria. Additional research on the colonization and persistence of resistant E. coli in calves is warranted to identify potential avenues for mitigation.

Reducing enteric methane emissions from dairy cattle: Two ways to supplement 3-nitrooxypropanol. Van Wesemael D, Vandaele L, Ampe B, Cattrysse H, Duval S, Kindermann M, Fievez V, De Campeneere S, Peiren N. J Dairy Sci. 2018 Dec 26. pii: S0022-0302(18)31111-1.

  • The aim of this work was to determine the effect of 3-nitrooxypropanol (3-NOP) on the enteric methane (CH4) emissions and performance of lactating dairy cows when mixed in with roughage or incorporated into a concentrate pellet.
  • After 2 pretreatment weeks without 3-NOP supplementation, 30 Holstein Friesian cows were divided into 3 homogeneous treatment groups: no additive, 3-NOP mixed in with the basal diet (roughage; NOPbas), and 3-NOP incorporated into a concentrate pellet (NOPconc).
  • The pretreatment period was followed by a 10-wk treatment period in which the NOPbasand NOPconc cows were fed 1.6 g of 3-NOP/cow per day. After the treatment period, a 2-wk washout period followed without 3-NOP supplementation.
  • On average for the total treatment period and compared with the no-additive group,
    • CH4production (g/d) was 28 and 23% lower for NOPbas and NOPconc, respectively.
    • Methane yield (g/kg of dry matter intake) was 23 and 24% lower for NOPbas and NOPconc, respectively.
    • Methane intensity (g/kg of milk) was 21 and 22% lower for NOPbas and NOPconc, respectively.
  • Moreover, supplying 3-NOP did not affect total dry matter intake, milk production, or milk composition.
  • The results of this experiment show that 3-NOP can reduce enteric CH4emissions of dairy cattle when incorporated into a concentrate pellet and that this reduction is not different from the effect of mixing in 3-NOP with the basal diet (roughage). This broadens the possibilities for using 3-NOP in the dairy sector worldwide, as it is not always feasible to provide an additive mixed in with the basal diet.

Components and dispersion characteristics of organic and inorganic odorous gases in a large-scale dairy farm. Guo H, Hao H, Zhang Q, Wang J, Liu J. J Air Waste Manag Assoc. 2018 Dec 21.

  • The rapid development of large-scale livestock husbandry has caused serious air pollution problems. Understanding the composition and dispersion characteristics of odorous gases can help control air pollution.
  • In this study, the gases in typical areas of a large-scale dairy farm were sampled and measured for volatile organic compounds (VOCs), hydrogen sulfide, and ammonia concentrations.
  • Fifty-two species of VOCs were identified.
    • Cowshed VOCs mainly consisted of halogenated hydrocarbons (16960 µg/m3), ketones (15700 µg/m3), esters (9889 µg/m3), and sulfur compounds (3677 µg/m3).
    • Oxidation pond VOCs were mainly composed of halogenated hydrocarbons (21940 µg/m3) and ketones (3589 µg/m3).
    • Solid-liquid separation tank VOCs comprised halogenated hydrocarbons (32010 µg/m3), ketones (7169 µg/m3) and sulfur compounds (1003 µg/m3).
  • The highest concentrations of ammonia and hydrogen sulfide were obtained from the milking parlor and solid-liquid separation tank, respectively.
  • The results of this work can provide a theoretical basis for the prevention and control of odorous gases in large-scale livestock farms.


Selected Articles on Dairy Intake and Human Health

Consumption of dairy product and its association with total and cause specific mortality – A population-based cohort study and meta-analysis. Mazidi M, Mikhailidis DP, Sattar N, Howard G, Graham I, Banach M; Lipid and Blood Pressure Meta-analysis Collaboration (LBPMC) Group. Clin Nutr. 2018 Dec 18. pii: S0261-5614(18)32583-4.

  • The intake of dairy products has been thought to be associated with an increased risk of coronary heart diseases (CHD) and total mortality due to its relatively high content of saturated fat. However, reports on this association particularly among US adults are conflicting and controversial.
  • The researchers used data from the 1999-2010 National Health and Nutrition Examination Surveys (NHANES) study to examine whether consumption of total dairy and dairy subgroups was associated with total and cause specific (CHD, cerebrovascular and cancer) mortality. Further, they carried out a systematic review and meta-analysis of prospective studies to check for consistency with the NHANES findings.
  • In the NHANES data set of 24,474 participants, 3520 deaths occurred during follow-up. Total mortality risk was lower when comparing the top quartile of total dairy and cheese consumers with the lower quartiles of consumption.
  • Using a similar model, the researchers found a negative association between total dairy and milk consumption with risk of cerebrovascular mortality, while milk consumption was associated with increased CHD mortality.
  • The meta-analysis with 636,726 participants indicated a significant inverse association between fermented dairy products and total mortality, while milk consumption was associated with higher CHD mortality.
  • Among American adults, higher total dairy consumption was associated with lower total and cerebrovascular mortality, while higher milk consumption was associated with higher risk of CHD. These findings do not support dogmatic public health advice to reduce total dairy fat consumption, although the association between milk consumption and CHD mortality requires further study.

Dairy Consumption and Cardiometabolic Diseases: Systematic Review and Updated Meta-Analyses of Prospective Cohort Studies. Soedamah-Muthu SS, de Goede J. Curr Nutr Rep. 2018 Dec;7(4):171-182.

  • Dairy products contain both beneficial and harmful nutrients in relation to cardiometabolic diseases. This article provides the latest scientific evidence regarding the relationship between dairy products and cardiometabolic diseases by reviewing the literature and updating meta-analyses of observational studies.
  • The researchers updated their previous meta-analyses of cohort studies on type 2 diabetes, coronary heart disease (CHD), and stroke with nine studies and confirmed previous results.
  • Total dairy and low-fat dairy (per 200 g/d) were inversely associated with a 3-4% lower risk of diabetes. Yogurt was non-linearly inversely associated with diabetes. Total dairy and milk were not associated with CHD. An increment of 200g of daily milk intake was associated with an 8% lower risk of stroke.
  • The latest scientific evidence confirmed neutral or beneficial associations between dairy products and risk of cardiometabolic diseases.

The importance of dairy products for cardiovascular health: whole or low fat?  Salas-Salvadó J, Babio N, Juárez-Iglesias M, Picó C, Ros E, Moreno Aznar LA. Nutr Hosp. 2018 Dec 3;35(6):1479-1490.

  • The nutritional guidelines incorporate dairy products as part of a balanced and healthy diet. In almost all guidelines it is announced that dairy products have to preferably be consumed as non or low-fat version. The reason behind this recommendation is the intake of saturated fatty acids. But lately, the research focus has been shifted towards the study of the food matrix, which allows assessing health effects considering all the components contained in the foods, and their impact in human health.
  • Dairy products are the perfect example to highlight the importance of the food matrix as a determinant of the effects of nutrients on health. The potentially harmful effects of saturated fatty acids on cardiometabolic health seem to be different when they are consumed within nutrient-rich foods such as yogurt, cheese or other dairy products.
  • Epidemiological studies with large population cohorts and long term follow-up show that consumption of dairy products, especially yogurt, is not associated with an increased cardiovascular risk.
  • Therefore, there is not enough scientific evidence to preferentially recommend the consumption of non-fat or low-fat dairy products to the general population, instead of its whole-fat version.

Nutrient-rich, high-quality, protein-containing dairy foods in combination with exercise in aging persons to mitigate sarcopenia. Phillips SM, Martinson W. Nutr Rev. 2018 Dec 17

  • Sarcopenic declines in muscle mass and function contribute to the risk of falls, reduced mobility, and progression to frailty in older persons. Mitigation of sarcopenia can be achieved by consumption of higher quality protein in sufficient quantities, which current research suggests are greater than the recommended intakes of approximately 0.8 g/kg bodyweight/d.
  • In addition, higher levels of physical activity and participation in exercise to support cardiovascular fitness and musculoskeletal function work additively with protein in attenuating sarcopenia.
  • Dairy foods provide high-quality protein and contain several nutrients of concern for older persons. This brief review provides an overview of the science underpinning why dairy foods should be a point of nutritional emphasis for older persons. Practical suggestions are provided for implementation of dairy foods into dietary patterns to meet the protein and other nutrient targets for older persons.
  • A food-based approach to achieving these protein targets would be advantageous, and the nutrient density of the protein-containing foods would be particularly important for older persons.

Yogurt and other fermented foods as sources of health-promoting bacteria. Kok CR, Hutkins R. Nutr Rev. 2018 Dec 1;76(Supplement_1):4-15.

  • Increased consumption of yogurt, kefir, and other fermented foods has been driven, in part, by the health benefits these products may confer. Epidemiological studies have shown that the consumption of fermented foods is associated with reduced risks of type 2 diabetes, metabolic syndrome, and heart disease, along with improved weight management.
  • The microorganisms present in these foods are suggested to contribute to these health benefits. Among these are the yogurt starter culture organisms Streptococcus thermophilus and Lactobacillus delbrueckii subsp bulgaricus as well as Bifidobacterium and Lactobacillus strains that are added for their probiotic properties.
  • In contrast, for other fermented foods, such as sauerkraut, kimchi, and miso, fermentation is initiated by autochthonous microbes present in the raw material. In both cases, for these fermentation-associated microbes to influence the gut microbiome and contribute to host health, they must overcome, at least transiently, colonization resistance and other host defense factors.
  • Culture and culture-independent methods have now clearly established that many of these microbes present in fermented dairy and nondairy foods do reach the gastrointestinal tract. Several studies have shown that consumption of yogurt and other fermented foods may improve intestinal and extraintestinal health and might be useful in improving lactose malabsorption, treating infectious diarrhea, reducing the duration and incidence of respiratory infections, and enhancing immune and anti-inflammatory responses.

The role of yogurt in food-based dietary guidelines. Gómez-Gallego C, Gueimonde M, Salminen S. Nutr Rev. 2018 Dec 1;76(Supplement_1):29-39.

  • In the modern food technology era, one of the aims of food safety and quality is to eliminate or reduce the number of microorganisms in food. This may now be changing. In particular, the importance of live microorganisms as beneficial food constituents is now being recognized.
  • Microorganisms present in food that contribute to the human diet include not only viable bacteria but also metabolites and bioactive components. Yogurt is one of the most biologically active foods consumed by humans. It is an excellent source of proteins, vitamins, and minerals. Additionally, the nutritional value is especially high relative to cost.
  • Potential nutritional benefits are also associated with the ingestion of the bacteria that are ordinarily present at the time of consumption. Thus, yogurt serves as a major source of live bacteria in the human diet, as well as a delivery vehicle for added probiotic bacteria.
  • Yogurt may provide a simple and affordable solution for enhancing the nutritional value of the diet, including the intake of live bacteria and their metabolites. A further benefit may be obtained when yogurt is used as a carrier for specific probiotic bacteria and/or prebiotic compounds.
  • These factors suggest that yogurt could have a more visible role in food-based dietary guidelines.

Carbon footprint and nutritional quality of different human dietary choices. González-García S, Esteve-Llorens X, Moreira MT, Feijoo G. Sci Total Environ. 2018 Dec 10;644:77-94.

  • Apart from industrial activities, our eating habits also have a significant environmental cost associated with crop cultivation, manufacturing processes, packaging, refrigeration, transport cooking and waste management.
  • In a context of growing social awareness of the role of different dietary choices in the environment, the review of different alternatives on the road to a healthy and sustainable diet should integrate relevant information on the nutritional quality of different eating habits.
  • Since dietary choices have an effect on environmental sustainability and human health, a literature review on different dietary choices has been conducted to determine the differences in carbon footprint and nutritional quality identifying the main hotspots trying to give advice towards the identification of sustainable diets.
  • The researchers identified that the so-called Mediterranean and Atlantic diets present high nutritional scores and low carbon footprints. On the contrary, the dietary choices identified in northern and Western Europe, as well as in the United States, have the highest carbon footprints, highlighting the contribution of dairy products as a basic source of high-quality nutrients and protein.
  • Broadly speaking, dietary choices rich in vegetables (e.g., vegan, vegetarian as well as Indian and Peruvian) have a better environmental profile than those rich in meat (mainly ruminant meat). In line with these findings, the shift in meat consumption habits from beef and veal to chicken, pork and poultry, the introduction of alternative foods to animal protein (e.g. quinoa) and the consumption of olive oil as a major source of vegetable oil may be compatible with a healthier and more environmentally friendly diet.
  • However, the complete elimination of meat and dairy products from the daily diet may not be feasible in case the supply of some micronutrients (e.g., calcium and vitamin D) is not guaranteed.
  • Limitations were identified in the consulted studies related to the consideration of the different system boundaries, as well as underlying uncertainties related to data sources. Therefore, efforts should be made to develop consistent and agreed-upon methods for estimating both the carbon footprint and nutritional quality scores.