Welcome to the December 2019 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

Symposium review: Real-time continuous decision making using big data on dairy farms. Cabrera VE, Barrientos-Blanco JA, Delgado H, Fadul-Pacheco L. J Dairy Sci. 2019 Dec 18. pii: S0022-0302(19)31101-4.

  • Dairy farms have embraced large and diverse technological innovations such as sensors and robotic systems, and procured vast amounts of constant data streams, but they have not been able to integrate all this information effectively to improve whole-farm decision making. Consequently, the effects of all this new smart dairy farming are not being fully realized.
  • Therefore, researchers are currently developing a real-time, data-integrated, data-driven, continuous decision-making engine known as “The Dairy Brain”, by applying precision farming, big data analytics, and the Internet of Things. This is a transdisciplinary research and extension project that engages multidisciplinary scientists, dairy farmers, and industry professionals.
  • Researchers are using the state-of-the-art database management system from the University of Wisconsin-Madison Center for High Throughput Computing to develop an Agricultural Data Hub that connects and analyzes cow and herd data on a permanent basis. This Dairy Brain concept can be illustrated with 3 practical applications:
  • Nutritional grouping that provides a more accurate diet to lactating cows by automatically allocating cows to pens according to their nutritional requirements aggregating and analyzing data streams from management, feed, Dairy Herd Improvement, and milking parlor records;
  • Early risk detection of clinical mastitis that identifies first-lactation cows under risk of developing clinical mastitis by analyzing integrated data from genetic, management, and DHI records;
  • Predicting clinical mastitis onset that recognizes cows at higher risk of contracting clinical mastitis, by continuously integrating and analyzing data from management and the milking parlor.
  • It can be demonstrated that with these applications it is possible to develop integrated continuous decision-support tools that could potentially reduce diet costs by $99/cow per year and also provide a new dimension for monitoring health events by detecting 90% of clinical mastitis cases a few milkings before disease onset.
  • This is an ongoing innovative project that is anticipated to transform how dairy farms operate.

Microbial contamination level and microbial diversity of occupational environment in commercial and traditional dairy plants. Stobnicka-Kupiec A, Gołofit-Szymczak M, Górny R. Ann Agric Environ Med. 2019 Dec 19;26(4):555-565.

  • In the dairy industry, microorganisms can play both a positive role in the food production system and a negative one, causing contamination of the working environment.
  • The aim of this study was to assess microbial contamination of the air and surfaces at workplaces in commercial dairies and traditional dairies.
  • Air and surface samples were collected in commercial dairies and in traditional dairies. Bacterial and fungal concentrations in the air and on surfaces were calculated and all isolated microorganisms taxonomically identified, based on their morphological, biochemical and molecular features.
  • Qualitative analysis revealed mainly the presence of saprophytic microorganisms; however, several pathogenic strains (Staphylococcus aureus, Streptococcus intermedius, Clostridium perfringens, Actinomyces spp., Streptomyces spp., Candida albicans) were also isolated from both the air and surface samples in the studied dairies.
  • The air and surfaces in traditional dairies were more polluted than those in commercial dairies; however, in both types of dairies, the levels of microbial contaminants did not exceed respective threshold limit values. Nevertheless, the presence of pathogenic microorganisms may increase health risk for dairy workers and influence the quality of products.
  • Hence, proper hygienic measures should be introduced and performed to guarantee high microbial quality of both production processes and milk products.

Invited review: Fate of antibiotic residues, antibiotic-resistant bacteria, and antibiotic resistance genes in US dairy manure management systems. Oliver JP, Gooch CA, Lansing S, Schueler J, Hurst JJ, Sassoubre L, Crossette EM, Aga DS. J Dairy Sci. 2019 Dec 16. pii: S0022-0302(19)31070-7.

  • Antibiotic residues, antibiotic-resistant bacteria, and antibiotic resistance genes can be found in dairy manure and may contribute to the spread of antibiotic resistance.
  • United States dairy operations use antibiotics (primarily β-lactams and tetracyclines) to manage bacterial diseases in dairy cattle. Although β-lactam residues are rarely detected in dairy manure, tetracycline residues are common and perhaps persistent.
  • Generally, <15% of bacterial pathogen dairy manure isolates are antibiotic-resistant, although resistance to some antibiotics (e.g., tetracycline) can be higher. Over 60 antibiotic resistance genes can be found in dairy manure (including β-lactam and tetracycline resistance genes).
  • Manure treatment systems have not been specifically designed to mitigate antibiotic resistance, though certain treatments have some capacity to do so. Generally, well-managed aerobic compost treatments reaching higher peak temperatures (>60°C) are more effective at mitigating antibiotic residues than static stockpiles, although this depends on the antibiotic residue and their interactions. Similarly, thermophilic anaerobic digesters operating under steady-state conditions may be more effective at mitigating antibiotic residues than mesophilic or irregularly operated digesters or anaerobic lagoons.
  • The number of antibiotic-resistant bacteria may decline during composting and digestion or be enriched as the bacterial communities in these systems shift, affecting relative antibiotic resistance genes abundance or acquire antibiotic resistance genes during treatment. Antibiotic resistance genes often persist through these systems, although optimal management and higher operating temperature may facilitate their mitigation.
  • Less is known about other manure treatments, although separation technologies may be unique in their ability to partition antibiotic residues based on sorption and solubility properties.
  • Needed areas of study include determining natural levels of antibiotic resistance in dairy systems, standardizing and optimizing analytical techniques, and more studies of operating on-farm systems, so that treatment system performance and actual human health risks associated with levels of antibiotic residues, antibiotic-resistant bacteria, and antibiotic resistance genes found in dairy manure can be accurately assessed.

Invited review: Compost-bedded pack barns for dairy cows. Leso L, Barbari M, Lopes MA, Damasceno FA, Galama P, Taraba JL, Kuipers A. J Dairy Sci. 2019 Dec 16. pii: S0022-0302(19)31071-9

  • Compost-bedded pack barns are receiving increasing attention as a housing system for dairy cows that has potential to improve animal welfare.
  • This article reviews current scientific knowledge about compost-bedded pack barns with the aim of providing a comprehensive tool for producers and researchers using this housing system.
  • In compost-bedded pack barns, cows are provided with an open bedded pack area rather than the individual stalls and concrete alleys found in freestall systems. The bedded pack, a mixture of organic bedding and cattle excreta, is cultivated frequently (1-3 times per day) to incorporate fresh manure and air into the pack, thus promoting an aerobic composting process.
  • Studies have indicated that compost-bedded pack barns, compared with conventional systems such as freestall barns, have the potential to improve the welfare of dairy cows. In particular, the main reported benefits include improved comfort during resting, better foot and leg health, and more natural animal behavior.
  • Research has also indicated that adequate udder health can be achieved in compost-bedded pack barns. However, because the bedded pack has been shown to contain high bacterial concentrations, proper management is essential to maintain adequate cow cleanliness and reduce the risk of mastitis.
  • Controlling pack moisture is consistently indicated as the most important issue with compost-bedded pack barns. Especially under cold and humid weather conditions, large amounts of bedding may be necessary to keep the pack adequately dry and comfortable for the cows. Nevertheless, the improvements in cow health may offset the higher costs of bedding.

Benefits and Trade-Offs of Dairy System Changes Aimed at Reducing Nitrate Leaching. Beukes P, Romera A, Hutchinson K, van der Weerden T, de Klein C, Dalley D, Chapman D, Glassey C, Dynes R. Animals (Basel). 2019 Dec 17;9(12). pii: E1158.

  • An important challenge facing global dairy industries is to develop farm systems that can maintain or increase production and profitability while reducing environmental impacts, including on water and climate.
  • Between 2011 and 2016, small-scale farm trials were run across three dairy regions of New Zealand (Waikato, Canterbury, Otago) to compare the performance of typical regional farm systems with farm systems implementing a combination of mitigation options most suitable to the region.
  • The trials ran for at least three consecutive years with detailed recording of milk production and input costs. Operating profit (NZ$/ha/year), nitrate leaching (kg N/ha/year), and greenhouse gas emissions (t CO2-equivalent/ha/year) were all expressed per hectare of milking platform to enable comparisons across regions.
  • Nitrate leaching mitigations adopted in lower-input (less purchased feed and nitrogen fertilizer) farm systems reduced leaching by 22 to 30 per cent, and greenhouse gas emissions by between nine and 24 per cent. The exception was the wintering barn system in Otago, where nitrate leaching was reduced by 45 per cent, but greenhouse gas emissions were unchanged due to greater manure storage and handling.
  • Important drivers of a lower environmental footprint are reducing nitrogen fertilizer and purchased feed. Their effect is to reduce feed flow through the herd and drive down both greenhouse gas emissions and nitrate leaching.
  • Emission reductions in the lower-input systems of Waikato and Canterbury came at an average loss of profit of approximately NZ$100/t CO2-equivalent (three to five per cent of industry-average profit per hectare).

Decarbonizing agriculture through the conversion of animal manure to dietary protein and ammonia fertilizer. Sagues WJ, Assis CA, Hah P, Sanchez DL, Johnson Z, Acharya M, Jameel H, Park S. Bioresour Technol. 2020 Feb;297:122493.

  • The decarbonization of agriculture faces many challenges and has received a level of attention insufficient to abate the worst effects of climate change and ensure a sustainable bioeconomy.
  • Agricultural emissions are caused both by fossil-intensive fertilizer use and land-use change, which in turn are driven in part by increasing demand for dietary protein.
  • To address this challenge, this study presents a synergistic system in which organic waste-derived biogas (a mixture of methane and carbon dioxide) is converted to dietary protein and ammonia fertilizer.
  • This system produces low-carbon fertilizer inputs alongside high-quality protein, addressing the primary drivers of agricultural emissions.
  • If the proposed system were implemented across the United States utilizing readily available organic waste from municipal wastewater, landfills, animal manure, and commercial operations, we estimate 30% of dietary protein intake and 127% of ammonia usage could be displaced while reducing land use, water consumption, and greenhouse gas emissions.

Public attitudes toward genetic modification in dairy cattle. Ritter C, Shriver A, McConnachie E, Robbins J, von Keyserlingk MAG, Weary DM. PLoS One. 2019 Dec 2;14(12):e0225372.

  • Genetic modification has been used to create dairy cattle without horns and with increased resistance to disease; applications that could be beneficial for animal welfare, farm profits, and worker safety.
  • The aim of this study was to assess how different stated purposes were associated with public attitudes toward these two applications using a mixed methods approach.
  • Using an online survey, 957 U.S. participants were randomly assigned to one of ten treatments in a 2 (application: hornless or disease-resistant) x 5 (purposes: improved animal welfare, reduced costs, increased worker safety, all three purposes, or no purpose) factorial design.
  • Participant attitudes were more favorable to disease resistance than to hornlessness. In the ‘disease-resistance’ group participants had more positive attitudes toward genetic modification when the described purpose was animal welfare versus reduction of costs.
  • Attitudes were less favorable to the ‘hornless’ application if no purpose was provided versus when the stated purpose was either to improve animal welfare or when all purposes were provided. Similarly, attitudes were less positive when the stated purpose was to reduce costs versus either improving animal welfare or when all purposes were provided.
  • Quantitative and qualitative analysis indicated that both the specific application and perceived purpose (particularly when related to animal welfare) can affect public attitudes toward genetic modification.

Key Risk Factors Affecting Farmers’ Mental Health: A Systematic Review. Daghagh Yazd S, Wheeler SA, Zuo A. Int J Environ Res Public Health. 2019 Dec 2;16(23). pii: E4849.

  • Recently, concern has increased globally over farmers’ mental health issues.
  • This paper presents a systematic review of the outcomes, locations, study designs, and methods of current studies on farmers’ mental health. In particular, this review of 167 articles aims to fill an important gap in understanding of the potential key risk factors affecting farmers’ mental health around the world.
  • The four most-cited influences on farmers’ mental health in the reviewed literature respectively were pesticide exposure, financial difficulties, climate variabilities/drought, and poor physical health/past injuries.
  • Comparative studies on the mental health of farmers and other occupational workers showed mixed results, with a larger portion identifying that psychological health disturbances were more common in farmers and farm-workers.
  • Knowledge of farmer psychological disorder risk factors and its impacts are essential for reducing the burden of mental illness. Further research will be required on climate change impacts, developing country farmers’ mental health, and information on how to reduce help-seeking barriers amongst farmers.


Selected Articles on Dairy Intake and Human Health

Whole milk compared with reduced-fat milk and childhood overweight: a systematic review and meta-analysis. Vanderhout SM, Aglipay M, Torabi N, Jüni P, da Costa BR, Birken CS, O’Connor DL, Thorpe KE, Maguire JL. Am J Clin Nutr. 2019 Dec 18. pii: nqz276.

  • The majority of children in North America consume cow-milk daily. Children aged >2 y are recommended to consume reduced-fat (0.1-2%) cow-milk to lower the risk of obesity.
  • The aim of this study was to evaluate the relation between cow-milk fat consumption and adiposity in children aged 1-18 years old. The search included observational and interventional studies of healthy children that described the association between cow-milk fat consumption and adiposity.
  • 28 studies met the inclusion criteria: 20 were cross-sectional and 8 were prospective cohort studies. No clinical trials were identified.
  • In 18 studies, higher cow-milk fat consumption was associated with lower child adiposity, and 10 studies did not identify an association.
  • Meta-analysis included 14 of the 28 studies (n = 20,897) that measured the proportion of children who consumed whole milk compared with reduced-fat milk and direct measures of overweight or obesity.
  • Among children who consumed whole (3.25% fat) compared with reduced-fat (0.1-2%) milk, the odds ratio of overweight or obesity was 0.61, but heterogeneity between studies was high.
  • Observational research suggests that higher cow-milk fat intake is associated with lower childhood adiposity. International guidelines that recommend reduced-fat milk for children might not lower the risk of childhood obesity.

Associations between Dairy Intake, Body Composition, and Cardiometabolic Risk Factors in Spanish Schoolchildren: The Cuenca Study. Lahoz-García N, Milla-Tobarra M, García-Hermoso A, Hernández-Luengo M, Pozuelo-Carrascosa DP, Martínez-Vizcaíno V. Nutrients. 2019 Dec 3;11(12). pii: E2940.

  • Full-fat dairy has been traditionally associated with obesity and cardiovascular disease (CVD); however, recent evidence shows that the amount of dairy intake might have a beneficial effect over these pathologies, regardless of their fat content.
  • The aim of this study was to examine the association between the intake of dairy products (including milk with different fat contents) with both adiposity and serum lipid concentration, adjusted by cardiorespiratory fitness, in Spanish schoolchildren.
  • A cross-sectional study of 1088 children, aged 8 to 11 years, was conducted in which body mass index (BMI), waist circumference (WC), fat mass percentage (FM%), fat mass index (FMI), blood lipid profile, dairy intake, and cardiorespiratory fitness were measured.
  • Results showed that children with lower BMI, WC, FM%, and FMI had higher whole-fat milk intake and lower skimmed and semi-skimmed milk intake than children with higher BMI, WC, FM%, and FMI. Children with normal levels of triglycerides and high-density lipoproteins (HDL) cholesterol consumed more whole-fat milk and less reduced-fat milk than children with dyslipidemic patterns.
  • These relationships persisted after adjustment for cardiorespiratory fitness. Our findings suggest that full-fat milk intake should be promoted in children without obesity or high cardiometabolic risk.

Ingestion of a Pre-bedtime Protein Containing Beverage Prevents Overnight Induced Negative Whole Body Protein Balance in Healthy Middle-Aged Men: A Randomized Trial. Karagounis LG, Beaumont M, Donato-Capel L, Godin JP, Kapp AF, Draganidis D, Pinaud S, Vuichoud J, Shevlyakova M, Rade-Kukic K, Breuillé D. Front Nutr. 2019;6:181.

  • Age related muscle wasting leads to overall reductions of lean body mass, reduced muscle strength, and muscle function resulting in compromised quality of life. Utilizing novel nutritional strategies to attenuate such losses is of great importance in elderly individuals.
  • The researchers aimed to test if a complete dietary supplement containing 25 grams of milk proteins and ingested in the evening before bed would improve protein metabolism over a 10-hour overnight period in healthy middle-aged male subjects.
  • In addition, the researchers also assessed the rates of muscle protein synthesis during the second half of the night in order to see if previously reported extended amino acidemia during sleep results in increased rates of muscle protein synthesis.
  • Seventeen healthy middle-aged male subjects (59.4 ± 3.2 years) consumed a dietary supplement drink at 9pm containing either 25 grams milk protein concentrate, 25 grams maltodextrin, 7.75 grams canola oil (treatment group), or an isocaloric protein void drink (placebo group).
  • Whole body protein balance was greater in the treatment group compared to placebo (P≤ 0.01). In contrast, no changes were observed on rates of muscle protein synthesis during the second half of the night.
  • In conclusion, the ingestion of a dietary supplement containing 25 grams of milk proteins significantly reduced the negative protein balance observed during the night. Therefore, pre-bedtime protein ingestion may attenuate overnight losses of lean tissue in healthy elderly men.

Association of milk consumption frequency on muscle mass and strength: an analysis of three representative Korean population studies. Lee JH, Lee HS, Kim H, Kwon YJ, Lee JW. Eur J Nutr. 2019 Dec 19.

  • Sarcopenia is an involuntary loss of muscle mass, strength, and physical performance associated with aging. Sarcopenia contributes to adverse health outcomes. Milk contains essential amino acids important for maintaining muscle.
  • In this study, the researchers investigated the relationships among milk consumption frequency, muscle mass, and strength in Korean adults.
  • The researchers analyzed the data from 16,173 adults in the 2008-2011 Korean National Health and Nutrition Examination Survey (KNHANES), 13,537 adults in the 2014-2016 KNHANES, and 8254 adults in the Korean Genome and Epidemiology Study (KoGES).
  • Milk consumption frequency was divided into two groups: (1) less than once per day (Milk < 1 group) and (2) greater than or equal to once per day (Milk ≥ 1 group).
  • Muscle strength was measured using the hand-grip strength test. The odds ratio for low skeletal muscle mass was 1.250 greater in the Milk < 1 group compared with the Milk ≥ 1 group. The adjusted mean for hand-grip strength was higher in the Milk ≥ 1 group.
  • After a mean follow-up of 9years, fat-free mass/body mass index was higher in the Milk ≥ 1 group than the Milk < 1 group.
  • In conclusion, the researchers found that a milk consumption frequency of greater than 1 serving per day was significantly associated with higher skeletal muscle index and muscle strength than lower milk intake.Milk consumption could help prevent sarcopenia in adults.

Higher intakes of dietary vitamin D, calcium and dairy products are inversely associated with the risk of colorectal cancer: a case-control study in China. Zhang X, Fang YJ, Feng XL, Abulimiti A, Huang CY, Luo H, Zhang NQ, Chen YM, Zhang CX. Br J Nutr. 2019 Dec 12:1-36.

  • The effects of dietary vitamin D, calcium and dairy products intakes on colorectal cancer risk remain controversial.
  • This study investigated the association between these dietary intakes and the risk of colorectal cancer in Guangdong, China.
  • From July 2010 to December 2018, a total of 2,380 patients with colorectal cancer and 2,389 sex- and age-matched controls were recruited.
  • Higher dietary vitamin D and calcium intakes were associated with 43% and 52% reductions in colorectal cancer risk, with odd ratios of 0.57 and 0.48, respectively, for the highest quartile (vs. lowest quartile) intakes.
  • A statistically significant inverse association was observed between the total dairy products intake and colorectal cancer risk, with an adjusted odds ratio of 0.32 for the highest vs. the lowest tertile.
  • Subjects who drank milk had a 48% lower risk of colorectal cancer than those who did not. The inverse associations of dietary vitamin D, calcium, total dairy products and milk intakes with the risk of colorectal cancer were independent of sex and cancer site.
  • This study supports the protective effects of high dietary vitamin D, calcium and dairy products intakes against colorectal cancer in a Chinese population.

Milk Consumption Decreases Risk for Breast Cancer in Korean Women under 50 Years of Age: Results from the Health Examinees Study. Shin WK, Lee HW, Shin A, Lee JK, Kang D. Nutrients. 2019 Dec 21;12(1). pii: E32.

  • Epidemiologic studies regarding breast cancer risk related to milk consumption remain controversial.
  • The aim of this study was to evaluate the association between milk consumption and the risk for breast cancer.
  • A total of 93,306 participants, aged 40-69 years, were included in the prospective cohort study between 2004 and 2013.
  • A total of 359 breast cancer cases were observed over a median follow-up period of 6.3 years. Milk consumption was not associated with decreased risk for breast cancer in the total population. In women under 50 years of age, however, milk consumption was inversely associated with breast cancer risk.
  • In the comparison between highest (≥1 serving/day) and lowest (<1 serving/week) intake categories of milk, the multivariate hazard ratio was 0.58 among women under 50 years of age.
  • In conclusion, these findings show that milk consumption in Korean women aged 50 or younger is associated with a decreased risk for breast cancer, when compared to those who never or rarely consumed milk.

Increased consumption of calcium from fat-free milk, energy restricted diet, and educational activities improves metabolic control in overweight type 2 diabetic patients. de Assis Costa J, Gomes JMG, Ribeiro PVM, Gonçalves Alfenas RC. Br J Nutr. 2019 Dec 9:1-29.

  • The American Diabetes Association (ADA) emphasizes the role of dietary macronutrients in type 2 diabetes (T2DM) glycemic control, giving little prominence to micronutrients. However, among the micronutrients, calcium seems to favor T2DM prevention and treatment.
  • The researchers assessed the effects of increased calcium consumption from fat-free milk in an energy-restricted diet and educational activities in the metabolic control of overweight type 2 diabetic patients.
  • Fourteen subjects with T2DM and low habitual calcium consumption (<600 mg/d)] were included in this randomized, crossover clinical trial. Subjects were randomly allocated to one of two interventions: drink containing 700 mg of calcium (DAIR) or drink containing 0 mg of calcium (CONT) for 90 consecutive days each. Energy-restricted diets (- 500 kcal/day), containing 800 mg of calcium from dietary sources/day were prescribed for both groups.
  • The results showed that there was a higher reduction of body fat %, waist circumference, hip circumference, neck circumference, waist-to-hip ratio, sagittal abdominal diameter, diastolic / systolic blood pressure, and an increase in fat-free mass % in DAIR than in CONT.
  • Blood markers such as uric acid, fasting glucose, Hb1Ac, PTH, and ALT concentrations were reduced, and vitamin D concentration increased after 90 days in DAIR compared with CONT.
  • The consumption of energy-restricted diet containing 1200 mg calcium/day seems to favor metabolic control in subjects with T2DM.