Welcome to the February 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

Greenhouse gas, water, and land footprint per unit of production of the California dairy industry over 50 years. Naranjo A, Johnson A, Rossow H, Kebreab E. J Dairy Sci. 2020 Feb 6. pii: S0022-0302(20)30074-6. CDRF FUNDED RESEARCH

  • Food production including dairy has been associated with environmental impacts and resource use that has been steadily improving when adjusted per unit of product.
  • The objective of this study was to conduct a cradle-to-farm gate environmental impact analysis and resource inventory of the California dairy production system to estimate the change in greenhouse gas emissions and water and land use over the 50-yr period between 1964 and 2014.
  • Using a life cycle assessment according to international standards and the Food and Agriculture Organization of the United Nations guidelines, the researchers analyzed contributions from dairy production in California to global environmental change.
  • Production of 1 kg of energy- and protein-corrected milk (ECM) in California emitted 1.12 to 1.16 kg of CO2equivalents (CO2e) in 2014 compared with 2.11 kg of CO2e in 1964, a reduction of 45.0 to 46.9% over the last 50 years, depending on the model used. Greater reductions in enteric methane intensity (i.e., methane production per kilogram of ECM) were observed (reduction of 54.1 to 55.7%) compared with manure GHG (reduction of 8.73 to 11.9%) in 2014 compared with 1964. This was mainly because manure management in the state relies on lagoons for storage, which has a greater methane conversion factor than solid manure storage.
  • Water use intensity was reduced by 88.1 to 89.9%, with water reductions of 88.7 to 90.5% in crop production, 55.3 to 59.2% in housing and milking, and 52.4 to 54% in free water intake. Improved crop genetics and management have contributed to large efficiencies in water utilization. Land requirements for crop production were reduced by 89.4 to 89.7% in 2014 compared with 1964. This was mainly due to dramatic increases in crop yields in the last 50 yr.
  • The increases in milk production per cow through genetic improvements and better nutrition and animal care have contributed to reductions in greenhouse gas emissions and land and water usage when calculated per unit of production (intensity) basis.

Precision feed restriction improves feed and milk efficiencies and reduces methane emissions of less efficient lactating Holstein cows without impairing their performance. Fischer A, Edouard N, Faverdin P. J Dairy Sci. 2020 Feb 26. pii: S0022-0302(20)30159-4.

  • A possible driver of feed inefficiency in dairy cows is overconsumption.
  • The objective was therefore to test precision feed restriction as a lever to improve feed efficiency of the least efficient lactating dairy cows.
  • An initial cohort of 68 Holstein lactating cows was monitored from calving to end of ad libitum feeding at 196 ± 16 days in milk, with the last 70 days being used to estimate feed efficiency. Feed restriction lasted during 92 days, with only the last 70 days being used for data analyses. A single diet was fed during ad libitum and restriction periods, and was based on 64.9% of corn silage and 35.1% of concentrates on a DM basis.
  • The 15 least efficient cows ate 2.6 kg of DM/d more than the 15 most efficient cows during ad libitum feeding with 2 g/kg of DMI lower methane yield, but similar daily methane emissions. Feed restriction decreased DMI by 2.6 kg of DMI/d for the least efficient cows, which was 1.8 kg of DMI/d more than the most efficient cows, and decreased daily methane emissions by 49.2 g/d for the least efficient cows, which was 22.4 g/d more than the most efficient cows.
  • Feed restriction had no significant effect on milk, body weight, or body weight change. Despite narrow efficiency differences, the most efficient cows during ad libitum feeding remained more efficient during feed restriction. The 2 efficiency groups no longer differed in feed efficiency during precision feed restriction.
  • Precision feed restriction seemed to bring the least efficient cows closer to the most efficient cows and to reduce their methane emissions without impairing their performance.

Looking for high-production and sustainable diets for lactating cows: A survey in Italy. Gislon G, Bava L, Colombini S, Zucali M, Crovetto GM, Sandrucci A. J Dairy Sci. 2020 Feb 26. pii: S0022-0302(20)30142-9.

  • The aim of the present study was to evaluate, through a survey conducted on commercial farms, the global warming potential (GWP) of different lactating cow total mixed rations (TMR) and to identify the best dietary strategies to increase feed efficiency (FE) and reduce enteric CH4
  • A total of 171 dairy herds were selected: data about dry matter intake (DMI), lactating cow TMR composition, and milk production and composition were provided by farmers.
  • The frequency distribution showed wide variation among farms for GWP (kg of CO2eq) of TMR: approximately 25% of the surveyed farms showed a diet GWP of 15 kg of CO2eq, 20% showed a GWP of 13 kg of CO2eq, and 16.7% showed a GWP of 17 kg of CO2 The variation among farms was due to the feedstuffs used.
  • Among feedstuffs, soybean meal (SBM) had the highest correlation with the GWP of the TMR. Moreover, diets with inclusion of SBM >15% of dry matter (DM) did not result in higher milk production than diets with a lower inclusion of SBM (≤15%).
  • Average daily milk production of cows was 29.8 kg with fat and protein contents of 3.86% and 3.40%, respectively. The average DMI (kg/d) of lactating cows was 22.3.
  • The results demonstrated that lower enteric CH4production was related to inclusion (% of diet DM) of ≤12% alfalfa hay and >30% corn silage. Diets with >34% neutral detergent fiber had higher CH4 production (>14.0 g/kg of fat- and protein-corrected milk) than those with lower neutral detergent fiber content. In contrast, lower enteric CH4 production (≤14.0 g/kg of fat- and protein-corrected milk) was related to diets characterized by net energy of lactation (NEL) >1.61 Mcal/kg and >4% ether extract.
  • The variability in TMR GWP shows significant potential for reducing the GWP of a diet through choice and inclusion levels of ingredients (mainly SBM) and the possibility of decreasing methane enteric emission associated with milk production on a commercial scale.

Agriculture, dairy and fishery farming practices and greenhouse gas emission footprint: a strategic appraisal for mitigation. Ghosh A, Misra S, Bhattacharyya R, Sarkar A, Singh AK, Tyagi VC, Kumar RV, Meena VS. Environ Sci Pollut Res Int. 2020 Feb 14

  • Rising global population would force farmers to amplify food production substantially in upcoming 3-4 decades. The easiest way to increase grain production is through expanding cropping area by clearing uncultivated land. This is attained by permitting deadly loss of carbon stocks, jeopardizing ecosystem biodiversity and deteriorating environmental quality.
  • The researchers aim to propose key agronomical tactics, livestock management strategy and advance approaches for aquaculture to increase productivity and simultaneously reduce the environmental impacts of farming sector.
  • For this, the researchers considered three major sectors of farming, i.e. agriculture, fishery and dairy. They collected literatures stating approaches or technologies that could reduce GHG emission from these sectors. Thereafter, they synthesized strategies or options that are more feasible and accessible for inclusion in farm sector to reduce GHG emission.
  • Agronomic practices like crop diversification, reducing summer fallow, soil organic carbon sequestration, tillage and crop residue management and inclusion of N2-fixing pulses in crop rotations are some of those.
  • Livestock management through changing animals’ diets, optimal use of the gas produced from manures, frequent and complete manure removal from animal housing and aquaculture management strategies to improve fish health and improve feed conversion efficiency could reduce their GHG emission footprint too.
  • Adapting of effective and economic practices GHG emission footprint reduction potential of farming sector could make farming sector a carbon neutral enterprise. To overcome the ecological, technological and institutional barriers, policy on trade, tax, grazing practice and GHG pricing should be implemented properly.

Annual rhythms of milk synthesis in dairy herds in 4 regions of the United States and their relationships to environmental indicators. Salfer IJ, Bartell PA, Dechow CD, Harvatine KJ. J Dairy Sci. 2020 Feb 11. pii: S0022-0302(20)30108-9.

  • The annual rhythms of milk and milk component yields are not well described and are important to dairy management. Recent analysis of federal milk marketing orders in the United States observed that the amplitude and time at peak (acrophase) of the rhythms of milk fat and protein concentration differ among regions, but the rhythms of milk and milk component yields are not well described.
  • The objective was to determine the annual rhythms of milk and milk component production from 4 US regions at the herd level and examine potential environmental factors entraining these rhythms.
  • Monthly Dairy Herd Improvement Association records of all available herds in Pennsylvania (PA), Minnesota (MN), Texas (TX), and Florida (FL) from the years 2003 to 2016 were obtained from Dairy Records Managements Systems.
  • Milk yield and fat and protein yields and concentrations fit a cosine function in all 4 states, indicating an annual rhythm. The amplitude (peak to mean) of the rhythm of milk yield varied by state and was lower in PA (1.2 kg) and MN (1.2 kg) compared with TX (3.1 kg) and FL (3.3 kg). The acrophases of milk yield and milk fat and protein yields and concentrations also varied by state, but all peaked between October and March.
  • The yearly pattern of milk yield closely followed the fixed yearly pattern of the day to day changes in day length, whereas the rhythms of milk fat and protein concentrations followed the yearly pattern of absolute day length.
  • The results suggest that the region of the United States in which a herd is located affects their annual rhythms of production, with a greater yearly variation in milk, fat, and protein yields occurring in the southern United States.

Socio-ecological Factors of Zoonotic Diseases Exposure in Colorado Dairy Workers. Palomares Velosa JE, Salman MD, Roman-Muniz IN, Reynolds S, Linke L, Magnuson R, McConnel CS, Rao S. J Agromedicine. 2020 Feb 13:1-11.

  • Zoonotic pathogens on dairy farms are a known risk for people who work and live there. Exposure and/or transmission of Salmonellaserovars,  coli (O157; H7), Campylobacter jejuni, and Cryptosporidium parvum have been documented to occur in the dairy farm environment. Social ecological factors have been identified as determinants of preventive behaviors of people at risk of infectious diseases.
  • This study described the effect of socio-ecological factors on selected zoonotic bacterial and protozoal diseases in 42 workers of two dairy farms.
  • Occupational exposure to Salmonella Dublin, E. coli, and Campylobacter spp. was confirmed. Self-efficacy and negative workplace perceptions were risk factors for SalmonellaDublin exposure (OR = 1.43 & 1.22, respectively). Additionally, safety knowledge and risk perceptions were protective factors of exposure (OR = 0.90).
  • Positive perceptions of supervisors and coworkers was a protective factor of Campylobacterexposure (OR = 0.89).
  • Results indicated that the presence of a supporting organizational environment, good communication with supervisors and coworkers, and training on prevention of zoonotic diseases would potentially reduce occupational exposures to zoonotic diseases on these farms.


Selected Articles on Dairy Intake and Human Health

A Randomized Study of the Effect of Replacing Sugar-Sweetened Soda by Reduced Fat Milk on Cardiometabolic Health in Male Adolescent Soda Drinkers. Chiu S, Siri-Tarino P, Bergeron N, Suh JH, Krauss RM. Nutrients. 2020 Feb 4;12(2). pii: E405.

  • Soda consumption in adolescents has been linked to poorer metabolic outcomes.
  • The researchers tested whether replacing soda with reduced fat milk would improve features of atherogenic dyslipidemia and other cardiometabolic risk factors.
  • Thirty overweight and obese adolescent boys who were habitual consumers of sugar-sweetened beverages were randomly assigned to consume 24 oz/day of sugar-sweetened soda or an energy equivalent of reduced fat (2%) milk for 3 weeks with crossover to the alternate beverage after a ≥ 2 weeks washout.
  • Lipid and lipoprotein measurements, C-reactive protein, and serum transaminases did not differ significantly between the soda and milk phases of the study.
  • Systolic blood pressure z-score and uric acid concentration were significantly lower after consuming milk compared to soda. Milk consumption also significantly decreased plasma glucosyl ceramide (d18:1/C16:0) and lactosylceramides (d18:1/C16:0 and d18:1/C18:0).
  • While no effects of replacing soda with milk on lipid and lipoprotein measurements were observed in these normolipidemic weight-stable adolescent boys, decreases in systolic blood pressure, uric acid, and glycosphingolipids suggest that an overall favorable effect on cardiometabolic risk can be achieved following a short-term dietary intervention.

Contribution of Milk Beverages to Nutrient Adequacy of Young Children and Preschool Children in the Philippines.Mak TN, Angeles-Agdeppa I, Tassy M, Capanzana MV, Offord EA. Nutrients. 2020 Feb 1;12(2). pii: E392.

  • Malnutrition is a major public health concern in the Philippines. Milk and dairy products are important sources of energy, protein, and micronutrients for normal growth and development in children.
  • This study aims to assess the contribution of different types of milk to nutrient intakes and nutrient adequacy among young and preschool children in the Philippines.
  • Filipino children aged one to four years (n= 2992) were analyzed while using dietary intake data from the 8th National Nutrition Survey 2013. Children were stratified by age and by milk beverage consumption type: young children milk (YCM) and preschool children milk (PCM), other milks (mostly powdered milk with different degrees of fortification of micronutrients), and non-dairy consumers (no milks or dairy products).
  • Half (51%) of Filipino children (all ages) did not consume any dairy on a given day, 15% consumed YCM or PCM, and 34% consumed other milks.
  • Among children one to two years, those who consumed YCM had higher mean intakes of iron, magnesium, potassium, zinc, B vitamins, folate, and vitamins C, D, and E (all p< 0.001) when compared to other milk consumers.
  • Non-dairy consumers had mean intakes of energy, total fat, fibre, calcium, phosphorus, iron, potassium, zinc, folate, and vitamins D and E that were far below the recommendations.
  • Children who consumed YCM or PCM had the highest odds in meeting adequacy of iron, zinc, thiamin, vitamin B6, folate, and vitamins C, D, and E as compared to other milks or non-dairy consumers.
  • This study supports the hypothesis that dairy consumers had higher intakes of micronutrients and higher nutrient adequacy than children who consumed no milk or dairy products. Secondly, YCM or PCM have demonstrated to be good dairy options to achieve nutrient adequacy in Filipino children.

The associations of major foods and fiber with risks of ischemic and hemorrhagic stroke: a prospective study of 418 329 participants in the EPIC cohort across nine European countries. Tong TYN, Appleby PN, Key TJ, Perez-Cornago A. Eur Heart J. 2020 Feb 24. pii: ehaa007.

  • The aim of this study was to investigate the associations between major foods and dietary fiber with subtypes of stroke in a large prospective cohort.
  • The researchers analyzed data on 418,329 men and women from nine European countries, with an average of 12.7 years of follow-up.
  • For ischemic stroke (4,281 cases), lower risks were observed with higher consumption of fruit and vegetables combined (per 200 g/day), dietary fiber (per 10 g/day), milk (per 200 g/day), yogurt (per 100 g/day), and cheese (per 30 g/day), while higher risk was observed with higher red meat consumption (per 50 g/day).
  • For hemorrhagic stroke (1,430 cases), higher risk was associated with higher egg consumption (per 20 g/day).
  • Risk of ischemic stroke was inversely associated with consumption of fruit and vegetables, dietary fiber, and dairy foods, while risk of hemorrhagic stroke was positively associated with egg consumption.
  • The apparent differences in the associations highlight the importance of examining ischemic and hemorrhagic stroke subtypes separately.

Associations between the Intake of Different Types of Dairy and Cognitive Performance in Dutch Older Adults: The B-PROOF Study. de Goeij LC, van de Rest O, Feskens EJM, de Groot LCPGM, Brouwer-Brolsma EM. Nutrients. 2020 Feb 13;12(2). pii: E468

  • Various dairy nutrients have been associated with cognitive performance. Several observational studies have explored associations between the intake of total dairy or some dairy subgroups and cognitive performance. However, studies on the potential impact of a broad variety of dairy subclasses are scarce.
  • Researchers examined the cross-sectional associations between a wide assortment of dairy products and cognitive performance.
  • A total of 619 Dutch community-dwelling adults aged ≥65 years completed a semi-quantitative Food Frequency Questionnaire.
  • After full adjustment, higher skimmed dairy, fermented dairy, and buttermilk consumption were associated with better executive functioning. Logistic regression analyses indicated that a 30 gram increase in Dutch cheese intake was associated with a 33% lower probability of poor information processing speed.
  • No associations were observed between dairy consumption and attention and working memory or episodic memory.

Effect of a low energy diet, containing a high protein, probiotic condensed yogurt, on biochemical and anthropometric measurements among women with overweight/obesity: A randomised controlled trial. Razmpoosh E, Zare S, Fallahzadeh H, Safi S, Nadjarzadeh A. Clin Nutr ESPEN. 2020 Feb;35:194-200.

  • The aim of this study was to determine the effect of low energy diet containing condensed processed yogurt (Kashk), as a high protein, calcium and probiotic enriched product, on glycemic control, lipid profile, anthropometric measurements and blood pressure among women with overweight/obesity.
  • 70 women with overweight/obesity were randomly assigned to receive either a low energy diet contained 50 g of Kashk (intervention group) or a low energy diet without Kashk (control group) for 8 weeks.
  • Between-group comparisons showed that the intervention group significantly decreased triglycerides and LDL cholesterol levels relative to the control group. Significantly greater reductions in body mass index, fat percent and waist circumference were observed in the intervention group compared to control.
  • Within-group comparisons revealed significant reductions in systolic blood pressure and weight in the intervention group.
  • Long-term consumption of Kashk, as a high protein and calcium product enriched with probiotic that is accompanied by a low energy diet, might have beneficial effects on anthropometric and biochemical indices, though more cross-over and parallel blinded trials with placebo groups are needed to confirm these results.

Dairy structures and physiological responses: a matter of gastric digestion. Mulet-Cabero AI, Mackie AR, Brodkorb A, Wilde PJ. Crit Rev Food Sci Nutr. 2020 Feb 14:1-16.

  • Digestion and health properties of food do not solely rely on the sum of nutrients but are also influenced by food structure. Dairy products present an array of structures due to differences in the origin of milk components and the changes induced by processing.
  • Some dairy structures have been observed to induce specific effects on digestion rates and physiological responses. However, the underlying mechanisms are not fully understood. Gastric digestion plays a key role in controlling digestion kinetics.
  • The main objective of this review is to expose the relevance of gastric phase as the link between dairy structures and physiological responses. The focus is on human and animal studies, and physiological relevant in vitrodigestion models.
  • Data collected showed that the structure of dairy products have a profound impact on rate of nutrient bioavailability, absorption and physiological responses, suggesting gastric digestion as the main driver.
  • Control of gastric digestion can be a tool for delivering specific rates of nutrient digestion. Therefore, the design of food structure targeting specific gastric behavior could be of great interest for particular population needs e.g. rapid nutrient digestion will benefit elderly, and slow nutrient digestion could help to enhance satiety.