Welcome to the Dairy Research Bulletin from June! 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

Preweaned heifer management on US dairy operations: Part V. Factors associated with morbidity and mortality in preweaned dairy heifer calves. Urie NJ, Lombard JE, Shivley CB, Kopral CA, Adams AE, Earleywine TJ, Olson JD, Garry FB. J Dairy Sci. 2018 Jun 20. pii: S0022-0302(18)30586-1.

  • The objective of this study was to evaluate morbidity and mortality in preweaned dairy heifer calves based on different health, feeding, and management practices, as well as environmental factors.
  • This study was conducted as part of the calf component of the National Animal Health Monitoring System’s Dairy 2014 study, which included 104 dairy operations in 13 states. The calf component was an 18-mo longitudinal study focused on dairy heifer calves from birth to weaning; data were collected on 2,545 calves.
  • The results showed that calves born at a higher birth weight had a lower risk of mortality and morbidity. An increase in serum IgG concentration decreased the risk of mortality and morbidity. The odds of mortality were 3.1 times higher in calves fed ≤0.15 kg of fat/d in the liquid diet compared with calves fed ≥0.22 kg of fat/d. The odds of mortality were 4.7 times higher in calves that experienced any disease throughout the preweaning period than in calves with no disease.
  • Calves housed in positive- or cross-ventilated systems had 2.2 times higher odds of developing disease compared with calves housed in natural ventilation systems. Average temperature-humidity index during the preweaning period was inversely correlated with morbidity; as temperature-humidity index increased, the predicted morbidity risk decreased.

Random mixtures of antimicrobial peptides inhibit bacteria associated with pasteurized bovine milk. Stern Bauer T, Hayouka Z. J Pept Sci. 2018 Jun 6:e3088.

  • The shelf life of pasteurized bovine milk is limited by microorganism activity as surviving bacteria continue to grow in the bovine milk, eventually causing milk spoilage.
  • In the current study, the researchers identified various pasteurized bovine milk-associated mesophilic and psychrotrophic bacteria.
  • The researchers designed random cationic peptide mixtures to add to milk products and packaging that possess strong antimicrobial and antibiofilm properties. These compounds are cheap and easy to synthesize and represent a new class of antimicrobial agents.
  • The study showed that adding random antimicrobial peptide mixtures to pasteurized milk were able to efficiently eradicate the bacteria in pasteurized bovine milk, and significantly reduce the growth of Bacillus subtilis. The researchers propose that these antimicrobial peptides could be used for integration in bioactive milk and food packaging to prevent bacterial growth and extend the shelf life of food.

Variations in methane yield and microbial community profiles in the rumen of dairy cows as they pass through stages of first lactation. Lyons T, Bielak A, Doyle E, Kuhla B. J Dairy Sci. 2018 Jun;101(6):5102-5114.

  • Considerable interest exists both from an environmental and economic perspective in reducing methane emissions from agriculture. In ruminants, CH4 is produced by a complex community of microorganisms that is established in early life but can be influenced by external factors such as feed. Although CH4 emissions were thought to be constant once an animal reached maturity, recent studies have shown that CH4 yield significantly increases from early to late lactation in dairy cows.
  • The aim of this study was to test the hypothesis that increases in CH4 yield over the lactation cycle are related to changes in rumen microbial community structure. Nine cows were monitored throughout their first lactation cycle. Methane and dry matter intake were measured to calculate CH4 per dry matter intake (CH4 yield) and ruminal fluid was collected during early, mid, and late lactation.
  • A significant difference in bacterial and archaeal community structure during early and late lactation was observed. Furthermore, when ruminal short-chain fatty acid concentrations were measured, the ratio of acetate and butyrate to propionate was significantly higher in late lactation compared with early lactation. Propionate concentrations were higher in cows with low CH4 yield during late lactation, but no differences were observed in bacterial or archaeal community structures.
  • In general, positive correlations were stronger between the most relatively abundant bacterial genera and acetate and butyrate concentrations in the cows with high CH4, and weaker between these genera and propionate concentration. This study indicates that increased CH4 yield in late lactation is reflected in significant changes in microbial community structure.

Housing, management characteristics, and factors associated with lameness, hock lesion, and hygiene of lactating dairy cattle on Upper Midwest United States dairy farms using automatic milking systems. Salfer JA, Siewert JM, Endres MI. J Dairy Sci. 2018 Jun 13.

  • The objectives of this cross-sectional study were to describe housing and management practices on farms using automatic milking systems in 2 states of the upper Midwest and to evaluate the association of various housing and management factors with 3 measures of animal welfare: prevalence of lameness, severe hock lesions, and dirty cows.
  • Fifty-four farms were visited once to collect facility measurements and observations, interview the dairy producer, and score cows for locomotion, hock lesions, and hygiene.
  • Number of cows fetched per automatic milking system, or manually brought to the automatic milking system if not milked voluntarily, was 4.7 ± 2.3 cows/automatic milking system per day (8% of cows) for free traffic flow farms and 3.3 ± 1.8 cows/automatic milking system per day (5% of cows) for guided traffic flow farms.
  • Cow resting surface was significantly associated with prevalence of lameness and severe lameness. Farms with sand-bedded freestalls (17.2%) and bedded packs (17.4%) had significantly lower lameness prevalence than farms with mattress freestalls (30.5%), waterbeds (25.0%), and mattresses with access to pasture (22.6%).
  • Manure removal system (manual, automatic, or slatted floor) was significantly associated with prevalence of severely dirty cows; farms with manual scraping had lower prevalence of severely dirty cows than farms where alley scraping was practiced automatically or slatted floors were used.
  • Dairy producers using automatic milking systems appeared to be successful with a variety of facility designs and management practices. Cow resting surface in automatic milking system herds was associated with some animal health and welfare measurements.

Milk production Life Cycle Assessment: A comparison between estimated and measured emission inventory for manure handling. Baldini C, Bava L, Zucali M, Guarino M. Sci Total Environ. 2018 Jun 1;625:209-219.

  • Measuring emissions from manure management operations (from the barns to the land) is a challenging task, subject to different uncertainties related to the spatial-temporal variability in the process leading to gaseous release.
  • At the same time, emissions inventory is a prerequisite of Life Cycle Assessment (LCA) studies. Manure management emissions are usually estimated using equations developed by Intergovernmental Panel on Climate Change (IPCC, in the case of greenhouse gases emissions) and European Environmental Agency (EEA) for Nitrogen-related emissions.
  • In the present study, the environmental impacts associated to three Italian dairy farms were calculated through a comparative LCA using two different approaches for complying the emission inventory. In the “estimated” approach the commonly adopted IPCC and EEA equations were used, while in the “measured” approach emissions actually measured were taken as input data to quantify the emissions associated to manure management.
  • The results showed that the IPCC equation underestimates the manure management emissions, leading to a 10-42% lower global warming potential comparing “estimated” to “measured” approach. On the other hand, ammonia related impact categories showed higher values if they were calculated using the estimated approach, underling that a safer level of estimation is maintained.

Relationship between climatic variables and the variation in bulk tank milk composition using canonical correlation analysis. Stürmer M, Busanello M, Velho JP, Heck VI, Haygert-Velho IMP. Int J Biometeorol. 2018 Jun 4.

  • Milk production and composition exhibit seasonal variation patterns depending on the availability of forage and feed resulting from temperature increases as well as other factors such as relative air humidity, solar radiation, wind speed, nutrition, and management practices.
  • In this study, the researchers used a multivariate approach to study the impact of climatic variables on milk composition, price, and monthly milk production at a dairy farm using bulk tank milk data. The data are from January 2014 to December 2016.
  • The study indicated that 10.2% of the variation in milk composition, pricing, and monthly milk production can be explained by climatic variables. Ambient temperature variables, together with temperature-humidity index, seem to have the most influence on variation in milk composition, especially on lactose content.

Differential effects of oilseed supplements on methane production and milk fatty acid concentrations in dairy cows. Kliem KE, Humphries DJ, Kirton P, Givens DI, Reynolds CK. Animal. 2018 Jun 19:1-9.

  • It is known that supplementing dairy cow diets with full-fat oilseeds can be used as a strategy to mitigate methane emissions, through their action on rumen fermentation. However, direct comparisons of the effect of different oil sources are very few, as are studies implementing supplementation levels that reflect what is commonly fed on commercial farms.
  • The objective was to investigate the effect of feeding different forms of supplemental plant oils on both methane emissions and milk fatty acid profile. Four multiparous, Holstein-Friesian cows in mid-lactation were randomly allocated to one of four treatment diets in with 28-day periods. Diets were fed as a total mixed ration with a 50:50 forage : concentrate ratio (dry matter basis) with the forage consisting of 75:25 maize silage : grass silage (dry matter).
  • Dietary treatments were a control diet containing no supplemental fat, and three treatment diets containing extruded linseed, calcium salts of palm and linseed oil, or milled rapeseed formulated to provide each cow with an estimated 500 g additional oil/day (22 g oil/kg diet dry matter).
  • There was no effect of treatment diet on dry matter intake or milk protein or lactose concentration, but oilseed-based supplements increased milk yield compared with the control diet and milk fat concentration relative to control was reduced by 4 g/kg by supplemental extruded linseed.
  • Feeding calcium salts of palm and linseed oil reduced methane production, and both linseed-based supplements decreased methane yield (by 1.8 l/kg dry matter intake) and intensity (by 2.7 l/kg milk yield) compared with the control diet, but feeding milled rapeseed had no effect on methane emission.
  • All the fat supplements decreased milk total saturated fatty acid concentration compared with the control, and saturated fatty acids were replaced with mainly cis-9 18:1 but also trans fatty acids.
  • Supplementing dairy cow diets with these oilseed-based preparations affected milk FA profile and increased milk yield. However, only the linseed-based supplements reduced methane production, yield or intensity, whereas feeding milled rapeseed had no effect.


Selected Articles on Dairy Intake and Human Health

The Consumption of Dairy and Its Association with Nutritional Status in the South East Asian Nutrition Surveys (SEANUTS). Nguyen Bao KL, Sandjaja S, Poh BK, Rojroongwasinkul N, Huu CN, Sumedi E, Aini JN, Senaprom S, Deurenberg P, Bragt M, Khouw I; SEANUTS Study Group.Nutrients. 2018 Jun 13;10(6). pii: E759.

  • Despite a major decrease in undernutrition worldwide over the last 25 years, underweight and stunting in children still persist as public health issues especially in Africa and Asia. Adequate nutrition is one of the key factors for healthy growth and development of children.
  • In this study, the associations between dairy consumption and nutritional status in the South East Asian Nutrition Survey (SEANUTS) were investigated. National representative data of 12,376 children in Indonesia, Malaysia, Thailand, and Vietnam aged between 1 and 12 years were pooled, representing nearly 88 million children in this age category.
  • It was found that the prevalence of stunting and underweight was lower in children who consumed dairy on a daily basis (10.0% and 12.0%, respectively) compared to children who did not use dairy (21.4% and 18.0%, respectively).
  • The prevalence of vitamin A deficiency and vitamin D insufficiency was lower in the group of dairy users (3.9% and 39.4%, respectively) compared to non-dairy consumers (7.5% and 53.8%, respectively).
  • This study suggests that dairy as part of a daily diet plays an important role in growth and supports a healthy vitamin A and vitamin D status.

The effect of daily fortified yogurt consumption on weight loss in adults with metabolic syndrome: A 10-week randomized controlled trial. Mohammadi-Sartang M, Bellissimo N, Totosy de Zepetnek JO, Brett NR, Mazloomi SM, Fararouie M, Bedeltavana A, Famouri M, Mazloom Z. Nutr Metab Cardiovasc Dis. 2018 Jun;28(6):565-574.

  • Obesity is a complex and multifaceted condition. Thus, functional foods need investigation as novel adjunct treatments for obesity.
  • The objective was to determine the effects of daily consumption of a fortified yogurt on weight loss in overweight and obese patients with metabolic syndrome on a caloric-restricted diet.
  • This was a randomized, double-blind, 10-week study. Participants were randomly allocated to two groups receiving either two servings (2 × 250 g)/day of fortified yogurt with whey protein, calcium, vitamin D, prebiotic fiber and probiotic cultures (n = 44), or a low-fat plain yogurt (n = 43). All participants were put on a calorie-restricted diet throughout the 10-week study.
  • Body mass decreased by 4.3 ± 1.9 kg in the plain yogurt group and by 5.1 ± 3.0 kg in the fortified yogurt group, following the 10-week intervention. Compared to plain yogurt, consumption of fortified yogurt resulted in a significant reduction in body fat mass, body fat percentage, waist circumference, insulin resistance, triglyceride concentration, and a significant increase in total vitamin D concentration, HDL cholesterol, and insulin sensitivity.
  • Consuming fortified yogurt for 10-weeks improved body composition and metabolic parameters, while on a caloric-restricted diet. Further research is needed to elucidate whether fortified yogurt can be used as a preventative strategy for metabolic syndrome in obese persons.

Daily Consumption of Synbiotic Yogurt Decreases Liver Steatosis in Patients with Nonalcoholic Fatty Liver Disease: A Randomized Controlled Clinical Trial. Bakhshimoghaddam F, Shateri K, Sina M, Hashemian M, Alizadeh M. J Nutr. 2018 Jun 20.

  • Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in developed and developing countries. The use of synbiotics (products which contain both prebiotics and probiotics) has been proposed as a probable management strategy for patients with NAFLD.
  • The researchers investigated the effects of synbiotic yogurt on hepatic steatosis and liver enzymes as primary outcomes and on oxidative stress markers, adipokine concentration, and gut peptide concentration as secondary outcomes in patients with NAFLD.
  • In this 24-week, randomized controlled clinical trial, 102 patients [50 men and 52 women; mean age: 40 years] were randomly assigned to 3 groups, including 2 intervention groups and 1 control group. The intervention groups consumed 300 g synbiotic yogurt containing 108 colony-forming units Bifidobacterium animalis/mL and 1.5 g inulin or conventional yogurt daily and were advised to follow a healthy lifestyle (i.e., diet and exercise). The control group was advised to follow a healthy lifestyle alone.
  • At the end of the study, the synbiotic yogurt group showed reduced NAFLD severity and improved liver enzyme concentrations compared with the conventional and control groups.

Comparing the Performance of Bread and Breakfast Cereals, Dairy, and Meat in Nutritionally Balanced and Sustainable Diets. Kramer GFH, Martinez EV, Espinoza-Orias ND, Cooper KA, Tyszler M, Blonk H. Front Nutr. 2018 Jun 7;5:51.

  • The objective of this study was to quantify the performance of food products in a sustainable diet based on the balance of their contribution to nutrient intake and environmental impact, within the context of the Dutch diet.
  • The study participants were women, aged 31-50 from The Netherlands. Bread & breakfast cereals, dairy, and meat were compared between 0 and 250% of current intake. Their performance is expressed in the relationship between the quantity of these food products and (1) the environmental impact of diets and (2) the nutrient balance of the diets.
  • The amount of bread & breakfast cereals in the optimized diets were inversely correlated with their environmental impact. The nutrient balance of the optimized diets was maintained despite varying cereal content, with the expected improvement over the current diet. Increasing amounts of dairy in the optimized diet were associated with an increase in environmental impact and meat with a steep increase. The nutrient balance of optimized diets with varying dairy and meat contents was also maintained at high levels, even at 0% content.
  • The researchers concluded that bread and breakfast cereals are sources of nutrients with a better environmental performance compared to dairy or meat within the context of the Dutch diet.