Dairy Research Bulletin: Selected Articles from May 2023 - California Dairy Research Foundation

Environmental Management and Sustainability

Abiotic and Biotic Drivers of Soil Fungal Communities in Response to Dairy Manure Amendment. Schlatter DC, Gamble JD, Castle S, Rogers J, Wilson M. Appl Environ Microbiol. 2023 May 22:e0193122.

Modern agriculture often relies on large inputs of synthetic fertilizers to maximize crop yield potential, yet their intensive use has led to nutrient losses and impaired soil health. Alternatively, manure amendments provide plant available nutrients, build organic carbon, and enhance soil health.
Manure amendments in agricultural systems can impact soil microbial communities via supplying growth substrates for indigenous microbes or by introducing manure-borne taxa. However, scientists lack a clear understanding of how consistently manure impacts fungal communities, the mechanisms via which manure impacts soil fungi, and the fate of manure-borne fungi in soils.
Researchers assembled soil microcosms using five soils to investigate how manure amendments impact fungal communities over a 60-day incubation. Further, they used autoclaving treatments of soils and manure to determine if observed changes in soil fungal communities were due to abiotic or biotic properties, and if indigenous soil communities constrained colonization of manure-borne fungi.
The researchers found that manure amended soil fungal communities diverged from nonamended communities over time, often in concert with a reduction in diversity. Fungal communities responded to live and autoclaved manure in a similar manner, suggesting that abiotic forces are primarily responsible for the observed dynamics.
Finally, manure-borne fungi declined quickly in both live and autoclaved soil, indicating that the soil environment is unsuitable for their survival.

Key nitrogen and phosphorus performance indicators derived from farm-gate mass balances on dairies. Ros MBH, Godber OF, Olivo AJ, Reed KF, Ketterings QM. J Dairy Sci. 2023 May;106(5):3268-3286.

Efficient management of N and P on dairy farms is critical for farm profitability and environmental stewardship. Annual farm-gate nutrient mass balance (NMB) assessments can be used to determine the nutrient-use efficiency of farms, set efficiency targets, and monitor the effect of management changes with minimal inputs required.
In New York, feasible N and P balances have been developed as benchmarks for dairy farm NMB, alongside key performance indicators (KPI) that serve as predictors for high NMB. Here, 3 years of NMB data from 47 farms were used to evaluate the main drivers of N and P balances and identify additional KPI.
From the 141 farm records, 26% met both the feasible N balances per hectare and per megagram of milk produced. For P, 53% of the records met both benchmarks. Imports, rather than exports, drove NMB primarily by feed and fertilizer purchases, consistent with earlier findings. Linear regression analysis showed that a selection of KPI currently used, particularly animal density, nutrient-use efficiency, and the amount of home-grown feed, explained a large portion of variation in NMB.
Heifer-to-cow ratio and the relative proportion of various forage crops may provide further insight into the drivers of feed and fertilizer imports and ultimately farm-gate NMB. This study provides avenues toward a better assessment of whole-farm nutrient management and means for farms to communicate progress to stakeholders and consumers.

Modeling the effects of heat stress in animal performance and enteric methane emissions in lactating dairy cows. Souza VC, Moraes LE, Baumgard LH, Santos JEP, Mueller ND, Rhoads RP, Kebreab E. J Dairy Sci. 2023 May 22:S0022-0302(23)00268-0.

Heat stress (HS) negatively affects dry matter intake (DMI), milk yield (MY), feed efficiency (FE), and free water intake (FWI) in dairy cows, with detrimental consequences to animal welfare, health, and profitability of dairy farms. Absolute enteric methane (CH₄) emission, yield (CH₄/DMI), and intensity (CH₄/MY) may also be affected.
Therefore, the goal of this study was to model the changes in dairy cow productivity, water intake, and absolute CH₄emissions, yield, and intensity with the progression (days of exposure) of a cyclical HS period in lactating dairy cows.
Heat stress was induced by increasing the average temperature by 15°C (from 19°C in the thermoneutral period to 34°C) while keeping relative humidity constant at 20% (temperature-humidity index peaks of approximately 83) in climate-controlled chambers for up to 20 days.

A database composed of individual records (n = 1,675) of DMI and MY from 82 heat-stressed lactating dairy cows housed in environmental chambers from 6 studies was used.

Dry matter intake and absolute CH₄emissions and yield reduced with the progression of HS up to 9 days, when it started to increase again up to 20 days. Milk yield and FE reduced with the progression of HS up to 20 days.
Methane intensity also reduced initially up to day 5 during HS exposure but then started to increase again following the DMI and MY pattern up to day 20. However, the reductions in CH₄emissions (absolute, yield, and intensity) occurred at the expense of decreases in DMI, MY, and FE, which are not desirable.
This study provides quantitative predictions of the changes in animal performance (DMI, MY, FE, FWI) and CH₄emissions (absolute, yield, and intensity) with the progression of HS in lactating dairy cows. The models developed in this study could be used as a tool to help dairy nutritionists to decide when and how to adopt strategies to mitigate the negative effects of HS on animal health and performance and related environmental costs.
Thus, more precise and accurate on-farm management decisions could be taken with the use of these models. However, application of the developed models outside of the ranges of temperature-humidity index and period of HS exposure included in this study is not recommended.

Quantifying methane emissions under field conditions under 2 different dairy production scenarios: Low-input versus high-input milk production. Zanon T, Fichter G, Mittermair P, Nocker L, Gauly M, Peratoner G. J Dairy Sci. 2023 May 10:S0022-0302(23)00232-1.

Livestock production systems with ruminants play a relevant role in the emission of the greenhouse gas CH₄, which is known to significantly contribute to global warming. Consequently, it is a major societal concern to develop strategies in mitigating such emissions.
In addition to breeding toward low-emitting cows, management strategies could also help in reducing greenhouse gas emissions from dairy farms. However, information is required for appropriate decision making.
This is the first study that considers different, already available equations to estimate CH₄emissions of small-scale dairy farms in the mountain region, which largely differ from large dairy farms in the lowlands concerning management and production.
For this study, 2 different production systems, both typical for small-scale dairy farming in mountain regions, were simultaneously run over 3 year at an experimental farm as follows:
1. A high-input production system, characterized by intensive feeding with high amounts of external concentrates and maize silage, year-round housing, and high yielding Simmental cattle breed.
2. A low-input production system, characterized by prevailing hay and pasture feeding and silage ban, thus covering most of the energy requirements by forage harvested on-farm and the use of the local Tyrolean Grey cattle breed.
Results reveal that feeding management has a significant effect on the amount of CH₄ The low-input production system produced less CH₄per cow and per day compared with the high-input production system. However, if calculated per kilogram of milk, the high-input scenario produced proportionally less CH₄ than the low-input one.
Findings of this study highlight the potential to assess in a fast and cost-effective way the CH₄emission in different dairy production systems. This information contributes to the debate about the future of sustainable milk production in mountain regions, where the production of feed resources is climatically constrained, and could be useful for breeding purposes toward lower CH₄-emissions.

Potential of Seaweeds to Mitigate Production of Greenhouse Gases during Production of Ruminant Proteins. De Bhowmick G, Hayes M. Glob Chall. 2023 Apr 8;7(5):2200145.

The potential of seaweed to mitigate methane is real and studies with red seaweeds have found reductions in methane produced from ruminants fed red seaweeds in the region of 60-90% where the active compound responsible for this is bromoform. Other studies with brown and green seaweeds have observed reductions in methane production of between 20 and 45% in vitro and 10% in vivo.
Benefits of feeding seaweeds to ruminants are seaweed specific and animal species-dependent. In some instances, positive effects on milk production and performance are observed where selected seaweeds are fed to ruminants while other studies note reductions in performance traits. A balance between reducing methane and maintaining animal health and food quality is necessary.
Seaweeds are a source of essential amino acids and minerals however, and offer huge potential for use as feeds for animal health maintenance once formulations and doses are correctly prepared and administered.
A negative aspect of seaweed use for animal feed currently is the cost associated with wild harvest and indeed aquaculture production and improvements must be made here if seaweed ingredients are to be used as a solution to control methane production from ruminants for continued production of animal/ruminant sourced proteins in the future.
This review collates information concerning different seaweeds and how they and their constituents can reduce methane from ruminants and ensure sustainable production of ruminant proteins in an environmentally beneficial manner.

Evaluation of 3 northwest European seaweed species on enteric methane production and lactational performance of Holstein-Friesian dairy cows. Muizelaar W, van Duinkerken G, Khan Z, Dijkstra J. J Dairy Sci. 2023 May 22:S0022-0302(23)00270-9.

Seaweeds have been studied for their ability to reduce enteric methane emissions of ruminants when fed as a feed supplement. In vivo research with dairy cattle is mainly limited to the seaweed species Ascophyllum nodosum and Asparagopsis taxiformis, whereas in vitro gas production research covers a broader range of brown, red, and green seaweed species from different regions.
The objective of the present study was to determine the effect of Chondrus crispus (Rhodophyta), Saccharina latissima (Phaeophyta), and Fucus serratus (Phaeophyta), 3 common northwest European seaweeds, on enteric methane production and lactational performance of dairy cattle.
Sixty-four Holstein-Friesian dairy cattle (16 primiparous, 48 multiparous) averaging 91 ± 22.6 days in milk and 35.4 ± 8.13 kg/d fat- and protein-corrected milk yield (FPCM) were randomly assigned to 1 of 4 treatments in a randomized complete block design. Cows were fed a partial mixed ration [54.2% grass silage, 20.8% corn silage, and 25.0% concentrate; dry matter (DM) basis] with additional concentrate bait in the milking parlor and the GreenFeed system (C-Lock Inc.). The 4 treatments consisted of a control diet without seaweed supplement (CON), or CON supplemented with 150 g/d (fresh weight of dried seaweed) of either C. crispus (CC), S. latissima (SL), or a 50/50 mix (DM basis) of F. serratus and S. latissima.
Milk yield (28.7 vs. 27.5 kg/d, respectively), fat- and protein-corrected milk (FPCM) yield (31.4 vs. 30.2 kg/d, respectively), milk lactose content (4.57 vs. 4.52%, respectively), and lactose yield (1,308 vs. 1,246 g/d, respectively) increased for SL compared with CON.
Milk protein content was lower for SL compared with the other treatments. Milk fat and protein contents; yields of fat, protein, lactose, and FPCM; feed efficiency; milk nitrogen efficiency; and somatic cell count did not differ between CON and the other treatments.
No effects were observed of the treatments compared with CON for DM intake, number of visits to the GreenFeed, or gas emission (production, yield, or intensity) of CO₂, CH₄, and H₂.
In conclusion, the seaweeds evaluated did not decrease enteric CH₄emissions and did not negatively affect feed intake and lactational performance of dairy cattle. Milk yield, FPCM yield, milk lactose content, and lactose yield increased, and milk protein content decreased, with S. latissima.

Effect of a garlic and citrus extract supplement on performance, rumen fermentation, methane production, and rumen microbiome of dairy cows. Khurana R, Brand T, Tapio I, Bayat AR. J Dairy Sci. 2023 May 22:S0022-0302(23)00273-4.

The aim of this trial was to determine the effect of a garlic and citrus extract supplement (GCE) on the performance, rumen fermentation, methane emissions, and rumen microbiome of dairy cows.
Fourteen multiparous Nordic Red cows in mid-lactation from the research herd of Luke (Jokioinen, Finland) were allocated to 7 blocks in a complete randomized block design based on body weight, days in milk, dry matter intake (DMI), and milk yield.
Animals within each block were randomly allocated to a diet with or without GCE. The experimental period for each block of cows (one for each of the control and GCE groups) consisted of 14 days of adaptation followed by 4 day of methane measurements inside the open circuit respiration chambers, with the first day being considered as acclimatization.
Methane production (g/day) and methane intensity (g/kg of energy-corrected milk) were lower by 10.3 and 11.7%, respectively, and methane yield (g/kg of DMI) tended to be lower by 9.7% in cows fed GCE compared with the control.
Dry matter intake, milk production, and milk composition were similar between treatments. Rumen pH and total volatile fatty acid concentrations in rumen fluid were similar, whereas GCE tended to increase molar propionate concentration and decrease the molar ratio of acetate to propionate.
Supplementation with GCE resulted in greater abundance of Succinivibrionaceae, which was associated with reduced methane. The relative abundance of the strict anaerobic Methanobrevibacter genus was reduced by GCE. The change in microbial community and rumen propionate proportion may explain the decrease in enteric methane emissions.
In conclusion, feeding GCE to dairy cows for 18 d modified rumen fermentation and microbiota, leading to reduced methane production and intensity without compromising DMI or milk production in dairy cows. This could be an effective strategy for enteric methane mitigation of dairy cows.

Animal Health and Food Safety

Impact of Selective Dry Cow Therapy on Antimicrobial Consumption, Udder Health, Milk Yield, and Culling Hazard in Commercial Dairy Herds. Lipkens Z, Piepers S, De Vliegher S. Antibiotics (Basel). 2023 May 12;12(5):901.

The intramammary application of long-acting antibiotics to all cows at dry-off (i.e., blanket dry cow therapy (BDCT)) is one of the main contributors to antimicrobial consumption in dairy cows. In the dairy sector, selective dry cow therapy (SDCT), i.e., only administering antimicrobials to cows when they are likely infected at drying off, is one of the recommended strategies to meet the justified public demands.
The main objective of the study was to evaluate whether or not implementing SDCT on commercial dairy farms reduces antimicrobial consumption without negatively affecting future performances when compared to blanket dry cow therapy BDCT.
Twelve commercial herds in the Flemish region of Belgium with overall good udder health management were enrolled in a randomized control trial, including 466 cows that were assigned to a BDCT (n= 244) or SDCT (n = 222) group within herds.
Cows in the SDCT group were dried off with internal teat sealants combined or not with long-acting antimicrobials according to a predefined algorithm based on test-day somatic cell count (SCC) data.
Total antimicrobial use for udder health between drying off and 100 days in milk was significantly lower in the SDCT group (i.e., a mean of 1.06 defined the course dose) compared to the BDCT group (i.e., a mean of 1.25 defined the course dose), although with substantial variation between herds. Test-day SCC values, milk yield, and the clinical mastitis and culling hazard in the first 100 days in milk did not differ between the BDCT and SDCT groups.
SCC-based and algorithm-guided SDCT is suggested to decrease the overall use of antimicrobials without jeopardizing cows’ udder health and milk yield.

Mitochondrial response to heat stress and its implications on dairy cattle bioenergetics, metabolism, and production. Marquez-Acevedo AS, Hood WR, Collier RJ, Skibiel AL. J Dairy Sci. 2023 May 18:S0022-0302(23)00261-8.

The dairy industry depends upon the cow’s successful lactation for economic profitability. Heat stress compromises the economic sustainability of the dairy industry by reducing milk production and increasing the risk of metabolic and pathogenic disease.
Heat stress alters metabolic adaptations, such as nutrient mobilization and partitioning, that support the energetic demands of lactation. Metabolically inflexible cows are unable to enlist the necessary homeorhetic shifts that provide the needed nutrients and energy for milk synthesis, thereby impairing lactation performance.
Mitochondria provide the energetic foundation that enable a myriad of metabolically demanding processes, such as lactation. Changes in an animal’s energy requirements are met at the cellular level through alterations in mitochondrial density and bioenergetic capacity. Mitochondria also act as central stress modulators and coordinate tissues’ energetic responses to stress by integrating endocrine signals, through mito-nuclear communication, into the cellular stress response.
In vitro heat insults affect mitochondria through a compromise in mitochondrial integrity, which is linked to a decrease in mitochondrial function. However, limited evidence exists linking the in vivo metabolic effects of heat stress with parameters of mitochondrial behavior and function in lactating animals.
This review summarizes the literature describing the cellular and sub-cellular effects of heat stress, with a focus on the impact of heat stress on mitochondrial bioenergetics and cellular dysfunction in livestock. Implications for lactation performance and metabolic health are also discussed.

Serum Mineral Levels in Dairy Cows Transiting from Feedlot to Pasture. Sizova EA, Miroshnikov SA, Notova SV, Tinkov AA, Skalny AV. Biol Trace Elem Res. 2023 May 15.

Balanced nutrition that includes adequate supply of protein, energy, vitamins, and minerals is one of the pillars of achieving optimal health in dairy operations.
The objective of the present study was to evaluate trace element and minerals levels in the serum of cows transiting from diets consumed in feedlot or under grazing.
A total of 30 healthy 5-6 years old cows of the Red Steppe breed were involved in the study. Blood samples were collected at the end of the feedlot period (end of April) and during the pasture period (end of June).
The obtained data demonstrate that serum K levels in cows during the feedlot period exceeded those in the pasture period by 50%, whereas serum P values in the pasture period were significantly higher than in the feedlot period by 20%.
Serum Li levels in cows during the feedlot feeding period were nearly 3-fold higher than the respective values in a pasture period. In addition, serum B, Sr, and Zn concentrations in cows during a pasture period exceeded those observed upon feedlot feeding by 38%, 40%, and 13%, respectively. In contrast, serum I and V levels in a feedlot period were 32% and 77% higher when compared to the respective values in a pasture period.
Multiple regression analysis demonstrated that Cr, Cu, I, Na, and V are positively associated with feedlot feeding. At the same time, serum Zn and to a lesser extent Sr values were directly associated with the pasture period.
Therefore, the results of the present study demonstrated that feedlot and pasture rations have a significant impact on trace element and mineral metabolism in dairy cows.

Effect of dairy cow personality traits on their adaptation to an automated milking system following parturition. Brasier JE, Schwanke AJ, DeVries TJ. J Dairy Sci. 2023 May 18:S0022-0302(23)00247-3.

The behavior of dairy cattle, including their personality, affects both milking activity (e.g., stepping and kicking during milking) and production (e.g., milk yield). Studying personality traits is important for both production and welfare, as personality traits influence responses to housing, management, nutrition, and social situations. Personality traits may be particularly important regarding voluntary milking in an automated milking system (AMS).
The objectives of this study were to determine how dairy cow personality traits affect their adaptation to an automated milking system (AMS) upon parturition, as well as if these personality traits are consistent across the transition from gestation to lactation.
Sixty Holstein dairy cows (19 primiparous and 41 multiparous) were assessed for personality traits using a combined arena test conducted at 24 days before parturition and 24 days after first introduction to an AMS, which occurred ~3 days after parturition. The combined arena test comprised 3 parts: a novel arena test, novel object test, and a novel human test.
Principal component analysis of the behaviors recorded during the personality assessment revealed 3 factors interpreted as personality traits (75% cumulative variance) in the pre-calving test interpreted as explore, active, and bold. The post-calving test revealed 2 factors (78% cumulative variance), interpreted as active and explore.
The ‘active’ trait had a moderate positive correlation between the pre- and post-calving tests, while exploration had a weak positive correlation between tests. Cows that scored high for activeness in the pre-calving test tended to have fewer fetching events and a higher coefficient of variation of milk yield in the first 7 days after introduction to the AMS, while bolder cows tended to have higher milk yield during that time period.
In the post-calving test, more active cows tended to have more frequent milkings and voluntary visits per day, as well as a lower cumulative milk yield from day 21 to 27 after introduction to the AMS. Overall, these results indicate that personality traits of dairy cows are associated with adaptation and performance in an AMS, and that personality traits are consistent across the transition period.
Specifically, cows that scored high for boldness and activeness adapted better to the AMS immediately after calving, while cows that scored low for activeness and high for boldness performed better in terms of milk yield and milking activity in early lactation.
This study demonstrates that personality traits affect milking activity and milk yield of dairy cows milked with an AMS and, therefore, may be useful for selection of cows who might best adapt to and use an AMS.

“If you were a cow, what would you want?” Findings from participatory workshops with dairy farmers. Mills KE, Payne PR, Saunders K, Zobel G. Animal. 2023 May;17(5):100779.

When looking to improve animal welfare, it is essential to understand the viewpoints of stakeholders in the industry. Previous research has engaged stakeholders such as farmers, veterinarians, and the public to better understand future dairy industry directions. However, the use of perspective-taking as a tool to overcome farmer’s focus on current barriers to the industry has not been explored.
Therefore, the aims of this study were to have farmers take the perspective of the cow, to elicit: (1) farm elements that are essential to create a cow-centric dairy system, and (2) how this system can be achieved in the next 50 years.
To do this, researchers employed participatory methods (photo elicitation, timelining) to generate discussion with 12 New Zealand dairy farmers. Pasture access is frequently cited as an integral component for promoting good welfare in dairy cows, thus, this cohort of farmers was considered a good case study as they all had experience managing cows in grazing systems.
Participants were asked to create a cow-centric farm design, and a pathway to implementation. Following thematic analysis of the multiple data sources, the results are presented under the following three themes: (1) cow-centric farm designs (environmental considerations, cow handling and care), (2) timeline to achieve and sequence of implementation (“low hanging fruit” and long-term investments), and (3) assumptions and resources needed (including financial considerations, technology, farmer buy-in, regulations and enforcement and other stakeholder involvement).
By better understanding how current industry practice aligns, and also differs, from what the cow would want, we can work towards future management systems that incorporate the requirements of all stakeholders, including the cow.

Human Health and Nutrition

Global contributions of milk to nutrient supplies and greenhouse gas emissions. White RR, Gleason CB. J Dairy Sci. 2023 May;106(5):3287-3300.

Globally, ruminant production systems used to synthesize meat and milk differ tremendously in terms of their efficiency, productivity, and environmental impacts. Regardless of this variability, milk has been repeatedly identified as an essential source of nutrients for humans.
The objective of this work was to characterize global contributions of fluid milk to human food and nutrient supplies, greenhouse gas emissions, and water withdrawal.
Data were leveraged from the United Nations Food and Agriculture Organization to estimate global supplies of agricultural products. Trade of agricultural products and waste of those products, along with use of human food for livestock feed were accounted for before estimating human nutrient supplies.
The contributions of milk to human-edible nutrient supplies were then enumerated in terms of their proportion of total nutrients supplied by the agricultural system and in terms of the human population’s requirement for that nutrient.
The researchers identified that fluid milk provides over 10% of consumable supplies of vitamin B₁₂, vitamin A, riboflavin, and calcium available for humans globally. In terms of human nutrient requirements, milk provides sufficient vitamin B₁₂to meet the needs of over 60% of the global population, riboflavin to satisfy 50% of the population, and calcium and phosphorus for over 35% of the population.
Compared with other foods, milk ranked among the highest in terms of nutrient-to-calorie ratio for numerous amino acids, phosphorus, calcium, and riboflavin.
Conditional dependencies were identified between greenhouse gas emissions and ruminant milk and meat, but not between water withdrawal and milk production.
When evaluating the trade-offs in nutrient use versus nutrient provision for producing milk or producing all ruminant products, the production of ruminants worldwide was associated with both net increases and net decreases of several key nutrients. Continued work focusing on strategies to reduce the environmental impact of milk production will improve the utility of milk for feeding the growing global population.

Effects of probiotics administration on lactose intolerance in adulthood: A meta-analysis. Ahn SI, Kim MS, Park DG, Han BK, Kim YJ. J Dairy Sci. 2023 May 22:S0022-0302(23)00271-0.

Milk is a valuable food source, containing high-quality proteins, calcium, and various trace elements. However, many populations cannot break down lactose smoothly in their gastrointestinal tract due to lactose intolerance, which acts as a barrier to milk consumption among adults.
Probiotics can be administered orally to achieve various health benefits, including improvement of antibiotic-associated or infectious diarrhea, antiallergic effects, improvement of intestinal health, and immune response enhancement. In general, Streptococcus thermophilus and Lactobacillus delbrueckii spp. Bulgaricus are known to be effective against lactose intolerance. They have higher β-galactosidase activity and are more effective than other strains.
This meta-analysis aimed to investigate the effect of probiotic administration on adults with lactose intolerance.
Twelve studies were identified from databases such as PubMed, Cochrane Library, and Web of Knowledge based on the inclusion and exclusion criteria.
The results showed that probiotic administration alleviated the symptoms of lactose intolerance, including abdominal pain, diarrhea, and flatulence. Among them, the area under the curve (AUC) showed the greatest decrease following probiotic administration.
In the meta-ANOVA test, abdominal pain and total symptoms decreased with single-strain probiotic administration. This combination was also effective for flatulence. The dosage of probiotics or lactose was significantly associated with a reduction in the total symptom score.
In conclusion, the administration of probiotics was effective at improving adult lactose intolerance, and it is expected that the results of this study could help improve the nutritional status of adults by increasing their consumption of milk and dairy products in the future.

The association between total protein, animal protein, and animal protein sources with risk of inflammatory bowel diseases: a systematic review and meta-analysis of cohort studies. Talebi S, Zeraattalab-Motlagh S, Rahimlou M, Naeini F, Ranjbar M, Talebi A, Mohammadi H. Adv Nutr. 2023 May 13:S2161-8313(23)00313-7.

Inflammatory bowel disease (IBD) is specified by recurrent inflammation of the intestinal tract that needs life-long supervision. Crohn’s disease (CD) and ulcerative colitis (UC) are 2 predominant forms of IBD. Although CD can lead to destruction anywhere along the digestive tract (across the mouth and anus), UC is mainly limited to the colon and rectum.
During the past several decades, the prevalence and incidence of IBD have exceeded globally. It is considered that approximately 1.5 and 3 million people in USA and Europe, as well as several thousand people in other regions over the globe, are affected. Comparable to other intestinal tract disorders, IBD imposes a vast economic burden on society and adversely affects the quality of life.
Therefore, researchers conducted a dose-dependent meta-analysis to examine the relation between total protein, animal protein and its sources with inflammatory bowel disease (IBD).
Prospective cohort study designs that investigated associations between dietary intake of various animal protein sources and with risk of IBD in the general population were identified. Eleven prospective cohort studies with 4,302,554 participants and 8067 cases were considered eligible.
Findings indicated that higher intake of dairy was significantly associated with a lower risk of IBD (RR: 0.81), Crohn’s disease (RR: 0.69), and ulcerative colitis (RR: 0.84). There was no association between different sources of animal protein and the risk of IBD.
The dose-response analysis suggested that each 100 g/d increment in dietary total meat consumption was associated with a 38% greater risk of IBD. Moreover, A positive linear association was found between total meat intake and risk of IBD.
Overall, among the dietary sources of protein, the risk of IBD increased only with increasing total meat intake, and the consumption of protein from dairy products was found to be a protective factor against the IBD risk.

Differences in gut metagenomes between dairy workers and community controls: a cross-sectional study. Trinh P, Roberts MC, Rabinowitz PM, Willis AD. bioRxiv. 2023 May 12:2023.05.10.540270.

As a nexus of routine antibiotic use and zoonotic pathogen presence, the live-stock farming environment is a potential hotspot for the emergence of zoonotic diseases and antibiotic resistant bacteria. Livestock can further facilitate disease transmission by serving as intermediary hosts for pathogens as they undergo evolution prior to a spillover event.
Previous metagenomic studies of livestock workers in China and Europe have reported increased abundance and carriage of antibiotic resistance genes in livestock workers. In light of this, researchers were interested in characterizing the microbiome and resistome of US dairy workers, whose exposure to the livestock farming environment places them at risk for facilitating community transmission of antibiotic resistant genes and emerging zoonotic diseases.
Using shotgun sequencing, the researchers investigated differences in the taxonomy, diversity and gene presence of the human gut microbiome of 10 dairy farm workers and 6 community controls, supplementing these samples with additional publicly available gut metagenomes.
The researchers observed greater abundance of tetracycline resistance genes and prevalence of cephamycin resistance genes in dairy workers’ metagenomes, and lower average gene diversity. They also found evidence of commensal organism association with plasmid-mediated tetracycline resistance genes in both dairy workers and community controls (including Faecalibacterium prausnitzii, Ligilactobacillus animalis, and Simiaoa sunii ).
However, they did not find significant differences in the prevalence of resistance genes or virulence factors overall, nor differences in the taxonomic composition of dairy worker and community control metagenomes.
In conclusion, this study presents the first metagenomics analysis of United States dairy workers, providing insights into potential risks of exposure to antibiotics and pathogens in animal farming environments. While this investigation found no strong evidence for differences in the abundance or carriage of antibiotic resistance genes and virulence factors between dairy worker and community control gut metagenomes, we did observe patterns in the abundance of tetracycline resistance genes and the prevalence of cephamycin resistance genes that is consistent with previous work.

Dairy Farm Work and Protection from Gastrointestinal Illness. VanWormer JJ, Bendixsen CG, Shukla SK. J Agromedicine. 2023 May 2:1-7.

Gastrointestinal (GI) disorders are a major public health burden in the United States. Due to close contact with animals, farmers may be a high risk subgroup for acute GI infections, though some studies suggest farm work is actually protective against GI illness.
The purpose of this study was to examine associations between dairy farm work and GI symptoms over 3 years.
A prospective, matched cohort study was used that included 70 adult dairy farm workers and 74 matched (age, gender, ZIP code) non-farm participants from central Wisconsin.
The outcome was mean GI symptom scores for abdominal pain, diarrhea, constipation, dyspepsia, nausea, and reflux, per the 23-item Gastrointestinal Symptoms Severity Index. After adjustment for potential confounding variables, linear regression results indicated dairy farm workers had significantly lower Gastrointestinal Symptoms Severity Index scores for abdominal pain, diarrhea, constipation, and dyspepsia.
Working on a dairy farm was associated with significantly less frequent and severe GI illness symptoms in adults. Future research should identify underlying causal pathways, including possible farm animal exposures, that influence beneficial gut microbiota that could inform therapeutic remedies to help prevent clinical GI disorders.

Fermented Whey Protein Supplementation Improves Muscular Strength, Muscle Parameters, and Physical Performance in Middle-Aged Korean Adults: An 8-Week Double Blind Randomized Controlled Trial. Kim CH, Jeon YB, Yoo DG, Kim KH, Jeong HJ, Kim BK, Park MH, Kim KH, Hwang JH, Cho GH, Kim SK, Lee KW, Kim SH. Food Sci Anim Resour. 2023 May;43(3):512-530.

Effective protein supplementation and regular exercise are two important factors for improving muscle health.
The present study evaluated the effects of fermented whey protein using kimchi lactic acid bacteria Lactobacillus caseiDK211 on skeletal muscle mass, muscle strength, and physical performance in healthy middle-aged males performing regular resistance exercises.
In this study, the effects of consuming fermented whey protein twice a day were investigated and compared with that of non-fermented supplementation.
Forty-eight males (average age 44.8 years) were randomly assigned to two groups: Fermented whey protein supplementation (FWPS) and non-fermented whey protein concentration supplementation (WPCS) groups. Each group ingested 37 g of FWPS or WPCS twice a day for eight weeks.
FWPS was effective in promoting the physical performance in dynamic balance measurement and muscle health, indicated through the increment in grip strength (left), upper arm circumference, and flat leg circumference from the baseline. However, similar improvements were not observed in the WPCS group.
These results imply that whey protein fermented by caseiDK211 is an effective protein supplement for enhancing muscle health in males performing regular resistance exercises.

Toward a New Definition of “Healthy” Food: Issues and Challenges. Siu K, Drewnowski A.Curr Dev Nutr. 2023 Apr 19;7(5):100080.

Dietary Guidelines for Americans (DGA) have become increasingly food-based guidelines. The Healthy United States-Style Eating Pattern features fruits, vegetables, whole grains, and low-fat dairy, with limits placed on added sugar, sodium, and saturated fat.
Recent measures of nutrient density have followed suit, incorporating both nutrients and food groups. Most recently, the United States Food and Drug Administration (FDA) has proposed to redefine the concept of a “healthy” food for regulatory purposes.
To qualify as healthy, foods will need to contain specific minimum amounts of fruits, vegetables, dairy, and whole grains, with limits placed on added sugar, sodium, and saturated fat. The present concern was that the proposed criteria, formulated by the FDA per Reference Amount Customarily Consumed, were so stringent that few foods would pass.
Therefore, researchers applied the proposed FDA criteria to foods in the USDA Food and Nutrient Database for Dietary Studies (FNDDS 2017-2018).
The criteria were met by 58% of fruits, 35% of vegetables, 8% of milk and dairy products, and 4% of grain products. Many foods commonly considered to be healthy by consumers and the USDA alike did not pass the proposed FDA criteria. Federal agencies seem to define healthy in different ways.
These findings have implications for the formulation of regulatory and public health policies. Key opinion leaders recommend that nutrition scientists be involved in the development of federal regulations and policies that affect American consumers and the food industry.

Innovation, Economics, and Dairy Alternatives

First gene-edited calf with reduced susceptibility to a major viral pathogen. Workman AM, Heaton MP, Sonstegard TS, et al. PNAS Nexus. 2023 May 9;2(5):pgad125.

Bovine viral diarrhea virus (BVDV) is one of the most important viruses affecting the health and well-being of bovine species throughout the world.
Here, researchers used CRISPR-mediated homology-directed repair and somatic cell nuclear transfer to produce a live calf with a six amino acid substitution in the BVDV binding domain of bovine CD46.
The result was a gene-edited calf with dramatically reduced susceptibility to infection as measured by reduced clinical signs and the lack of viral infection in white blood cells.
The edited calf has no off-target edits and appears normal and healthy at 20 months of age without obvious adverse effects from the on-target edit.
This precision bred, proof-of-concept animal provides the first evidence that intentional genome alterations in the CD46gene may reduce the burden of BVDV-associated diseases in cattle and is consistent with our stepwise, in vitro and ex vivo experiments with cell lines and matched fetal clones.

A review of oleogels applications in dairy foods. Chowdhury B, Sharma A, Akshit FNU, Mohan MS, Salunke P, Anand S. Crit Rev Food Sci Nutr. 2023 May 25:1-19.

The characteristics of dairy products, such as texture, color, flavor, and nutritional profile, are significantly influenced by the presence of milk fat. However, saturated fatty acids account for 65% of total milk fat. With increased health awareness and regulatory recommendations, consumer preferences have evolved toward low/no saturated fat food products.
Reducing the saturated fat content of dairy products to meet market demands is an urgent yet challenging task, as it may compromise product quality and increase production costs. In this regard, oleogels have emerged as a viable milk fat replacement in dairy foods.
This review focuses on recent advances in oleogel systems and explores their potential for incorporation into dairy products as a milk fat substitute. Overall, it can be concluded that oleogel can be a potential alternative to replace milk fat fully or partially in the product matrix to improve nutritional profile by mimicking similar rheological and textural product characteristics as milk fat. Furthermore, the impact of consuming oleogel-based dairy foods on digestibility and gut health is also discussed.
A thorough comprehension of the application of oleogels in dairy products will provide an opportunity for the dairy sector to develop applications that will appeal to the changing consumer needs.

The Efficacy of Bacteriocins Against Biofilm-Producing Bacteria Causing Bovine Clinical Mastitis in Dairy Farms: A New Strategy. Raheel I, Mohammed AN, Mohamed AA. Curr Microbiol. 2023 May 31;80(7):229.

Using an alternative bio-product is one of the most promising ways to control bovine mastitis and avoid new intra-mammary infections.
The aims of this study were to ascertain the prevalence of biofilm-forming bacteria responsible for causing clinical mastitis in dairy herds and to assess the effectiveness of bacteriocins, produced by Bacillus subtilis, in controlling the growth of these bacteria in the milk of animals.
A total of 150 milk samples were collected from cows and buffalos suffering from mastitis and the etiological agents were isolated and identified by the VITEK-2-COMPACT-SYSTEM®. Additionally, the capability of the bacterial isolates to produce biofilms was determined. RT-PCR was used to detect enterotoxin-producing genes (sed and seb), resistance genes (mecA and blaZ), and biofilm-associated genes (icaA and fnbA) in the isolated bacteria.
The susceptibility patterns of the bacterial isolates to bacteriocins were assessed using an agar well-diffusion assay. S. aureus was significantly more capable of producing biofilms than coagulase-negative Staphylococcus isolates. S. ubris was the strongest biofilm producer among the Streptococcus species.
The sensitivity profiles of the Staphylococcus spp. (S. aureus and coagulase-negative Staphylococcus) and their biofilm producers to bacteriocins were significantly higher (100% and 90%, respectively) at the same concentration.
Bacteriocins had a lethal effect on Staphylococci, Streptococci, and biofilm development at a dose of 250 µg/mL. In dairy farms, bacteriocins are a viable alternative treatment for the prevention and control of bovine clinical mastitis.

Parental Perception of Children’s School Lunch Milk. Racette CM, Nishku S, Drake MA.J Dairy Sci. 2023 May 18:S0022-0302(23)00260-6.

School lunch programs are mandated by the US Code of Federal Regulations (CFR) to serve pasteurized milk that is skim or 1% fat and fortified with vitamins A and D (Office of the Federal Register, 2021a).
In recent years, proposals have been made to alter nutritional requirements for school lunches and school lunch milk, including changes to the milkfat and flavor options available.
The objective of this study was to evaluate parental understanding and perception of school lunch milk to better understand how changes to school lunch milk are perceived by parents. Four focus groups (n = 34) were conducted with parents of school-aged children (5-13 y) who purchased milk as part of a lunch at school.
Participants were asked about school lunch milk, including nutritional content, packaging, and flavoring. Focus groups included a build-your-own milk activity and discussion of children’s milk products currently available on the market. Two subsequent online surveys were conducted with parents of school-aged children (Survey 1 n = 216, Survey 2 n = 133).
Both surveys included questions to evaluate knowledge of milk nutrition and attitudes regarding milk and flavored milk. Agree/disagree questions were used in both surveys to assess parental opinions of school lunch milk.
Parents were familiar with the flavor options and packaging of school lunch milk, but expressed limited familiarity with school lunch milk fat content. Parents perceived milk to be healthy and a good source of vitamin D and calcium.
From survey results, parents placed the highest importance on school lunch milk packaging, followed by milk fat percentage and flavoring over label claims and heat treatment. The ideal school lunch milk for parents was unflavored (white milk) or chocolate, 2% fat, and packaged in a cardboard gabletop carton.
For school lunch chocolate milk, 3 distinct clusters of parents with differing opinions for children’s chocolate milk were identified. Parents are largely unfamiliar with the specific attributes and nutritional profile of milk served in schools but believe that schools should offer milk to their children as part of breakfast and lunch.
Parents in both surveys also displayed a preference for 2% fat milk over low-fat options, which provides actionable insight for both governmental bodies determining educational and nutritional policies for school meals and fluid milk producers seeking to optimize their products intended for schools.

Parent and physician beliefs, perceptions and knowledge of plant milks for children. Soczynska I, da Costa BR, O’Connor DL, Jenkins DJA, Birken CS, Juando-Prats C, Maguire JL; TARGet Kids! collaboration. Nutr Health. 2023 May 8:2601060231171299.

Parent and physician perceptions of plant milk are unclear
The aim of this study was to explore parent and physician perceptions of plant milk for children and to gain a better understanding of why parents and physicians might choose plant milk for children.
A mixed methods study was conducted using a questionnaire and interviews with parents and physicians participating in the TARGet Kids! cohort study. Questionnaire data were analyzed using descriptive statistics. Interview transcripts were analyzed using thematic analysis.
The results showed that parents reported a variety of reasons for choosing plant milk for their children including concerns around allergies, the environment, animal welfare, plant-based diet, health benefits, taste and hormones in cow’s milk.
Parents gave their children various types of plant milks and physicians provided various recommendations to parents of children not consuming cow’s milk.
This study identified that 79% of parents and 51% of physicians were unaware that soy milk is the recommended cow’s milk substitute for children. Additionally, 26% of parents did not know some plant milks are not fortified and can contain added sugar.
Three main themes were identified from interviews about why parents and physicians may choose plant milk for children: (i) healthiness of plant milk; (ii) concerns about hormones; and (iii) environmental impacts.
In conclusion, parents and physicians choose the milk that they believe is healthiest for their child or patient. However, a lack of clarity on the effects of plant milk consumption on children’s health resulted in conflicting views on whether plant milk or cow’s milk is healthier for children.

Consumer perception of plant-based yogurt: Sensory drivers of liking and emotional, holistic and conceptual associations. Jaeger SR, Cardello AV, Jin D, Ryan GS, Giacalone D. Food Res Int. 2023 May;167:112666.

Plant-based (PB) yogurts is a rapidly expanding food category with the potential to reduce many of the negative environmental impacts associated with the farming of dairy cattle and related greenhouse gas emissions.
Within the context of growing consumer demand for PB products, this research aimed to identify the main drivers of consumer acceptance of PB yogurts through data drawn from a consumer study of 113 adult New Zealand participants who tasted a representative range of commercially available vanilla-flavoured PB yogurts, and provided sample evaluations using a multi-variable measurement approach comprised of liking ratings, emotional responses, sensory characterizations, and holistic / conceptual perceptions.
The primary finding of this study was that the overall acceptability of currently available PB yogurts is low, leading to poor attitudes and low willingness to consume PB yogurts. The examined products were characterized by the presence of several sensory attributes that negatively impacted consumer liking, either because they were unexpected or because their intensity level was too high.
Among the main sensory issues identified were perceived sourness (acidity), lumpy appearance and non-white color. In contrast, vanilla flavor and a creamy/smooth texture were identified as the main drivers of liking.
One of the key insights gained from the study was that negative emotional activation, caused by the presence of unexpected sensory attributes in the samples, was the main driver of product rejection. This was likely due to the disparity between consumers’ sensory expectations, formed primarily based on their experience with dairy yogurts, and the actual experience upon tasting the PB yogurts.
Overall, the findings indicate that the sensory properties of currently available PB yogurts are a significant barrier to their adoption by most consumers and that addressing these sensory deficiencies is essential to achieving mainstream market acceptance of these products.