Milk Components Research Articles

Energy balance of dairy cows predicted by mid-infrared spectra data of milk using Bayesian approaches

Information on dry matter intake (DMI) and energy balance (EB) at the animal and herd level is important for management and breeding decisions. However, routine recording of these traits at commercial farms can be challenging and costly. Fourier-transform mid-infrared (FT-MIR) spectroscopy is a noninvasive technique applicable to a large cohort of animals that is routinely used to analyze milk components and is convenient for predicting complex phenotypes that are typically difficult and expensive to obtain on a large scale. We aimed to develop prediction models for EB and use the predicted phenotypes for genetic analysis. First, we assessed prediction equations using 4,485 phenotypic records from 167 Holstein cows from an experimental station. The phenotypes available were body weight (BW), milk yield (MY) and milk components, weekly-averaged DMI, and FT-MIR data from all milk samples available. We implemented mixed models with Bayesian approaches and assessed them through 50 randomized replicates of a 5-fold cross-validation. Second, we used the best prediction models to obtain predicted phenotypes of EB (EBp) and DMI (DMIp) on 5 commercial farms with 2,365 phenotypic records of MY, milk components and FT-MIR data, and BW from 1,441 Holstein cows. Third, we performed a GWAS and estimated heritability and genetic correlations for energy content in milk (EnM), BW, DMIp, and EBp using the genomic information available on the cows from commercial farms. The highest correlation between the predicted and observed phenotype (ry,y^) was obtained with DMI (0.88) and EB (0.86), while predicting BW was, as anticipated, more challenging (0.69). In our study, models that included FT-MIR information performed better than models without spectra information in the 3 traits analyzed, with increments in prediction correlation ranging from 5% to 10%. For the predicted phenotypes calculated by the prediction equations and data from the commercial farms the heritability ranged between 0.11 and 0.16 for EnM, DMIp and EBp, and 0.42 for BW. The genetic correlation between EnM and BW was -0.17, with DMIp was 0.40 and with EBp was -0.39. From the GWAS, we detected one significant QTL region for EnM, and 3 for BW, but none for DMIp and EBp. The results obtained in our study support previous evidence that FT-MIR information from milk samples contribute to improve the prediction equations for DMI, BW, and EB, and these predicted phenotypes may be used for herd management and contribute to the breeding strategy for improving cow performance.

Effects of dietary forage-to-concentrate ratio and forage type on milk phospholipids and fatty acid composition of polar lipids

The effects of grass silage and red clover silage on milk fatty acid (FA) composition are extensively studied, but little is known of their effects on minor lipid constituents of milk fat globule membrane. We investigated the effects of forage:concentrate (FC) ratio in grass silage-based diets and forage type (grass silage vs. red clover silage) on selected molecular species of milk phospholipids (PL) and the FA composition of PL. Ten multiparous Nordic Red cows were offered following dietary treatments: grass silage-based diets containing 70:30 (HG) or 30:70 (LG) FC ratio or a red clover silage-based diet (RC) comprising 50:50 FC ratio on a dry matter basis. The most abundant molecular species within the phosphatidylcholines was 16:0-18:1 phosphatidylcholine that was increased by 18% in HG compared with LG milk. Dietary treatments did not affect the relative proportion of 18:1-18:1+18:0-18:2 phosphatidylethanolamine that was the most prevalent species (ca. 44%-45%) in that class. We identified the d18:1-22:0 sphingomyelin as the most abundant sphingomyelin species that tended to increase in HG milk compared with LG. The FC ratio did not affect the relative proportions of saturated FA nor monounsaturated FA in PL, but the proportion of cis-9 18:1 was elevated in HG versus LG milk, whereas the proportion of 18:2n-6 was 50% higher in LG versus HG milk. The RC diet increased monounsaturated FA and 18:3n-3 levels in PL compared with grass silage-based diets and decreased the relative proportion of saturated FA. However, the RC diet did not affect the relative proportion of polyunsaturated FA in PL, although red clover silage typically increases the proportion of polyunsaturated FA in milk fat. This study provides valuable knowledge of the minor lipid components in milk on species level in relation to common feeding strategies in high-forage systems.

Analysis of reproduction success, growth and milk trajectories and response to nutritional challenge in two Alpine goat lines selected on divergent longevity

This study aims to investigate whether the variation in reproduction success, growth, and milk trajectories is associated with different adaptive strategies in the short term (response to an acute nutritional challenge), using two Alpine goat lines. A total of 382 Alpine goats (179 low longevity (low_LGV) and 203 high longevity (high_LGV)), selected for divergent functional longevity from a commercial population, were monitored for 4 years and recorded for BW, reproduction and milking performance. Every year, an average of fifty primiparous goats were exposed to a 2-d nutritional challenge in early lactation. A polynomial model was used to analyse the lifetime trajectory of lactation and BW. A piecewise model was used to analyse the individual milk yield and responses of milk components to the nutritional challenges. The statistical analysis revealed that the two lines had a similar performance for total milk yield in the first lactation, BW at birth and at first kidding, litter size and weight, kidding interval and interval from the first insemination to conception. BW trajectories revealed that low_LGV goats had a greater BW in pregnancy but then lost more weight in early lactation compared to high_LGV goats, which showed a greater BW after kidding. Milk trajectories showed that the high_LGV goats had a higher initial milk yield, an earlier but less marked lactation peak and more persistency in milk production in late lactation than low_LGV goats. Except for milk protein content, quite similar response and recovery profiles of milk yield and milk fat content were observed during the challenge for both lines. The response to the challenge was positively correlated to the initial level of milk production in early lactation but negatively correlated with milk production decline after the peak. This finding suggests that the low_LGV goats were more adapted to allocate resources to meet an expected physiological change such as gestation and lactation. However, high_LGV goats allocate more than low_LGV goats for structural mass and may better cope with an unexpected environmental change such as nutritional deficit.

OR18-02 Mammary Insulin Sensitivity Increases At The Onset Of Lactation And Promotes Metabolic Pathways Supporting Breast Milk Synthesis

Abstract Disclosure: X. Meng: None. H. Rostom: None. A. Fry: None. T. Elajnaf: None. F. Hannan: None. The initiation of lactation during postpartum days 1-4 is hormonally regulated and critical for successful breastfeeding. Insulin represents a key lactogenic hormone as evidenced by women with diabetes mellitus who have delayed lactation onset. However, the role of insulin in lactation and its influence on mammary cells are unclear. We utilised clinical and cellular approaches to investigate this, and recruited n=38 healthy pregnant women (age range 26-42 years) following informed consent and measured serum insulin at 36 weeks’ gestation and during post-partum days 1-4 (1). Serum insulin progressively decreased from 36 weeks’ gestation to day 4 post-partum (244±33pmol/L vs 37±4pmol/L, p<0.0001). Moreover, reverse transcription-quantitative PCR (RT-qPCR) of lactating human mammary epithelial cells (HMECs) isolated from breast milk showed a >20-fold increase in insulin receptor expression compared to non-lactating HMECs (p<0.01, n=4). These findings indicated an increase in both systemic and mammary insulin sensitivity at lactation onset. We hypothesised that insulin promotes lactation by influencing mammary metabolism and used cultured HMECs to evaluate this. Stimulation of HMECs with 10nM insulin caused a >7-fold increase (p=0.001, n=5) in the phosphorylation of Akt, a signalling protein required for initiating lactation. Akt influences oxidative phosphorylation and glycolysis, and we assessed these processes by measuring oxygen consumption rate (OCR) and extracellular acidification rate (ECAR), respectively. Cultured HMECs treated with 10nM insulin for ≤18hrs showed increased OCR (22±0.9 vs. 17±0.4pmol O2/min/106 cells for control HMECs, p<0.05, n=4) and ECAR (0.23±0.003 vs. 0.18±0.002mpH/min/106 cells for control HMECs, p<0.001, n=4), consistent with increased oxidative phosphorylation and glycolysis. HMECs treated with 10nM insulin for 8hrs had significant upregulation of genes encoding glycolytic enzymes, namely hexokinase 2 (>4-fold increase, p<0.0001, n=4) and pyruvate kinase M1/2 (1.4-fold increase, p<0.05, n=4). However, RT-qPCR analysis of HMECs showed that insulin did not increase expression of genes mediating oxidative phosphorylation, suggesting an Akt-mediated post-transcriptional mechanism. In summary, increased mammary insulin sensitivity together with insulin-stimulated oxidative phosphorylation and glycolysis may support mammary function and milk component synthesis at the onset of lactation. Reference: (1) Rostom, H. et al. Protocol for an observational study investigating hormones triggering the onset of sustained lactation: the INSIGHT study. BMJ Open 12, e062478. Presentation: Saturday, June 17, 2023

Effects of oyster glycogen intramammary challenge on primiparous cow milk somatic cell counts, milk yields, and milk composition

Mastitis is a common and costly disease in the dairy industry that reduces milk production in affected mammary glands. The local mechanisms that result in reduced milk production of affected mammary glands are incompletely understood; elucidation of these mechanisms is dependent on the use of hypothesis testing studies, but few experimental models exist. The objective of this study was to develop a mastitis challenge model, using a split udder design, to reduce milk yields by approximately 15% in udder halves challenged with oyster glycogen, a known inducer of leukocyte recruitment, relative to udder halves treated with saline. Four primiparous Holstein cows in mid lactation were used. One udder half of each cow was randomly selected and challenged with oyster glycogen (OYGLN), and the opposite udder half was treated with saline (SAL). Milk yields and components were measured at each milking (3×/d) for 3 d postchallenge. No signs of clinical mastitis were observed. Milk somatic cell scores, yields, and components were similar between OYGLN and SAL udder halves at time of challenge. Milk somatic cell scores markedly increased in OYGLN halves postchallenge and were greater than SAL halves for the duration of the trial. Lactose concentrations of OYGLN udder halves were transiently lower than in SAL udder halves, but protein concentrations were greater at 2 milkings postchallenge in OYGLN halves. Milk yields and energy-corrected milk yields did not differ between OYGLN and SAL udder halves overall, nor at any postchallenge milking. A single intramammary challenge of oyster glycogen was unsuccessful in eliciting a disparity in milk yields between challenged and saline control udder halves despite the marked leukocyte infiltration observed in the former. These results indicate an incomplete understanding of how milk yields are reduced in mammary glands affected by subclinical mastitis and that transient somatic cell recruitment and infiltration alone do not directly reduce milk yields during subclinical mastitis.

Human milk oligosaccharide composition and associations with growth: results from an observational study in the US.

Breast milk is the recommended source of nutrients for newborns and infants. Human milk oligosaccharides (HMO) are the third most abundant solid component in human milk and their composition varies during lactation. Our objective was to investigate longitudinal and cross-sectional changes in HMO composition and whether these changes were associated with infant growth up to 24 months of age. Associations with maternal characteristics were also investigated. 24 HMOs were quantified in samples taken at 2 weeks (n = 107), 6 weeks (n = 97) and 3 months (n = 76), using high performance liquid chromatography. Body length, weight, and head circumference were measured at 8 timepoints, until 24 months. Clusters of breast milk samples, reflecting different HMO profiles, were found through a data-driven approach. Longitudinal associations were investigated using functional principal component analysis (FPCA) and used to characterize patterns in the growth trajectories. Four clusters of samples with similar HMO composition were derived. Two patterns of growth were identified for length, body weight and head circumference via the FPCA approach, explaining more than 90% of the variance. The first pattern measured general growth while the second corresponded to an initial reduced velocity followed by an increased velocity ("higher velocity"). Higher velocity for weight and height was significantly associated with negative Lewis status. Concentrations of 3'GL, 3FL, 6'GL, DSNLT, LNFP-II, LNFP-III, LNT, LSTb were negatively associated with higher velocity for length. We introduced novel statistical approaches to establish longitudinal associations between HMOs evolution and growth. Based on our approach we propose that HMOs may act synergistically on children growth. A possible causal relationship should be further tested in pre-clinical and clinical setting.

Detection of β-lactoglobulin under different thermal-processing conditions by immunoassay based on nanobody and monoclonal antibody.

The problems of inaccurate detection values of thermal-processed β-lactoglobulin (β-LG) content seriously affect the screening of allergens. A monoclonal antibody (mAb) against β-LG was successfully prepared and a highly sensitive sandwich ELISA (sELISA) was constructed with specific nanobody (Nb) as the capture antibody with detection limit of 0.24ng/mL. Based on this sELISA, the ability of Nb and mAb to recognize β-LG and β-LG interacting with milk components was explored. Combined with protein structure analysis to elaborate the mechanism of shielding β-LG antigen epitopes during thermal-processing, thus enabling the differentiation between pasteurized and ultra-high temperature sterilized milk, the detection of milk content in milk-containing beverages, and the highly sensitive detection and analysis of β-LG allergens in dairy-free products. The method provides methodological support for identifying the quality of dairy products and reducing the risk of β-LG contamination in dairy-free products.

Potential of Raman spectroscopy for in-line measurement of raw milk composition

A method for the in-line measurement of raw milk composition is beneficial for the dairy industry as it allows processors to make timely decisions, i.e., standardization, prior to the milk entering a process. It facilitates more enhanced operational control and offers the potential for improved process efficiencies. One such technology of potential commercial value is Raman spectroscopy due to its ability to measure macromolecules in an aqueous environment and compatibility with in-line measurements. This study investigated the suitability of Raman spectroscopy to measure macro components (fat, protein, and lactose) in raw milk. 80 raw milk samples were analysed using a Raman spectroscopy instrument coupled with an optical fibre probe. Variations in process variables such as temperature and the effect of agitation on Raman spectral features (intensity, shape, and wavelength shift) were considered prior to model development. Due to the overlapping response of fat, protein, and lactose in the Raman spectrum of raw milk, multivariate regression models were developed for their quantification. The developed partial least squares (PLS) regression models predicted the percentage of fat, protein, and lactose in raw milk with a root mean square error of prediction (RMSEP) of 0.15, 0.11 and 0.04, coefficient of determination for prediction (R2p) 0.96, 0.89 and 0.89, and the ratio of prediction error to deviation (RPD) of 8.16, 3.16, and 2.89.

Human milk oligosaccharides (HMOS) for infant health and microbiome development

HMO stands HUMAN MILK OLIGOSACCHARIDES, which act as a prebiotic found naturally in breastmilk. They are the third largest solid component in breast milk after lactose and fat.

Multi-Trait Single-Step Genomic Prediction for Milk Yield and Milk Components for Polish Holstein Population.

The objective of our study was to evaluate the predictive ability of a multi-trait genomic prediction model that accounts for interactions between marker effects to estimate heritability and genetic correlations of traits including 305-day milk yield, milk fat percentage, milk protein percentage, milk lactose percentage, and milk dry matter percentage in the Polish Holstein Friesian cow population. For this aim, 14,742 SNP genotype records for 586 Polish Holstein Friesian dairy cows from Poland were used. Single-Trait-ssGBLUP (ST) and Multi-Trait-ssGBLUP (MT) methods were used for estimation. We examined 305-day milk yield (MY, kg), milk fat percentage (MF, %), milk protein percentage (MP, %), milk lactose percentage (ML, %), and milk dry matter percentage (MDM, %). The results showed that the highest marker effect rank correlation was found between milk fat percentage and milk dry matter. The weakest marker effect rank correlation was found between ML and all other traits. Obtained accuracies of this study were between 0.770 and 0.882, and 0.773 and 0.876 for MT and ST, respectively, which were acceptable values. All estimated bias values were positive, which is proof of underestimation. The highest heritability value was obtained for MP (0.3029) and the lowest heritability value was calculated for ML (0.2171). Estimated heritability values were low for milk yield and milk composition as expected. The strongest genetic correlation was estimated between MDM and MF (0.4990) and the weakest genetic correlation was estimated between MY and ML (0.001). The genetic relations with milk yield were negative and can be ignored as they were not significant. In conclusion, multi-trait genomic prediction can be more beneficial than single-trait genomic prediction.

Seasonal effects on multiparous dairy cow behavior in early lactation

Controlled studies have shown that heat stress abatement positively influences health, productivity, behavior, and reproductive performance of dairy cows during all stages of the lactation cycle. Based on previous findings, the present study focused on a better understanding of how seasonal changes affect the behavior of multiparous lactating dairy cows kept in typical free-stall housing with the objective to aid in the management of lactating cows exposed to variable environmental conditions. Automated monitoring devices (Nedap, the Netherlands) were used to assess behavioral activity of mature Holstein dairy cows during the “hot season” (HS; n = 19; July, August, and September) and the “cool season” (CS; n = 15; December, January, and February) under normal management conditions. Cows received a leg tag to measure daily lying time, and number of steps and standing bouts, and a neck tag to measure eating and rumination time. All cows were housed in sand-bedded freestall barns equipped with cooling systems (soakers and fans). Behavior, milk production and milk components were recorded for the first 9 wk of lactation after calving. Average temperature-humidity index (THI) was 78.2 ± 0.4 (± standard error) in the HS and 54.4 ± 0.2 in the CS. Fat-corrected milk yield was greater in the CS compared with HS during the first 5 wk of lactation. Milk protein percentage was lower in CS during the first 2 wk of lactation. In contrast with HS, milk fat percentage was greater in the CS. Compared with CS, overall, during HS cows spent less time eating, lying down, and tended to spend less time ruminating. In addition, exposure to high THI resulted in increases in standing bouts, and overall standing time in HS relative to CS. No differences in number of steps were observed between HS and CS. In summary, exposure to high THI during lactation seems to negatively affect the behavior and consequently the daily time budget of lactating Holstein cows, even under housing conditions with active cooling. A better understanding on how different seasons affect the daily time budget of lactating dairy cows may contribute to the development of more effective management strategies to decrease the negative effects of heat exposure.

Effects of non-genetic factors on milk yield and chemical composition of milk from Holstein-Friesian cows

Background: It is necessary to determine the extent and direction of environmental factors to accurately assess cow performance in terms of milk yield and milk components. Although many studies have explored environmental factors affecting milk yield, there is not enough information about the effects and direction of environmental factors on milk composition. Objective: To determine the effects of non-genetic factors, such as calving season, lactation number, lactation stage, animal age, and herd size on milk yield, chemical composition of raw milk, and Somatic Cell Count (SCC) in Holstein-Friesian cows. Methods: Data were obtained from 15,354 raw milk samples of 5,118 Holstein-Friesian cows at 276 dairy farms in Türkiye. The data analysis was performed using the General Linear Model (GLM) feature of the SPSS statistics program. Results: Mean fat (F), protein (P), dry matter (DM), lactose (L), urea (U), and Log10SCC values of milk were 3.74 ± 0.01, 3.19 ± 0.01, 11.36 ± 0.03, 4.32 ± 0.01%, 21.57 ± 0.28 mg/dL, and 5.244 ± 0.01 cells/mL, respectively. Peak milk yield (PMY), lactation milk yield (LMY), 305-day milk yield (305-d MY), and SCC values were 33.7 ± 0.13, 8,538.33 ± 89.64 kg, 6,479.42 ± 168.96 kg, and 224,164.34 ± 4,402.79 cells/mL, respectively. Conclusion: Dairy farms in Türkiye should improve protein, dry matter, and urea contents in milk and investigate in detail the relationship between raw milk urea, subclinical mastitis, and reproductive features.

Technological parameters for the production of soft cheese depending on the linear origin of cows

Relevance. One of the important products in the diet of Russian citizens is milk. In addition, it is not only a food product, but also a raw material for the dairy industry, from which a wide range of dairy products, including cheeses, is produced. Dairy cattle, in particular cows, are used for production. The study of the suitability of milk of a new genetic formation of the Middle Urals zone for cheese production is of both scientific and practical interest.The aim of the work is to study the influence of the linear origin of cows on technological parameters in the production of soft cheese and its quality.Results. As a result of the research, it was found that in the manufacture of «Adyghe cheese» according to GOST 32263 the best quality was a clot from the milk of cows of the Montvik Chieftain line. To obtain it, less calcium chloride and whey were spent than in the manufacture of cheeses from the milk of cows of other Holstein lines. In milk from cows of this line, the duration of operations for the formation of a clot and work with it, as well as for self-pressing, were shorter. The introduction of rennet improves the clot and reduces the duration of self-pressing, which has a positive effect on the quality of the product, the efficiency of using milk components, such as protein and fat, has increased. Cheeses obtained from the milk of cows of this group were distinguished by higher levels of fat in dry matter, fat and protein per 100 g of the product and better nutritional value.

Biological Relevance of Goat Milk Oligosaccharides to Infant Health.

Milk is often regarded as the gold standard for the nourishment of all mammalian offspring. The World Health Organization (WHO) recommends exclusive breastfeeding for the first 6 months of the life of the infant, followed by a slow introduction of complementary foods to the breastfeeding routine for a period of approximately 2 years, whenever this is possible ( Global Strategy for Infant and Young Child Feeding; WHO, 2003). One of the most abundant components in all mammals' milk, which is associated with important health benefits, is the oligosaccharides. The milk oligosaccharides (MOS) of humans and other mammals differ in terms of their concentration and diversity. Among those, goat milk contains more oligosaccharides (gMOS) than other domesticated dairy animals, as well as a greater range of structures. This review summarizes the biological functions of MOS found in both human and goat milk to identify the possible biological relevance of gMOS in human health and development. Based on the existing literature, seven biological functions of gMOS were identified, namely, MOS action as prebiotics, immune modulators, and pathogen traps; their modulation of intestinal cells; protective effect against necrotizing enterocolitis; improved brain development; and positive effects on stressor exposure. Overall, goat milk is a viable alternate supply of functional MOS that could be employed in a newborn formula.

Feeding spent hemp biomass to lactating dairy cows: Effects on performance, milk components and quality, blood parameters, and nitrogen metabolism

The legalization of industrial hemp by the 2018 Farm Bill in the United States has driven a sharp increase in its cultivation, including for cannabinoid extraction. Spent hemp biomass (SHB), produced from the extraction of cannabinoids, can potentially be used as feed for dairy cows; however, it is still illegal to do so in the United States, according to the US Food and Drug Administration Center for Veterinary Medicine, due to the presence of cannabinoids and the lack of data on the effect on animals. To assess the safety of this byproduct as feed for dairy cows, late-lactation Jersey cows (245 ± 37 d in milk; 483 ± 38 kg body weight; 10 multiparous and 8 primiparous) received a basal total mixed ration (TMR) diet plus 13% alfalfa pellet (CON) or 13% pelleted SHB for 4 wk (intervention period [IP]) followed by 4 wk of withdrawal period (WP), where all cows received only the basal TMR during WP. The dry matter intake (DMI), body weight, body condition score, milk yield, milk components, and fatty acid profile, blood parameters, N metabolism, methane emission, and activity were measured. Results indicated that feeding SHB decreased DMI mainly due to the low palatability of the SHB pellet, as the cows consumed only 7.4% of the total TMR with 13.0% SHB pellet offered in the ration. However, milk yield was not affected during the IP and was higher than CON during the WP, leading to higher milk yield/DMI. Milk components were not affected, except for a tendency in decreased fat percentage. Milk fat produced by cows fed SHB had a higher proportion of oleate and bacteria-derived fatty acids than CON. The activity of the cows was not affected, except for a shorter overall lying time in SHB versus CON cows during the IP. Blood parameters related to immune function were not affected. Compared with CON, cows fed SHB had a lower cholesterol concentration during the whole experiment and higher β-hydroxybutyric acid during the WP, while a likely low-grade inflammation during the IP was indicated by higher ceruloplasmin and reactive oxidative metabolites. Other parameters related to liver health and inflammatory response were unaffected, except for a tendency for higher activity of alkaline phosphatase during IP and a lower activity of gamma-glutamyl transferase during WP in the SHB group versus CON. The bilirubin concentration was increased in cows fed SHB, suggesting a possible decrease in the clearance ability of the liver. Digestibility of the dry matter and protein and methane emission were not affected by feeding SHB. The urea, purine derivatives, and creatinine concentration in urine was unaffected, but cows fed SHB had higher N use efficiency and lower urine volume. Altogether, our data revealed a relatively low palatability of SHB affecting DMI with minimal biological effects, except for a likely low-grade inflammation, a higher N use efficiency, and a possible decrease in liver clearance. Overall, the data support the use of SHB as a safe feed ingredient for lactating dairy cows.

Novel details on the dissociation of casein micelle suspensions as a function of pH and temperature

Membrane filtration is a widespread process for fractionation and recombination of milk components. Although the dissociation of micellar caseins has been studied in detail in skim milk, it is important to better understand the dissociation dynamics occurring between the colloidal and noncolloidal fractions in systems of modified composition. This research aimed at understanding the dissociation of casein proteins in micellar fractions depleted of whey proteins. Casein micelle dispersions were tested at neutral pH and pH 6 (using glucono-δ-lactone as acidulant), after incubation at 4°C or 22°C, and compared with skim milk. The ionic composition of the serum phase was measured using inductively coupled plasma-mass spectrometry, and the protein distribution analyzed using reversed phase-HPLC coupled with mass spectrometry. When incubated at 22°C, there were no differences in casein micelle dissociation between skim milk and whey protein-depleted micelles (∼2.6% dissociated casein). No additional dissociation occurred by lowering the pH from 6.8 to 6 at 22°C, albeit there were more soluble ions at low pH (71% Ca and 65% P). At 4°C, there was an increased amount of β-casein found in the serum phase (23-33% of total β-casein). In addition, there was an uneven dissociation behavior of the various genetic β-casein variants, whereof A2 was more readily released with cooling. In skim milk, approximately 22%, 18%, and 14% of κ-, αS2, and αS1-caseins, respectively, were dissociated from the micellar phase upon cooling and acidification to pH 6.0. This was in contrast to whey protein-depleted casein suspensions, in which only 6%, 5%, and 3% of κ-, αS2, and αS1-caseins, respectively, had dissociated. The results suggested that the whey proteins in the serum phase play a role in the equilibrium between colloidal and soluble caseins in milk. This is of great relevance in processes such as cold membrane fractionation, where more attention should be given to the protein composition in the serum phase, especially when concentration is combined with fractionation of the serum proteins.

Impact of breastfeeding and other early-life factors on the development of the oral microbiome.

The oral cavity is home to the second most diverse microbiome in the human body. This community contributes to both oral and systemic health. Acquisition and development of the oral microbiome is a dynamic process that occurs over early life; however, data regarding longitudinal assembly of the infant oral microbiome is scarce. While numerous factors have been associated with the composition of the infant oral microbiome, early feeding practices (breastfeeding and the introduction of solids) appear to be the strongest determinants of the infant oral microbiome. In the present review, we draw together data on the maternal, infant, and environmental factors linked to the composition of the infant oral microbiome, with a focus on early nutrition. Given evidence that breastfeeding powerfully shapes the infant oral microbiome, the review explores potential mechanisms through which human milk components, including microbes, metabolites, oligosaccharides, and antimicrobial proteins, may interact with and shape the infant oral microbiome. Infancy is a unique period for the oral microbiome. By enhancing our understanding of oral microbiome assembly in early life, we may better support both oral and systemic health throughout the lifespan.

Immunomodulatory Effect of Infectious Disease of a Breastfed Child on the Cellular Composition of Breast Milk.

Recent studies suggest that the content of immune components in milk is influenced by the mother's health and also by the infant she feeds. We aimed to evaluate the effect of a child's respiratory tract infection on the cellular composition of breast milk (neutrophils, monocytes, eosinophils, lymphocytes, and their subpopulations). Twenty-six breastfeeding mothers whose children were hospitalized for respiratory tract infections were enrolled in the study. The control group consisted of 23 mothers of healthy children. Regarding the children, baseline laboratory blood tests were performed, and nasal swabs were taken for the presence of RS virus. In the next step, milk samples were collected from the mothers to assess the cellular composition of the milk, including neutrophils, monocytes, eosinophils, lymphocytes, and their subpopulations. Significantly higher percentages of T lymphocytes (helper and cytotoxic lymphocytes) were observed in the milk of the studied mothers. There was a significantly higher percentage of milk lymphocytes in the group of affected children with confirmed RSV etiology than in children with excluded RSV etiology. A significant positive correlation was observed between the duration of infection and the percentage of milk NK cells and between milk CD19 lymphocytes and the child's serum leukocytosis. This study may provide evidence of a link between cells in breast milk and disease in the breastfed infant. The severity of the infection, its duration, and the etiological agent of the infection may affect the cellular composition of milk.

Effects of Age, Calving Season and Specific Gravity of First Milking Colostrum on Milk Components and Somatic Cell Count in Early Lactation Anatolian Buffalo (Bubalus bubalis) Cows

This study aimed to evaluate the milk components and somatic cell count (SCC) of Anatolian buffalo cows at different stages of lactation (days 15th, 30th, 45th and 60th of lactation) by determining the effects of the age of the cow, calving season and specific gravity of colostrum (SGC) on these milk quality traits. The experiment was conducted using 62 healthy lactating primiparous and multiparous Anatolian buffalo cows at two private farms in Samsun, Türkiye. The SGC values at the second hour (first milking) after birth were measured using a colostrometer, and the milk components were analyzed using a milk analyser. In addition, the SCC in milk was measured with a portable cell counter. The data are divided into three groups: age (≤80 mo and >80 mo), calving season (spring and summer) and SGC (

Evaluation of Nutrition According to Milk Metabolites and Components in Seasonal Dependence in Dairy Cows

Abstract The objective of this study was to evaluate the nutrition according to the milk metabolites and components during the seasonal dependence of the dairy cows. In the summer time, it was confirmed that significantly lower content of milk protein and fat (P < 0.001) and lower milk, protein, and fat yields (P < 0.001) occurred, compared to the autumn period. The content of milk lactose was not statistically significant (P > 0.5). The evaluation of nutrition according to protein in milk and milk urea in the summer period was confirmed in the 2nd group of milk samples which represented 53 % of the group’s higher content of milk urea, higher content of urinary nitrogen excretion, and a lower nitrogen utilization efficiency compared to the 1st group of milk samples. The autumn period was confirmed in the 2nd group of milk samples which represented 53 % of the group with higher milk yield and lower content of milk proteins and milk fat compared to the 1st group of milk samples. The evaluation of nutrition using the analysed content of milk urea and proteins in milk represents a suitable tool for evaluating the impact of malnutrition or overfeeding of energy and protein on milk production and other components.