Cow's Milk Research Articles

Immunotherapy and biologics in the management of IgE-mediated food allergy: Systematic review and meta-analyses of efficacy and safety.

Human adults, children, and adolescents with IgE-mediated FA. IT and/or biologics. Placebo or standard-of-care (allergen avoidance). Efficacy (desensitization, sustained unresponsiveness (SU), remission), quality of life, and safety (systemic and local adverse reactions (AR)). The Cochrane RoB tool was used to assess the risk of bias. It was reported according to PRISMA and registered in PROSPERO CRD4202229828. After screening, 121 studies were included (111 for IT and 10 for biologics). Most studies had a high risk of bias and showed high heterogeneity in design and results. Metanalysis showed a positive effect of biologics and IT in terms of relative risk (RR) for achieving tolerance to the culprit food compared to avoidance or placebo. Omalizumab for any FA showed a RR of 2.17 [95% confidence interval: 1.22, 3.85]. For peanut allergy, oral IT (OIT) had a RR of 11.94 [1.76, 80.84] versus avoidance or placebo, sublingual IT (SLIT) had a RR of 3.00 [1.04, 8.66], and epicutaneous IT (EPIT) of 2.16 [1.56, 3.00]. OIT had a RR of 5.88 [2.27, 15.18] for cow's milk allergy, and of 3.43 [2.24, 5.27] for egg allergy. There was insufficient data on SLIT or EPIT for the treatment of egg and milk allergies. Most ARs reported were mild. For OIT the most common AR involved the gastrointestinal system and for EPIT, AR's most commonly affected the skin. There was limited data on severe or life-threatening ARs. There was limited evidence for long term efficacy and quality of life. In conclusion, biologics and IT, alone or in combination, are effective in achieving desensitization while on active treatment but more evidence is needed on long-term tolerance as current evidence is not of high quality. Adverse events while on therapy are generally mild to moderate but a long-term comprehensive safety profile is missing. There is a critical need to optimize and standardize desensitization protocols and outcome measures to facilitate our understanding of the efficacy and safety as well as to allow for comparison between interventions.

In Vitro and In Silico Characterization of N-Formylated Two-Peptide Bacteriocin from Enterococcus faecalis CAUM157 with Anti-Listeria Activity.

Enterococcus faecalis CAUM157 (KACC 81148BP), a Gram-positive bacteria isolated from raw cow's milk, was studied for its bacteriocin production. The antimicrobial activity of CAUM157 was attributed to a two-peptide class IIb bacteriocin with potent activity against food-borne pathogen Listeria monocytogenes and periodontal disease-causing pathogens (Prevotella intermedia KCTC 15693T and Fusobacterium nucleatum KCTC 2488T). M157 bacteriocins exhibit high temperature and pH stability and resist hydrolytic enzyme degradation and detergent denaturation, potentially due to their structural conformation. Based on amino acid sequence, M157A and M157B were predicted to be 5.176kDa and 5.182kDa in size, respectively. However, purified bacteriocins and chemically synthesized N-formylated M157 peptides both showed 5.204kDa (M157A) and 5.209kDa (M157B) molecular mass, confirming the formylation of the N-terminal methionine of both peptides produced by strain CAUM157. Furthermore, the strain demonstrated favorable growth and fermentation with minimal bacteriocin production when cultured in whey-based media, whereas a 1.0% tryptone or soytone supplementation resulted in higher bacteriocin production. Although Ent. faecalis CAUM157 innately harbors genes for virulence factors and antimicrobial resistance (e.g., tetracycline and erythromycin), its bacteriocin production is valuable in circumventing the need for live microorganisms, particularly in food applications for pathogen control.

Sensory profile and consumer perception of plant-based non-dairy milk jellies

This study focused on the organoleptic characteristics and consumers’ purchasing decision of milk jellies made with lactose-free cow milk and various plant-based non-dairy milk, including almond milk, coconut milk, oat milk and soymilk. All milk alternatives were measured for the CIE color system. The hedonic scale was used to evaluate product liking on appearance, color, taste, flavor, texture, and overall acceptability–still, the scaling test assigned for the purchasing intention. The results showed that milk alternatives' lightness, taste, and flavor preference affected consumers' liking and purchasing decisions for nondairy milk jellies. Preference mapping showed the relevance of the high lightness of milk alternatives and product acceptability. Coconut milk jelly was the most preferred, as did lactose-free milk jelly, while soymilk jelly was the least.

The effect of a first occurrence of digital dermatitis in early lactation on risk of culling and time-to-pregnancy in lactating dairy cows

Digital dermatitis (DD) is one of the most prevalent types of hoof lesion reported in dairy cows. This higher prevalence in dairy herds is consequential, as DD can not only lead be painful and lead to lameness in severe instance, but DD has also been found to have a negative long-term impact on reproductive per­formance and longevity. However, the impact of a first instance of DD in cows with no previous lesion history on these negative outcomes is largely unknown, as most previous studies do not account or the impact of lesion chronicity. The objective of this study was to evaluate the effect of a first occurrence of DD in the first 60 days in milk (DIM) in cows with no previous record­ed instance of DD on risk of culling and time-to-pregnancy in the first 180 DIM in dairy cows.

Development of novel lactose‐free Tigernut milk pudding with no added sugar and determination of physicochemical and organoleptic attributes

SummaryDeveloping health‐oriented novel products (e.g. no sugar added for diabetes and lactose‐free for lactose intolerance) supports diverse consumer needs, promotes healthier eating habits and fosters inclusivity in the food sector. This study aimed to develop a Tigernut milk pudding (TNP), an alternative to dairy‐based pudding and assess its physicochemical and sensory attributes. TNP was formulated by incorporating hydrocolloids κ‐carrageenan (KC), konjac powder (KP) and corn starch (CS), then compared with a commercial milk pudding (CMP) and traditionally prepared raw cow milk pudding (RMP). The crude protein, fat, ash and moisture levels ranged from 5.62% to 8.04%, 5.25% to 7.03%, 2.81% to 3.98% and 68.71% to 74.76% respectively. Lightness (L*) ranged from 69.87 to 77.89, while a* ranged from 0.36 to 0.86 and b* ranged from 8.13 to 9.97. Syneresis ranged from 4.98% to 8.00%, slightly higher than RMP (4.98%) and CMP (4.87%), while pH levels ranged from 6.31 to 6.89, nearly acidic to neutral pH range. Total soluble solids ranged from 2.90 °Brix to 3.67 °Brix. The bacterial count was in the marginal range below 105 CFU g−1, with no presence of Salmonella spp. or E. coli. Total antioxidant properties showed total flavonoid and phenolics, ranging from 306.24 mg QE/100 g to 358.58 mg QE/100 g and 39.06 mg GAE/100 g to 54.81 mg GAE/100 g respectively. An overall organoleptic rate of 3.50 was attained with 0.25% KC, 0.50% KP and 2.50% CS, achieving a desired texture comparable to CMP. The novel study on using Tigernut milk in pudding explores its plant‐based, vegan‐friendly, lactose‐free attributes as a healthy dairy milk alternative. With desirable physicochemical properties, promising improved nutrition, potential health benefits and possible contribution to food security and enhanced resource efficiency, TNP could be considered for commercialisation.

Influence of stimulating basics on the level of iron in the blood of Saanen kids

Goat milk is becoming increasingly attractive for the food sector due to some advantages compared to cow milk: it has higher fat content, protein levels, magnesium, potassium, phosphorus, cobalt, vitamins B1, B2, C, and some amino acids. The Saanen breed is the most attractive for farms since, along with the qualitative superiority of milk, this breed is characterized by increased milk yield. Currently, the main goal of research in goat breeding is to preserve and improve animals’ genetic potential under intensive exploitation conditions when any environmental factor (incredibly inadequate feeding) can negatively affect the productive qualities of animals. The period of their prenatal and early postnatal ontogenesis is especially significant. One of the critical indicators of metabolic processes in the body of young animals is iron, which enhances oxidative processes and promotes the reproduction of erythrocyte hemoglobin. The study showed the influence of the age factor on an increase in the concentration of iron in the blood and better absorption of iron in the presence of copper in the body. The effectiveness of using an iron-containing preparation in combination with protein hydrolysate, a source of protein necessary for the formation of enzymes and hormones involved in regulating iron metabolism in the body, has been noted.

Newborn care knowledge and practices among care givers of newborns and young infants attending a regional referral hospital in Southwestern Uganda.

A child born in developing countries has a 10 times higher mortality risk compared to one born in developed countries. Uganda still struggles with a high neonatal mortality rate at 27/1000 live births. Majority of these death occur in the community when children are under the sole care of their parents and guardian. Lack of knowledge in new born care, inappropriate new born care practices are some of the contributors to neonatal mortality in Uganda. Little is known about parent/caregivers' knowledge, practices and what influences these practices while caring for the newborns. We systematically studied and documented newborn care knowledge, practices and associated factors among parents and care givers. To assess new born care knowledge, practices and associated factors among parents and care givers attending MRRH. We carried out a quantitative cross section methods study among caregivers of children from birth to six weeks of life attending a regional referral hospital in south western Uganda. Using pretested structured questionnaires, data was collected about care givers' new born care knowledge, practices and the associated factors. Data analysis was done using Stata version 17.0. We interviewed 370 caregivers, majority of whom were the biological mothers at 86%. Mean age was 26 years, 14% were unemployed and 74% had monthly earning below the poverty line. Mothers had a high antenatal care attendance of 97.6% and 96.2% of the deliveries were at a health facility Care givers had variant knowledge of essential newborn care with associated incorrect practices. Majority (84.6%) of the respondents reported obliviousness to putting anything in the babies' eyes at birth, however, breastmilk, water and saliva were reportedly put in the babies' eyes at birth by some caregivers. Hand washing was not practiced at all in 16.2% of the caregivers before handling the newborn. About 7.4% of the new borns received a bath within 24 hours of delivery and 19% reported use of herbs. Caregivers practiced adequate thermal care 87%. Cord care practices were inappropriate in 36.5%. Only 21% of the respondents reported initiation of breast feeding within 1 hour of birth, Prelacteal feeds were given by 37.6% of the care givers, water being the commonest prelacteal feed followed by cow's milk at 40.4 and 18.4% respectively. Majority of the respondents had below average knowledge about danger signs in the newborn where 63% and mean score for knowledge about danger signs was 44%. Caretaker's age and relationship with the newborn were found to have a statistically significant associated to knowledge of danger signs in the newborn baby. There are variable incorrect practices in the essential new born care and low knowledge and awareness of danger signs among caregivers of newborn babies. There is high health center deliveries and antenatal care attendance among the respondents could be used as an opportunity to increase caregiver awareness about the inappropriate practices in essential newborn care and the danger signs in a newborn.

5 Rumen microbiome and metabolome in dairy cattle performance

Abstract Cattle rumen microbiome converts fibrous feed to nutrients that directly influence cattle’s growth and performance. Recent research has revealed the composition and function of rumen microbiome can affect many economically important traits in cattle such as feed efficiency, milk/meat yield and quality, methane emission, metabolic health and so on. In this presentation, the research on the assessment of to what extent the rumen microbiome and its metabolites, as well as host metabolites contribute to milk production and quality traits will be focused and discussed. It has been evident that some dairy cows can produce large amounts of milk under the same nutritional and management conditions. Recent research has revealed that in addition to host genetics and diet, parity and days in milk of dairy cows can affect the rumen microbiota, and both core and pan rumen bacteriome can potentially contribute to variations of milk production traits. Additionally, the analysis of rumen metagenomics and metabolomics of dairy cows with varied milk production yield showed that some key bacterial taxa (for example, Prevotella species), and their functions (such as branched-chain amino acids biosynthesis, methanogenesis), some rumen microbial metabolites (mainly amino acids, carboxylic acids, and fatty acids) significantly differed between high and low production cows. Further integrated analysis with serum metabolomics of the cos revealed the varied contributions of rumen microbial composition, functions, metabolites, and the serum metabolites to the milk protein yield of a dairy cow, a potential new trait that can be used for high-quality milk production, respectively. The fundamental understanding of the role of rumen microbiome and its metabolome contributing to milk yield and protein yield traits can provide novel insights into future manipulation of rumen microbiome to enhance milk production and quality.

Optimization of the stabilizers and cow milk levels for the production of camel milk-based yogurt using response surface methodology

The production of yoghurt from camel milk (CML) is limited due to weak gel formation. As a trial to produce CML-set-type yoghurt, sixteen treatments were prepared from CML, cow milk, and stabilizers (gelatin and gum-Arabic; 1:1) using a D-optimal design. A desirable hardness of set-type yoghurt was obtained from CML (56%), cow milk (42%), and stabilizers (2%). Another study was designed to choose the best combination of stabilizers (1, 1.5 or 2% of gelatin in combination with 1% of gum-Arabic). The increased levels of gelatin resulted in a significant increase (p < 0.05) in the viscosity and consistency index of yoghurt milk, an increase (p < 0.05) in yoghurt hardness and viscosity, and a reduction in syneresis (p < 0.05). In conclusion, an acceptable set-type yoghurt can be produced by using a combination of CML and cow milk (1.3:1) and a stabilizers' mixture of gelatin (1 or 1.5%) and gum-Arabic (1%).

ELISA based Monitoring and Quantification of Tetracycline Residues in Fresh and Powdered Cow Milk Commercialized in Constantine Region (Northeast Algeria)

Background: This study aimed to identify tetracycline residues in milk consumed in the region of Constantine (northeast Algeria) using ELISA based tetracyclin kit. Methods: A total of 180 samples were analyzed (fresh cow milk and imported powdered milk). To compare ELISA and HPLC detection values, 22 fresh milk ELISA positive samples were confirmed by HPLC analysis. Result: 92.5% of fresh milk samples contained tetracycline residues at values between 5 and 74 µg/L and 33.3% of the samples showed concentrations between 49 and 74 µg/L, that exceed the MRLs recommended by the FDA. No significant differences (p greater than 0.01) were found between the values obtained by the two methods.

Draft genome sequencing of Enterococcus avium strains isolated from bovine mastitis.

We performed whole-genome sequencing of four multidrug-resistant Enterococcus avium strains isolated from milk (4M1), feces (4F1 and 4F2), and farm soil (4S1) of mastitic dairy cows. The draft genomes of E. avium strains 4M1, 4F1, 4F2, and 4S1 were approximately 4.2 Mbp, with 39.1% GC content and 66.5× coverage.

Dynamic Gastrointestinal Digestion of Bovine, Caprine and Ovine Milk Reconstituted from Commercial Whole Milk Powders.

The global dairy market has been increasingly diversified with more dairy product offerings of milk products from different animal species. Meanwhile, milk powders remain the main exported dairy product format due to their ease of transportation. In this work, we studied the structural changes, protein hydrolysis and nutrient delivery during dynamic gastric digestion and small intestinal digestion of cow, goat and sheep milk reconstituted from commercial whole milk powders. The results show that the reconstituted milks digest similarly to processed fresh milk. The digestion behaviors of the three reconstituted ruminant milks are broadly similar (gastric coagulation, kinetics of gastric emptying of protein and fat and the high digestibility in the small intestine) with some differences, which are likely contributed by the processing history of the milk powders. The delivery of individual amino acids to the small intestine differed between the early and late stages of gastric digestion, which were primarily affected by the abundance of amino acids in caseins and whey proteins but also by the difference between milk types associated with their gastric coagulation behaviors. This work showed that powdered milk is similar to fresh processed milk in digestion behavior, and the inherent differences between ruminant milks can be modified by processing treatments.

Challenges When Assessing Water-Related Environmental Impacts of Livestock Farming: A Case Study of a Cow Milk Production System in Catalonia

Water availability is a local issue of growing importance in Mediterranean areas where water scarcity linked to climate change and population growth is already leading to increased competition for this resource. This study is aimed at the following: (i) assessing the water-related environmental impacts (water use, freshwater ecotoxicity and eutrophication, marine eutrophication, acidification, human toxicity, and ionizing radiation) along the production chain of cow milk in Catalonia, northeastern Spain; and (ii) addressing the issues encountered (modelling choices, data gaps and inconsistencies) which t can affect the quality of results when performing a water-footprint comprehensive assessment, focusing on water use and associated water scarcity impacts. The scope included the process from the extraction of raw materials up to the distribution of the packaged fat- and protein-corrected milk to the distribution centres of the supermarket chains and markets. Results showed the farm stage to be determinant (contributing to over 60% of the impact), due to the impact of feed production. Impact results were in the range of the European benchmark given by the Product Environmental Footprint Category Rules for dairy products, except for the water scarcity footprint which was one order of magnitude larger than the reference value, due to water scarcity in Spain. Considering compound feed ingredients with a lower water scarcity footprint, and research into slurry treatment for its use as irrigation and cleaning water (without compromising safety and health) could help reduce this impact. Water accounting and traceability along the production chain could support the dairy industry to take responsibility for the consequences of their production choices.

Effect of pulsed ultraviolet light on the degree of antigenicity and hydrolysis in cow's milk proteins

AbstractIn order to reduce the quantity of allergens that are causing harm to consumer, it is imperative that the proteins found in cow's milk undergo controlled hydrolysis. Investigated were the effects of different pulsed UV light fluences (0.1–10 J/cm2) on samples of commercial cow's milk proteins (CCMP: casein (CN), α‐lactalbumin (α‐LA), and β‐lactoglobulin (β‐LG)) and reconstituted cow's milk proteins (RCMP). The degree of hydrolysis (DH) and sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE) profiles in RCMP and CCMP, as well as the degree of antigenicity in RCMP, were assessed for this purpose. The DH increased in CCMP and RCMP samples at the highest fluence applied. SDS PAGE profiles showed a decrease in the intensity of the bands of the CCMP samples for fluences of 5 and 10 J/cm2; however, this was not the case for α‐LA. Finally, the degrees of antigenicity measured with Elisa assay in CN and β‐LG were reduced by 24% and 47%, respectively, at a fluence of 10 J/cm2. Therefore, this nonthermal technology could be an alternative to conventional treatments to reduce the allergenic potential of cow's milk proteins; however, future clinical trials to confirm an anti‐allergenic effect on consumer are needed.Practical ApplicationsPulsed UV light is a nonthermal technology of great relevance in the dairy industry. The aim of this article was to generate knowledge of the effect of pulsed UV light on allergenic dairy proteins. Therefore, this article aimed to demonstrate that pulsed UV light can be a novelty compared with conventional methods of inactivation of commercial and reconstituted dairy allergenic proteins.

A real-world cross-sectional study evaluating the role of an oral amino acid-based supplement in nutrient intake by preschoolers on a cow's milk elimination diet.

Food allergy has several negative nutritional consequences and may persist beyond the first year of lives. This study aimed to assess the role of a complete oral amino acid-based supplement in the diet of children on cow's milk protein elimination diet because of food allergy. This study included two groups of children aged 1-5 years paired by age and socioeconomic status: (1) study group, on cow's milk protein elimination diet plus an oral amino acid-based supplement, and (2) control group, on cow's milk protein elimination diet. Sociodemographic, clinical, anthropometric, and dietary data were obtained through online interviews. Two 24-h dietary recalls were collected on nonconsecutive days. Both groups comprised mostly boys. The study group presented lower values of body mass index. The frequency of feeding difficulties was similar between groups. The study group had a higher intake of energy, protein, carbohydrates, calcium, iron, zinc, phosphorus, magnesium, copper, selenium, vitamins D, E, B1, B2, B6, and B12, niacin, and folic acid compared to the control group. A higher proportion of children in the study group had adequate intake according to the recommendations made for energy, carbohydrates, iron, phosphorus, selenium, vitamins A, D, E, B1, B2, and B6, and folic acid. The use of a complete oral amino acid-based supplement has a positive effect on the diet quality of preschoolers on cow's milk elimination diet because of food allergy, promoting higher intake of energy, calcium, vitamin D, and other essential nutrients.

Knowledge and Attitude of Community Pharmacists Toward Cow Milk Protein Allergy Complications and Treatment in Children: A Cross-Sectional Study in Sudan.

Cow's milk protein allergy is the most frequent type of food allergy in newborns and young children. It affects numerous body systems. A community pharmacist possessing adequate knowledge and appropriate practices is crucial for the management of the disease. : This study aimed to assess the knowledge and attitude of community pharmacists toward the complications and treatment of cow milk protein allergy. A descriptive cross-sectional study was conducted among 332 randomly selected community pharmacists in the Capital of Sudan (Khartoum state). Data were collected using a validated and internally consistent (Cronbach Alpha = 0.712) self-administered questionnaire Descriptive statistics and Chi-square analysis were conducted using Statistical Package for the Social Sciences version 25. The response rate was 95.8%, and about 47.8% of the population had 1-5 years of experience as community pharmacists, and 37.4% of them had a post-graduate degree. Only 30.8% of respondents had good knowledge, while 40.6% had poor knowledge, and 28.6% had scored as having fair knowledge of complications of Cow's milk protein allergy. Regarding knowledge toward treatment, 65.1% of respondents had a poor knowledge, 24.5% had fair knowledge, and only 10.4% had good knowledge. Overall, 39.62% of participants had a positive attitude, and 60.38% had a negative attitude toward this disease. Data analysis showed no significant association between the sociodemographic characteristics of respondents and their knowledge and attitude. Community pharmacists in Khartoum State had inadequate knowledge and attitude about the complications and treatment of cow milk protein allergy. As a result, we recommend the implementation of strategies to raise pharmacists' knowledge and attitude.

Basophil allergen threshold sensitivity to casein (casein-specific CD-sens) predicts allergic reactions at a milk challenge in most but not all patients.

The basophil activation test is an emerging clinical tool in the diagnosis of cow's milk allergy (CMA). The aim was to assess the association between the basophil allergen threshold sensitivity to the major milk protein casein (casein-specific CD-sens), the levels of milk- and casein-specific Immunoglobulin E antibodies (IgE-ab), and the severity of allergic reactions at milk challenges. We enrolled 34 patients aged 5-15 (median 9) years who underwent a double-blind placebo-controlled milk-challenge (DBPCMC) as screening before inclusion in an oral immunotherapy study for CMA. The severity of the allergic reaction at the DBPCMC was graded using Sampson's severity score. Venous blood was drawn before the DBPCMC. Milk- and casein-specific IgE-ab were analyzed. Following in vitro stimulation of basophils with casein, casein-specific CD-sens, was determined. Thirty-three patients completed the DBPCMC. There were strong correlations between casein-specific CD-sens and IgE-ab to milk (rs = 0.682, p < .001), and between casein-specific CD-sens and IgE-ab to casein (rs = 0.823, p < .001). There was a correlation between the severity of the allergic reaction and casein-specific CD-sens level (rs = 0.395, p = .041) and an inverse correlation between casein-specific CD-sens level and the cumulative dose of milk protein to which the patient reacted at the DBPCMC (rs = -0.418, p = .027). Among the 30 patients with an allergic reaction at the DBPCMC, 67% had positive casein-specific CD-sens, 23% had negative casein-specific CD-sens, and 10% were declared non-responders. Two thirds of those reacting at the DBPMC had positive casein-specific CD-sens, but reactions also occurred despite negative casein-specific CD-sens. The association between casein-specific CD-sens and the severity of the allergic reaction and cumulative dose of milk protein, respectively, was moderate.

Sensitive and rapid detection of ciprofloxacin and ofloxacin in aqueous samples by a facile and green synthesized copper nanocluster as a turn-on fluorescent probe

The present method reports a rapid, inexpensive and sensitive sensing system based on fluorescence turn-on strategy for trace detection of ciprofloxacin (CIP) and ofloxacin (OFL) in aqueous samples. In a one pot method, copper nanocluster whose dimensions are less than 15 nm, were easily prepared and decorated with sodium gluconate (Gl@CuNCs) as a biocompatible material.The Gl@CuNCs were characterized with XRD, TEM, DLS, TG-DTA techniques as well UV–Vis, FT-IR and fluorescence spectroscopies.The maximum fluorescence emission of Gl@CuNCs at 414 nm with excitation at 322 nm shifted to higher wavelength upon addition of CIP and OFL. A good linear relationship between fluorescence emission and drug concentration was achieved in the concentration range of 0.005–0.3 μg mL−1 (15–900 nM for CIP and 14–830 nM for OFL). The limits of detection (LOD) for the determinations of CIP and OFL were calculated to be 9 and 8 nM, respectively. Furthermore, even a 100-fold higher concentration of interfering species had no significant effect on the detection of CIP and OFL. The proposed method was successfully used to determine CIP and OFL in drinking water, cow milk, human urine and serum samples with satisfactory recoveries.

A comprehensive integration of factors affecting vitamin B12 concentration in milk of Holstein cows: genetic variability, milk productivity, animal characteristics, and feeding management

Daily vitamin B12 (VB12) requirements of humans can naturally be fulfilled by animal product consumption, especially products from ruminants because of bacteria dwelling in their rumen. Indeed, only bacteria can synthesize this vitamin. Milk is hence an excellent source of VB12. This cross-sectional study was undertaken to unravel factors, such as genetic variation, diet and cow characteristics, and milk production, explaining the large variation in milk B12 concentration among cows by using an integrative approach. Milk samples from 2 consecutive milkings were collected from 3,533 Canadian Holstein cows (1,239 first, 932 s, and 1,362 third and more lactations) located in 99 herds with various feeding management. For genetic variation analysis purpose, pedigrees were traced back for 3 complete generations for each sire and dam. A total of 10,021 identities were used in the subsequent genetic analyses. Milk VB12 averaged 4.2 ng/mL with a range between 0.7 and 9.0 ng/mL. Dietary fiber (NDF from forage, dietary NDF, ADF, and lignin) increased and dietary components related to energy (non-fiber carbohydrate, starch, net energy of lactation, and percentage of concentrate) decreased VB12 in milk. Milk VB12 varied with days in milk, with a similar pattern as milk fat and protein concentration lactation curves. Milk VB12 increased as age at calving increased. When disregarding the herd variance, heritability value was 0.37, meaning that milk VB12 can be modified by genetic selection. The final model including factors related to the diet, animal characteristics and milk productivity, and genetic variation explained 79% (pseudo-R2) of the milk VB12 variation. When excluding the random effect of the cow, i.e., excluding the animal and genetic relationships, the pseudo-R2 dropped to 43%, reinforcing the importance of genetic variation in explaining milk VB12 variation. To our knowledge, the present study is the most comprehensive evaluation of factors affecting milk VB12 variation including the greatest number of cows from various lactation stages.

Interpretable machine learning reveals microbiome signatures strongly associated with dairy cow milk urea nitrogen

Interpretable machine learning reveals microbiome signatures strongly associated with dairy cow milk urea nitrogen