The aim of this study was to investigate the association of the rs43389227, rs43390124 and rs482883241 single-nucleotide polymorphisms (SNPs) of the bovine calcium channel, voltage-dependent, alpha-2/delta subunit 1 (CACNA2D1) gene with milk yield and quality traits in Holstein cattle. For this purpose, 166 Holstein dairy cows were genotyped for these three SNPs. Correlation analyses showed that the rs43389227 SNP was associated with 305-day milk yield (P < 0.05). Besides, rs43390124 SNP was found to be associated not only with 305-day milk yield but also with milk fat, milk quality traits, somatic cell score, electrical conductivity and pH (P < 0.05). The results of this study suggest that the rs43389227 and rs43390124 SNPs could be used in breeding for the improvement of milk yield and milk quality in cattle. Furthermore, based on its association with mastitis related traits, the rs43390124 SNP was considered as a potential indicator of mastitis susceptibility.

We investigated the effect of adding 3 levels of sodium bicarbonate (SB: 0, 0.74 and 1.47% of total mixed ration (TMR) dry matter) to a low-roughage TMR (20.8% wheat silage, 9% wheat hay and 2.3% clover hay) on feed intake, production (milk and milk-component yields), whole-tract apparent digestibility, rumen pH and rumination time. After 2 wk of receiving the same TMR, 42 mid-lactation multiparous cows were blocked into groups of 3 according to their dry matter intake and energy-corrected milk (ECM) yield and divided into 3 treatment groups. The experimental rations were fed for 7 wk while monitoring intake, production and rumination. Rumen pH was measured after 6 h without access to feed and 6 h after feeding (at 0600 and 1500 h) every other week, and feces samples were taken for whole-tract apparent digestibility at wk 7. Dietary SB level did not affect intake, ECM yield, digestibility or efficiency. Dietary SB concentration negatively correlated with daily rumination time but did not affect rumen pH measured before or after feeding. Lactating cows may, therefore, increase their rumination time to compensate for lack of buffer but overall, removing SB from a wheat-based, low roughage TMR does not impair intake or milk or milk-component yields.

Meeting the buffer requirements of concentrate-fed dairy cows is a challenging task. We evaluated the effect of supplementing different feed additives to diets containing K2CO3 on feed intake, nutrient digestion and milk production of dairy cows. Eight peak lactation high yielding Holstein cows were used in a replicated 4 × 4 Latin square design with 4 periods of 21 d (14 d for diet adaptation and 7 d for sampling and data collection). Treatments comprised control (a diet containing a rumen buffer with the active component of K2CO3 at 6% of dietary dry matter (DDM) and containing 10% K); yeast, the control diet supplemented with live Saccharomyces cerevisiae yeast (0.06% of DDM); essential oils (EO), the control diet supplemented with essential oils (0.02% of DDM) and; peptides, the control diet supplemented with biogenic peptides (0.16% of DDM). Feed intake was greater (P < 0.001) in the yeast treatment (33.2 kg/d) compared to the others (30.9 to 32.1 kg/d). Dry matter and starch digestibilities were similar across the treatments. Cows that were supplemented with EO had a greater energy-corrected milk yield than control, and those supplemented with yeast and peptides were intermediate. Milk protein production was greater (P < 0.01) in EO and peptide treatments than in the control, with yeast treatment intermediate. In high-concentrate diets containing K2CO3, supplementing with yeast increased feed intake while supplementing wth essential oils increased energy-corrected milk yield, with small effects on milk protein yield.

This study aimed to evaluate the effect of marine-based rumen buffer (Lithothamnium calcareum) supplementation on rumen health as well as milk yield and composition and also behavioural and metabolic parameters of dairy cows. Thirty-six lactating multiparous Holstein cows were used with a milk yield average of 39 kg/d and 64 d in milk. The experiment was conducted over 60 d using two groups: control (CON; n = 18) was supplemented with sodium bicarbonate at 1.1% dry matter and a treatment group that received Lithothamnium calcareum at 0.5% of dry matter (LITHO; n = 18). Each group was fed daily with the buffers mixed to the total mixed ration containing 29.28% starch. Ruminal fluid collections were performed weekly to evaluate pH and volatile fatty acids. Feeding behaviour data were obtained through automatic feeders, while overall behavioural data were obtained using monitoring collars. Milk yield was recorded daily and adjusted for fat and energy. Milk samples were retrieved once weekly for analysis of fat, protein, lactose and total solids. Blood samples were collected weekly for metabolic analysis and faecal samples were collected weekly to evaluate pH and starch concentrations. LITHO produced more fat- and energy-corrected milk (P ≤ 0.01) as well as the highest percentage of fat and solids (P < 0.05) when compared to the CON group. Data on feeding behaviour showed an increased eating time (P ≤ 0.01) in the LITHO group but a higher eating rate (P < 0.01) in the CON group. Animals from the LITHO group had lower faecal pH (P < 0.05). The treatment did not affect dry matter intake, animal behaviour, ruminal acid–base balance, or faecal starch. In summary, Lithothamnium calcareum supplementation at 0.5% of dry matter improved milk yield, milk composition and, presumably, feed conversion efficiency.

Our aim was to evaluate a foster cow–calf rearing system on the adoption or acceptance of fostered calves, milk production and udder health, as well as calf health and weight gain, and to compare this fostering system to traditional rearing. The foster group (FG) consisted of 8 cows each suckling 3 fostered calves with continuous contact. The control group (CG) was a conventional milking system, whereby cows and control calves were kept separate. The duration of the experiment was 8 weeks. Behavioural observations were carried out after the calves were introduced to the FG to find out if and how many calves were adopted or accepted (complete or incomplete maternal behaviour expressed, respectively). Milk production (let down) was recorded daily for CG and once a week for FG (after 8-h of no suckling). Milk samples were collected once a week from both groups for California mastitis test, Wisconsin test, and somatic cell count. A daily record of the incidence of diarrhoea was made on the calves and they were weighed once a week. Results showed that six of the eight FC cows had adopted the three calves, whilst one adopted two calves and accepted one and one adopted one calf and accepted two. One other cow refused all three calves from the outset and was removed from the study. Milk production at a single milking was 2.52 ± 1.04 (mean ± sd) 10.07 ± 0.76 l for FG and CG, respectively. Udder health improved over time in FG as evidenced by a progressive reduction in SCC. The average weight gain for FG calves was higher than for CG (700.7 ± 97.7 vs. 471 ± 188.7 g/d). In conclusion, the foster-cow rearing system was well received by most cows, the udder health on FG showed an improvement in comparison to the CG, and a higher weight gain was found in FC compared to the CC in a traditional rearing system.

This research paper compares fertility traits, health indicators and health management routines of Swiss dairy farms characterized by short vs. long productive lifespans (SPL vs. LPL). We evaluated whether a longer productive lifespan will result in poorer cow health based on herdbook data from breeders associations (n = 142), farm questionnaire data (n = 67), veterinary treatment data (n = 64) and data obtained during farm visits (n = 30). Dairy farms were selected in such a way that they contrasted in terms of length of productive lifespan, but were representative of the Swiss dairy sector. Fertility performance was better on farms with LPL indicated by a lower number of inseminations per heifer, shorter average number of days open and shorter calving intervals. Consistently, the proportion of antibiotic veterinary treatments due to fertility problems was by tendency higher on SPL farms, as was the number of antibiotic treatments due to other problems (i.e. other than fertility, udder or locomotion problems). Other types of veterinary medical treatments did not differ by productive lifespan profiles. Average somatic cell score and proportions of test day records with elevated somatic cell count (SCC) were significantly higher on farms with LPL. However, this increase was smaller than what could be expected due to the age difference between contrasting productive lifespan profiles and was not associated with higher treatment incidences for clinical mastitis. Locomotion scores and lameness incidence did not differ by productive lifespan profile. Apart from a slightly higher proportion of farms with LPL practicing abrupt drying off, cow health management routines did not differ significantly between farms of contrasting productive lifespans. We conclude that a longer productive lifespan is not at the expense of health, even if the SCC level increased with age. Fertility, limb and udder health should be the main focus when aiming for a long productive lifespan.

This research paper describes a test of association of sire with susceptibility to mastitis, using a custom-bred population of dairy cattle. We hypothesised that sire daughters ranked as more resistant to intramammary infections in their first two lactations would be more resistant to an intramammary challenge in their third lactation. Mastitis phenotypes were generated for a Holstein-Friesian × Jersey crossbred research herd of 864 cows, bred from six defined sires and managed as two cohorts in a seasonal calving system in New Zealand. Naturally occurring new intramammary infections (IMI) and clinical mastitis (CM) were monitored in their first two lactations from herd records, milking staff observations and bacteriology of quarter milk samples collected at four time-points during each lactation. The animals retained to their third lactation were then exposed to a single intramammary challenge with Streptococcus uberis. We used a relative risk (RR) analysis to rank performance of sire daughters for pathogen-specific phenotypes for new IMI and CM, and somatic cell count (SCC) traits, and their clinical outcomes to the challenge. Generally, daughters of sire B had the highest RR for new IMI or CM by a major pathogen, whereas daughters of sires A and C had a consistently lower risk. The RR for sires E, D and F were intermediate and inconsistent across major pathogens. Daughters of sire B ranked highest for all CM cases and SCC traits whereas sires A and C ranked lowest. Following intramammary challenge, daughters of sires A and C were more likely to develop CM, whereas daughters of sire B and F were less likely to develop CM. Thus, the hypothesis was rejected. The results revealed strong associations between sire and pathogen-specific mastitis phenotypes, and validated use of SCC and CM traits in sire selection and breeding programmes to improve mastitis resistance.

This study describes the spread of intramammary infections (IMI) during the first lactation of heifers that were naturally infected with Staphylococcus aureus before parturition and introduced into a herd with a high prevalence of this organism. The heifers were monitored during their first lactation to determine potential spread and persistence of IMI and to characterize the isolates that caused IMI. Milk samples were obtained from all the cows in the lactating herd at the beginning of the study and one year later. S. aureus isolated at both these sampling times were compared with those obtained from the heifers to analyse their clonal and phylogenetic relationships, employing pulse-field gel electrophoresis (PFGE), multi-locus sequence typing and Fourier transform infrared spectroscopy. Most S. aureus isolated from mammary secretions of heifers before parturition established chronic IMI during the first lactation. PFGE typing discriminated 3 clusters that were associated with origin of isolates, number of lactations and clonal complex. Differences both in the presence and expression of genes associated with virulence determinants among the major pulsotypes infecting lactating cows and those from heifers that developed persistent IMI were detected, which are indicative of distinct adaptive capacities to generate IMI.

We address the hypothesis that bioinformatics analysis can effectively identify miRNAs and target genes associated with the innate immune response to Staphylococcus aureus-induced mastitis in cows. Gram-positive bacteria, such as S. aureus, are some of the mastitis pathogens that cause subclinical infection and pose one of the most severe threats to dairy cattle due to their contagiousness and incidence. Therefore, newer molecular markers must be identified to predict bovine mastitis non-invasively with low error and high specificity. To address this, we conducted in-silico analysis to identify hub genes related to the innate immune system specific to the S. aureus pathogen in subclinical mastitis infections in cows, and experimental validation of the miRNAs of these determined hub genes was completed. As a result of bioinformatic analysis, we identified five hub genes (TLR2, MYD88, CASP4, NOD2 and TBK1) related to the innate immune system that are specific to the S. aureus pathogen. We investigated the expression levels of miRNAs associated with these genes (bta-miR-15a, bta-miR-16b, bta-miR-23a, bta-miR-27a-3p, bta-miR-103, bta-miR-146b, and bta-mir-374b) using real-time quantitative PCR. Except for bta-miR-15a and bta-miR-23a, all miRNAs studied varied in expression between healthy cows and cows with subclinical mastitis infected with S. aureus. This is the first study to bioinformatically determine hub genes specific to the innate immune system and the S. aureus pathogen in subclinical mastitis infections and then validate the determined miRNAs in milk between healthy and subclinical mastitis infected cows. The findings of our study expand our understanding of the roles of these miRNAs in cows with S. aureus-infected subclinical mastitis.

Milk fat synthesis is tightly regulated by hormones and growth factors. Leptin is a versatile peptide hormone that exerts pleiotropic effects on metabolic pathways. In this study, we evaluated the expression and function of leptin and its long form receptor OB-Rb in dairy cow mammary tissues from different physiological stages and in cultured mammary epithelial cells. The results showed that the expression of leptin and OB-Rb were significantly higher in the mammary tissues of lactating cows as compared with dry cows, suggesting that they are related to milk component synthesis. In cultured dairy cow mammary epithelial cells, leptin treatment significantly increased OB-Rb expression and intracellular triacylglycerol content. Transcriptome analysis identified the difference in gene expression between leptin treated cells and control cells, and 317 differentially expressed genes were identified. Gene ontology and pathway mapping showed that lipid metabolism-related gene expression increased and signal transduction pathway-related genes were the most significantly enriched. Mechanistic studies showed that leptin stimulation enhanced sterol regulatory element-binding protein 1 expression via activating the phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) signaling pathway, which in turn up-regulated the expression of genes related to milk fat synthesis. Moreover, we found that fatty acid synthesis precursors, acetate and β-hydroxybutyrate, could positively regulate the expression of leptin and OB-Rb in bovine mammary epithelial cells, thereby potentially increasing milk fat synthesis. Our study provided novel evidence in the regulation of leptin on milk fat production in mammary glands of dairy cows, as well as experimental basis for artificial regulation of milk fat

Milk is a fundamental food matrix that is widely consumed. Milk fat is important for producing dairy products such as butter, cream, cheese and whole milk powder. Aside from flavour, it has been linked to human health and its chemistry can be modulated by various means towards a more healthy fatty acid profile. Industry and stakeholders have different interests in milk fat, based on specific policies which reflect the type of research and funding initiatives currently performed in different countries. This position paper summarizes the current state-of-the-art with regards to milk fat research and industry as well as stakeholder initiatives, and then highlights new developments based on information gathered from North America (United States and Mexico), Europe (United Kingdom, Spain, Italy, and Finland), Africa (Egypt), Asia (China and Bangladesh) and Oceania (New Zealand). South America is an important contributor to the dairy industry but will not be considered here and thus this paper must be considered cross-continental rather than global. This manuscript intends to show a wide ‘picture’ of milk fat from different angles in different parts of the globe.

In free-range (extensive) dairy farming the wealth and type of consumed vegetation positively affects milk characteristics such as flavour. As free-range feeding is included as a requirement in the specifications of certain protected designation of origin cheeses, there is a need to develop methodology to identify different animal feeding regimes. This study evaluated goat milk based on two feeding regimes, namely free-range and intensive (controlled diet fed exclusively at the farm). Conventional mid-infrared spectroscopy (4000–400 cm−1) using Fourier transformed infrared technology was assessed for the discrimination of 65 milk samples obtained during spring time from the same dairy farm and breed of animals, which could be categorized as intensive and free-range feeding regimes. Chemometric analysis, whereby a supervised method of orthogonal partial least-square-discriminant analysis was applied, was shown to be essential for interpreting the spectroscopic data. The produced model returned distinct clusters of the two milk types, intensive and free-range with 95.4% correct classification accuracy.

We evaluated the effect of including 0, 2, 5, 10, 20, 40 and 100% of individual milk from cows at extended lactation (more than 315 d in milk) on milk ethanol stability (MES), pH, acidity and ionic calcium (iCa) of the bulk tank milk. The study was carried out on commercial dairy farms in Brazil using milk samples of individual cows, bulk tank and their mixtures. Samples of individual cows were classified as low (≤74%), intermediate (76–78%) and high (≥80%) stability classes based on MES. Data were submitted to Anova, multiple linear regression analysis and logistic regression. Low, intermediate and high stability milk had values of 108, 89 and 79 mg/dl for iCa, and 21, 23 and 20 for acidity, respectively, but similar values for pH and DIM. MES increased linearly with pH, while it decreased linearly with iCa. When individual milks presented higher MES than bulk tank milk, MES and pH increased linearly with individual milk inclusion and DIM, while iCa decreased with individual milk inclusion. When individual milks presented lower MES than bulk tank milk, MES decreased, while iCa increased linearly with individual milk inclusion. Inclusion of milk with higher MES than the bulk tank decreased the odds of low stability, while inclusion of individual milk with lower MES than bulk tank increased it. At extended lactation, 73% of cows produced milk with acceptable (intermediate or better) MES, and iCa was the only functional variable related to MES. Effects of the mixture of individual milks into bulk tank milk functional traits depend on whether individual cows present values higher or lower than bulk tank.

In this research paper we introduce and validate an enhanced method for the detection of sodium benzoate and potassium sorbate in milk. Sodium benzoate and potassium sorbate are widely employed as preservatives in the food industry; however, their use to restrict microbial growth in milk is prohibited. Our novel method achieved performance indicators in accordance with the criteria outlined by the International Conference on Harmonization. The extraction process involved sample dilution in acetonitrile (1:1 v/v), followed by subsequent centrifugation, filtration and injection into a high-performance liquid chromatography system with a photodiode array detector. The detection and quantification limits for sodium benzoate were determined to be 0.204 and 0.618 mg/l, respectively, while for potassium sorbate, these values were 0.108 and 0.328 mg/l, respectively. The accuracy ranged from 92.67 to 99.53%, with pH 4.0 selected as the optimal condition to ensure adequate resolution of the preservatives. The proposed method stands out due to its simplicity and speed, using a single reagent in modest quantities during sample preparation. This approach reduces toxicity and minimizes the production of pollutants during disposal. Furthermore, the novel method requires less raw material and energy consumption, aligning with the principles of green chemistry. Its lower quantitation limits render it more sensitive when compared to the official analysis. The preparation, separation, and simultaneous detection of these preservatives in a short period of time make this method suitable for integration into industrial workflows.

Nonfat set yogurts are very popular in Japan because of their health properties, but have the disadvantage of being hard and having large curd particles compared to fat-containing yogurts. We investigated the effect of lactose hydrolysis on nonfat set yogurt to determine whether this technique can improve the sensory evaluation and the texture of a nonfat set yogurt. We prepared nonfat yogurt mixes with 0, 50, 75, and 100% lactose hydrolysis and fermented them. The sensory properties, physical properties, fermentation characteristics, extracellular polysaccharide (EPS) concentration and lactic acid bacteria count were then assessed. The results demonstrated that the lactose hydrolysis rate had no effect on the fermentation time. The 75% lactose hydrolysis increased the EPS concentration and inhibited post-acidification. The 100% lactose hydrolysis increased the number of Lactobacillus delbrueckii subsp. bulgaricus (L. bulgaricus) and further increased the EPS concentration, and despite the increase in the number of L. bulgaricus, the 100% lactose hydrolysis suppressed post-acidification. The results of a sensory evaluation showed that the 100% lactose hydrolysis increased the yogurt's viscosity and overall acceptability and suppressed its acidity. The physical-properties evaluation revealed that when the lactose hydrolysis rate was ≥75%, the curd hardness decreased, and the curd particles became smaller. We inferred that these sensory and physical changes originated from an increase in the EPS concentration, and we thus speculate that a 100% lactose hydrolysis rate before fermentation would be a useful means of solving the hardness and large curd particles of nonfat set yogurt.

This research paper focuses on enrichment of yoghurt containing probiotic Lactobacillus casei with persimmon (Diospyros kaki) powder in concentrations of 0 (Control) and then 0.5, 1.0, 1.5 and 2.0% (A–D respectively) and determination of some characteristics of the product during refrigerated storage for 21 d. Powder addition affected the color characteristics, textural properties, titratable acidity and water-holding capacity values. The viability of both yoghurt bacteria (Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus) and L. casei increased proportionally to adding persimmon powder for all storage days. Furthermore, addition of fruit powder increased short-chain fatty acid and polyunsaturated fatty acid contents. According to sensory analysis results, sample D had the lowest scores from the panelists, whereas the Control together with samples B and C were the most liked yoghurts in terms of flavor characteristics. In terms of overall acceptability, all of the samples received scores over three points on a five-point scale throughout storage. This study indicates that persimmon powder enriched yoghurt is a good vehicle for L. casei and yoghurt bacteria with improved fatty acid profile and acceptable sensory characteristics.

This Research Communication describes the frequency of occurrence of P. fluorescens, P. putida and P. aeruginosa in raw goat milk stored at 4 and 9°C, to evaluate the spoilage potential and capacity of these species and the presence of the aprX gene, responsible for the synthesis of metalloprotease aprX. Samples of raw goat milk stored at 4 and 9°C for 72 h were plated on Pseudomonas CFC agar base (25°C for 48 h). The presence of P. fluorescens, P. putida, P. aeruginosa and aprX gene were confirmed by polymerase chain reaction. The isolates were evaluated for their proteolytic and lipolytic spoilage capacity and potential using milk agar (10%) and tributyrin agar base (1%), respectively (21°C for 72 h). A total of 184 strains of Pseudomonas spp. were obtained. At both temperatures, P. fluorescens was the most frequent, mostly proteolytic, and the only one to express high proteolytic and lipolytic potentials. Regardless of the temperature, all isolated strains of P. putida were lipoproteolytic, with a predominance of protease synthesis. Strains of P. aeruginosa (4,3%) were isolated occasionally (4.3% of total isolates) but only at 4°C, and 75% of these were lipoproteolytic. The storage temperature of raw goat milk influenced the frequency of P. aeruginosa, but not its spoilage potential. The presence of the aprX gene was verified in most strains isolated from all species at the two temperatures evaluated, although some of these strains did not express proteolytic capacity. Most isolates of Pseudomonas spp. showed lipoproteolytic capacity, which emphasizes the importance of ensuring low initial populations of this genus in raw chilled goat milk when it is used to produce dairy products.

We assessed the chemical, microbiological, rheological and sensory parameters of a fermented dairy product (FDP) containing a galactooligosaccharide (GOS) preparation. This was made from a solution of dried whey and skim milk containing 25% (w/w) lactose using a new enzyme with high transgalactosylation activity (Nurica: Danisco A/S). Conversion of the high initial lactose content enabled a good yield of 56% GOS to be achieved. The obtained GOS preparation was applied to the FDP with a probiotic culture of Bifidobacterium animalis ssp. lactis in amounts of 0, 2, 10, and 20% (w/w). The FDPs were stored and monitored for 9 weeks. Bifidobacteria showed counts higher than 106 CFU/g throughout the storage period. GOS were not significantly utilized during fermentation and their changes during storage were also insignificant. Gel strength after fermentation showed a slight decrease with increasing doses of GOS preparation, but after 6 weeks of storage, the differences were no longer evident. The sensory analysis revealed the overall acceptability of the prepared FDPs, whilst the highest dose (20% GOS preparation) led to a sweeter taste.

Hybrid yoghurts combining dairy and plant-based derivatives present a novel approach to enhancing consumer acceptance of plant-based products, which is increasingly significant due to dietary trends and lactose intolerance. This study investigates the production of hybrid yoghurt blending cow's milk (CM) with soy (C:S) and oat (C:O) drinks in various ratios (90%, 70%, and 50% cow's milk), assessing their acceptability and quality. Notably, the C:S (70:30) and C:O (70:30) ratios resulted improved viscosity over time, although still less than CM. The hybrid yoghurts exhibited a favourable pH gradient, enhancing the acidic environment critical for flavour. Sensory analysis revealed that C:O (70:30) offered more favourable attributes on the just-about-right scale, scoring overall 6.86/10. Importantly, microbial analysis confirmed the safety of all hybrid products for consumption, with no harmful microorganisms detected.