Lactose Content Research Articles

Localized mammary gland changes in milk composition and venous blood metabolite concentrations result from sterile subclinical mastitis

Subclinical mastitis reduces milk yield and elicits undesirable changes in milk composition, but the mechanisms resulting in reduced milk production in affected mammary glands are incompletely understood. This study investigated the effects of sterile inflammation on mammary gland metabolism by assessing changes in milk and venous blood composition. Mid-lactation primiparous Holstein cows (n = 4) had udder halves randomly allocated to treatments; quarters of 1 udder half were infused with 2 billion cfu of formalin fixed Staphylococcus aureus (FX-STAPH) and quarters of the opposite udder half infused with saline (SAL). Blood samples were collected from the right and left subcutaneous abdominal veins in 2.6 h intervals until 40 h post challenge and analyzed for blood gas and metabolite concentrations. Milk from FX-STAPH udder halves had significantly increased SCS by first milking at 8 h post-challenge. By 16 h post-challenge, FX-STAPH udder halves had increased concentrations of protein and lactate and lower lactose concentrations than SAL udder halves. Milk fat concentrations, milk yields, energy corrected milk yields, and the ferric reducing antioxidant power of milk were not significantly different between SAL and FX-STAPH udder halves. Venous blood of FX-STAPH halves had marginally greater concentrations of saturated O2, partial pressures of O2, and glucose concentrations than SAL halves. Conversely, total and partial pressures of CO2 did not differ between udder half treatments suggesting a shift in local metabolite utilization in FX-STAPH udder halves. These results indicate that changes in milk composition resulting from mastitis are accompanied by changes in some key blood metabolite concentrations. The shift in venous blood metabolite concentrations, along with the marked increase in milk lactate, suggests that local mammary tissue and/or recruited and immune cells alters metabolite usage in mammary tissues. Future studies are needed to quantify the uptake of key milk precursors during mastitis.

A preliminary study on milk composition of three buffalo breeds located in Polonnaruwa, Sri Lanka

Buffaloes have great potential to be developed as one of the main dairy animals in Sri Lanka because of their higher adaptability to local conditions compared to European dairy cattle breeds. Processing dairy products such as curd, cheese, and yoghurt from buffalo milk has several advantages due to its greater quantities of total solids, solid-nonfat, and protein. However, milk composition and coagulation properties largely depend on the breed. Therefore, this research aimed to investigate the milk composition of three major buffalo breeds in Sri Lanka. The milk of the Lanka buffalo contained 18.1% total solids, 10.7% solid non-fat (SNF), 7.5% fat, 4.9% protein, 4.9% lactose, and 0.9% minerals. The milk of the Murrah crossbreed contained 15.4% total solids, 10.1% SNF, 5.3% fat, 4.2% protein, 5.1% lactose, and 1.1% minerals. The milk of the Nili-Ravi crossbreed contained 16.6% total solids, 10.2% SNF, 6.4% fat, 4.1% protein, 4.9% lactose, and 1.1% minerals. The results indicate that milk composition varies among the breeds in which the milk of the Lanka buffalo has significantly higher amounts of total solids, SNF, and fat. Protein, lactose, and mineral contents do not vary signiticantly.

Study on Sensory Evaluation and Chemical Changes Occurred in Mahua (Madhuca longifolia) Flower Burfi during the Storage

In the present study, the cow milk was standardized to 4% fat. The Burfi was prepared by addition of crushed dried Mahua flowers in the proportion of 100:0 (T₁), 90:10 (T₂), 85:15 (T3), 80:20 (T4) and 75:25 (T5) with 30 % sugar was added. The objectives of the present investigations were to study the chemical and sensory changes during storage of the selected treatment i.e. T4 (80% khoa: 20% crushed dried Mahua flower) at room temperature and refrigerated temperature at the interval of 0, 5, 10, 15, 20, 25 days. The study aimed to investigate the quality of the burfi during storage. The data obtained was statistically analyzed by Factorial Randomized Block Design. Sensory evaluation studies were conducted by a panel of judges and it was found that the burfi prepared by using 20 parts of crushed dried Mahua flowers and 80 parts of khoa was having the highest overall acceptability scores. The overall acceptability scores of selected treatment were decreased from 5th days onwards. But burfi was acceptable up to 15 days and 25 days onwards at room temperature and refrigerated temperature, respectively. The results regarding the chemical analysis revealed that the fat, protein, lactose, ash, titratable acidity and total solids content of burfi was increased after 0th day to 25th day in both room and refrigerated condition. While, moisture and solids not fat content reported decrease in trend in both room and refrigerated temperature. The rate of changes was found more in room temperature conditions.

Hydroponic barley supplementation fed with high-protein diets improves the production performance of lactating dairy cows

The study investigated the effects of dietary protein level and the inclusion of hydroponic barley sprouts (HB) on lactation performance, blood biochemistry and N use efficiency in mid-lactation dairy cows. Treatments were arranged in a 2 × 2 factorial design with 2 crude protein (CP) levels [16.8% and 15.5% of dry matter (DM)], with HB (4.8% of DM, replacing 4.3% of alfalfa hay and 0.5% of distillers dried grains with solubles (DDGS)) or without HB. Forty-eight multiparous Holstein dairy cows (146 ± 15 d in milk, 40 ± 5 kg/d of milk) were randomly allocated to 1 of 4 diets: high protein diet (16.8% CP, HP), HP with HB (HP+HB), low protein diet (15.5% CP, LP), or LP with HB (LP+HB). An interaction between CP × HB on dry matter intake (DMI) was detected, with DMI being unaffected by HB inclusion in cows fed the high CP diets, but was lower in cows fed HB when the low CP diet was fed. A CP × HB interaction was also observed on milk and milk protein yield, which was higher in cows fed HB with HP, but not LP. Inclusion of HB also tended to reduce milk fat content, and feeding HP resulted in a higher milk protein and milk urea N content, but lower milk lactose content. Feed efficiency was increased by feeding HP or HB diets, whereas N efficiency was higher for cows fed LP or HB diets. There was an interaction on the apparent total-tract digestibility of DM and CP, which was higher when HB was fed along with HP, but reduced when fed with LP, whereas the digestibility of ADF was increased by feeding low protein diets. In conclusion, feeding a low protein diet had no adverse effect on cow performance, while feeding HB improved milk and milk component yield, and N efficiency when fed with a high CP diet, but compromised cow performance with a low CP diet.

Milk quality of Italian Mediterranean buffalo as affected by temperature-humidity index during late spring and summer

A total of 18 Italian Mediterranean buffalo cows were subjected to fortnightly milk sampling from May to July 2022. Air temperature and relative humidity were monitored throughout the trial. Temperature-humidity index (THI) was calculated and ranged from 69 to 79, so that 3 classes were set to study the effect of different THI on milk quality: THI less than 72 (THI<72), THI ranging from 72 to 76 (THI72-76), and THI over 76 (THI>76). Individual milk samples from buffalo cows were analyzed for milk composition and coagulation traits, fatty acid and amino acid composition, and enzymatic and mineral profiles. The THI>76 class registered higher lactose content and poorer milk clot characteristics in comparison with THI<72. Exposure to a THI over 76 resulted in increased SFA and short-chain fatty acid contents in milk, as well as in the highest atherogenic and thrombogenic index values and the lowest essential amino acid content. Moreover, the lowest values of calcium, copper, and selenium contents were found in the milk of buffalo cows exposed to a THI over 72. Results confirm that Italian Mediterranean buffalo express a good level of thermo-tolerance, even though exposure to a daily THI over 76 has a deleterious effect on some nutritional and technological properties of milk.

Comparison of selected nutritional analysis of goat and cow milk kefir using Indonesian kefir grains

Kefir is a fermented dairy beverage produced with kefir grains. It is high in probiotics and provides nutrition and health benefits. The effect of different level of kefir grains and incubation time on the chemical characteristics of goat and cow milk kefir was investigated. Kefir samples were prepared using 3 and 5% (w/v) kefir grains with incubation times of 12 and 24 hours. The addition of kefir grains significantly affected the pH, acidity, lactose, and protein content compared to control. There is no significant difference on pH, acidity, lactose, and protein in between both kefirs prepared in this study regardless of the treatments. The results showed that 5% (w/v) kefir grains with 24 hours incubation time was suggested to be the best milk kefir preparation for both goat milk and cow milk kefir.

β-Galactosidase isolated from Ranunculus arvensis seeds to synthesize trisaccharide: Kinetics and thermodynamic properties

β-Galactosidase was isolated from Ranunculus arvensis seeds using DEAE-cellulose, Sephadex G-100, and Con A sepharose-4B chromatography. The enzyme was purified to electrophoretic homogeneity with a specific activity of 50 U/mg of protein and a yield of 7.1%. The molecular mass of the isolated β-galactosidase, as estimated by SDS-PAGE, was 18 kDa, indicating that it was a monomeric form The purified β-galactosidase has a glycoproteinic nature when applied to Con-A-Sepharose-4B chromatography. An activation energy (Ea) of 11 kcal/mol of lactose, pH 5.0, and 50 °C were found to be the optimum parameters to purify β-galactosidase from R. arvensis seeds. The residual activity test was carried at 55–75 °C, allowing calculating the half-lives of 533–48 min, enthalpy (ΔH° = 110.38–110.21 kJ/mol), free energy (ΔG° = 109.88–109.77 kJ/mol), and entropy (ΔS° = 1.52–1.26 J/mol·K). The β-galactosidase produced from this species is better than the previously described enzyme due to its kinetic and thermodynamic properties, and it could be used in various industrial applications. Purified β-galactosidase, when incubated with high lactose concentration, showed transgalactosylation activity, leading to trisaccharides as a major product of total galactooligosaccharide (GOS). Therefore, the purified β-galactosidase could be used as a potential alternative in the food industry and would be further explained for trisaccharide synthesis.

Physicochemical and sanitary parameters of bovine bulk milk processing centers in the Amazon region, Peru

Evaluating quality and microbiological parameters in bovine milk processing centers is essential for ensuring public health and product quality and positively impacting the local economy. This study aimed to evaluate the physicochemical and sanitary parameters of bovine milk in the Amazon region. For this purpose, 31 samples were collected from milk processing centers in the region. The following quality parameters were evaluated: somatic cell count; physicochemical parameters: fat, protein, nonfat solids, lactose, ash, pH, and density; and microbiological parameters: mesophilic aerobic bacteria and total coliforms in the raw milk. For data analysis, mean comparison tests were performed using Kruskal‒Wallis and Tukey tests, and cluster and principal component analysis was performed using R software version 4.3.2 and InfoStat version 2018p. The results for the 31 milk processing centers showed significant differences in all the parameters evaluated; fat, somatic cell count, and density were within the technical specifications of the Supreme Decree N° 007-2017-MINAGRI. Microbiological analyses revealed significant variability in total coliforms and mesophilic aerobic bacteria. Cluster analysis revealed five groups with similar characteristics, with Group 1 exhibiting high somatic cell, lactose, and ash contents and Group 3 exhibiting higher fat contents. Principal component analysis highlighted the significant contributions of total coliforms, aerobic bacteria, and somatic cells to the degradation of milk quality. Although somatic cell counts meet specific standards, elevated levels of coliforms and aerobic bacteria are of concern. These findings are essential for ensuring food safety and improving milk quality.

Studies on Chemical Changes in Burfi Enriched with different Herbs

The investigation was carried out to study the chemical changes taking place in burfi by the addition of several herbs and their comparison with the control product. Different herbs, viz., Withania somnifera (Ashwgandha), Asparagus racemosus (Shatavari), and Ocimum sanctum (Tulsi), were incorporated into the blend in the ratio of 5:4:1, respectively, to develop herbal burfi. The combination of herbs was added at levels of 1.00, 1.25, 1.50, and 2.00% by weight of khoa to obtain products designated T1, T2, T3, and T4, respectively. The control product (T0) was prepared in a similar manner but was devoid of herbs. Proximate analysis, including moisture, total solids, fat, lactose, protein, and ash, was conducted. The results show that moisture content decreased significantly (P≤0.05) with increasing herb addition, while total solids increased. Protein content increased with higher herb percentages, likely due to the protein content of the added herbs. Fat and lactose content remained unchanged with herb addition, as herbs do not contribute significantly to these components. Ash content increased with higher herb addition rates, though not significantly (P≥0.05). Overall, the addition of herbs influenced the chemical composition of burfi, impacting moisture, total solids, protein, and ash content with varying degrees of significance.

Combining thermosonication microstress and pineapple peel extract addition to achieve quality and post-acidification control in yogurt fermentation

This work investigated the effects of the combined use of thermosonication-preconditioned lactic acid bacteria (LAB) with the addition of ultrasound-assisted pineapple peel extracts (UU group) on the post-acidification potential, physicochemical and functional qualities of yogurt products, aimed at achieving prolonged preservation and enhancing functional attributes. Accordingly, the physical–chemical features, adhesion properties, and sensory profiles, acidification kinetics, the contents of major organic acids, and antioxidant activities of the differentially processed yogurts during refrigeration were characterized. Following a 14-day chilled storage process, UU group exhibited acidity levels of 0.5–2 oT lower than the control group and a higher lactose content of 0.07 mg/ml as well as unmodified adhesion potential, indicating that the proposed combination method efficiently inhibited post-acidification and delayed lactose metabolism without leading to significant impairment of the probiotic properties. The results of physicochemical analysis showed no significant changes in viscosity, hardness, and color of yogurt. Furthermore, the total phenolic content of UU-treated samples was 98 μg/mL, 1.78 times higher than that of the control, corresponding with the significantly lower IC50 values of DPPH and ABTS radical scavenging activities of the UU group than those of the control group. Observations by fluorescence inverted microscopy demonstrated the obvious adhesion phenomenon with no significant difference found among differentially prepared yogurts. The results of targeted metabolomics indicated the proposed combination strategy significantly modified the microbial metabolism, leading to the delayed utilization of lactose and the inhibited conversion into glucose during post-fermentation, as well as the decreased lactic acid production and a notable shift towards the formation of relatively weak acids such as succinic acid and citric acid. This study confirmed the feasibility of thermosonication-preconditioned LAB inocula, in combination with the use of natural active components from fruit processing byproducts, to alleviate post-acidification in yogurt and to enhance its antioxidant activities as well as simultaneously maintaining sensory features.

Physicochemical composition of Criolla and Criolla x Saanen goat milk according to age and parity in the central highlands of Peru

Present study aimed to analyze the physicochemical composition of goat milk based on the type of animal, age, and parity in Chupuro, Junin region in the country of Peru. A total of 24 goats were randomly selected, and divided into two groups: 12 native goats and 12 native goats crossed with Saanen. These groups (G1, G2, and G3) included three age categories (1.8, 2.5, and 3.2 years) and three parity levels (first, second, and third parity). The animals were monitored and fed considering their conversion and nutritional requirements. Before the morning milking, 100 ml of milk was extracted in sterile bottles, followed by agitation for 3 to 5 minutes, and the samples were transported using conservation and cooling techniques in a thermal box with ice cubes. These samples were analyzed in the special laboratory. Measurements of pH, acidity, density, lactose, total solids, fat, and protein were conducted using milk analyzer. The findings for the Criollo breed revealed a pH of 6.35 ± 0.31, a lactose concentration of 4.35%, total solids of 11.62 ± 1.31%, protein content of 4.12 ± 0.35%, and fat content of 3.40 ± 0.91%. In comparison, the Criollo x Saanen crossbreed exhibited a pH of 6.43 ± 0.13%, a lactose concentration of 4.45%, total solids of 12.63 ± 0.92%, protein content of 4.26 ± 0.28%, and fat content of 3.95 ± 0.69%. The results indicated that there were no significant differences in the types of milk from native goats and native goats crossed with Saanen. However, significant differences (P&lt;0.05) were observed in density, lactose, total solids, fat, and protein between groups of different ages and parity levels. Crossbreeding with the Saanen breed is well received in the region, as it serves to improve milk production, with favorable percentages of fat, protein, lactose, and total solids.

Physicochemical characteristics of milk sold in family production units in the Atoyac River Basin in Puebla and Tlaxcala, Mexico

Objective: To determine the physicochemical characteristics and possible adulteration of raw milk marketed in dairy family systems located in the Atoyac River Basin in Puebla-Tlaxcala. Design/methodology/approach: The physical characteristics of milk were determined: pH, acidity and freezing point; and chemical characteristics: fat, protein, lactose, minerals, non-fat solids, total solids and water content. This milk is produced and sold by 264 family production units to three cheese companies in the Atoyac River Basin in the states of Puebla and Tlaxcala. The data were analyzed by company and subsequently grouped with the Cluster technique of the SAS software. Results: Significant differences (p&lt;0.05) were found in the physical and chemical characteristics of the milk marketed by the producers with the three processing companies. In general, the milk is acid and adulterated with an average of 11.49% water; this results in a loss of $0.67/liter and in a dilution of its components, particularly protein and lactose, which leaves it outside the parameters established by normativity. The multivariate analysis generated four groups of producers and suggests the possibility that a group of producers adulterates with water, but also adds some kind of compound to increase the fat content to mask the adulteration. Limitations on study/implications: The study of this topic, where the economic interests of the primary actors in the production chain can be affected, is delicate and difficult to carry out; however, it is necessary in order to know the quality of the products that are generated and their implication in the economy and the health of consumers. Findings/conclusions: This study showed that the milk marketed by producers to processing companies does not comply with current regulations due to adulteration with water and the possible addition of compounds that replace fat; therefore, verification programs for compliance of the regulations are required, hoping with this that producers will receive a fair price for their production and will not have the need to adulterate the milk.

A Stochastic Frontier Approach to Study the Relationship between the Hygienic Quality of Bulk Tank Sheep Milk and Technical Efficiency of the Coagulation Process.

Sheep milk from local breeds is important for the production of high-quality cheeses throughout the Mediterranean region, such as Manchego cheese in Spain. To maintain sustainable and efficient production, it is necessary to reach a better understanding of how the composition and hygiene of the milk affect the coagulation process, with the aim of optimizing production yield. This study implemented a stochastic production frontier function to estimate the potential production of curd and efficiency using data from the four seasons of a study of 77 Manchega sheep farms. The Cobb-Douglas production frontier model was estimated using the maximum likelihood estimation method. The results showed that the content of protein, lactose, and fat exhibited increasing returns to scale, with protein content being the most significant factor for curd production. Approximately half of the inefficiency was due to factors related to the technological properties and the hygiene of the milk. The pH, curd firmness, and concentration of lactic acid bacteria improved the efficiency of coagulation, while the concentration of spores of lactate-fermenting Clostridium spp., Pseudomonas spp., staphylococci, and catalase-negative gram-positive cocci favored the inefficiency of the coagulation process. To date, this is the first study to evaluate the effect of different factors, such as microbial groups, milk composition, and technological properties, on the efficiency of the coagulation process in dairy sheep.

The Relation between Milk Lactose Concentration and the Rumination, Feeding, and Locomotion Behavior of Early-Lactation Dairy Cows.

This study hypothesizes that higher in-line milk lactose concentrations are indicative of enhanced dairy cow behaviors-including increased rumination, feeding, and locomotion activities-reflecting superior overall health and well-being. It posits that fluctuations in milk lactose levels have a substantial impact on the physiological and behavioral responses of dairy cows, thereby affecting their milk yields and compositions. Each cow's milk lactose, fat, protein, and fat-to-protein ratio were continuously monitored using the BROLIS HerdLine in-line milk analyzer (Brolis Sensor Technology, Vilnius, Lithuania). The RumiWatch noseband sensor (RWS; ITIN + HOCH GmbH, Fütterungstechnik, Liestal, Switzerland) was employed to measure the biomarkers of the rumination, feeding, and locomotion behavior. The measurements were recorded over 5 days at the same time (during morning milking). A total of 502 cows were examined. During these 5 days, 2510 measurements were taken. Based on the lactose content in their milk, the cows were divided into two categories: the first group consisted of cows with milk lactose levels below 4.70%, while the second group included cows with milk lactose levels of 4.70% or higher. Our study showed that cows with higher milk lactose concentrations (≥4.70%) produced significantly more milk (16.14% increase) but had a lower milk protein concentration (5.05% decrease) compared to cows with lower lactose levels. These cows also exhibited changes in rumination and feeding behaviors, as recorded by the RWS: there was an increase in the mastication and rumination behaviors, evidenced by a 14.09% rise in other chews and a 13.84% increase in rumination chews, along with a 16.70% boost in bolus activity. However, there was a notable 16.18% reduction in their physical activity, as measured by the change in time spent walking.

Reduction of maillard browning in spray dried low-lactose milk powders due to protein polysaccharide interactions

Lactose hydrolysed concentrated milk was prepared using β-galactosidase enzyme (4.76U/mL) with a reaction period of 12 h at 4 °C. Addition of polysaccharides (5 % maltodextrin/β-cyclodextrin) to concentrated milk either before or after lactose hydrolysis did not result in significant differences (p > 0.05) in degree of hydrolysis (% DH) of lactose and residual lactose content (%). Three different inlet temperatures (165 °C, 175 °C and 185 °C) were used for the preparation of powders which were later characterised based on physico-chemical and maillard browning characteristics. Moisture content, solubility and available lysine content of the powders decreased significantly, whereas, browning parameters i.e., browning index, 5-hydroxymethylfurfural, furosine content increased significantly (p < 0.05) with an increase in inlet air temperature. The powder was finally prepared with 5 % polysaccharide and an inlet air temperature of 185 °C which reduced maillard browning. Protein-polysaccharide interactions were identified using Fourier Transform infrared spectroscopy, fluorescence spectroscopy and determination of free amino groups in the powder samples. Maltodextrin and β-cyclodextrin containing powder samples exhibited lower free amino groups and higher degree of graft value as compared to control sample which indicated protein-polysaccharide interactions. Results obtained from Fourier Transform infrared spectroscopy also confirmed strong protein-polysaccharide interactions, moreover a significant decrease in fluorescence intensity was also observed in the powder samples. These interactions between the proteins and polysaccharides reduced the maillard browning in powders.

Heterologous Expression of Phycocyanobilin in Escherichia coli and Determination of Its Antioxidant Capacity In Vitro.

Phycocyanobilin (PCB) is a blue pigment with antioxidant, anti-inflammatory, and anticancer properties. It is used in the medical and cosmetic industries. In this study, a high-expression plasmid, pET-30a-PCB, was constructed for expression of PCB in Escherichia coli BL21(DE3). The PCB was analyzed using UV-visible absorptionspectrum, MALDI-TOF-MS, and fluorescence spectra. The stability and half-life of PCB in different serum were determined. The yield of PCB was optimized through single-factor and orthogonal experiments. The optimal expression conditions were determined as a lactose concentration of 5mmol/L, an induction time of 8h, an induction temperature of 27°C, and an induction duration of 22h. PCB yield of 6.5mg/L was achieved and subsequently purified using nickel-affinity chromatography. The purified PCB was quantified indirectly using Hist-tag ELISA detection, and the concentration was 11.66μg/L. In the range of 0-33μg/mL, the total antioxidant capacity and reducing the capacity of PCB were stronger than Vitamin E (Ve), with 1,1-diphenyl-2-picrylhydrazil (DPPH) scavenging reaching up to 87.07%, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) free radical (ABTS) scavenging up to 100%, hydroxyl radicals (·OH) scavenging up to 64.19%, hydrogen peroxide (H2O2) scavenging up to 78.75%, This study provides theoretical evidence for PCB as a potent antioxidant.

Rheological and tribological properties of native potato starch agglomerated by fluidized bed granulator

We explored the rheological and tribological properties of potato starch agglomerated with a sugar binder (maltodextrin or lactose) at various concentrations by using a fluidized bed granulator. The magnitudes of consistency index and apparent viscosity of agglomerated potato starch (APS) decreased as the binder concentration was increased. Moreover, APS with a sugar binder showed lower viscoelastic moduli and higher tan δ values compared to APS with water as the binder (the control). The gel strength of all agglomerates decreased as the sugar concentration was increased. All samples showed anti-thixotropic behavior, and especially, APS with 20 % lactose showed a small anti-thixotropic area. Utilizing the Arrhenius equation clearly elucidated the effect of temperature on the apparent viscosity of all the samples. Although the maltodextrin concentration had little influence on the activation energy of APS, it increased as the lactose concentration was increased. APS samples with a sugar binder showed greater friction coefficient values compared to the control, with maltodextrin having a significant impact. The findings indicate that the rheological and tribological properties of APS rely on the type and concentration of sugar binder.

Association between Single Nucleotide Polymorphisms of PRKD1 and KCNQ3 Gene and Milk Quality Traits in Gannan Yak (Bos grunniens).

Protein kinase D1 (PRKD1) functions primarily in normal mammary cells, and the potassium voltage-gated channel subfamily Q member 3 (KCNQ3) gene plays an important role in controlling membrane potential and neuronal excitability, it has been found that this particular gene is linked to the percentage of milk fat in dairy cows. The purpose of this study was to investigate the relationship between nucleotide polymorphisms (SNPs) of PRKD1 and KCNQ3 genes and the milk quality of Gannan yak and to find molecular marker sites that may be used for milk quality breeding of Gannan yak. Three new SNPs were detected in the PRKD1 (g.283,619T>C, g.283,659C>A) and KCNQ3 gene (g.133,741T>C) of 172 Gannan lactating female yaks by Illumina yak cGPS 7K liquid-phase microarray technology. Milk composition was analyzed using a MilkoScanTM milk composition analyzer. We found that the mutations of these three loci significantly improved the lactose, milk fat, casein, protein, non-fat milk solid (SNF) content and acidity of Gannan yaks. The lactose content of the TC heterozygous genotype population at g.283,619T>C locus was significantly higher than that of the TT wild-type population (p < 0.05); the milk fat content of the CA heterozygous genotype population at g.283,659C>A locus was significantly higher than that of the CC wild-type and AA mutant populations (p < 0.05); the casein, protein and acidity of the CC mutant and TC heterozygous groups at the g.133,741T>C locus were significantly higher than those of the wild type (p < 0.05), and the SNF of the TC heterozygous group was significantly higher than that of the mutant group (p < 0.05). The results showed that PRKD1 and KCNQ3 genes could be used as candidate genes affecting the milk traits of Gannan yak.

Low Lactose Yogurt with Blueberry Jam: Development and Sensory Acceptance

Introduction: The lactose-intolerant public represents an important portion of the population; however, the diversification of products that serve this population is still very limited. Objective: In this bias, this study aimed to develop a low-lactose yogurt added with blueberry jelly, combining sensory and functional characteristics of the fruit. Methods: Different concentrations of β-galactosidase were evaluated in the fermentations, in addition to four formulations of blueberry jelly that were sensorially tested for preference, a formulation was selected and its global acceptance and purchase intent were verified. Results: The use of 1.5 g L- 1 of β-galactosidase allowed for a more significant reduction of lactose during the fermentation process. Of the four jelly formulations tested, the whole fruit was sensory preferred, and the low-lactose two-layer yogurt showed 86% acceptance and 74% purchase intention. Conclusion: It was possible to develop a product with low lactose content and sensorially pleasant to the consumer.

Decreased lactose percentage in milk associated with quarter health disorder and hyperketolactia, a proxy for negative energy balance, in dairy cows

Several studies have described variations in lactose content (LC) in dairy cows during udder quarter health disorder or negative energy balance (NEB). However, their joint effects on LC have never been described. This was the aim of a longitudinal observational study performed on 5 Quebec dairy farms using automatic milking systems. Quarter milk samples were collected every 14 d from 5 to 300 DIM. Quarter health status was described by combining SCC level (SCC- or SCC+: < or ≥100,000 cells/mL) and infectious status (Patho- or Patho+: presence or absence of pathogens on a milk culture). Cows with NEB in early lactation (DIM <70) were identified using milk β-hydroxybutyrate (BHB) content: 0.15 mM = BHB-; 0.15 - 0.19 mM = BHB+; > 0.19 mM = BHB++. A total of 14,505 quarter cisternal milk samples were collected from 380 lactating cows. The quarter LC was analyzed using a mixed linear regression model with the following fixed effects: quarter health status, parity, time interval between last milking and sampling, quarter milk yield (in kg/d), DIM, and herd. A random quarter intercept with a repeated measures correlation structure and a cow random intercept were also specified. The LC of SCC+ quarters was lower (-0.17 ± 0.013% pts) compared with LC of SCC- quarters for both primiparous and multiparous cows. Over the 162 bacterial species identified, only 8 species had a prevalence greater than 4.0%, and just 5 of them were associated with a reduction in LC: Staphylococcus aureus, Staph. chromogenes, Streptococcus dysgalactiae, Staph. epidermidis, and Staph. simulans. Cows identified as BHB+ and BHB++ in early lactation had a lower LC (-0.05 ± 0.019% and -0.13 ± 0.020% pts, respectively) compared with BHB- cows. For BHB++ cows, in both parity groups the decrease in LC (-0.20 ± 0.025% pts) was higher in SCC+ quarters compared with SCC- quarters. Moreover, the additive effect of the quarter health status and NEB on milk LC was greater with larger increases in BHB. Our findings highlight the necessity to jointly take into consideration both quarter health status and milk BHB concentration when using LC as a biomarker for NEB.