Journal of Dairy Research最新文献

We tested the hypothesis that milk proteins, through microencapsulation, guarantee protection against bioactive substances in coffee silverskin extracts. Therefore, the aim of this study was to carry out technological, nutritional and physicochemical characterisation of a coffee silverskin extract microencapsulated using instant skim milk powder and whey protein concentrate as wall materials. The aqueous extract of coffee silverskin was spray-dried using 10% (w/v) skim milk powder and whey protein concentrate. The samples were characterised by determining the water content, water activity, particle size distribution, colour analysis and total phenolic compound content as well as antioxidant activity using 2,2-diphenyl-radical 1-picrylhydrazyl scavenging methods, nitric oxide radical inhibition and morphological analysis. The product showed water activity within a range that ensured greater stability, and the reduced degradation of the dried coffee silverskin extract with whey protein concentrate resulted in better rehydration ability. The luminosity parameter was higher and the browning index was lower for the encapsulated samples than for the pure coffee silverskin extract. The phenolic compound content (29.23 ± 8.39 and 34.00 ± 8.38 mg gallic acid equivalents/g for the coffee silverskin extract using skimmed milk powder and whey protein concentrate, respectively) and the antioxidant activity of the new product confirmed its potential as a natural source of antioxidant phenolic compounds. We conclude that the dairy matrices associated with spray drying preserved the bioactive and antioxidant activities of coffee silverskin extracts.

This research paper addresses the hypothesis that there is an optimal amount of intestinally available oleic acid (provided via abomasal infusion) to produce higher-oleic acid milk fat with satisfactory functional characteristics of cream and butter oil. A control and four increasing doses of free fatty acids from high oleic sunflower oil (HOSFA) were infused into the abomasum of four lactating dairy cows in a crossover experimental design with 7-d periods. Treatments were: (1) control (no HOSFA infused), (2) HOSFA (250 g/d), (3) HOSFA (500 g/d), (4) HOSFA (750 g/d), and (5) HOSFA (1000 g/d). All treatments included meat solubles and Tween 80 as emulsifiers. Viscosity, overrun and whipping time as well as foam firmness and stability were evaluated in whipping creams (33% fat). Solid fat content (from 0 to 40°C), melting point and firmness were determined in butter oil. Whipping time of cream increased linearly and viscosity decreased linearly as infusion of HOSFA increased. Overrun displayed a quadratic response, decreasing when 500 g/d or more was infused. Foam firmness and stability were not affected significantly by HOSFA. For butter oil, melting point, firmness, and solid fat content decreased as HOSFA infusion increased. Changes in 21 TG fractions were statistically correlated to functional properties, with 6-10 fractions showing the highest correlations consistently. Decisions on the optimal amount of HOSFA were dependent on the dairy product to which milk fat is applied. For products handled at commercial refrigeration temperatures, such as whipping cream and butter oil, the 250 g/d level was the limit to maintain satisfactory functional qualities. Palmitic acid needed to be present in at least 20% in milk fat to keep the functional properties for the products.

This research paper analyzes the stability of raw cow milk in the alcohol test and seeks to understand to know the factors that influence milk stability and the occurrence of unstable non-acid milk. Milk samples were collected from the cooling tanks of rural farmers in the state of Paraná twice in summer and twice in winter. The farms were classified according to the production system: pasture with supplementation and feedlot. The following variables were analyzed: stability in the alcohol test, titratable acidity, ionized calcium concentration (iCa), chemical composition of milk, somatic cell count and standard plate count. The results showed that milk stability was greater in winter vs. summer, when the milk contained higher iCa, and in the feedlot vs. pasture system. The Pearson Correlation between variables (ethanol stability, milk composition, iCa, cooling tank temperature, milk volume, number of milking, number of cows milked, fat/protein ratio, distance and travel time) were analyzed. Stability was negatively correlated with iCa concentration and positively with lactose content. Logistic regression of the risk of unstable non-acid milk at 72% alcohol (UNAM₇₂) showed that only iCa and lactose were determinants, while evaluation of the same risk at 78% alcohol revealed iCa, titratable acidity, lactose and milk urea nitrogen as risk factors. Under the dairy farming conditions of Paraná state, the frequency of UNAM₇₂ was low (12.16%) and was higher in summer and in pasture systems with supplementation. In conclusion, in dairy herds bred with high technological level, with adequate nutritional and health management, the frequency of UNAM is low and is related to nutritional management abnd, perhaps, heat stress, factors that alter iCa and lactose levels.

The aim of the study was to evaluate the effect of total mixed ration particle size (length) and breed of cow on intake dynamics, animal performance and CH₄ emissions, comparing high yielding Holstein and low yielding Girolando cows. The experimental design was 2 × 2 Latin Square arranged as a crossover factorial scheme with two diets (short particle size, SPS and long particle size, LPS) and the two breed compositions. The design comprised two periods of 26 d each, where all data collection was performed at cow level. No influence of the particle size occurred for the passage rate, neutral detergent fiber digestibility, performance and milk composition, methane emissions or ruminal fermentation parameters. Girolando cows had greater dry matter intake (DMI) when fed SPS, while Holsteins had the same (P < 0.05). Girolando cows had lower dry matter digestibility when fed LPS compared to SPS, while Holsteins had the opposite effect (P < 0.05). Also, the digestibility of crude protein and non-fibrous carbohydrates decreased in Girolando cows fed LPS, but not in Holsteins (P < 0.05). Girolando cows reduced DMI by 10.6% when fed LPS diet (P < 0.05). Girolando had an increased eating rate (+24 g of DM/min; P < 0.05) compared to Holstein cows, but Holstein cows had a lower CH₄ intensity (by 29.7%: P < 0.05). Girolando cows increased the dry matter intake when fed a diet with short particle size, while the same did not happen in Holsteins. Dry matter digestibility increased in Holsteins when fed long particle size, while the opposite was observed in Girolando cows. Nutrient digestibility was reduced in Girolando cows when fed short particle size. Particle size did not influence eating time, eating rate, feed trough visits, visits with intake, milk yield and composition regardless of the breed. Reducing particle size increased CH₄ intensity in both breeds.

This Research Communication aims to compare the effect of A1A2 and A2A2 cow milk diets on the biochemical and histological parameters of rats. The rats were divided into four groups and fed with a normal diet, A2 milk powder, A1A2 or A2A2 cow milk diets for 90 d. Blood glucose, kidney function, liver function and lipid profile were examined during the experimental period. The study showed an increase in the body weight of the A1A2 group whereas a slight decrease in the A2A2 group, and blood glucose levels increased from d 0 to day 90 in all experimental groups. However, none of these changes were found to be statistically insignificant (P > 0.05). Moreover, no significant changes were recorded in other parameters (serum glutamic pyruvic transferase and serum glutamic-oxaloacetic transaminase for liver function, bilirubin direct, cholesterol, triglycerides, creatinine and uric acid). The histology of the liver, kidney and pancreas also showed no changes in all groups. Overall, this study revealed no significant difference in the nutritional values of A1A2 and A2A2 milk types and hence equally beneficial for health. Although the present study showed no significant difference in the effect of both milk types in 90 d, further studies might be conducted to evaluate their longer term effects.

This research communication was designed to evaluate the effects of different levels of diet restriction on the composition and ethanol stability (MES) of raw bovine milk. This research was carried out using three electronic databases: Scopus, Pubmed and Web of Science. The main inclusion criteria were: (i) original research, (ii) use of alcohol (ethanol) test as a method to assess milk stability, (iii) measure different levels of feed restriction and (iv) allow access to the raw data of articles. Of the nine publications that addressed the subject filtered by the systematic review, seven fitted the selection criteria and were selected to perform the meta-analysis. Feed restriction (reduction of 20, 30, 40 and 50% of the dietary dry matter offered) decreased (P < 0.01) milk yield (-18%), ethanol stability (-5%), acidity (-4%), protein (-3%) and lactose (-2%) concentrations, but did not affect the values of pH, density, fat and total solids concentrations, nor somatic cell count. The correlation between milk yield and MES was low but positive and numerically higher in the control group compared with the restriction group. The milk of cows fed the control diet presented greater ethanol stability (76.5%) compared with milk of cows fed the restrictive diet (72.8%). This decrease by up to 4 percentage units due to restriction levels ranging from 20 to 50% of diet intake may cause limitations in milk processing at the dairy industry, increasing milk rejection.

This research paper addresses the hypothesis that mast cells (MCs) contribute to the formation of mammary fibrosis. MCs are important immune regulatory and immune modulatory cells that play major roles in the inflammatory process. Since there is no detailed knowledge, this research study aimed to comparatively investigate the presence, localization, and immunophenotypes of MCs in healthy and mastitic mammary tissues. A total of 264 mammary samples were evaluated for the examination of mast cells and fibrosis. The mean mast cell number in both acute and chronic mastitis samples were very significantly higher than the control group P < 0.001). A 7.9-fold increase in the number of mast cells was found when the chronic mastitis group was compared with the control (healthy) group. Immunohistochemistry revealed presence of all three immune phenotypes in control and mastitic mammary samples (tryptase + (MC_T), chymase + (MC_C) and both chymase and tryptase + (MC_TC). The mean MC_T, MC_C, and MC_TC numbers in the chronic mastitis group were found to be significantly higher than the control (P < 0.001 for all three phenotypes) but did not differ significantly between control and acute mastitis samples. When the mean numbers of MC_T, MC_C, and MC_TC in the control group and chronic mastitis group were compared, a 10.5, 7.8, and a 4.1-fold increase was observed, respectively. The amount of connective tissue was strongly increased in tissues with chronic mastitis and a 3.01-fold increase was detected compared to the control group. A statistically significant relation was also found between the amount of fibrosis and the increased number of total MCs (P < 0.001).

This Research Communication investigates how well U.S. dairy farmers understand the voting behaviour and willingness to pay of consumers for products with production traits relevant to animal health, welfare and biotechnology. Accurately understanding consumer behaviour is key to making sound production decisions and reducing risks. Comparing survey data with the literature shows that U.S. dairy farmers correctly assess consumer attitudes and behaviour over animal welfare practices like pain-controlled dehorning but could improve knowledge of attitudes towards antibiotic use and novel biotechnologies like gene editing.

The aim of this study was to evaluate the effect of the sprinkler cycle and flow rate on physiological, behavioural, and productive responses in dairy buffaloes. Nine Nili Ravi lactating buffaloes were subjected to three sprinkler cycles and two flow rates using a double replicated 3 × 3 Latin square design. The flow rates were 1.25 and 2 l/min, and the sprinkler cycles (minutes water on/off, number of cycles/h) were: 3/3, 10 cycles; 3/6, 7 cycles and 3/9, 5 cycles. The showering was applied from 0800 till 1630 h daily. In the first square of 21 d, each of the three sprinkler cycles was applied using a 1.25 l/min flow rate for 7 d per cycle. In the later square, the same treatments (sprinkler cycles) were applied using the 2 l/min flow rate. The average temperature humidity index during the study period was 85.7 ± 3.8 (Mean ± sd). The result showed that the 3/3 treatment group had lower body temperature and respiration rate than the other groups. The buffaloes in the 3/3 group produced 0.5 and 0.7 kg more milk with 1.4 and 2.4% more fat than the 3/6 and the 3/9 treatment groups, respectively. Similarly, the 2 l/min flow rate had a lower core body temperate and respiration rate and higher milk yield than the 1.25 l/min group. The 3/3 showering cycle with a 2 l/min flow rate appeared effective in improving physiological responses and milk yield in dairy buffaloes.