Individual Milk Samples Research Articles

Comparison of methods for measurement of somatic cell count in goat milk

The aim of the study was to compare the efficiency of determining the number of somatic cell count in goat milk by different methods. Somatic cells in individual samples of milk from 28 goats were studied using analyzers "Somatos", "SomaCount Flow Cytometer" and by the counting method in milk films stained according to Romanovsky – Giemsa, May-Grünwald and with pyronin Y. For the counting of somatic cells in goat milk by Prescott and Breed method, it is recommended to stain milk films by the May-Grünwald method, because the cytoplasm and nuclei of somatic cells are clearly stained, and the cost of dyes is much less than the pyroninY method. When counting cells in milk films stained by any method, no samples with the SCC up to 100 ´ 103 cells/ml were found. Direct counting of somatic cells in milk films stained by any method reveals a greater number of cells than with the help of devices. It was found that the fat content in goat milk with SCC >3000 ´ 103 cells/ml is significantly higher (P < 0.05) compared to milk with SCC < 1000 ´ 103 cells/ml. The quality of goat's milk smears for counting of somatic cells quantity stained by the May-Grünwald method corresponds to the recommended method with pyronin Y, and the cost of dyes is 28.4 times lower. The distribution of somatic cell ranges is similar between different methods of staining smears, which once again proves the accuracy of the method of direct cell counting in milk films, although it is more labor-intensive than hardware methods.

Characterization and monitoring of changes during lactation in the profile of multiple bioactive compounds of milk from grazing mares.

Mare milk has often been considered a food product with potential functional properties. However, the bioactive compound composition of mare milk, including vitamins and other minor bioactive compounds, as well as factors affecting this composition have scarcely been studied. Therefore, the present study aimed to characterize the changes during lactation in the content of water- and fat-soluble vitamins and total polyphenols, and the total antioxidant capacity of mare milk from semi-extensive farms. A total of 310 individual milk samples from 18 mares belonging to three commercial farms and 12 lactation times were analyzed. Ascorbic acid (vitamin C), thiamine (vitamin B1), riboflavin (vitamin B2), nicotinic acid and niacinamide (vitamins B3), pantothenic acid (vitamin B5), pyridoxal and pyridoxine (vitamins B6), folic acid (vitamin B9), cyanocobalamin (vitamin B12), tocopherols and tocotrienols (vitamin E) and retinol and retinyl esters (vitamin A) were quantified using liquid chromatography. Total polyphenols and antioxidant capacity assays were analyzed using spectrophotometry. The concentration of most bioactive compounds tended to decline as lactation progressed, with the exception of polyphenols and the total antioxidant capacity that oscillated during lactation. On the other hand, the effect of the different semi-extensive management of the farms was only significant for vitamin B3 content. To the best of our knowledge, the present study provides the most in-depth description of the vitamin profile of mare milk as well as new insights into polyphenol content and antioxidant capacity of mare milk. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Supplementation of isoacids to lactating dairy cows fed low or high forage diets: Effects on performance, digestibility, and milk fatty acid profile

Our objective was to determine the effects of isoacids (ISO) on the lactation performance, digestibility, and milk fatty acid (FA) profile of Holstein cows fed 2 forage NDF levels (FL). The study was 10-wk long (including 2-wk for covariate) utilizing a randomized complete block design. Sixty-four mid-lactating Holstein cows [662 ± 71 kg BW, 119 ± 51 DIM, 2 ± 0.9 parity] were blocked by parity, DIM, and prior milk yield (MY) for multiparous cows or genetic merit for primiparous cows, and randomly assigned to 1 of the 4 diets (n = 16). Diets were arranged as a 2 × 2 factorial, with 2 FL containing 21 (HF) and 17% forage NDF (LF) without (WIA) or with ISO supplementation (IA, 7.85 mmol/kg DM and 3.44 mmol/kg DM for isobutyrate and 2-methylbutyrate, respectively). Diets were balanced for similar NEL (1.58 Mcal/kg DM), CP (16.0%) and total NDF (27.2%). Feed intake and MY were recorded daily. Nutrient digestibility for each cow was determined using indigestible NDF as a marker, and fecal samples were collected at 8-time points (4 h intervals between samples). Individual cow milk samples composited over a 10-wk period were analyzed using gas chromatography for FA profile. The statistical model included FL, ISO, and FL × ISO as fixed effects and block as a random effect (lme4 in R). The ISO did not affect DMI (P = 0.13), while LF had greater DMI than HF diets (27.8 vs. 26.0 kg/d; P < 0.01). However, ISO increased MY (34.7 vs. 37.2 kg/d; P < 0.01) and ECM (41.9 vs. 39.0 kg/d; P < 0.01) by 7% in HF but not in the LF diet, suggesting FL × ISO interaction (P = 0.04). Interestingly, ISO increased ADG (0.4 kg/d) but decreased MUN by 9% only in LF diet as indicated by FL × ISO interaction (P < 0.01). Additionally, ISO increased DM, OM, NDF, and CP digestibility by 10-24% in HF (P < 0.01), but not in LF (FL × ISO; P > 0.05). As expected, ISO increased milk odd chain FA profiles in the IA groups irrespective of FL, e.g., the IA had greater C15:0 (1.87 vs. 1.54 g/100g FA; P = 0.03) and a tendency to be greater C17:0 levels (0.86 vs. 0.76 g/100g FA; P = 0.05) compared with WIA groups. Overall, ISO improved MY and nutrient digestibility in the HF whereas it increased ADG and decreased MUN in LF diet. Additionally, ISO increased milk odd chain FA (C15:0 and C17:0) regardless of FL.

Comparison of Extraction Methods for the Detection of Avian Influenza Virus RNA in Cattle Milk.

Since early 2024, a multistate outbreak of highly pathogenic avian influenza H5N1 has been affecting dairy cattle in the USA. The influenza viral RNA concentrations in milk make it an ideal matrix for surveillance purposes. However, viral RNA detection in multi-component fluids such as milk can be complex, and optimization of influenza detection methods is thus required. Raw bulk tank milk and mastitis milk samples were artificially contaminated with an avian influenza strain and subjected to five extraction methods. HCoV-229E and synthetic RNA were included as exogenous internal process controls. Given the high viral load usually observed in individual raw milk samples, four out of five tested methods would enable influenza detection in milk with normal texture, over a time window of at least 2 weeks post-onset of clinical signs. Nevertheless, sample dilution 1:3 in molecular transport medium prior to RNA extraction provided the best results for dilution of inhibitory substances and a good recovery rate of influenza RNA, that reached 12.5 ± 1.2% and 10.4 ± 3.8% in two independent experiments in bulk milk and 11.2 ± 3.6% and 10.0 ± 2.9% on two cohorts of mastitis milk samples. We have also shown compatibility of an influenza RT-qPCR system with synthetic RNA detection for simultaneous validation of the RNA extraction and RT-qPCR processes.

Fluctuations in somatic cell count and their impact on individual goat milk quality throughout lactation

The somatic cell count (SCC) is used by the dairy industry as an indicator of milk quality and udder health. However, in goats, its reliability is significantly masked by non-infectious variables such as the milk secretion process and physiological lactation changes. Additionally, notable individual variability between goats might exist. This study aimed to investigate fluctuations in SCC in individual goats during an entire lactation and to examine the relationship between SCC and milk parameters such as bacterial count and chemical composition. Individual milk samples from 40 Norwegian dairy goats from the University herd were collected monthly across an entire lactation including the pasture period. The goats were categorized based on SCC levels to analyze patterns in chemical components within these groups. Notably, goats exhibited increased SCC and decreased bacterial counts when moved to summer grazing pastures. At that stage milk samples from goats with the highest SCC (>2000 ×103 cells/mL) showed a distinct decrease in individual bacterial counts (IBC). Several milk components, especially lactose, protein, and various minerals were affected by the SCC level, as well as pH. These effects were further amplified when considering the interaction with the lactation stage, influencing a broader range of variables. The results presented in this study provide new insights into the SCC's effect on milk composition and its critical role. These insights underscore the necessity for establishing lactation-specific thresholds for interpretation, as well as for making adjustments in quality payments.

Prevalence of Neospora caninum and associated risk factors in semi-intensive female water buffaloes reared in Greece, using an ELISA kit on milk samples

Neospora caninum is an apicomplexan (family: Sarcocystidae) protozoan parasite with a global distribution. In the N. caninum life cycle, dogs and other related canids are the definitive hosts, while other animals such as water buffaloes (Bubalus bubalis) constitute the intermediate host for this parasite. In many countries, the water buffalo is of high economic importance, providing valuable high-quality products for human needs. Although knowledge concerning the prevalence of this parasite in intermediate animal host populations is crucial, data from water buffalo are scarce. Keeping this in mind, the aim of this study was to examine the presence and assess the prevalence rates of N. caninum infection in water buffaloes in Northern Greece, where this animal husbandry sector started to raise, as well as to determine associated risk factors, with the application of a commercially available Neospora ISCOM ELISA test kit, developed for the detection of antibodies against N. caninum in milk samples The study was conducted during January–June 2023 in a total of 172 individual raw milk samples, collected from dairy buffaloes, reared under a semi extensive system, in three different farms. Information on the status of N. caninum infection in buffaloes from Greece was so far unknown with a lack of epidemiological or risk factors associated. For the detection of N. caninum, the commercially available Neospora ISCOM ELISA test kit (SANOVIR ®, Svanova Biotech AB, Uppsala, Sweden) was utilized. Results demonstrated the presence of N. caninum in water buffaloes from Greece for the first time. All positive N. caninum animal were asymptomatic, with absence of any disease signs. The overall prevalence of infection was 22.10%, whereas the main risk factors include the presence of dogs as well as the low biosecurity measures.

Identification and Prioritization of Organic Pollutants in Human Milk from the Yangtze River Delta, China.

Pollutants in human milk are critical for evaluating maternal internal exposure and infant external exposure. However, most studies have focused on a limited range of pollutants. Here, 15 pooled samples (prepared from 467 individual samples) of human milk from three areas of the Yangtze River Delta (YRD) in China were analyzed by gas chromatography quadrupole time-of-flight mass spectrometry. In total, 171 compounds of nine types were preliminarily identified. Among these, 16 compounds, including 2,5-di-tert-butylhydroquinone and 2-tert-butyl-1,4-benzoquinone, were detected in human milk for the first time. Partial least-squares discriminant analysis identified ten area-specific pollutants, including 2-naphthylamine, 9-fluorenone, 2-isopropylthianthrone, and benzo[a]pyrene, among pooled human milk samples from Shanghai (n = 3), Jiangsu Province (n = 6), and Zhejiang Province (n = 6). Risk index (RI) values were calculated and indicated that legacy polycyclic aromatic hydrocarbons (PAHs) contributed only 20% of the total RIs for the identified PAHs and derivatives, indicating that more attention should be paid to PAHs with various functional groups. Nine priority pollutants in human milk from the YRD were identified. The most important were 4-tert-amylphenol, caffeine, and 2,6-di-tert-butyl-p-benzoquinone, which are associated with apoptosis, oxidative stress, and other health hazards. The results improve our ability to assess the health risks posed by pollutants in human milk.

Mastitis challenges in Serbian dairy farming: a study on somatic cell counts and pathogen distribution

Mastitis is pressing concern for dairy herds due to its economic impact and potential health risks. Somatic cell counts (SCC), reflecting udder health, plays a crucial role in mastitis diagnosis. Current research explores the distribution of SCC and its correlation with various mastitis-causing pathogens in dairy farms in Serbia. The study analyzed 194 individual cow milk samples and microbiological testing was conducted under aseptic conditions to isolate and identify mastitis pathogens. The microscopic reference method was employed for assessing SCC in the milk samples. Among mastitis-associated isolates, bacteria were present in 28.87 %, yeast in 12.38 %, while in 5.15 % of milk samples, both bacteria and yeast were present. The relationship between SCC in various sample types (negative, bacteria-positive, yeast-positive, and samples with both bacteria and yeast) was noted. Importantly, samples with both bacteria and yeast presence had the highest SCC. While SCC is a valuable tool for monitoring udder health and the effectiveness of mastitis control programs, its response to specific pathogens is complex and doesn’t allow differentiation between pathogen types easily. This research highlights the challenges in distinguishing pathogen types based solely on SCC.

Molecular identification of Coxiella burnetii in raw milk samples collected from farm animals in districts Kasur and Lahore of Punjab, Pakistan

Coxiella burnetii is the worldwide zoonotic infectious agent for Q fever in humans and animals. Farm animals are the main reservoirs of C. burnetii infection, which is mainly transmitted via tick bites. In humans, oral, percutaneous, and respiratory routes are the primary sources of infection transmission. The clinical signs vary from flu-like symptoms to endocarditis for humans’ acute and chronic Q fever. While it is usually asymptomatic in livestock, abortion, stillbirth, infertility, mastitis, and endometritis are its clinical consequences. Infected farm animals shed C. burnetii in birth products, milk, feces, vaginal mucus, and urine. Milk is an important source of infection among foods of animal origin. This study aimed to determine the prevalence and molecular characterization of C. burnetii in milk samples of dairy animals from two districts in Punjab, Pakistan, as it has not been reported there so far. Using a convenience sampling approach, the current study included 304 individual milk samples from different herds of cattle, buffalo, goats, and sheep present on 39 farms in 11 villages in the districts of Kasur and Lahore. PCR targeting the IS1111 gene sequence was used for its detection. Coxiella burnetii DNA was present in 19 of the 304 (6.3%) samples. The distribution was 7.2% and 5.2% in districts Kasur and Lahore, respectively. The results showed the distribution in ruminants as 3.4% in buffalo, 5.6% in cattle, 6.7% in goats, and 10.6% in sheep. From the univariable analysis, the clinical signs of infection i.e. mastitis and abortion were analyzed for the prevalence of Coxiella burnetii. The obtained sequences were identical to the previously reported sequence of a local strain in district Lahore, Sahiwal and Attock. These findings demonstrated that the prevalence of C. burnetii in raw milk samples deserves more attention from the health care system and veterinary organizations in Kasur and Lahore of Punjab, Pakistan. Future studies should include different districts and human populations, especially professionals working with animals, to estimate the prevalence of C. burnetii.

Triplex immunomagnetic separation combined with loop-mediated isothermal amplification on a microfluidic chip for simultaneous visual detection of Escherichia coli O157:H7, Salmonella enteritidis and Staphylococcus aureus in milk

Escherichia coli O157:H7, Salmonella enteritidis, and Staphylococcus aureus are widely present in food and can cause serious and large-scale cases of illness worldwide every year. Herein, we developed a triplex immunomagnetic separation (IMS) combined with loop-mediated isothermal amplification (LAMP) on a microfluidic chip (triplex IMS-mLAMP) for the simultaneous detection of these three important foodborne pathogenic bacteria. To optimize the triplex IMS method, the CEs of the three types of IMBs were determined for different particle sizes, amounts and incubation times. Under optimal reaction conditions, the CEs for the three bacteria were between 65.4% and 71.1% in PBS, and between 41.1% and 47.5% in milk, respectively. After triplex IMS, DNA from target bacteria captured by magnetic beads was extracted and subjected to a multiplexed LAMP reaction in a centrifugal microfluidic chip that allowed for the simultaneous detection of up to 8 individual milk samples. The results were judged directly by the color change. The method only detected the three target bacteria and did not show cross-reaction with other bacteria, exhibiting a high level of specificity. Sensitivity experiments confirmed a detection limit of the triplex IMS-mLAMP as low as 1.2 × 102 CFU/mL for E. coli O157:H7 and S. enteritidis, and 2.5 × 102 CFU/mL for S. aureus in milk samples. The overall testing time of the triplex IMS-mLAMP was just 80 min. This is the first report that IMS-mLAMP was used for simultaneous capture and detection of E. coli O157:H7, S. enteritidis, and S. aureus in milk. This cost-effective, easy-to-use, no need for expensive laboratory-based equipment, integrated on-chip colorimetric multi-target detection system opens a novel pathway for rapid diagnostic screening of pathogens in food.

Cyclical heat stress during lactation influences the microstructure of the bovine mammary gland

This study aimed to evaluate the impact of heat stress on mammary epithelial cell (MEC) losses into milk, secretory mammary tissue structure, and mammary epithelial cell activity. Sixteen multiparous Holstein cows (632 ± 12 kg BW) approximately 100 d in milk housed in climate-controlled rooms were paired by body weight and randomly allocated to one of 2 treatments, heat stress (HS) or pair feeding thermoneutral (PFTN) using 2 cohorts. Each cohort was subjected to 2 periods of 4 d each. In period 1, both treatments had ad libitum access to a common total mixed ration and were exposed to a controlled daily temperature-humidity index (THI) of 64. In period 2, HS cows were exposed to controlled cyclical heat stress (THI: 74 to 80), while PFTN cows remained at 64 THI and daily dry matter intake was matched to HS. Cows were milked twice daily, and milk yield was recorded at each milking. Individual milk samples on the last day of each period were used to quantify MEC losses by flow cytometry using butyrophilin as a cell surface marker. On the final day of period 2, individual bovine mammary tissue samples were obtained for histomorphology analysis, assessment of protein abundance, and evaluation of gene expression of targets associated with cellular capacity for milk and milk component synthesis, heat response, cellular proliferation, and autophagy. Statistical analysis was performed using the GLIMMIX procedure of SAS. Milk yield was reduced by 4.3 kg by HS (n = 7) compared with PFTN (n = 8). Independent of treatment, MEC in milk averaged 174 cells/mL (2.9% of total cells). There was no difference between HS vs. PFTN cows for MEC shed or concentration in milk. Alveolar area was reduced 25% by HS, and HS had 4.1 more alveoli than PFTN. Total number of nucleated MEC per area were greater in HS (389 ± 1.05) compared with PFTN (321 ± 1.05); however, cell number per alveolus was similar between groups (25 ± 1.5 vs. 26 ± 1.4). There were no differences in relative fold expression for GLUT1, GLUT8, CSN2, CSN3, LALBA, FASN, HSPA5, and HSPA8 in HS compared with PFTN. Immunoblotting analyses showed a decrease abundance for phosphorylated STAT5 and S6K1, and an increase in LC3 II in HS compared with PFTN. These results suggest that even if milk yield differences and histological changes occur in the bovine mammary gland after 4 d of heat exposure, MEC loss into milk, nucleated MEC number per alveolus, and gene expression of nutrient transport, milk component synthesis, and heat stress related targets are unaffected. In contrast, the abundance of proteins related to protein synthesis and cell survival decreased significantly, while an upregulation of proteins associated with autophagy in HS compared with PFTN.

Assessment of Heavy Metals and Trace Elements in the Human Milk of Women Living in Latvia and an Evaluation of Influencing Factors.

During lactation, heavy metals and trace elements can be mobilised from the maternal body stores and excreted via human milk. A total of 66 mature human milk samples were collected from lactating women in Latvia between 2016 and 2017 to analyse the content of As, Cd, Pb, Al, Sn, and Ni. Additionally, 50 mature human milk samples were collected between 2022 and 2023 to analyse the content of Cd and Pb. The content of heavy metals and trace elements in human milk was determined using ICP-MS. Only two individual human milk samples contained heavy metals above the method's detection limit-one with an arsenic content of 0.009 mg kg-1 and one with a lead content of 0.047 mg kg-1. The preliminary data show that human milk among lactating women in Latvia contains only insignificant amounts of heavy metals and trace elements. Concern over such content should not be a reason to choose formula feeding over breastfeeding. Nevertheless, heavy metals, trace elements and other pollutants in human milk should be continuously monitored.

Impact of genetic κ-casein variants (A, B, E) on chymosin-induced milk coagulation properties: Application of a new LC–MS-based genotyping method

This study evaluated the impact of κ-casein (κ-CN) protein phenotype (AA (n = 18), AB (n = 18), AE (n = 5), BB (n = 3)) in the raw milk of 44 individual Holstein cows from a single farm on coagulation properties using diffusion wave spectroscopy. κ-CN variants were analyzed using a newly developed LC–MS method in individual milk samples, and relative milk protein fractions were quantified by LabChip-analysis. κ-CN fractions expressed in the percentage of total milk protein, total casein, and β- and κ-CN were then calculated. The gross composition of the individual milk samples and variation between individual cows was analyzed and was rather large, as expected. Traits were analyzed using an ANCOVA model with pH as a covariate.Our results showed that mean percentages of κ-CN fractions increased for κ-CN phenotypes in the order AA < AE < AB < BB. Rennet coagulation time was slightly affected, but curd firmness was significantly affected by κ-CN phenotype (BB > AE > AB > AA) when controlling for pH.

On-farm NIR sensor for milk analysis: Exploitation of bias monitoring and bias correction

Long-term studies have shown a bias drift over time in the prediction performance of near-infrared spectroscopy measurement systems. This bias drift generally requires extra laboratory reference measurements to detect and correct for this bias. Since these reference measurements are expensive and time consuming, there is a need for advanced methodologies for bias drift monitoring and correction without the need for taking extra samples. In this study, we propose and validate a method to monitor the bias drift and two methods to tackle it. The first method requires no extra measurements and uses a modified version of Partial Least Squares Regression to estimate and correct the bias. This method is based on the assumption that the mean concentration of the predicted component remains constant over time. The second method uses regular bulk milk measurements as a reference for bias correction. This method compares the measured concentrations of the bulk milk to the volume-weighted average concentrations of individual milk samples predicted by the sensor. Any difference between the actual and calculated bulk milk composition is then used to perform a bias correction on the predictions by the sensor system. The effectiveness of these methods to improve the component prediction was evaluated on data originating from a custom-built sensor that automatically measures the NIR reflectance and transmittance spectra of raw milk on the farm. We evaluate the practical use case where models for predicting the milk composition are trained upon installation of the sensor at the farm, and later used to predict the composition of subsequent samples over a period of more than 6 months. The effectiveness of the fully unsupervised method was confirmed when the mean concentration of the milk samples remained constant, while the effectiveness reduced when this was not the case. The bulk milk correction method was effective when all relevant samples for the component were measured by the sensor and included in the analyzed bulk milk, but is less effective when samples included in the bulk which are not measured by the sensor system. When the necessary conditions are met, these methods can be used to extend the lifetime of deployed prediction models by significantly reducing the bias on the predicted values.

Diagnostic accuracy of the Enferplex Bovine TB antibody test using individual milk samples from cattle.

Bovine tuberculosis is usually diagnosed using tuberculin skin tests or at post-mortem. Recently, we have developed a serological test for bovine tuberculosis in cattle which shows a high degree of accuracy using serum samples. Here, we have assessed the performance of the test using individual bovine milk samples. The diagnostic specificity estimate using the high sensitivity setting of the test was 99.7% (95% CI: 99.2-99.9). This estimate was not altered significantly by tuberculin boosting. The relative sensitivity estimates of the test using the high sensitivity setting in milk samples from comparative skin test positive animals was 90.8% (95% CI: 87.1-93.6) with boosting. In animals with lesions, the relative sensitivity was 96.0% (95% CI: 89.6-98.7). Analysis of paired serum and milk samples from skin test positive animals showed correlation coefficients ranging from 0.756-0.955 for individual antigens used in the test. Kappa analysis indicated almost perfect agreement between serum and milk results, while McNemar marginal homogeneity analysis showed no statistically significant differences between the two media. The positive and negative likelihood ratio were 347.8 (95% CI: 112.3-1077.5) and 0.092 (95% CI: 0.07-0.13) respectively for boosted samples from skin test positive animals. The results show that the test has high sensitivity and specificity in individual milk samples and thus milk samples could be used for the diagnosis of bovine tuberculosis.

The Transmission of Campylobacter Strains in Dairy Herds in Different Housing Systems.

Cattle are frequent carriers of Campylobacter spp.; therefore, these bacteria may be transmitted to humans through meat or milk. Campylobacter spp. in raw milk derives most commonly from secondary fecal contamination during the milking process; however, the udder excretion of Campylobacter may be a cause of milk-borne infection. Studies were carried out on a Campylobacter-positive farm with two different housing systems (with free-stall and tie-stall systems). The sampling process comprised several stages, including samples being taken from animals, such as from raw milk and feces, and from the environment, such as the from floor in the milking parlor and from teat cups. None of the individual raw milk samples or swabs from the floor in the parlor before the milking process were positive for Campylobacter spp. Simultaneously, Campylobacter spp. was isolated from all swabs from the floor after the milking process and in the bulk tank milk samples from the two farms. The incidence of Campylobacter isolated from fecal and teat swab samples ranged from 15.4% to 26.7% and from 8.9% to 25%, respectively. Altogether, 59 recovered Campylobacter isolates were classified, based on sequencing of the flaA short variable region, showing 15 different allele types, and the majority of them were distributed among one farm. Analysis of the virulence and antimicrobial properties showed that genes related to adherence, invasion and cytotoxicity were widely distributed among the Campylobacter recovered strains. In relation to AMR, multidrug resistance was noted in 16.1% of strains.

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.

Changes in milk fat globule membrane proteins along lactation stage of Laoshan dairy goat

The milk fat globule membrane (MFGM) is a complex structure with numerous functions, and its composition is affected by many factors. There have been few systematic investigations on goat MFGM proteome profiling during lactation. Individual milk samples from 15 healthy dairy goats were obtained at six lactation time points for investigation of the MFGM proteome using both data-independent acquisition (DIA) and data-dependent acquisition (DDA) proteomics techniques combined with multivariate statistical analysis. Using the DIA method, 890 variably abundant MFGM proteins were discovered throughout the lactation cycle. From 1 to 240 d, butyrophilin subfamily 1 member A1, lipoprotein lipase, perilipin-2, and adipose triglyceride lipase were upregulated, while APOE, complement C3, clusterin, and IgG were downregulated. Furthermore, from 1 to 90 d, annexin A1, annexin A2, and antithrombin-III were downregulated, then upregulated by d 240. Albumin had a high degree of connectedness, indicating that it was a key protein, according to protein–protein interaction research. Overall, our findings gave new insights into the biological features of MFGM protein in goat milk throughout lactation, which may aid in the creation of specialized MFGM products and infant formula.

The use of Brix refractometer as a simple and economic device to estimate the protein content of sheep milk

In this study, 737 individual sheep milk samples were collected 2 times from morning milkings to evaluate the relationships between Brix refractometer measurements and milk constituents— protein and fat percentages—to verify its ability to predict milk constituents. The Pearson's simple (rSP) and partial (rPP) correlations between milk constituents were calculated, and several first- and second-order regressions were tested to predict the protein and fat percentages. The rSP coefficients between the Brix refractometer measurement and fat (rSP = 0.46) and protein (rSP = 0.87) contents were different from the rPP coefficients, particularly for fat percentage (rPP = 0.04 and rPP = 0.82, for fat and protein percentages, respectively). The results of the forecasts can be considered satisfactory only for the first order regression that predicted the percentage of milk protein, while the regression that predicted the percentage of fat + milk protein presented a weak forecasting capacity.

Milk Composition and Productivity of Holstein Cows in Ryegrass Grazing and Crude Glycerin in The Diet

Objective: The aim of this project was to evaluate the effect of crude glycerin addition in the diet, milk composition and milk yield in dairy milking cows on different stages of lactation. Theoretical framework: It is necessary to balance the supply of protein and energy in the diet of lactating cows. Within this context, a by-product of the Biodiesel industry, called crude glycerin, is low cost and has a high energy value for ruminants, since its main component is glycerol, which ruminants have the capacity to use as a precursor gluconeogenic (Chung et al., 2007). Methods: The experiment was performed with Holstein cows (n=18), divided in two groups of treatment: 1) Basal diet without crude glycerin addition, 2) Diet with 10% of crude glycerin addition in the dry matter. Individual milk samples were collected for the analysis of the percentage of Fat, Protein, Lactose, Total Solids and Somatic Cell Count (Cs mL-1), as well as milk production (liters -1 and corrected for 4% fat). Results and conclusion: It was concluded that the addition of crude glycerin in the diet had no significant effect on the milk production and composition of cows of the Dutch breed. Originality/value: The study results have crucial implications for cow nutrition strategies. Implication of the research: The study results have crucial implications for strategies in the Nutrition of the cows.