Hasil untuk "Dairying"

Hanyu Shi, Haotian Zheng

ABSTRACT: This study investigates the functionality of mesoscale whey protein particles (WPP) derived from fiber- and ribbon-shaped whey protein assemblies produced via a liquid antisolvent precipitation-based method. The air-water (A-W) interfacial characteristics, foaming properties, and heat stability of WPP were evaluated and compared with the original whey protein source, whey protein isolate (WPI). Adsorption dynamics and dilatational rheology at the A-W interface were characterized using pendant drop and oscillating drop methods, respectively. Foamability and foam stability were assessed using a dynamic foam analyzer, and heat stability was evaluated by examining changes in particle size distribution (PSD) profiles and turbidity before and after heat treatment at 95°C for 5 min. Whey protein particles achieved a quasi-equilibrium surface pressure comparable to WPI after 3 h of adsorption but showed lower dilatational elastic moduli during dilatational deformation. Although WPI exhibited faster surface adsorption, no significant difference was observed in the rate constant of penetration (kp) between WPP and WPI. Compared with WPI, reconstituted freeze-dried WPP dispersions did not improve foamability, likely due to slower A-W interface adsorption associated with their larger particle sizes; however, they demonstrated enhanced foam stability, evidenced by a longer 75%-volume lifetime. This improvement is likely attributed to the entrapment of WPP within the lamellae and Plateau borders of foam structure, which may increase local viscosity and block the liquid drainage channels, thereby retarding foam collapse. Moreover, WPP exhibited minimal changes in their PSD and turbidity after heat treatment, suggesting enhanced heat stability relative to WPI.

Denis Kučević, Ksenija Čobanović, Mirko Ivković et al.

The aim of this study was to investigate the prevalence of subclinical ketosis in dairy cows based on elevated levels of milk β-hydroxybutyrate (BHB), somatic cell count (SCC), and oth¬er milk components. The analyzed data were obtained through routine analyses Dairy Herd Improvement (DHI) milk samples, by Fourier-transform infrared (FTIR) spectroscopy. The initial dataset included a total of 23,492 Holstein cow milk samples collected between January 2022 and January 2025 on six farms located in the Province of Vojvodina, Serbia. After outlier removal, final data set included 22,915 milk samples. Based on the concentration of β-hydroxy¬butyrate (BHB), 75 % of the samples were in the first negative group (BHB<0.10 mmol/L), with an average concentration of 0.03 mmol/L. The second, suspicious-negative group (BHB 0.11- 0.15 mmol/L) comprised 15 % of the samples, with an average of 0.13 mmol/L. In addition, 6 % of the samples fell into the third, suspicious-positive group (BHB 0.16-0.20 mmol/L), with an average of 0.18 mmol/L, while the fourth, positive group (BHB>0.20 mmol/L) comprised 4 % of the samples, with an average concentration of 0.34 mmol/L. Through the analysis of the milk components, it was determined that in the first period, at 5-42 days in milk (DIM), significantly affected all observed parameters. The lactose content is decreasing, while fat, protein, total solids, milk fat/protein (F/P) ratio, SCC and urea are increasing. The results highlight the potential of using milk samples from Dairy Herd Improvement (DHI) programs to monitor elevated levels of milk BHB and SCC at the herd level. This approach may serve as a useful tool for estimating the prevalence of subclinical ketosis in dairy cows. Additionally, different BHB thresholds might be needed for different periods of lactation.

B.J. Sepulveda, O. González-Recio, A.J. Chamberlain et al.

ABSTRACT: Ruminant digestion emits methane, a potent greenhouse gas contributing to global warming and reducing feed efficiency. Reducing enteric methane emissions (EME) through breeding decisions is theoretically possible, yet measuring these emissions on commercial farms is currently challenging and costly. It is common for EME to be measured using different technologies, which may show weak correlations between them, complicating the combination of reference populations, especially between countries. Here, using the same sequencing strategy, we identified a group of ruminant metagenomic features (a core) present in at least 90% of 410 dairy cows in Australia and 434 in Spain. With subsets of this core (the breeding core subsets) we estimated larger reductions on EME than using direct selection on EME. A combination of direct selection on EME and indirect selection on the breeding core subsets was estimated to produce even larger reductions. Combining the principal components of the core with some genera, Kyoto Encyclopedia of Genes and Genomes ontology and Clusters of Orthologous Groups could enhance EME reductions in breeding programs. We estimated an EME reduction of 0.41 phenotypic standard deviations per generation by selecting the top 30% of individuals with desirable ruminal microbiota profiles. An R Shiny application to estimate those reductions is provided. Additionally, the breeding core subsets could predict EME irrespective of each population's EME trait (sulfur hexafluoride in Australia and sniffers in Spain). These results suggest that rumen metagenome features could be used as selection criteria for genomic selection programs to reduce EME, as many of these features are heritable and correlated with EME. Features in the core could connect EME from different cattle populations, irrespective of the methane phenotype used in those populations. We propose that our methodology should be applied to much larger datasets to improve the accuracy of identifying a breeding core. Therefore, we propose a global effort to validate a common core of EME-associated ruminal features.

Maha M. Bikheet, Hanaa M. Hassan, Maha O.A. Omar et al.

ABSTRACT: The antibacterial efficacy of clove extracts (Syzygium aromaticum) prepared using 80% ethanol and water against pathogenic bacteria was evaluated, along with the development of a novel antimicrobial milk beverage incorporating these extracts. Seven flavored milk beverage (FMB) treatments were prepared: a control and 6 with clove extracts at 0.5%, 0.7%, and 1% for each solvent. The effects on physicochemical, phytochemical, antioxidant, microbiological, color, and sensory properties were assessed over 15 d of storage at 4 ± 1°C. The ethanolic clove extract exhibited significantly higher antimicrobial activity against Staphylococcus aureus, Listeria monocytogenes, Escherichia coli O157, Salmonella typhi, and Klebsiella pneumoniae, with inhibition zone diameters of 20 mm, 21 mm, 20 mm, 19 mm, and 20 mm, respectively, compared with the aqueous extract. On d 0, the sample of 1% ethanolic clove extract (FMB3) showed the highest proximate analysis values, including TS (22.41%), protein (4.61%), fat (4.58%), ash (0.97%), and gross energy (108.65 Kcal). It also showed the highest pH (6.7), flavor score (19.20), texture score (9), and overall acceptability score (39.50), and the lowest carbohydrate content (12.27%), lightness value (69.60), and yellowness value (97.47). Over the 15-d storage period, the total phenolic content (TPC), total flavonoid content (TFC), and total antioxidant capacity (TAC) increased, with the FMB3 sample exhibiting the highest TPC (58.70 mg/100 g), TFC (46.15 mg/100 g), and TAC (487.10 mg/100 g). All beverages remained free from yeasts and molds, and FMB3 exhibited the lowest bacterial count (5.13 log cfu/mL). The results indicate that ethanolic clove extract effectively inhibits spoilage and pathogenic organisms and enhances the sensory and functional properties of FMB. This finding offers a promising approach for improving the quality and safety of dairy products.

A.J. Schwanke, K.M. Dancy, H.W. Neave et al.

ABSTRACT: The objectives of this study were to determine: (1) if dairy cow personality traits and concentrate allowance are associated with the behavior and performance of cows during training to use an automated milking system (AMS); and (2) if these factors were associated with the behavior and performance of cows after AMS training. Twenty-nine mid- to late-lactation Holstein cows (218 ± 49 DIM), who were milking on a rotary parlor and had never previously been milked in an AMS, were enrolled in this study. Cows were assigned to 1 of 2 dietary treatments, consisting of a basal partial mixed ration (PMR) common to both treatment groups, with a concentrate allowance (on a DM basis) of (1) 2.0 kg/d in the AMS (L-Tx), or (2) 6.0 kg/d in the AMS (H-Tx). Cows were trained to use the free-traffic AMS, with supervised milkings, over 72 h and were milked in this system for 63 d after training was complete. Variables relating to feeding behavior, milking activity, and production were measured from the start of AMS training until the end of the study. Between 42 and 63 d after AMS introduction, each cow was assessed for personality traits using a combined arena test consisting of exposure to a novel environment, novel object, and novel human. Principal components analysis of behaviors observed during the personality assessment revealed 2 factors (interpreted as boldness and activeness traits) that together explained 85% of the variance; each cow received a score for each trait. Associations between dietary treatment and personality traits with feeding behavior, milking activity, and production were analyzed using mixed-effect linear and logistic regression models. Cows with greater scores for the active trait produced less milk during the 3 d of AMS training compared with cows with lower scores. Within the H-Tx, more active cows had a 3.92 times greater risk of kicking off teat cups during AMS training than less active cows. However, during the 8 wk after training, more active cows had a 1.37 times lesser risk of teat cup kickoffs than those that were less active. Cows on the H-Tx produced 4.4 kg/d more ECM compared with cows on the L-Tx in the 8 wk after training. During the 8 wk after AMS training the cows on the H-Tx consumed an average of 21.4 kg/d of PMR and were delivered 4.6 kg/d of AMS concentrate, whereas the L-Tx cows consumed 23.4 kg/d PMR and were delivered 2.0 kg/d of AMS concentrate. The results indicate that both dairy cow personality traits and AMS concentrate allocation influence their response to AMS training and subsequent feeding and milking behavior and production.

H.C. Azevedo, H.D. Blackburn, E.A. Lozada-Soto et al.

ABSTRACT: Computer-assisted sperm analysis (CASA) has become the predominant tool for assessing bull semen in AI programs. Despite such popularity CASA's ability to predict fertility has been limited, especially when emphasis is based on single motion characteristics. Our hypothesis is that numerical sets of CASA measures provide a more effective method to differentiate the potential fertilization capacity of bulls and that bulls can be clustered based on sets of CASA measures. Therefore, we used CASA to evaluate frozen-thawed semen samples from 307 Holstein and 152 Jersey bulls sourced from USDA Agricultural Research Service's National Animal Germplasm Program gene bank. Sperm was evaluated immediately after thawing and 30 min later. We evaluated sperm kinetic and morphometric means and variances to capture the structure of CASA data in relation to various sources of variation. These data were subjected to univariate and multivariate statistical methods to investigate animal and management factors affecting sperm characteristics measured by CASA. Clustering with K-means identified 4 clusters of bulls based upon each cluster's set of CASA parameters after thawing. There was little overlap among clusters for sets of CASA measures. At the extremes, bull cluster 1 (BC1, n = 180) and BC3 (n = 101) had different sire conception rates (SCR) −0.07 versus −1.29, respectively, and sets of CASA measures. Interestingly, bull cluster 2 (BC2) had CASA measures that could be perceived as negative, for example, cell size at 8.18 mm2 versus 6.37 mm2 for bull cluster 4 (BC4) and total motility of 29.7% versus 48.7% for BC3, but SCR for BC2 were higher (−0.79) than those for BC3 (−1.29). Despite such discrepancies for some BC2 CASA values it appears the potentially negative effects were offset by the levels of other CASA values. Our findings suggest improved approaches for using CASA could lie in evaluating multiple CASA measures as sets within specific numerical ranges rather than as independent measures.

Jason R. Graham, Maria E. Montes, Victor B. Pedrosa et al.

ABSTRACT: Precision livestock farming technologies, such as automatic milk feeding machines, have increased the availability of on-farm data collected from dairy operations. We analyzed feeding records from automatic milk feeding machines to evaluate the genetic background of milk feeding traits and bovine respiratory disease (BRD) in North American Holstein calves. Data from 10,076 preweaning female Holstein calves were collected daily over a period of 6 yr (3 yr included per-visit data), and daily milk consumption (DMC), per-visit milk consumption (PVMC), daily sum of drinking duration (DSDD), drinking duration per-visit, daily number of rewarded visits (DNRV), and total number of visits per day were recorded over a 60-d preweaning period. Additional traits were derived from these variables, including total consumption and duration variance (TCV and TDV), feeding interval, drinking speed (DS), and preweaning stayability. A single BRD-related trait was evaluated, which was the number of times a calf was treated for BRD (NTT). The NTT was determined by counting the number of BRD incidences before 60 d of age. All traits were analyzed using single-step genomic BLUP mixed-model equations and fitting either repeatability or random regression models in the BLUPF90+ suite of programs. A total of 10,076 calves with phenotypic records and genotypic information for 57,019 SNP after the quality control were included in the analyses. Feeding traits had low heritability estimates based on repeatability models (0.006 ± 0.0009 to 0.08 ± 0.004). However, total variance traits using an animal model had greater heritabilities of 0.21 ± 0.023 and 0.23 ± 0.024, for TCV and TDV, respectively. The heritability estimates increased with the repeatability model when using only the first 32 d preweaning (e.g., PVMC = 0.040 ± 0.003, DMC = 0.090 ± 0.009, DSDD = 0.100 ± 0.005, DS = 0.150 ± 0.007, DNRV = 0.020 ± 0.002). When fitting random regression models (RRM) using the full dataset (60-d period), greater heritability estimates were obtained (e.g., PVMC = 0.070 [range: 0.020, 0.110], DMC = 0.460 [range: 0.050, 0.680], DSDD = 0.180 [range: 0.010, 0.340], DS = 0.19 [range: 0.070, 0.430], DNRV = 0.120 [range: 0.030, 0.450]) for the majority of the traits, suggesting that RRM capture more genetic variability than the repeatability model with better fit being found for RRM. Moderate negative genetic correlations of −0.59 between DMC and NTT were observed, suggesting that automatic milk feeding machines records have the potential to be used for genetically improving disease resilience in Holstein calves. The results from this study provide key insights of the genetic background of early in-life traits in dairy cattle, which can be used for selecting animals with improved health outcomes and performance.

Rodrigo L.A. Palhano, Ronaldo A. Martins, Guilherme S. Lemos et al.

ABSTRACT: Cattle lameness remains a significant concern, causing economic losses and compromising animal welfare. Claw horn lesions have been identified as a major cause of lameness in dairy cows, but their correlation with high-energy diets and ruminal acidosis remains unclear. Hence, the primary objective of this study was to assess the effects of a high-starch diet and a conventional diet on the rumen environment, acute-phase proteins, and metabolic alterations, with a particular focus on insulin resistance and the consequent implications for the histology of the hooves in Holstein steers. A total of 16 animals were divided into the high-starch (HS; 37% starch) and conventional (CON; 16.8% starch) groups. Glucose tolerance tests (GTT), blood analyses, rumen fluid analyses, and histological evaluations of the hoof tissue were conducted over a 102-d experimental period. The HS group showed a lower ruminal pH than the CON group, and with values indicating SARA. The plasma glucose and IGF-1 concentrations were higher in the HS group, suggesting an anabolic state. Both groups exhibited an increase in the insulin area under the curve (AUC) after the GTT on d 102. Histological analysis of the hooves showed a reduction in the length and width of the epidermal lamella in both groups. We found a significant negative correlation between the insulin AUC and the length and width of the epidermal lamella. Because both groups were similarly affected, the hypothesis that histological alterations were caused by the experimental diets still needs confirmation. Additionally, the development of SARA was not essential for the observed histological changes in the hoof. Further studies are warranted to thoroughly investigate the role of insulin and IGF-1 imbalances in claw health.

Joanne Marshall, Derek Haley, Lena Levison et al.

ABSTRACT: The removal (culling) of dairy cows from the farm is a regular and required management practice. The main objectives of this study were to describe the involvement of bovine veterinarians in Ontario, Canada, in dairy cull cow management decisions, their expectations of current producer practices, and their perspectives on welfare issues and best management practices for cull dairy cows. Between February and May 2021, a province-wide survey was conducted among all members of the Ontario Association of Bovine Practitioners (OABP), with questions addressing veterinarians' background and demographics, veterinary clinic characteristics, cull cow management, down cow management, and learning preferences. The response rate for the survey was 25.1%, with 45 responses meeting all eligibility criteria. Dairy veterinarians would like to have greater involvement in cull cow management; when asked for desired involvement in culling decisions, 57.5% of veterinarians would like to be involved in culling decisions most of the time or always. Most (70.0%) veterinarians believed that cull cow welfare has improved over the last decade. However, most respondents also identified at least one area of management (farm of origin, transportation, auction, slaughter) as currently being a high risk to cull cow welfare. Given the frequency of their visits, trust by dairy producers, and knowledge, herd veterinarians are among those in the best position to improve the care of cull dairy cows. Information generated from this survey can be used to inform the development of improved decision-making tools for culling cows, and this, along with increased veterinarians' involvement in cull cow management, could improve the economic and welfare outcomes of culling decisions for dairy producers.

Yichen Tian, Kaiqing Yang, Yaoqiang Shi et al.

ABSTRACT: In recent years, food safety incidents caused by Escherichia coli have occurred and have endangered human health. Due to the complex matrix of milk samples and the long pretreatment time, the existing methods cannot quickly detect E. coli in milk samples. It is necessary to enrich the E. coli in the complex matrix to improve the detection sensitivity. The E. coli outer membrane protein A (OmpA) is widely present on the cell membrane of E. coli and may be used as a new target to enrich E. coli. In this study, the purified recombinant OmpA protein was used to immunize BALB/c mice to produce polyclonal antibody. Immunomagnetic beads were combined with the polyclonal antibody to enrich the E. coli in the artificially contaminated milk samples. The products of immunoprecipitation were further used for PCR assay. The bacteria in the PCR sample can be pre-enriched, and the limit of detection is 10 × 100 cfu/mL, which is about 100 times more sensitive than samples not processed by this method. Then, the artificially contaminated milk, coffee, juice, and soybean milk samples were tested separately, and it was found that the E. coli gene could be amplified. The whole analysis time was about 120 min, including the enrichment of bacteria and the detection of eluate. We found that OmpA combined with immunomagnetic beads was more efficient, fast, and convenient than the conventional method. Bacteria can be enriched more efficiently without extracting genomic DNA and culturing bacteria. Therefore, this method has potential value for improving the detection sensitivity and shortening the detection time of E. coli in food samples.

Nicolò Amalfitano, Lucio Flavio Macedo Mota, GuilhermeJ.M. Rosa et al.

ABSTRACT: To devise better selection strategies in dairy cattle breeding programs, a deeper knowledge of the role of the major genes encoding for milk protein fractions is required. The aim of the present study was to assess the effect of the CSN2, CSN3, and BLG genotypes on individual protein fractions (αS1-CN, αS2-CN, β-CN, κ-CN, β-LG, α-LA) expressed qualitatively as percentages of total nitrogen content (% N), quantitatively as contents in milk (g/L), and as daily production levels (g/d). Individual milk samples were collected from 1,264 Brown Swiss cows reared in 85 commercial herds in Trento Province (northeast Italy). A total of 989 cows were successfully genotyped using the Illumina Bovine SNP50 v.2 BeadChip (Illumina Inc.), and a genomic relationship matrix was constructed using the 37,519 SNP markers obtained. Milk protein fractions were quantified and the β-CN, κ-CN, and β-LG genetic variants were identified by reversed-phase HPLC (RP-HPLC). All protein fractions were analyzed through a Bayesian multitrait animal model implemented via Gibbs sampling. The effects of days in milk, parity order, and the CSN2, CSN3, and BLG genotypes were assigned flat priors in this model, whereas the effects of herd and animal additive genetic were assigned Gaussian prior distributions, and inverse Wishart distributions were assumed for the respective co-variance matrices. Marginal posterior distributions of the parameters of interest were compared before and after the inclusion of the effects of the 3 major genes in the model. The results showed that a high portion of the genetic variance was controlled by the major genes. This was particularly apparent in the qualitative protein profile, which was found to have a higher heritability than the protein fraction contents in milk and their daily yields. When the genes were included individually in the model, CSN2 was the major gene controlling all the casein fractions except for κ-CN, which was controlled directly by the CSN3 gene. The BLG gene had the most influence on the 2 whey proteins. The genetic correlations showed the major genes had only a small effect on the relationships between the protein fractions, but through comparison of the correlation coefficients of the proteins expressed in different ways they revealed potential mechanisms of regulation and competitive synthesis in the mammary gland. The estimates for the effects of the CSN2 and CSN3 genes on protein profiles showed overexpression of protein synthesis in the presence of the B allele in the genotype. Conversely, the β-LG B variant was associated with a lower concentration of β-LG compared with the β-LG A variant, independently of how the protein fractions were expressed, and it was followed by downregulation (or upregulation in the case of the β-LG B) of all other protein fractions. These results should be borne in mind when seeking to design more efficient selection programs aimed at improving milk quality for the efficiency of dairy industry and the effect of dairy products on human health.

Hao Wu, Yangling Zhang, Li Li et al.

ABSTRACT: Lactococcus lactis, a lactic acid bacterium, has been widely used in the fermented dairy products. The acid tolerance of L. lactis is of great importance to food fermentation and probiotic applications. As the first barrier of bacteria, the cell wall has a protective effect on strains under many stress conditions, whereas the regulatory mechanism has rarely been reported. Here, based on the transcription analysis of 9 cell wall or membrane-related genes of L. lactis F44 under acid stress, the transcription levels of DACB, DLTD, YLBA, HRTA, WP_080613266.1 (1610), and ERFK genes were significantly increased. We constructed 9 overexpressing strains with the cell wall or membrane-related genes, respectively. It was demonstrated that the survival rates under acid stress of DACB, DLTD, and ERFK were significantly higher than that of wild-type F44. To investigate the regulatory mechanism, a DNA pull-down assay was used to identify the transcriptional regulators of these 3 genes. It was discovered that the 2-component system (TCS) transcriptional regulator TCSR7 bound to the upstream region of DLTD involved in the teichoic acid (TA) alanylation. The combination was confirmed through an electrophoretic mobility shift assay in vitro. Reverse-transcription quantitative PCR results indicated that TCSR7 upregulated the expression of DLTD gene. In addition, the transcription level of TCSR7 increased approximately 1.8-fold (log2 fold change) under acidic conditions. In summary, this study found that TCSR7 was induced by acid stress to upregulate the transcription level of the DLT operon genes, which might increase the positive charge on the cell membrane surface to increase the acid tolerance of the strain. This study lays the foundation for the regulatory mechanism of TA alanylation under acid stress.

Jardeson S. Pinheiro, Lethiane G. Rocha, Dhones R. de Andrade et al.

ABSTRACT: We aimed to evaluate the incidence of unstable non-acid milk (UNAM) in cows fed either sugarcane or corn silage. Second, we aimed to evaluate the effect of daily variation (d 1 to 4) and alcohol grades (72, 78, and 80%) on UNAM incidence. The experiment was conducted as a split-plot crossover design, with 2 periods and 2 roughage types (sugarcane or corn silage). Thirteen multiparous Holstein cows with an average of 281 ± 29 d in milk were randomly distributed into 2 diets. Individual blood (analysis of total proteins, albumin, urea, calcium, phosphorus, magnesium, iron, chloride, glucose, and lactate) and milk samples (analysis of protein, fat, lactose and total solids, somatic cell count, and characterization of the protein profile) were collected during the last 4 d of each period. For UNAM identification, the alcohol test was conducted in milk samples at 4°C; specifically, if the sample presented the formation of clots, this would be noted as positive for UNAM. In addition, the Dornic acidity analysis was performed in the same samples to evaluate the true milk acidity. The use of sugarcane and higher degrees of alcohol were associated with increased UNAM. We observed no daily variation in UNAM. Nevertheless, we found no roughage type effect on the variables most commonly associated with UNAM, such as changes in salts in the casein micelle and, consequently, the zeta potential and the κ-casein (CN) fraction. The Pearson correlation analysis showed that the zeta potential and the concentrations of αS2-CN, blood ionic calcium, lactate, and glucose increased as the incidence of UNAM increased, showing a positive correlation among these variables. In contrast, the concentrations of lactose, phosphorus, and potassium decreased as UNAM increased, presenting a negative correlation. This study brought important discoveries to unveil why cows manifest UNAM. For instance, higher alcohol grades and cows fed with sugarcane had increased the incidence of UNAM. Additionally, animals with a higher incidence of UNAM (sugarcane-fed cows) were related to increased ionic calcium and glucose and changes in milk protein profile, with lower levels of BSA, β-CN, and α-lactalbumin and greater αS1-CN content, all of which were correlated with UNAM. Nonetheless, this trial also provides evidence for the need for further studies to better understand the physiological mechanisms that directly affect the stability of milk protein.

N. Ma, J.A. Abaker, G. Wei et al.

ABSTRACT: Although high-concentrate diet feeding can temporarily increase milk production, it can cause a series of metabolic diseases, such as subacute ruminal acidosis (SARA) and milk fat depression. The main purpose of this experiment was to study the effects of a high-concentrate diet on the inflammatory response, oxidative stress, and milk fat synthesis in the mammary gland of dairy cows. Twelve Holstein cows equipped with rumen fistulas were randomly divided into 2 groups, each with 6 cows, fed a low-concentrate diet (LC) and a high-concentrate diet (HC). On d 20 and 21 of the experiment, rumen fluid was collected to measure pH, and milk samples were collected for milk component analysis and lipopolysaccharide (LPS) concentration testing. On d 21, mammary vein blood was collected to detect the LPS concentration. At the end of the 21-d experimental period, mammary gland tissue was collected, and the expression of inflammatory response-, oxidative stress-, and milk fat synthesis-related genes and proteins in the mammary gland was analyzed by real-time quantitative PCR and western blot. The pH of rumen fluid in the HC group was significantly lower than that in the LC group, and the pH of 2 time points in the HC group was lower than 5.6, indicating that a high-concentrate diet induced SARA. The LPS concentration of the peripheral blood in HC group increased significantly compared with that in the LC group. For the inflammatory response, the proinflammatory cytokines (IL-6 and IL-1α) and innate immune factors (lingual antimicrobial peptide and tracheal antimicrobial peptide) in the mammary gland of the HC group were significantly increased, and the TLR4-NF-κB signaling pathway was activated. For oxidative stress, after HC diet feeding, the content of malondialdehyde in mammary vein blood and mammary gland tissue increased, the content of glutathione in mammary vein blood decreased, the activity of superoxide dismutase and the total antioxidant capacity in mammary gland tissue and mammary vein blood decreased, and the expression of antioxidant enzymes and antioxidant transcription factor nuclear factor, erythroid 2 like 2 (NFE2L2) in mammary gland decreased. For milk fat metabolism, HC diet feeding reduced the milk fat content in milk samples and the triacylglycerol content in the mammary gland and inhibited the expression of de novo synthase (ACACA and FASN), long-chain fatty acid converting enzymes (ACSL1 and SCD), fatty acid transporters (CD36, FATP, FABP3, and LPL), triacylglycerol synthase (AGPAT6, DGAT1, and LPIN1), lipid droplet releasing enzyme (PLIN1), and transcription factors sterol regulatory element binding protein (SREBP1) and peroxisome proliferator activated receptor gamma (PPARG). In summary, a HC diet can induce SARA with increased concentration of LPS in the peripheral vein, stimulate inflammatory reactions and oxidative stress, and inhibit milk fat synthesis in the mammary gland of dairy cows.

Gizem Şendoğan, Ecem Akan, Oktay Yerlikaya et al.

In this study, the content of hippuric and benzoic acid of goat milk kefir produced with commercial lyophilized kefir cultures and kefir grain was investigated. 9 commercial kefir culture and 1 kefir grain were used in production of goat milk kefir. Based on the obtained results, hippuric acid was not found in kefir samples during the storage period, whereas goat milk samples contained hippuric acid (14.8 mg/kg). Benzoic acid levels of kefir samples ranged from 8.5 to 26.6 mg/kg during the 28-day storage period. The highest Lactobacillus and Lactococcus counts were observed in kefir sample produced with kefir grain while this sample was one of the sample containing the lowest (11.2 mg/kg) benzoic acid levels. In conclusion, the research results showed that starter kefir cultures and microbiota used in kefir production and storage period had a significant effect on the formation of benzoic acid levels (p<0.05).

Mattia Boiani, U. Sundekilde, L. Bateman et al.

Abstract The influence of dairy cow feeding regime was investigated using 1H nuclear magnetic resonance (NMR). Two different NMR analytical systems were deployed: high field 1H NMR to investigate the influence on milk metabolomics and low field NMR to characterise proton relaxation linked to changes in the state of mozzarella cheese moisture during ripening. The metabolomics results showed that grass-based feeding increased the concentration of a biological marker that signifies near-organic milk production conditions. On the other hand, the investigation of cheese moisture distribution showed that grass-based diets reached final moisture partitioning in a shorter time, which implied the formation of a more compact protein structure in the cheese matrix. These results indicate that pasture-based dairying may be differentiated in terms of the provenance of milk produced along with the accrual of additional benefits during ripening of the resulting mozzarella cheeses.

A. P. Kunadu, Eurydice F Aboagye, Esi K. Colecraft et al.

This cross-sectional study was aimed at assessing consumer perceptions and microbiological quality of the fresh cow's milk products available in selected dairying communities in Ghana. Twenty-six focus groups (FGs) were conducted to understand the perceptions on barriers and facilitators to dairy consumption. These included six FGs for lactating mothers and five FGs for each of the following categories: pregnant women, women of reproductive age with children younger than 5 years, not pregnant and nonlactating women, and males. A separate quantitative survey followed and included 176 women of reproductive age (18 to 49 years) and 90 males (18 to 59 years) from 15 dairying communities in the Greater Accra, Eastern, and Central regions of Ghana. Also, 120 locally sourced fresh milk products were assessed for counts of total coliforms, fecal coliforms, and Enterococcus spp., and presence of pathogenic Streptococcus spp. , Escherichia coli, and Klebsiella pneumoniae by using standard microbiological methods. Fecal coliforms in dairy products, such as brukina, wagashi, and yogurt exceeded the specified limit of 10 CFU/mL, while the prevalence of E. coli and K. pneumoniae were 70 and 65%, respectively. Generally, respondents perceived indigenous dairy as unsafe. These perceptions were formed on the basis of visual cues of environmental and personal hygiene. Of the indigenous milk products consumed, brukina, a fermented milk and millet gruel (33%) and wagashie, a soft unfermented cheese (29%), were the most popular. However, only 19% of wagashie and 21% of brukina consumers believed these products were safe. Consistently, the odds of consuming a particular milk product was significantly higher if the consumer believed it was safe. Poor sanitation and unhygienic processing of otherwise healthy but perishable indigenous milk products has justifiably fueled the mistrust of consumers and may hinder potential intervention efforts to increase milk production and consumption in Ghana.

PRATAP SINGH BIRTHAL, GHANSHYAM PANDEY, JAYA JUMRANI et al.

Owing to several price and non-price factors, India’s dairy sector has grown remarkably in the past four decades. In this paper, we assess relative contributions of such factors to the growth of diary sector. Our results showed that dairying, in terms of both animal stock and yield, is not much responsive to prices of output as well as inputs. However, in the long run, the yield responds positively to technological change in animal breeding, feed supplies, veterinary services and markets. These findings lead us to argue that the dairy policy should focus on pushing up adoption of yield-enhancing technologies, provision of animal health, breeding and extension services, and strengthening of market linkages.

R. Kala, E. Samková, Lenka Pecová et al.

KALA ROBERT, SAMKOVÁ EVA, PECOVÁ LENKA, HANUŠ OTO, SEKMOKAS KĘSTUTIS, RIAUKIENĖ DALIA. 2018. An Overview of Determination of Milk Fat: Development, Quality Control Measures, and Application. Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, 66(4): 1055 – 1064. Milk fat content is an important indicator of milk quality because of nutritional and technological aspects of dairying. In this sense the milk fat determination is important practice procedure. The work goal was to do an effective overview and comparison of reference and routine methods of fat determination during their development. Nowadays, there exist a number of methods for determining milk fat content. Reference methods require accurate analysis in compliance with the International Standard ISO, whereas routine methods perform analysis using routine instrumental techniques for faster and cheaper results with acceptable accuracy. Quality control measures have a significant role for result determination reliability and they include internal quality controls, external quality controls, precision of evaluation, and blank samples. In conclusion, due to continuous development and improvement, routine methods will be used more often.

A. Nag, S. Jha, A. Mohammad et al.