Quarter Level Research Articles

Inflation Rate Determinants in Saudi Arabia: A Non-Linear ARDL Approach

Inflation across the globe after the COVID-19 pandemic has shown some persistence and followed an upward trend well above inflation targets and beyond normal historical movements. The Saudi inflation rate followed similar patterns of global trends, surging significantly and persisting well above the pre-pandemic levels. This paper examines determinants of inflation in Saudi Arabia, considering internal and external factors, and evaluates whether inflation responds to common global shocks or is largely influenced by macroeconomic variabilities within the economy. Findings and analyses in this paper are based on both conventional Auto Regressive Distributive Lag (ARDL) and non-linear ARDL (NARDL) models using quarterly level data to capture short-run dynamics and long-run relationships between inflation rate and examined macroeconomics variables, namely oil prices real effective exchange rate, money supply, and government spending. Reported results reveal an asymmetrical relationship between oil price fluctuations and inflation rate volatilities in Saudi Arabia. Inclines in oil prices lead to higher inflation, while the decline in oil prices does not alleviate inflationary pressures, and these results are consistent both in the short-run and the long run. The influence of pass-through real effective exchange rate is also evident in transmitting global shocks to local consumer prices in the long run, where a depreciation in real effective exchange rate results in a higher cost of imported goods, exerting additional stresses on local inflation. For factors within the economy, findings indicate a substantial long-term inflationary effect of money supply on the inflation rate in Saudi Arabia, where a one percent increase in the money supply led to more than one-third increase in inflation in the long run. On the other hand, while the influence of government spending on inflation was statistically significant, its impact is less pronounced in explaining the inflation rate’s variations. The analysis reveals that the evaluated variables exert a stronger influence on inflation in the long run. This underscores the critical need for policymakers to consider the cumulative effects of these determinants when formulating effective long-term inflation stabilization policies.

Subclinical Mastitis in Small-Holder Dairy Herds of Gansu Province, Northwest China: Prevalence, Bacterial Pathogens, Antimicrobial Susceptibility, and Risk Factor Analysis.

This cross-sectional study assessed the prevalence, bacterial distribution, antimicrobial susceptibility, and potential risk factors associated with subclinical mastitis (SCM) in small-holder dairy herds in Gansu Province, Northwest China. Forty small-holder cow farms were randomly selected from eight cities/counties in six districts of Gansu Province, and a total of n = 530 lactating cows were included in this study. SCM prevalence was noted at 38.87% and 9.72% at the cow and quarter levels, respectively, based on the California Mastitis Test (CMT). The prevalence of the recovered bacterial species was noted as follows: S. agalactiae (36.02%), S. aureus (19.43%), coagulase-negative staphylococci (CNS) (16.11%), S. dysgalactiae (12.80%), E. coli (9.00%), and S. uberis (6.64%). All isolated bacteria were 100% multi-drug-resistant (MDR) except S. aureus (87.8% MDR). Antimicrobial susceptibility profiles revealed the increased resistance (>85%) of these pathogens to penicillin, streptomycin, trimethoprim-sulfamethoxazole, vancomycin, and erythromycin. However, these pathogens showed increased susceptibility to ampicillin, amoxicillin-sulbactam, ceftazidime, neomycin, kanamycin, spectinomycin, norfloxacin, ciprofloxacin, and doxycycline. The multivariate regression analysis demonstrated that old age, high parity, late lactation, lesions on teats, previous history of clinical mastitis, higher milk yield, and milking training were found to be potential risk factors (p < 0.001) associated with developing SCM in small-holder dairy cows in Gansu Province, China. These findings highlight the need for routine surveillance, antimicrobial stewardship, and effective preventive strategies to mitigate SCM in small-holder dairy production and their possible impacts, i.e., increased antimicrobial resistance and infection, on public health.

Prevalence, Risk Factors, and Antimicrobial Resistance of Staphylococcus and Streptococcus Species Isolated from Subclinical Bovine Mastitis.

Subclinical mastitis (SCM) is a prevalent serious disease among dairy cows worldwide. It poses a significant challenge to the dairy industry, animal welfare, and a threat to public health. The present study aimed to investigate the molecular detection, prevalence, and antimicrobial resistance of Staphylococcus spp. and Streptococcus spp. isolated from raw composite milk samples obtained from SCM dairy cattle in Bangladesh. A total of 612 quarters milk samples obtained from 153 cows were analyzed for SCM using the California Mastitis Test. Bacterial isolation and identification were carried out and bacterial species were confirmed using molecular polymerase chain reaction methods. Antimicrobial susceptibility testing was performed using disc diffusion method. The findings revealed that the prevalence of SCM was 70.3% (26/37), 35.95% (55/153), and 23.04% (141/612) in the herd, cow, and quarter levels, respectively. Among the positive samples, 92.7% (51/55) were Staphylococcus spp. (S. aureus, S. chromogenes, and S. simulans) and the remaining isolates were 7.3% (4/55) Streptococcus spp. (Streptococcus agalactiae and Streptococcus dysgalactiae). The most prevalent species was S. chromogenes, accounting for 67.3% (37/55). Antimicrobial susceptibility testing showed that 65.5% of isolates were susceptible to cefoxitin, whereas, 89.1% were resistant to penicillin. Overall, 12 isolates (21.8%) out of 55 were resistant to more than three classes of antimicrobials and were defined as multidrug-resistant isolates. Methicillin-resistance gene was detected in 61.1% of the cefoxitin-resistant isolates. A multivariate logistic regression analysis identified five potential risk factors including the lack of post-milking teat disinfection (OR: 3.06), absence of immediate feeding after milking (OR: 9.81), poor udder hygiene (OR: 7.83), tick infestation (OR: 13.76), and absence of dry cow therapy (OR: 3.31). The findings of the current study underscore the urgent requirement for targeted interventions, considering the identified factors to effectively manage and control SCM in dairy cows.

International Air Cargo Volume Forecasting based on the Stacking Fusion Model

Accurate forecasting of international air cargo volumes is crucial for air cargo carriers, which optimizes operational efficiency and profitability and strengthens market competitiveness and risk response capabilities. This study focuses on the open-source cargo data of over 100 international airlines in India from January 2015 to March 2017. Firstly, the missing data must be dealt with. Then, histograms and probability density plots are used to depict the distribution of the cargo volume and analyze the dynamics of the cargo volume of each company at annual and quarterly levels. Subsequently, key factors affecting cargo volumes are analyzed, with a special focus on the cargo performance of the Top 5 airlines, which is visualized in box plots. Given the time-series nature of cargo data, this study adopts the data sequential partitioning method. It innovatively utilizes the Stacking ensemble learning framework, integrating regression models such as Random Forest, Decision Tree, Extreme Gradient Boosting, and K-Nearest Neighbor as the base learners. The meta-learner is constructed to integrate the outputs of each base model, and the hyperparameters of the model are optimized by grid search and cross-validation. Comparison results show that the Stacking model has a higher R² value and lower MSE than any single base learners, indicating that it is more effective in international air cargo volume prediction. The prediction model based on stacking ensemble learning provides an effective strategy for improving air cargo prediction accuracy.

Geo-Spatial Technology for Identifying Optimal Well Locations in Kolugala Pahalagama Grama Niladhari Division for Effective Groundwater Management

This study utilized Geographic Information System (GIS) technology to pinpoint optimal locations for establishing wells, addressing the issue of declining water yields in the Kolugala Pahalagama Grama Niladhari Division (GND); a geographically diverse region. The research integrated geospatial data, including geolocations of sample wells, garbage pits and quarterly water level measurements collected through field surveys. Several thematic layers, namely, geology, elevation, slope, drainage density, soil type, and land use types were analysed to delineate groundwater potential zones within the GND. Satti's analysis hierarchy was employed to assign appropriate weights to these factors, reflecting their influence on groundwater recharge and well productivity. Spatial analysis revealed that 9.64% of the area displayed very good groundwater potential, 42.17% had good potential, 39.76% showed moderate potential, and 7.23% exhibited poor potential. The distribution of existing wells was also evaluated, showing that 6% were located in very good groundwater potential zones, 56% in good groundwater potential zones and 38% in moderate groundwater potential zones. Despite this, only 34% of the wells were placed in regions suitable for the establishment of wells, while the majority, 66%, were located in unsuitable areas. Notably, 18 wells displayed lower water levels, likely due to their excessive distance from neig-bouring wells. Further spatial analysis identified 29 hectares as unsuitable and 54 hectares as suitable for the future establishment of wells. These findings underscore the significance of geographic factors in the placement of wells, emphasising the need for strategic planning to ensure that wells are sited in areas with high groundwater potential, thus improving long-term water yield sustain-ability in the region.

Assessment of Lactococcus Cremoris preparations for the pre- and post-milking teat disinfection

Good hygienic milking practices including the disinfection of the cow teat skin before and after milking aimed at preventing the occurrence of new intramammary infections (IMI) in dairy cows. This practice is generally performed using disinfectants, and in the current context of attention to the emergence of resistances, it is of greatest interest to evaluate alternative solutions that can expand treatment options. We assessed the efficacy of a pre-dipping and a post-dipping product based on the bacteriocin-containing culture of Lactococcus cremoris strain FT27, as compared to commercial disinfectants. FT27 was selected for the bactericidal activity in vitro against food pathogens. In the present study, it also revealed a high bactericidal activity against the main mastitis pathogens, most likely related to Nisin A production, according to genomic and proteomic analysis. The lactococcus-based preparations were applied in two commercial dairy farms in Northern Italy. Overall, 298 dairy cows were enrolled, 141 in the treated group (TR), and 157 in the control group (CTR). The cows were sampled at quarter level every two weeks for 3 months. During the trial, all cows showed a good health status. The hygiene level for udder, flanks and legs was generally good (on average < 3 score); the udder hygiene was significantly worse (P < 0.01) in the CTR group. The teat apex hyperkeratosis was overall low (on average < 2 score). We recorded no significant differences between the two experimental groups in the Somatic Cell Count (SCC) values and the bacteriological results. The overall frequency of new IMI was low, ranging 0.6 − 0.5% for S. aureus in the TR or CTR group respectively, to 2.6–4.4% for NASM. Regarding Str. spp., the new IMI accounted for 1.7% or 1.9% in the TR or CTR group, respectively. Notably, the incidence of S. aureus new IMI did not increase during the study, even though neither of the two herds segregated the positive cows. The non-inferiority test showed that the Lactococcus-based pre- and post-dipping products had an efficacy comparable to proven commercial disinfectants in maintaining udder health and preventing new IMI, thus representing a possible alternative to current teat dip products.

Energy transitions of declining energy industries: the effect of renewable portfolio standards on the U.S. coal industry

Abstract This study examines the influence of Renewable Portfolio Standards (RPS) on coal industry employment and wages in the top 10 U.S. coal-producing states from 2001 to 2018, with a specific focus on the 2003-2009 RPS adoption period. Employing a difference-in-differences methodology and utilizing data encompassing employment, gas prices, and RPS-related MWh at the quarterly level, our findings reveal that RPS had only temporary and minor adverse effects on coal employment. These effects manifested with a delay of up to four quarters but dissipated within two years. Moreover, RPS had no significant impact on state’s coal sector wages.

Impact of federal antipsychotic use policy in nursing homes on new diagnoses for approved indications in dementia residents.

Federal policies targeting antipsychotic use among nursing home (NH) residents may have increased reporting of diagnoses for approved uses, including schizophrenia, Tourette's syndrome, and Huntington's Disease (called "exclusionary diagnoses" because they exclude residents from the antipsychotic quality metric). We assessed changes in new exclusionary diagnoses among long-stay NH admissions specifically with dementia following federal policies. Retrospective, quarterly, interrupted time-series analysis (2009-2018) of new long-stay NH residents with dementia and no exclusionary diagnoses reported before NH admission. The National Partnership and the addition of facility level antipsychotic use to the Five Star Quality Rating system were key time exposures. Outcome was quarterly facility level predicted percentage of exclusionary diagnoses within 2 years of admission stratified by NH characteristics. For 264,095 long-stay admissions, mean percentage of new exclusionary diagnoses was 2.2% before the Partnership. After the Partnership, there was an unadjusted increase in the percentage over time (slope change, 0.044, p = 0.018), but the percentage never exceeded 2.9%. The Partnership contributed to a one-time decrease in diagnoses in NHs with an intermediate percentage of Black residents (-1.29%, p = 0.004). Before the Partnership, diagnoses were increasing among not-for-profit relative to for-profit NHs (0.044; p = 0.012), but after the Partnership, the pattern reversed. For-profit NHs saw an increase (+0.034, p = 0.002); not-for-profit NHs experienced a decrease (-0.014, p = 0.039). Quality Rating modifications had no significant effect. Exclusionary diagnosis reporting among long-stay NH residents with dementia, the group most at risk from antipsychotics, did not increase in response to federal policies. Evaluation of reasons for the observed increase in exclusionary diagnoses among non-dementia NH residents is warranted along with continued attention to how to incentivize the appropriate use of medications in residents with dementia that is crucial for high-quality NH care.

An observational study to investigate the association of teat skin condition with clinical mastitis risk

The importance of teat canal integrity and its adjacent tissues in the dynamics of IMI is well documented, whereas research on the relationship between teat skin condition and clinical mastitis occurrence is scarce. The objective of this prospective cohort study was to investigate the association of teat skin condition with clinical mastitis occurrence in a closed cohort from a commercial dairy farm with a thrice daily milking schedule in the Northeast United States. We tested the hypothesis that quarters with teats with altered skin condition would have higher odds of clinical mastitis than those with normal skin. Teat skin condition from 2,670 cows was assessed during a single visit and categorized into (1) normal, (2) dry skin, (3) skin lesion, and (4) dry skin and skin lesion. Cows were monitored for 2 wk after the teat skin condition assessment, and the occurrence of clinical mastitis at the quarter level was documented. A generalized linear mixed model with a logit link and a binomial distribution revealed an association between teat skin condition and the occurrence of clinical mastitis. Compared with quarters with teats with normal teat skin, the odds (95% CI) of clinical mastitis were 0.98 (0.60–1.60) for teats with dry skin, 1.88 (0.97–3.66) for teats with a skin lesion, and 4.87 (1.71–13.85) for teats with dry skin and a skin lesion. We conclude that quarters from teats with dry skin and skin lesions had higher odds of clinical mastitis. In addition, we found evidence that quarters with teats with skin lesions have higher odds of clinical mastitis than those with normal teat skin, though future studies are needed. The results from this study show that teat skin condition should be considered in mastitis control programs on dairy operations.

Milk yield and quality at udder quarter level are influenced by quarter position, pathogen, and somatic cell score

There is a paucity of information about milk composition and quality at the quarter level from complete milking of the udder, mainly because of the difficulties of sampling procedures which imply the adoption of a vacuum system connected to four independent buckets. The objective of this study was to evaluate the effect of quarter position, intramammary infection status, and somatic cells on milk yield and composition at the mammary quarter level of Simmental cows. Milk samples were collected during three consecutive days, after milking individual mammary quarters of 10 lactating cows separately, for a total of 120 quarter milk samples. Samples were analysed for composition, somatic cell count (SCC), differential SCC, and bacterial culture. Somatic cell count was log-transformed to somatic cell score (SCS) to achieve normality of distribution. Sources of variation of milk yield and quality traits were investigated using a linear mixed model which included the fixed effects of quarter position (1 to 4), pathogen presence (positive or negative), and SCS class (low, medium-low, medium-high, and high). The interaction between cow and quarter position was included as random effect. Quarter position significantly affected milk yield, with rear udder quarters yielding more milk compared to their front counterparts, but with negligible effects on milk composition. Classes of SCS influenced milk composition, in a way that quarters with high SCS had lower lactose content and higher differential SCC. This study is a contribution towards the possibility to better understand physiological processes at cow udder quarter level.

Concentrations of antimicrobial components in milk at dry off and postpartum and their relationships to new high somatic cell counts at quarter level in dairy cows.

We investigated the antimicrobial components in cow milk at dry off and postpartum and their contribution in preventing new high SCC at quarter level. Milk samples from 72 quarters of 19 lactating cows were collected at last milking before dry off and at 7 d after parturition. Milk yield of each cow was recorded and SCC, IgG, IgA, lactoferrin, lingual antimicrobial peptide (LAP), and S100A7 concentrations in each quarter milk sample were measured. The postpartum milk yield was significantly higher than that at dry off. The IgG, IgA and lactoferrin concentrations in milk at dry off were significantly higher than those at postpartum, whereas the LAP concentration was lower. Quarters with SCC < 300 000 cells/ml at both dry off and postpartum were classified as persistent low SCC (PL) whereas those that rose above that same threshold postpartum were classified as new high SCC (NH). At dry off, IgG and LAP concentrations in milk were significantly higher in PL than in NH. These results suggest that high LAP concentrations during the dry period may contribute toward the prevention of new high SCC.

Efficacy of targeted therapy of environmental mastitis using on-farm culturing in small dairy herds

The aim of the study was to evaluate treatment protocols for improvement of clinical and bacteriological cure rate of non-severe clinical mastitis (CM) and selective dry cow therapy (SDCT). Mastitis management based on on-farm commercial culture system MicroMastTM and data analysis were implemented into two dairy herds. Quarters with evidence of Gram-positive agents were treated using benzyl penicillin or amoxicillin and/or by amoxicillin with clavulanic acid. In herd A, 31 quarters of non-severe CM were recorded. Of them, Streptococcus uberis was isolated in 16 (51.6%), non-aureus staphylococci (NAS) in 8 (25.8%), E. coli in 5 (16.1%) and no growth in 2 (6.5%) cases. Bacteriological cure was observed in 24/29 (82.8%) quarters. Antimicrobial consumption was reduced from 3.56 to 2.33 doses per case. Under the SDCT protocol, 28 quarters (13.2%) of 53 cows dried-off were included, achieving a reduction by 86.8% on the quarter level. In herd B, 23 quarters of non-severe CM were recorded. Of them, S. uberis and Escherichia coli were identified equally in 8 (34.8%) samples and NAS in 2 (8.7%) samples and with no growth in 5 (21.7%) cases. Bacteriological cure was achieved in 17/18 quarters (94.4%). Antimicrobial consumption was reduced from 4.45 to 1.83 doses per case. Only 5 (1.7%) quarters of 72 cows were included for SDCT with reduction in consumption of antimicrobials by 98.3% on the quarter level. In summary, innovated treatment protocols based on results of on-farm culture enabled a significant reduction of antimicrobial consumption and improvement of bacteriological cure rate in conditions of practise.

162 Evaluating the Potential of a Thermal Imaging System to Identify Subclinical Mastitis in Dairy Cattle

Abstract The objective was to evaluate the potential for the use of a thermal imaging system for the identification of subclinical mastitis in dairy cows. Multiparous Holstein dairy cows (n = 131) within 150 days in milk (DIM; range 65 to 155) were enrolled in the study at a commercial dairy farm in central Texas. Milk samples (10 mL) were collected from each quarter separately and evaluated for somatic cell counts (SCC; n*1000), fat (%), protein (%), lactose (%), SNF (%), BHBA (mM/L), acetone (mM/L), and milk urea nitrogen (MUN; mg/dL). A minimum of four thermal images per cow representing all four quarters were captured using a handheld infrared camera (Fluke TiS 75+) from approximately one-meter distance from the cow. All images were taken inside the milking parlor and after the morning milking during February 2023 to minimize the impact of daily ambient temperatures. Skin temperatures from each quarter (maximum, minimum, average) were extracted using Fluke Connect software. A total of 524 quarter-level milk samples and corresponding udder images were obtained, and 10 images were discarded from analyses due to the lack of appropriate resolution and focus. To prevent collinearity, a correlation matrix was developed using PROC CORR in SAS and variables with significant correlations were removed from the model. Subclinical mastitis was defined at the quarter level when SCC &amp;gt; 250,000. Statistical analyses were performed using mixed linear regression models (PROC MIXED) with cow and DIM as random effects in the model, and logistic regression model (PROC LOGISTIC) was fitted to evaluate the probability of the disease based on temperature and milk variables. Maximum and average udder temperatures did not demonstrate a significant relationship with subclinical mastitis status whereas minimum udder temperature was greater in sick quarters (29.6 ± 0.52 vs 27.5 ± 0.45; P = 0.003). Increased minimum udder temperature was also associated with BHBA (P &amp;lt; 0.0001), acetone (P &amp;lt; 0.0004), and MUN (P &amp;lt; 0.0007) concentrations in milk. Cows with subclinical mastitis had decreased BHBA (0.14 ± 0.037 vs 0.28 ± 0.031; P = 0.0036) and acetone (0.017 ± 0.003 vs 0.044 ± 0.003; P &amp;lt; 0.001). Odds of subclinical mastitis were associated with MUN values in milk (OR 0.94; CI 0.89 - 0.98) but not with any udder surface temperature variables. We conclude that an increase in the minimum temperature of the udder could be used as an indicator of subclinical mastitis but studies with larger datasets and using advanced image analysis techniques are warranted to validate these results.

On the empirical validity of “Gendered reactions to terrorist attacks can cause slumps not bumps” (Holman et al. 2022)

AbstractM. R. Holman, J. L. Merolla and A. Zechmeister (2022) propose women (compared to men) political leaders experience significant drops in public approval ratings after a transnational terrorist attack. After documenting how survey‐based evaluations of then‐Prime Minister Theresa May suffered after the 2017 Manchester Arena attack, Holman et al. (2022) assemble a country–quarter level panel database to explore the generality of their hypothesis. They report evidence suggesting women (compared to men) leaders systematically experience decreased public approval rates after major transnational terrorist attacks (‐value of 0.020). We find that result disappears once any of the following adjustments is implemented: (i) excluding election quarter covariates (), (ii) correcting objective coding errors in the election quarter covariates (), (iii) excluding the May–Manchester observation () or (iv) clustering standard errors at the country level (). Exploring all combinations of the five control groups Holman et al. (2022) incorporate in their specification, none of them clears the 5% threshold of statistical significance once the corrected election quarter variables are employed. We conclude that the empirical evidence does not provide sufficient support for Holman et al.'s (2022) abstract claim that “conventional theory on rally events requires revision: women leaders cannot count on rallies following major terrorist attacks.”

Prevalence of Camel Mastitis and Its Associated Risk Factors in and around Garowe District, Puntland, Somalia

Mastitis is one of the main issues that cause economic inefficiencies in dairy farms. It has numerous infectious and non-infectious origins and is divided into clinical and subclinical forms. A cross sectional study of camel mastitis was conducted on 88 lactating camels from Garowe District Puntland between May to August 2023 to estimate the prevalence and causes of mastitis, as well the risk factors involved on disease. Prevalence of mastitis was assessed by using California mastitis test (CMT) and bacterial cultured. The overall prevalence of mastitis at animal level was camels examined for mastitis was found a prevalence of 39.7% (35/88) in the current study. The overall quarter level prevalence was 47.7% (168/352). Among these 10(11.4%) and 25(28.4%) were found to be positive with clinical and sub-clinical mastitis respectively, based on clinical examination and mastitis indicator paper (Table 2). Regarding Result analysis showed that there was a statistically significant association (P&lt;0.05) among four the risk factors (tick infected, wound stage of lactation and poor hygienic). Tick infestation and udder lesions were significantly associated with camel mastitis (P &lt; 0.05). Bacteriological examination of CMT along with bacteriological culture methods were used. The study cultured a positive camel milk samples revealed that Staphylococcus spp was the major causative agents for both clinical and sub clinical camel mastitis (45.7%) followed by Streptococcus agalactiae (25.7%), E. coli (14.3%), Klebsiella spp. (8.6%) and Micrococcus (5.7%) respectively. The study demonstrated that camel mastitis is a problem which warrants appropriate control measures in order to improve the health of camels and quality of camel milk production in the study area. The isolation of genera of pathogenic bacteria from the camel milk samples suggests the need for strict hygienic measures during the production and handling of camel milk to reduce public health hazards. Furthermore, public education should be given to improve their awareness about the importance of proper herd health management and hygienic milking practices. In order to minimize the adverse effect of mastitis on the yield, quality of milk and zoonotic impact of the pathogen. The prevalence of camel mastitis in the study area was found to be significantly high. Therefore, implementation of integrated approaches has great importance in the study sites for the prevention and control of mastitis hence minimizing economic loss and prevents significant public health risks.

Effect of intramammary infection and inflammation on milk protein profile assessed at the quarter level in Holstein cows

In this study we wanted to investigate the associations between naturally occurring subclinical intramammary infection (IMI) caused by different etiological agents (i.e., Staphylococcus aureus, Streptococcus agalactiae, Streptococcus uberis, and Prototheca spp.), in combination with somatic cell count (SCC), on the detailed milk protein profile measured at the individual mammary gland quarter. An initial bacteriological screening (time 0; T0) conducted on individual composite milk from 450 Holstein cows reared in 3 herds, was performed to identify cows with subclinical IMI. We identified 78 infected animals which were followed up at the quarter level at 2 different sampling times: T1 and T2, 2 and 6 wk after T0, respectively. A total of 529 quarter samples belonging to the previously selected animals were collected at the 2 sampling points and analyzed with a reversed phase HPLC (RP-HPLC) validated method. Specifically, we identified and quantified 4 caseins (CN), namely αS1-CN, αS2-CN, κ-CN, and β-CN, and 3 whey protein fractions, namely β-lactoglobulin, α-lactalbumin, and lactoferrin (LF), which were later expressed both quantitatively (g/L) and qualitatively (as a percentage of the total milk nitrogen content, % N). Data were analyzed with a hierarchical linear mixed model with the following fixed effects: days in milk (DIM), parity, herd, SCC, bacteriological status (BACT), and the SCC × BACT interaction. The random effect of individual cow, nested within herd, DIM and parity was used as the error term for the latter effects. Both IMI (i.e., BACT) and SCC significantly reduced the proportion of β-CN and αS1-CN, ascribed to the increased activity of both milk endogenous and microbial proteases. Less evident alterations were found for whey proteins, except for LF, which being a glycoprotein with direct and undirect antimicrobial activity, increased both with IMI and SCC, suggesting its involvement in the modulation of both the innate and adaptive immune response. Finally, increasing SCC in the positive samples was associated with a more marked reduction of total caseins at T1, and αS1-CN at T2, suggesting a synergic effect of infection and inflammation, more evident at high SCC. In conclusion, our work helps clarify the behavior of protein fractions at quarter level in animals having subclinical IMI. The inflammation status driven by the increase in SCC, rather the infection, was associated with the most significant changes, suggesting that the activity of endogenous proteolytic enzymes related to the onset of inflammation might have a pivotal role in directing the alteration of the milk protein profile.

The mouthpiece chamber vacuum pattern indicates the cessation of milk flow and suits as an indicator to reduce teat end vacuum at a quarter level

We investigated the suitability of the quarter mouthpiece chamber vacuum (MPCV) as an indicator for cessation of quarter milk flow to potentially adjust the teat end vacuum at a quarter level. We tested the hypothesis that a MPCV increase is a clear indicator of quarter milk flow cessation. In addition, we tested if a quarter-individual vacuum reduction at MPCV increase reduces the mechanical effect on the teat. Ten dairy cows were milked twice daily with a quarter-specific vacuum supply with continuously high (51 kPa; TRT51) or low vacuum setting (41 kPa; TRT41), or high vacuum setting combined with a quarter-specific vacuum reduction by 10 kPa immediately after the quarter-specific MPCV increase (TRT51/41). Whole udder milk flow was continuously recorded. Each treatment was repeated at 4 subsequent milkings. The high vacuum settings (TRT51; TRT51/41) reached higher values in peak flow rate and average milk flow and consequently shorter machine-on time. The time from start of milking until the steep increase of the MPCV was shorter in front than rear quarters, and hence the time from start of MPCV increase until end of milking was longer in front than rear teats. Teat condition of the right front teats was measured for teat wall diameter by ultrasound and teat tissue thickness by cutimeter at 5 and 20 min after each experimental milking. The teat measurements were taken at the teat tip (distal barrel) and 2 cm above the teat tip (proximal barrel). The proximal teat wall diameter tended to be higher in TRT51 than in TRT41, both 5 and 20 min after milking. The distal teat wall diameter at 5 min was greater in TRT51 than in TRT41. In TRT51/41 the teat wall diameter at both locations was intermediate, not significantly different from either TRT51 or TRT41. The distal teat tissue thickness was greater in TRT51 than in TRT41, and tended to be greater in TRT51/41 than in TRT41 at 5 min. The proximal teat tissue thickness at 5 min was higher in TRT51 and TRT51/41 than in TRT41. The teat tissue thickness decreased from 5 to 20 min only in the proximal barrel. The quarter-individual MPCV increase appears to be a suitable indicator of the cessation of milk flow. The lack of a significant reduction of mechanical effect on the teat by a reduced vacuum of 41 kPa indicates that the vacuum level chosen may be still too high under conditions of a separate vacuum supply for each quarter, which prevents a vacuum drop caused by the whole udder milk flow.

Milk as diagnostic fluid for udder health management.

Mastitis is the major disease affecting milk production of dairy cattle, and milk is an obvious substrate for the detection of both the inflammation and its causative infectious agents at quarter, cow, or herd levels. In this review, we examine the use of milk to detect inflammation based on somatic cell count (SCC) and other biomarkers, and for the detection of mastitis pathogens through culture-based and culture-free methods. The use of SCC at a cow or bulk milk level to guide udder health management in lactation is well-established, and SCC is increasingly used to guide selective dry cow treatment. Other markers of inflammation include electrical conductivity, which is used commercially, and markers of disease severity such as acute phase proteins but are not pathogen-specific. Some pathogen-specific markers based on humoral immune responses are available, but their value in udder health management is largely untested. Commercial pathogen detection is based on culture or polymerase chain reaction, with other tests, for example, loop-mediated isothermal amplification or 16S microbiome analysis still at the research or development stage. Matrix-assisted laser desorption ionisation time of flight (MALDI-ToF) is increasingly used for the identification of cultured organisms whilst application directly to milk needs further development. Details of test sensitivity, specificity, and use of the various technologies may differ between quarter, cow, and bulk milk applications. There is a growing array of diagnostic assays that can be used to detect markers of inflammation or infection in milk. The value of some of these methods in on-farm udder health improvement programs is yet to be demonstrated whilst methods with proven value may be underutilised.

Associations between subclinical intramammary infection and milk fatty acid profile at the quarter level in Holstein cattle.

Mastitis, especially the subclinical form, is the most common economic and health problem in dairy cows. Little is known about changes in milk fatty acid (FA) composition according to infection/inflammation status of the mammary gland. The aim of this study was to investigate the associations between naturally occurring subclinical intramammary infection (IMI) from different pathogens, i.e. Streptococcus agalactiae, Staphylococcus aureus, Streptococcus uberis and Prototheca spp., and the detailed milk FA profile assessed at quarter level in Holstein cows. After an initial bacteriological screening (T0) on 450 Holstein cows reared in three dairy herds, we identified 78 cows positive at the bacteriological examination. These animals were followed up at the quarter level two weeks (T1) and six weeks (T2) after T0. In total, 600 single-quarter samples were obtained at T1 and T2. Individual FAs were determined using the gas chromatography analytical method. Investigated traits were 70 individual FAs, 12 FA groups, and six desaturation indices. The associations between subclinical IMI combined with somatic cell count (SCC) and milk FA profile were investigated using a hierarchical linear mixed model (i.e., observational unit was quarter within cow) with the following fixed effects: days in milk (DIM), parity, herd, SCC, bacteriological status (BACT, positive and negative), and the SCC × BACT interaction. The random effect of individual cow nested within herd, DIM and parity was used as the error term for the latter effects. The most significant associations were detected at T2. Notably, IMI reduced the proportions of individual short-chain FA, especially 4:0 and 6:0 (-14%), but increased the proportion of the most abundant medium-chain FA (MCFA), 16:0 (+4%). A reduction in the desaturation indices was observed mostly for 14:1 index (-9%), in line with the reduction in 14:1 (-10%). Somatic cell count significantly affected 14 individual FAs. In particular, samples with high SCC (≥200 000) had significantly lower proportions of 8:0, 10:0, 11:0, 12:0, and 13:0 compared with samples with low SCC (<200 000). Increasing SCC in animals positive at the bacteriological examination were associated with a reduction in total MCFA at T2 (while in negative animals, they remained constant across SCC classes), possible evidence that elongation of the FA chain from 11 to 16 carbons is affected by a combination of infection and SCC. This study showed that subclinical IMI and SCC are mainly associated with reductions in the synthesis of FA and the desaturation process in the mammary gland.

Prevalence of mastitis in Algerian dromedary camels and antimicrobial resistance of the causative Staphylococci

To investigate the prevalence, bacterial spectrum of mastitis, and antimicrobial resistance of the causative staphylococci in Algerian dromedary camels, a total of 200 lactating camels were first examined for clinical mastitis and the healthy quarters were examined for subclinical mastitis using the California Mastitis Test (CMT). Milk samples from the affected quarters were collected aseptically and analysed using conventional bacteriological isolation and identification procedures. Staphylococcal isolates were then analysed for antimicrobial resistance. The overall prevalence of mastitis in camels based on CMT and clinical examination was 35 % (70/200), of which 7.5 % (15/200) was clinical mastitis and 27.5 % (55/200) was subclinical mastitis. At the quarterly level, the overall prevalence was 11.87 % (95/800), of which 2.62 % (21/800) was clinical mastitis and 9.25 % (74/800) was subclinical mastitis. A total of 98 bacterial isolates were identified from the 95 cultured milk samples. Staphylococci (70.4%) were the predominant isolates, with 31.63 % identified as coagulase-positive staphylococci (CPS) including S. aureus at 25.51 % and 38.77 % identified as coagulase-negative staphylococci (CNS). The remaining isolates were Micrococcus sp., Streptococcus sp., Bacillus sp., E. coli, and Enterococcus. Antibiotic susceptibility testing revealed that 24 (34.78 %) of the isolates were susceptible to all antimicrobial drugs tested, while 21.73 % (15/69) were multidrug resistant strains. The highest resistance rates were found for penicillin, tetracycline and erythromycin with 33.33 %, 31.48 % and 21.74 %, respectively. Therefore, the implementation of integrated approaches in the study is of great importance for the prevention and control of mastitis to improve the quality of camel milk, minimize economic losses and avoid significant public health risks.