Potential Novel Biomarkers for Mastitis Diagnosis in Sheep

Thermal Imaging and Dimensionality Reduction Techniques for Subclinical Mastitis Detection in Dairy Sheep

Subclinical mastitis is a common and economically significant disease that affects dairy sheep production. Thermal imaging presents a promising avenue for non-invasive detection, but existing methodologies often rely on simplistic temperature differentials, potentially leading to inaccurate assessments. This study proposes an advanced algorithmic approach integrating thermal imaging processing with statistical texture analysis and t-distributed stochastic neighbor embedding (t-SNE). Our method achieves a high classification accuracy of 84% using the support vector machines (SVM) algorithm. Furthermore, we introduce another commonly employed evaluation metric, correlating thermal images with commercial California mastitis test (CMT) results after establishing threshold conditions on statistical features, yielding a sensitivity (the true positive rate) of 80% and a specificity (the true negative rate) of 92.5%. The evaluation metrics underscore the efficacy of our approach in detecting subclinical mastitis in dairy sheep, offering a robust tool for improved management practices.

Coagulase-Negative Staphylococci as an Etiologic Agent of Ovine Mastitis, with a Focus on Subclinical Forms

The objective of this review is to investigate the distribution and the characteristics of coagulase-negative Staphylococci (CoNS) implicated in ovine mastitis, and especially in subclinical cases, in order to provide a global perspective of the current research data and analyze specific critical aspects of the issue. PRISMA guidelines were implemented in the search of the last 20 years of the related literature in two databases. In total, 139 studies were included in this review. Relevant data were tracked down, assembled, and compared. Regarding the geographical distribution, most studies originated from Europe (68), followed by South America (33). Lacaune was the most examined breed, while S. epidermidis was the predominantly identified species, representing approximately 39% of the obtained isolates. Antibiotic resistance in the relevant bacteria was documented mostly for Penicillin (32.8%) and Amoxicillin (32.1%), while biofilm- and toxin-associated genes were encountered in variable rates because significant inequalities were observed between different articles. Significantly higher rates of antimicrobial resistance were detected in Asia and South America compared to Europe. Finally, the diagnostic procedures carried out in the respective studies were evaluated. Conventional culture and biochemical tests were mostly performed for simple strain identification; therefore, further molecular investigation of isolates should be pursued in future studies, as this will provide important data regarding specific aspects of the implication of CoNS in ovine mastitis.

Clinicopathological study on camel mastitis at Matrouh Governorate

Objective

Camel mastitis is indeed a serious problem that can have significant impacts on animal health and production as well as pose a potential public health hazard. This work aimed to identify the bacterial species responsible for camel mastitis and evaluate the associated immunological and clinicopathological alterations in infected camels.

Materials and Methods

Raw milk and blood samples were collected from 40 apparently healthy she-camels, and 40 she-camels suffered from clinical mastitis (CMG). Milk samples were subjected to bacteriological examination. Serum immunological, biochemical, and hematological parameters were estimated and statistically analyzed.

Results

Similar bacterial species were obtained from the two groups with different isolation rates.Staphylococcus epidermidis and Escherichia coliwere the dominant species in the apparently healthy group, whilePseudomonas aeruginosaandBacillus cereus were the dominant species in CMG. A significant (p < 0.05) elevation of the pro-inflammatory cytokines, acute phase proteins (APPs), free radicals, total protein, Glob, kidney and liver function tests, and triglyceride concentrations were detected in CMG, and a significant (p < 0.05) decrease in the anti-inflammatory cytokine, antioxidants, Alb, glucose, and T/LDL/HDL-cholesterol concentrations was observed in CMG. Microcytic hypochromic anemia with hypoferremia, hypotransferrinemia, hyperferritinemia, and neutrophilic leukocytosis was depicted in CMG. The estimated pro-inflammatory cytokines, APPs, and total antioxidant capacity (TAC) yielded high sensitivity and specificity, but the highest likelihood ratio was for TAC, fibrinogen (Fb), and ferritin, and the highest percentages of increase were for IL-1α and IL-1β.

Conclusion

The study emphasizes the importance of hygienic preventive measures to control camel mastitis and the importance of supportive treatment to reverse the hemato-biochemicaland iron profile changes that result from the immune response in mastitic she-camels. TAC, Fb, ferritin, IL-1α, and IL-1β are good biomarkers for camel mastitis.

Effects of Dietary Omega-3 Enrichment on the Chemical Composition and the Pathogenic Microbiota of Ovine Milk

The demand for ovine milk and ovine dairy products is constantly increasing due to their exceptional sensorial characteristics and their health benefits for consumers. However, dairy fat content and composition are of particular concern for consumers as well as the medical community, as there are risk factors for coronary disease, diabetes mellitus, cancer, and other serious diseases. For this reason, attempts have been made to control/regulate the fat composition of ovine milk by modifying sheep dietary intake of polyunsaturated fatty acids. In this experimental trial, a group of sheep were fed for 30 days a diet enriched in flaxseeds and lupines, feed ingredients rich in omega-3 fatty acids, aiming to investigate the effects on fat composition and the microbiota of ovine milk. Chemical analysis of the collected milk showed that the omega-3 and omega-6 content was increased. On the opposite, the atherogenic and thrombogenic indexes decreased. Of importance was the semi-protective effect on the udder by the increased omega-3 dietary intake, as depicted by its impact on the biodiversity of the pathogenic microbiota. These findings suggest that ovine milk could be modified under specific conditions to be more appropriate for the consumption by people belonging to high-risk groups for various diseases.

Utilization of 2D and 3D cell cultures for the modelling of intramammary infection in sheep

Ovine mastitis is defined as the inflammation of the sheep udder, most commonly caused in response to intramammary infections. Based on the occurrence of clinical signs, mastitis is characterized as either clinical or subclinical (SCM). The impact of ovine SCM on the overall sustainability of dairy sheep farms has been substantially documented underpinning the significance of efficient diagnosis. Although SCM can be detected in cows, the performance and the validity of the methods used do not transfer in dairy sheep. This fact challenges the development of evidence-based ovine udder health management protocols and renders the detection and control of ovine mastitis rather problematic. Currently, cell culture-based models are being successfully used in biomedical studies and have also been effectively used in the case of bovine mastitis. The objective of the present study was to culture ovine primary mammary cells for the development of 2D and 3D cell culture-based models for the study of ovine mammary gland and to focus on the first stages of the intramammary infection by common mastitis-inducing pathogens. Cells were infected by E. coli and S. aureus mimicking the first stages of natural intramammary infections. The secreted proteins were subjected to mass-spectrometry resulting in the identification of a total of 79 distinct proteins. Among those, several had already been identified in healthy or mastitic milk, while others had not been previously detected for in the ovine mammary secretome. Our results suggest that the development of cell-based models for studying specific stages of intramammary infection has the potential to be beneficial for the udder health management in dairy sheep.

Safety Issues Regarding the Detection of Antibiotics Residues, Microbial Indicators and Somatic Cell Counts in Ewes’ and Goats’ Milk Reared in Two Different Farming Systems

Milk samples of ewes’ and goats’ unprocessed milk were collected from milk tanks from various farms in Epirus, Greece and classified in two groups according to the type of farming. Analyses of the samples included microbial inhibition assays to detect the presence of antibiotic residues, isolation of Staphylococcus aureus and Escherichia coli strains as microbiological indicators for susceptibility to antimicrobial medicines, Somatic Cells and Coagulase Negative Staphylococci (CNS) counts. These findings were correlated with each other as well as to the stage of the lactation period and to the type of the farming practices. Monitoring of bulk tank milk for residues of antibiotics should be performed after heating of the milk, on a regular basis, and should include at least two different tests. The results point out that the type of farming affects the CNS counts as well as the prevalence of residues in the milk. Furthermore, the inverse correlation between CNS counts and prevalence of residues of antibiotics suggests a possible protective role of CNS. Resistance of the bacterial indicators to antibiotics was random and relatively rare, perhaps acquired in past due to misuse of antibiotics, turning the indicator microorganisms to reservoir of resistance.

Age-Related Changes in Acute Phase Reaction, Cortisol, and Haematological Parameters in Ewes in the Periparturient Period

Simple Summary

The acute phase response (APR), which comprises a series of specific physiological reactions, is a systemic reaction of the organism to disturbances in its homeostasis caused by infection, inflammation, tissue damage, and stress. Even in healthy ewes, during pregnancy and the transition period, corticosteroids are released which cause the physiological acute phase response. Both in humans and animals, the immune system, like many other physiological systems, is dysregulated with age and a process known as immunoaging occurs. Knowledge of APPs, cortisol, and haematological parameters and factors that influence their alteration could be useful for establishing herd health in ewes during the periparturient period. Understanding how these factors interact with the immune system will help in developing disease control and management strategies that will aid in maintaining good health in ewes and lambs, resulting in greater reproduction.

Abstract

A well-functioning immune system is the basis for protection against infectious and metabolic diseases, and a smooth return to homeostasis. The periparturient period is considered critical because major changes in the endocrine, behavioural, digestive, and immune systems dysregulate immune function, leading to immunosuppression. With age, the immune system could become dysregulated. The purpose of the present investigation was to compare changes in plasma concentrations of acute phase proteins, cortisol, and haematological parameters in the peripheral blood of two age-related groups of healthy ewes to get a better understanding of changes around lambing. Two groups of ewes were enrolled in the study: 3-year-old (young; n = 9) and 7-year-old ewes (old; n = 9). All females were synchronised and inseminated. In blood plasma, serum amyloid A (SAA) and cortisol concentrations were measured using ELISA tests, a spectrophotometric method to determine haptoglobin (Hp), and a thrombin clottable estimation to determine the fibrinogen (Fb) concentration. The blood parameters were examined using an automated haematological analyser. In clinically healthy ewes, no significant effect of age was observed in SAA, Hp, Fb and cortisol concentration in most of analysed terms. SAA, Hp, Fb, and cortisol fluctuations typical for the periparturient period were observed. There were no age-associated differences in red or white blood cell parameters.