Association between udder morphology and in vitro activity of milk leukocytes in high yielding crossbred cows (original) (raw)
Related papers
Frontiers in Veterinary Science, 2021
Milk somatic cell counts (SCCs) have been used as a gold standard to monitor mammary health as well as an indicator of raw milk quality. The present work was undertaken to compare the changes in the milk SCC, milk differential leukocyte counts (DLCs), phagocytic activity (PA) of milk neutrophils and macrophages (by nitroblue tetrazolium assay), extracellular trap formation (PicoGreen assay) and mRNA expression of various genes in milk neutrophils and macrophages (reverse transcription-polymerase chain reaction), and milk plasma cortisol concentration (enzyme-linked immunosorbent assay) in healthy, subclinical mastitis (SCM), and clinical mastitis (CM) cows. Milk was collected from healthy, SCM, and CM cows grouped based on their SCCs and California mastitis test with eight cows in each group. Milk SCC was estimated by SCC counter, and DLC was done after staining the milk slide under a microscope at 100×. Total SCCs in healthy, SCM, and CM cows were on an average of 128.30, 300.3, and 694.40 × 10 3 cells/mL, respectively. Milk DLCs indicated a lower percentage of macrophage and lymphocytes and a higher (p < 0.05) percentage of neutrophils in SCM and CM compared to healthy milk. The percentage of mature segmented neutrophils was lower, whereas immature band neutrophils were higher (p < 0.05) in the SCM and CM groups as compared to healthy cows. The viability, in vitro PA, and extracellular trap formation of neutrophils were lower (p < 0.05) in SCM and CM milk samples as compared to healthy samples. However, the PA of macrophage remained unchanged in all the studied groups. The relative mRNA expression of Toll-like receptors (TLR2, TLR4), myeloperoxidase, and interleukin 2α (IL-2α) receptor (CD25) were minimum in healthy samples and increased (p < 0.05) with the progress of mammary inflammation. However, CD44 decreased (p < 0.05), and CD62L remained unchanged in mastitis as compared to healthy cows. Plasma cortisol concentrations were higher (p < 0.05) in mastitis as compared to healthy cows and were negatively correlated with the number of milk macrophages and the functions of milk phagocytes. Estimation of total SCC, milk DLC, and activity of milk phagocytes is essential for effective control and prevention of incidence of mastitis in dairy cows.
Veterinary World, 2015
The present study was aimed to study the use of cell counts as an early indicator of mammary health. Materials and Methods: Milk and blood cell counts were estimated from 8 healthy, 8 subclinical (SCM), and 8 clinically mastitis (CM) groups of Karan Fries (KF) cows. Results: Total leucocyte counts and neutrophil percent in blood and milk somatic cells and milk neutrophil percent of healthy cows increased significantly (p<0.05) in SCM cows and CM cows. Viability of blood and milk neutrophils was more in healthy cows, but decreased significantly (p<0.05) in SCM and CM cows. Significant (p<0.05) decrease were also observed in both the blood and milk lymphocytes and monocytes of SCM and CM cows. Phagocytic activity (PA) of blood neutrophils also decreased significantly (p<0.05) in SCM cows. There was no difference between the PA of SCM and CM cows. Milk neutrophil percent was more in the SCM and clinically infected milk than in the blood of these cows. About 96-97% of the neutrophils had segmented nucleus in both healthy and subclinical milk, whereas, 2-3% were having band shaped or immature nuclei. There was a significant decrease in the segmented neutrophils, whereas, band neutrophils increase significantly to about 5% in the infected milk of mastitic cows. Viability of the milk neutrophils decreased more in case of subclinical and clinical milk as compared to that of blood. PA was found to be highest in the milk of healthy group of cows, but decreased significantly (p<0.05) in subclinically infected cows. However, there was no difference between the PA of milk neutrophils of SCM and CM cows. PA of milk was also found to be significantly lower in the milk of healthy cows when compared to that of blood neutrophils. Conclusion: This study indicated that percent neutrophils and their type in conjunction with milk somatic cell counts can be used as a more reliable indicator of mammary health in cows.
Factors Affecting the Patterns of Total Amount and Proportions of Leukocytes in Bovine Milk
Animals
Differential leukocyte count (DSCC) in milk is considered important to improve knowledge of udder immune response. The investigations on milk DSCC were limited by the techniques available until recently, when a high-throughput tool to perform DSCC opened the way to explore these factors in rapid and economically sustainable ways. We hypothesized that DSCC alone does not fully describe the pattern of these cells, since the total amount is also influenced by milk yield and SCC. Therefore, this study was designed to describe DSCC and total amount of different leukocytes in milk during the course of lactation in cows differing in parity and in levels of SCC. This study considered 17,939 individual milk tests from 12 dairy herds in Lombardy Region, where DCC testing was applied in the period of February 2018–December 2019 (23 months). The samples were divided into two subsets—“healthy” (HS) with SCC ≤200,000 cells/mL and “inflamed” (IS) with SCC >200,000 cells/mL. Cow in HS have a P +...
Milk Leucocyte Population Patterns in Bovine Udder Infection of Different Aetiology
Journal of Veterinary Medicine Series B, 2000
This study compared the different leucocyte populations in milk from udders infected with different mastitic pathogens and in different stages of infection. Milk samples were collected from quarters free of intramammary infection, acutely infected with Escherichia coli or Staphylococcus aureus and chronically infected with S. aureus, coagulase-negative staphylococci (CNS) or Streptococcus dysgalactiae. Udder bacteriological status was confirmed after three consecutive bacteriological examinations from weekly quarter milk samples. At the time of the trial, milk samples were tested for somatic cell count (SCC) and differential cell count by both light microscopy (LM) and flow cytometry. Monoclonal antibody (mAb) CD11a/CD18 was used in order to differentiate between leucocytes and epithelial cells when tested by flow cytometry. Udder quarters free of intramammary infection had a mean SCC lower than 107 × 10 3 cells/ml in which the epithelial cells were the main cell type followed by polymorphonuclear cells (PMNs), while macrophages and lymphocytes had a lower concentration. Only 56 % of the cells were labelled with the mAb anti-CD11a/CD18. In either acute E. coli-or S. aureus-infected quarters, SCC were significantly higher (P ³ 0.0001) than in samples from the time of inoculation, with over 90 % of the cells labelled with the mAb anti-CD11a/CD18. The main cell type was neutrophils. In chronically infected cows, differences in SCC and in leucocyte patterns were found between infecting pathogens as well as between quarters harbouring the same pathogen. In all the chronically infected quarters, SCC was significantly higher (P ³ 0.05) than in uninfected ones. The distribution of the leucocyte patterns in the quarters infected with S. dysgalactiae did not differ from that in quarters with acute infection with both E. coli and S. aureus. In the cows chronically infected with S. aureus or CNS, the proportion of PMN was higher but not significantly different from quarters free of intramammary infection, while epithelial cells were significantly lower (P ³ 0.05). The T lymphocytes bearing CD4 + or CD8 + were significantly higher in quarters chronically infected with S. aureus than in quarters free of intramammary infection and in quarters acutely infected with either E. coli or S. aureus. In all samples B cells were negligible.
Czech Journal of Animal Science, 2016
The goal of this work was to understand how polymorphonuclear leukocytes (PMN), the first line of cellular defence, integrate and prioritize multiple chemotactic signals to navigate during periods of demand like subclinical mastitis (SCM), clinical mastitis (CM), pregnancy (P), and calving (C). For this, blood and milk samples were collected from five groups of crossbred cows (healthy, with SCM, CM, pregnant, and newly calved). Maximum viability was seen in the PMN of healthy cows, whereas minimum viability was observed in CM cows. Phagocytic activity (PA) of blood and milk PMN decreased significantly (P < 0.05) at C and in CM cows. Chemotactic activity of blood PMN was minimum in C followed by CM, SCM, and P cows. PA was found to be negatively correlated with the plasma cortisol levels and inverse relationship was observed between the plasma interleukin-8 (IL-8) levels and the chemotactic activity of neutrophils. There was a significantly (P < 0.05) higher expression of CXCR1 and IL-8 on both blood and milk PMN of CM cows followed by C and SCM cows. Minimum expression of selectin (CD-62L) was seen on blood PMN isolated around calving, whereas maximum expression of integrin (CD-11b) was in CM cows. Healthy and P cows showed the highest expression of CD-62L on blood PMN but its expression remained unaltered in milk PMN. Irrespective of physiological stage of the cows, immune suppression was found to be always cortisol dependent. Observing the neutrophil activity and mRNA expression of genes isolated from cow neutrophils can be used as indicators to assess the health/physiological status promptly for immediate therapeutic or management-related actions.
Deeper exploration of inflammatory cell populations in milk to monitor udder health in dairy cows
Scientia Agricola
The present study explored the predictive values of milk leukocyte differentials (MLD) as a basis for improving the diagnosis of intramammary infections (IMIs) and subclinical mastitis. Quarter milk samples were collected for bacteriological analysis, quarter somatic cell count (qSCC), and MLD. The MLD were assessed using the cytospin technique, direct microscopic smears, and flow cytometry. The predictive values of each single leukocyte population and useful potential indices that could better reflect immune complexity were also calculated. Changes in the percentage of any leukocyte alone failed to substantially improve the predictive value of qSCC in diagnosing IMIs. Although certain parameters increased the area under the receiver operating characteristic curve (ROC curve) as a result of increased specificity values, a slight reduction in sensitivity was observed. The so-called CD8 complex was a unique parameter which improved both the sensitivity (78.79 %) and the specificity (80.77 %) in IMI diagnosis, resulting in the highest area under the ROC curve (0.87). To diagnose subclinical mastitis, the percentage of macrophages and the sum of the percentage PMNLs and T CD8 + cells divided by the percentage of macrophages showed the highest predictive values (sensitivity = 79.63, specificity = 73.68, and area under the ROC curve = 0.83) in the differentiation of the inflammatory condition status of cows. In conclusion, this study provides further insights into using T CD8 + lymphocytes in diagnosing bovine IMIs, combined with PMNLs and macrophages. The antidromic trend of macrophages vs. PMNLs and T CD8 + lymphocytes due to the increasing qSCCs was crucial to differentiating quarters under both inflammatory and non-inflammatory conditions.
The Veterinary Journal, 2010
The association of common bacterial pathogens in milk samples during calving with udder shape or the presence of 'teat-end' lesions was investigated in 240 dairy cows from two herds. Sixty-three of 120 cows (53%) in one herd (herd A) and 54/120 animals (45%) in a second herd (herd B) had normal-shaped udders. The remaining animals had udder shapes defined as follows: large pendulous (18% herd A, 26% herd B); large between hindquarter (10% herd A, 17% herd B); overall small (8% herd A, 5% herd B); or small but pendulous (11% herd A, 7% herd B). At calving teat-end lesions were present in 63% and 76% of the quarters of herd A and B animals, respectively. There was no herd effect on udder shape or teatend lesions.
Translational Animal Science
The use of milk leukocyte differential (MLD) test has been proposed as a complement to somatic cell count (SCC) to assess the presence and the severity of intramammary infection. However, detailed information regarding the behavior of MLD under different physiological or pathological stages of the cow is nonexistent. The objective was to analyze the association between milk leukocyte proportions provided by a commercial automated MLD test and multiple cow and quarter-level variables. The study population consisted of 104 Holstein cows (32 primiparous and 72 multiparous) in one farm. Cows were categorized by days in milk as early (<50 DIM; n=29), middle (50–250 DIM; n=25), and late lactation (>250 DIM; n = 50). Milk from 416 quarters was collected and analyzed for lymphocytes (LYM), neutrophils (NEU), and macrophages (MAC) counts using an automated milk fluorescence microscopy system. Concurrently, a sterile composite milk sample was collected from each cow for pathogen identif...
Differential Leukocyte Count Method for Bovine Low Somatic Cell Count Milk
Journal of Dairy Science, 2003
Whereas many differential leukocyte count methods for high somatic cell count (SCC) milk from mastitic cows are available, only a few have been developed for low SCC milk. We have developed a flow cytometric differential leukocyte count method for low SCC milk. The procedure consists of 1) 1.5 ml of diluted milk sample (30%, vol/vol dilution with PBS), 2) centrifugation, 3) leukocyte labeling with SYTO 13 and 4) flow cytometric analysis. Four major leukocyte populations can be clearly identified in the green fluorescence-side scatter dot plot: lymphocytes and monocytes (LM), polymorphonuclear neutrophils (PMN), mature macrophages (MΦ), and cells with apoptotic features based on chromatin condensation and nuclear fragmentation. The optimal processing temperature was 20°C. Significant differences among samples with similar differential leukocyte counts were found. Storage of milk samples during 2 d at 7°C had no effect on differential leukocyte count. Using the new method, differential leukocyte count was performed in low SCC milk samples from cows in early, mid, and late lactation. In accordance with previous studies, PMN and MΦ percentages were lower and LM percentages were higher in early lactation than in the other stages of lactation. The percentage of cells with apoptotic features was higher in early lactation than in mid and late lactation. In conclusion, a rapid, simple, accurate, and reproducible standard procedure was developed to determine the differential leukocyte count (MΦ, PMN, LM, and cells with apoptotic features) of bovine low SCC milk.