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1.
Staphylococcus aureus is a major pathogen associated with mastitis, a disease affecting both women and dairy cows. The longitudinal profiles of bovine peripheral blood and mammary gland lymphocyte phenotypes in response to S. aureus-induced mastitis were investigated in dairy cows. Increased percentage of CD4 lymphocytes in the mammary gland between 1 and 8 days post-inoculation, increased milk CD4 protein density per cell between 1-8 days post-inoculation, and a statistically significant negative correlation between post-inoculation bacterial counts in milk and blood lymphocyte CD4 protein density were found. Together with blood and milk leukocyte counts, the milk lymphocyte CD4/CD8 ratio and the milk lymphocyte CD4 protein density were more informative indicators than milk somatic cell counts and bacteriology for identification of early vs. late inflammatory phases. These findings suggest that CD4+ lymphocytes play a protective role in the early stages of S. aureus-induced mastitis.  相似文献   

2.
Changes in inflammatory parameters, leukocyte surface markers, functional responses and cytokine mRNA expression of leukocytes of dairy cows with naturally occurring chronic Staphylococcus aureus (S. aureus) mastitis and healthy cows were determined to elucidate the leukocyte responses to S. aureus infection of the mammary gland. Increased values in inflammatory parameters and matrix metalloproteinase activities in milk revealed the characteristics of cows with chronic mastitis. Expression of L-selectin and CD18 molecules on neutrophils and proportion of CD8 cells in milk from cows with S. aureus mastitis were significantly (P<0.05) increased compared with those found in healthy cows. The FcR-stimulated CL response of blood neutrophils was significantly (P<0.05) decreased in cows with S. aureus mastitis. Significantly (P<0.05) decreased mitogenic responses of lymphocytes were found in cows with S. aureus mastitis; however, the values were not restored to those of healthy cows when stimulated with both mitogens and the cytokine IL-1β. The mRNA expression of TNF-α, IL-1β and IL-8 on milk leukocytes from cows with S. aureus was found to be increased compared with that of healthy cows. The changes of immune responses found in cows with S. aureus mastitis appear to be influenced by the severity and duration of inflammation in infected quarters. The down-regulation of the leukocyte functions found in cows with S. aureus mastitis appears to be associated with the progress of the chronic stage of S. aureus mastitis.  相似文献   

3.
OBJECTIVE: To evaluate L-selectin (CD62L) and Mac-1 (CD11b) expression at the surface of blood and milk neutrophils during the early inflammatory response to Escherichia coli-induced mastitis in cows. ANIMALS: 6 healthy Holstein heifers in early lactation. PROCEDURE: Blood and milk samples were collected before and after intramammary administration of 10(4) CFU's of E coli in the left mammary gland quarters. Bacterial counts and electrolyte concentrations in milk, rectal temperature, differential blood leukocyte counts, milk somatic cell counts, neutrophil viability, and the expression of CD62L and CD11b on blood and milk neutrophils were determined longitudinally. RESULTS: Bacteria grew during the first 6 hours after inoculation with a pronounced leukocytic influx. Coincident with neutrophil influx was an increase in CD62L+ and CD11b+ milk neutrophils, as well as an improved viability of milk neutrophils. The peak of the inflammatory reaction was reached approximately 12 hours after E coli inoculation. From that time forward, changes in CD62L and CD11b expression were opposed to each other, with a decrease in CD62L expression and an increase in CD11b expression on blood and milk neutrophils; the magnitude of the differences in CD62L and CD11b expression between blood and milk neutrophils decreased. Percentages of CD62L+ and CD11b+ milk neutrophils increased to percentages that were similar to blood neutrophils (ie, approx 92%). CONCLUSIONS AND CLINICAL RELEVANCE: The presence of adhesion molecules on a large percentage of milk neutrophils during the acute inflammatory response, together with the changes in receptor density, suggest a major role for CD62L and CD11b in neutrophil function during coliform mastitis.  相似文献   

4.
We explored the hypothesis that the outcome of bacterial invasion (infection or no infection) may depend on immunologic factors when bacterial and environmental factors are kept constant. Leukocyte surface molecules (CD3, CD2, CD4, CD8, CD11b, and CD45r) were assessed before and 3 times after intramammary infusion of Staphylococcus aureus in 5 dairy cows. The somatic cell count (SCC/mL), bacterial count (colony-forming units [CFUs]/mL), ratio of milk phagocytes (mononuclear [Mphi] plus polymorphonuclear [PMN] cells) to lymphocytes (P/L index), and ratio of PMN to Mphi cells (PMN/Mphi index) were determined. Although all cows showed evidence of inflammation resulting from the infusion (the median P/L ratio was 11 times greater 1 d after infusion than before infusion), bacteria were not obtained from the milk of 2 cows. Threshold-like responses, resulting in bacterial counts that approached zero (indicating no infection) and SCCs of less than 500000/mL, were observed when the milk CD2+ lymphocyte proportion exceeded 73% (P < or = 0.007). At 1 d after infusion, 7 immune factors distinguished infected cows from those without infection with more than 95% confidence: compared with infected cows, uninfected cows had higher proportions of CD3+, CD2+, CD4+, and CD8+ T cells, higher densities of CD3 and CD2 molecules per cell, and a higher density of CD11b molecules on milk Mphi cells. At 7 d after infusion, the PMN/Mphi index was lower (94% confidence) in uninfected than in infected cows. At 14 d, the CD2, CD8, and CD45r marker densities were lower than those at 1 d (P < 0.02), findings compatible with memory function. Synergism was suggested by the combined effects of the proportions of CD3+, CD2+, and CD11b+ cells, which explained 75.5% of the bacterial-count variability (P < 0.001); alone, none of these markers predicted CFU variability. These results support further studies aimed at identifying cows capable (or incapable) of early bacterial clearance.  相似文献   

5.
Zhen YH  Jin LJ  Li XY  Guo J  Li Z  Zhang BJ  Fang R  Xu YP 《Veterinary microbiology》2009,133(4):317-322
The objective of this study was to estimate the efficacy of specific egg yolk immunoglobulin (IgY) to bovine mastitis caused by Staphylococcus aureus. Eighteen lactating cows with clinical mastitis and 18 lactating cows with experimental mastitis (1 quarter per cow) were randomly assigned to three treatments: IgY (20mg/ml) infusion, penicillin (100mg/ml) infusion and no infusion. Treatments for clinical mastitis and experimental mastitis were performed by a 6-day course of intramammary infusion with a dosage of 10ml at an interval of 12h. Milk samples were collected at morning milking time for testing color, clot, somatic cell counts (SCC) and bacterial count. For most of the cows treated with IgY and penicillin, the milk color and clot recovered to normal form during the therapy course. The milk SCCs and bacterial counts of treated cows decreased compared to those of untreated cows (p<0.05). The cure rates by IgY for experimental and clinical mastitis were 83.3% and 50%, respectively, and those by penicillin were 66.7% and 33.3%, respectively. These results showed the potential of specific IgY to be an alternative therapy for mastitis caused by S. aureus.  相似文献   

6.
The effect of rbGM-CSF intramammary infusion on the subclinical mastitis was evaluated by the somatic cell count (SCC) and expression of adhesion molecules (CD62L and CD11b) on the surface of neutrophils (PMN) in blood and milk. Fifteen cows diagnosed to have subclinical mastitis were used in this study. Seven cows showed a decrease in the SCC (decreased group), whereas 8 cows showed an increase in the SCC (increased group) 7 days after infusion of rbGM-CSF compared to pre infusion level. The percentage of CD62+ cells tended to be lower and CD11b+cells tended to be higher at 6 h on blood PMN in the decreased group of cows. Increased group of cows showed opposite tendencies. The mean fluorescent intensity of these adhesion molecules expressed on PMN in blood and milk was similar in both groups. These results suggested some association between expression of adhesion molecules and changes in SCC by rbGM-CSF. Responsiveness of PMN adhesion molecules to rbGM-CSF might determine the changes in SCC of the subclinical mastitic cows after infusion of rbGM-CSF.  相似文献   

7.
Two separate experiments evaluated ID-1 (a commercial bovine whey product containing 5200 pg of thymosin alpha 1/ml) as an immunotherapeutic agent in lactating cows. In the first experiment, cows without mastitis were evaluated for blood leukogram, milk production, total and differential milk cell counts, lymphocyte (Lc) blastogenesis, and neutrophil (PMN) functions (random and directed migration under agarose, chemiluminescence, ingestion of bacteria, iodination, cytochrome C reduction, antibody-independent neutrophil-mediated cytotoxicity, and antibody-dependent cell-mediated cytotoxicity) before and after ID-1 therapy. ID-1 treatment resulted in a significant treatment group by time period interaction for the relative proportion of mononuclear cells (MNC) in milk (P less than 0.009) and for PMN random migration (P less than 0.01). Based on these interactions, ID-1 treatment appeared to slightly increase the proportion of small MNC in milk and to increase random migration from pretreatment levels by 73% more than increases observed in controls. No significant effect of ID-1 treatment on milk production, total milk somatic cell counts, Lc blastogenesis, or other PMN functions was observed. In cows with experimental Staphylococcus aureus intramammary infections, ID-1 treatment resulted in a significant decline in blood leukocyte count (P less than 0.001) and blood PMN count (P less than 0.02), and maintained PMN random migration (P less than 0.01) while controls declined and abrogated a depression in the ability of Lc to respond to mitogens (P less than 0.05) that developed in controls as a result of S. aureus mastitis. Injection of ID-1 into cows had no adverse effect on their overall health or level of milk production, but did cause subtle and potentially favorable changes in several in vitro immune parameters. In spite of these subtle changes which might indicate increased resistance to mastitis, cows actually developed a more severe S. aureus intramammary infection based on a 9% increase in log 10 bacterial shedding in milk.  相似文献   

8.
We wished to determine the expression of trafficking/adhesion molecules on the surface of lymphocytes isolated from infected mammary glands of cows challenged with either Serratia marcescens or Staphylococcus uberis. Healthy Holstein cows in mid lactation were infected by intramammary infusion with S. marcescens or S. uberis. Following infection, milk samples were collected at various time points. Body temperatures of the cows were taken, and milk was analyzed for colony forming units (CFU) of bacteria and somatic cell counts (SCC). Leukocytes were isolated from the milk and analyzed by flow cytometry. Percentages and types of lymphocytes were determined as well as expression of CD62L, CD11a, LPAM-1 and CD44 on these cells. We found that the percentage of lymphocytes expressing either CD62L or CD11a showed a marked increase 12 h post infection (PI) with S. marcescens that was not seen in cows infected with S. uberis. Conversely, the percentage of lymphocytes expressing CD44 increased in cows infected with S. uberis at 12 h PI, but the increase was not seen in cows infected with S. marcescens. Expression of LPAM-1 was low at all time points in both groups of cows. Body temperatures became elevated in both groups of cows, peaking at 24 h PI in S. marcescens-infected cows and dropping thereafter. In contrast, temperatures of S. uberis-infected cows continued to rise and were still elevated 96 h PI. CFU of bacteria isolated from mammary glands of S. marcescens-infected cows dropped precipitously 24 h PI but continued at high levels in S. uberis-infected cows. SCC began falling in S. marcescens-infected cows 48 h PI but continued to increase in S. uberis-infected cows. Thus, a greater percentage of lymphocytes in milk had a phenotype consistent with recruitment from the peripheral pool following infection with S. marcescens than was seen following infection with S. uberis. Concurrent with the increases seen in percentages of this lymphocyte phenotype, clinical signs lessened in the S. marcescens-infected cows.  相似文献   

9.
Summary The effect of intramammary injection of recombinant bovine interleukin-8 (rbIL-8, 1 mg/10 ml of saline) on quarter milk levels of somatic cell count (SCC), chemiluminescence (CL) activity and counts of total bacteria and Staphylococcus aureus (S. aureus) was investigated, using 10 Holstein cows with an early stage or a late stage of subclinical mastitis naturally infected with S. aureus. In the late-stage group, milk SCC and CL activity had significant rises with maximum levels at 6 h, following maintained high levels thereafter post-cytokine injection. The counts in milk total bacteria and S. aureus were insignificantly decreased, being increased back on day 7 post-cytokine injection. Thus, the cytokine was inefficient for the late-stage subclinical mastitis. However, in the early-stage group milk SCC and CL activity declined to under pre-injection levels on day 7 after marked and significant rises at 6 h and day 1 post-cytokine injection. The milk total bacterial count decreased significantly on days 0.25 and 2. Furthermore, the milk S. aureus count was decreased significantly on days 1, 2, 3 and 7 by the cytokine injection. These results suggest that the rbIL-8 has a potential as a therapeutic agent of the subclinical mastitis of dairy cows, if the cytokine is applied at an initial stage of infection.  相似文献   

10.
The aim of this study was to investigate the importance of bacterial growth for the severity of experimental Escherichia coli mastitis, indirectly expressed as the area under the curve of bacterial counts in milk over time. The association of pre-infusion somatic cell count and post-infusion influx of inflammatory cells in milk with severity of infection was also examined. Bacterial growth was studied through culture in milk samples (in vitro) and through monitoring of bacterial counts in milk during the early phase of infection (in vivo) in 36 cows. Individual variation in bacterial counts was more than 2 x 10(2)-fold after 6 h of in vitro incubation, and more than 8 x 10(2)-fold 6 h after intramammary infusion. In vitro growth in milk was not associated with in vivo growth during the early phase of infection, nor with severity of E. coli mastitis. Somatic cell count before experimental E. coli mastitis was negatively associated with in vivo bacterial growth during the early phase of infection (R2 = 0.28), but was not associated with severity of E. coli mastitis (R2 = 0.06). In vivo bacterial growth during the early phase of infection (positive association; R2 = 0.41), together with influx of inflammatory cells in milk, expressed as mean hourly increase of somatic cell count between 6 and 12 h post-infusion (negative association; R2 = 0.11), are major determinants for the severity of experimental E. coli mastitis (R2 = 0.56).  相似文献   

11.
The objectives of this study were to determine 1) the effect of intramammary infection on calf weaning weight, milk somatic cell count, and milk composition, and 2) the effect of parity on percentages of infected cows, infected quarters, and blind quarters. The number of infected quarters, milk somatic cell counts, milk components, and intramammary infection were studied at weaning in 164 beef cows. The percentage of infected cows ranged from 61.9% at first parity to 66.7% at fifth to ninth parities. Cows with three or four infected quarters had higher (P < .01) milk somatic cell counts than cows with zero, one, or two infected quarters. Among bacterial isolates, Staphylococcus aureus-infected quarters had the highest (P < .01) milk somatic cell count. Percentages of butterfat and lactose were lower (P < .01) in milk from infected quarters than from uninfected quarters. Infections by S. aureus and coagulase-negative staphylococci were the most common and accounted for 67 to 78% of the infections. Percentages of infected quarters and infections caused by S. aureus increased with parity (P < .01). Intramammary infections did not affect (P > .10) calf weaning weight. In conclusion, intramammary infection had no effect on calf weaning weight but increased milk somatic cell count and decreased the percentage of protein, lactose, solids-not-fat, and butterfat. The number of infected and blind mammary quarters increased with parity.  相似文献   

12.
Experimental mastitis was induced in cows by intramammary infusion of endotoxin, Staphylococcus aureus or Streptococcus agalactiae. The inflammatory response was monitored by somatic cell counting and N-acetyl-beta-D-glucosaminidase (NAGase). NAGase activity was analysed in fresh milk samples in parallel with samples treated by a cycle of freezing and thawing combined with detergent treatment to release the cell-bound NAGase. Before the udder reacted by inflammation, the total NAGase activity consisted of free extracellular activity. Later on when the inflammation was established, much of the milk NAGase remained sequestered intracellularly. S agalactiae was linked with a high degree of cellular NAGase sequestration indicating a blockage of the lysosomal release function from the phagocytes. S aureus delayed the inflammatory response.  相似文献   

13.
Udder health problems associated with Staphylococcus aureus infections in dairy cows are difficult to control and antibiotics have limited effects. Lately, more interest has been directed towards ways to stimulate the innate immune mechanisms of the animal for better prevention and treatment of mastitis. The objectives of this study were to investigate if intramammary infusion at drying off with the immune modulator beta1,3-glucan can make the udder more resistant to experimental intra mammary S. aureus infection at this time, and to study if intramammary infusion of beta1,3-glucan into lactating udder quarters with chronic subclinical S. aureus infection can stimulate the clearing of the infection. Another aim was to evaluate the effect of beta1,3-glucan on the expression of major histocompatibility complex (MHC class II) on mammary leucocytes, measured by flow cytometry, during these circumstances. The results indicated a slight, but not statistically significant, positive effect of beta1,3-glucan at drying off on the clinical and anti-bacterial response to S. aureus infection, but no therapeutic effect of beta1,3-glucan treatment of udder quarters with chronic subclinical S. aureus mastitis. However, the proportion of MHCII+ milk lymphocytes tended to increase after glucan infusion in those udder quarters indicating a stimulation of the antigen presenting ability. To further evaluate a possible preventive effect of beta1,3-glucan infusion at drying off more studies are needed involving a larger number of animals.  相似文献   

14.
Bovine mastitis phases induced by Staphylococcus aureus were assessed in 6 lactating cows before challenge and at 1, 4-8, and 9-14 days postinoculation (dpi). Milk lymphocytes, macrophages, and polymorphonuclear cells (PMN) were counted by conventional (manual) cytology, identified by CD3+ and CD11b+ immunofluorescence and counted by flow cytometry (based on leukocyte forward and side light scatter values). Somatic cell counts (SCC) and recovery of bacteria were recorded at the same times. Preinoculation samples showed a lymphocyte-dominated composition. At 1 dpi, the percentage of PMN increased and that of lymphocytes decreased. At 4-8 dpi, PMN were predominant, but the percentage of mononuclear cells increased above that at 1 dpi and further increased by 9-14 dpi (when lymphocytes approached prechallenge values). Based on leukocyte percentages, 3 indices were created from the data: 1) the PMN/lymphocyte percentage ratio (PMN/L), 2) the PMN/macrophage percentage ratio (PMN/M), and 3) the phagocyte (PMN and macrophage)/lymphocyte percentage ratio (Phago/L). Significant correlations were found between cytologic and flow cytometric data in all of these indicators (all with P < or = 0.01). These indices identified nonmastitic, early inflammatory (1-8 dpi), and late inflammatory (9-14 dpi) animals. In contrast, SCC and bacteriology did not. Although sensitivity of the SCC was similar to that of Phago/L, the specificity of SCC was almost half that of the Phago/L index. Based on flow cytometry indicators, an algorithm for presumptive diagnosis of bovine mastitis was developed. Flow cytometry provides results as valid as those obtained by conventional (manual) cytology, shows greater ability to identify mastitic cases than does SCC, and may identify 3 mammary gland health-related conditions.  相似文献   

15.
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 x 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 < 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 < 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 < 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.  相似文献   

16.
OBJECTIVE: To determine the anti-inflammatory effects of glycyrrhizin (GL) in lactating cows with mastitis attributable to naturally occurring infection with coagulase-negative staphylococci (CNS). ANIMALS: 12 lactating Holstein cows with mastitis attributable to infection with CNS and 2 healthy cows without mastitis. PROCEDURE: Clinical signs, number of bacteria in milk, somatic cell count (SCC) in milk, concentrations of alpha-lactalbumin and lactoferrin in milk, and concentration of histamine in milk were investigated before and after intramammary infusion of GL (6 cows) or antimicrobials (6 cows). Glands of 2 healthy cows were infused with staphylococcal enterotoxin; milk leukocytes were then harvested and incubated with various doses of GL. RESULTS: In cows infected with CNS that had a low bacterial concentration in milk, infusion of GL alone resulted in significant improvements in swelling, firmness of glands, and number of clots in milk, and it decreased the SCC, but not significantly. Percentage of neutrophils decreased significantly (to < 30%) by 2 days after infusion. Use of lactoferrin as a marker of inflammation in mammary glands revealed a decrease in concentrations, whereas use of alpha-lactalbumin as a marker of recovery for mammary glands revealed significant increases in concentrations in the GL-infused group. Accompanying these anti-inflammatory effects, a decrease in the concentration of histamine in milk was observed in the GL-infused group. Glycyrrhizin decreased histamine production by milk leukocytes in a concentration-dependent manner. CONCLUSIONS AND CLINICAL RELEVANCE: Infusion of GL may regulate intramammary inflammation through modulation of inflammatory mediators such as histamine.  相似文献   

17.
Changes in the milk antibody levels against Staphylococcus aureus were measured at the start of an experimental intramammary instillation of either S. aureus (Study I) or Staphylococcus hyicus (Study II). A commercial enzyme-linked immunosorbent assay system was used. Twenty-one Holstein cows were enrolled in Study I and 15 Holstein cows were used in Study II. Pathogen instillation began 21 days before the start of the non-lactating period. Cows received intramammary antibiotic treatment in all quarters immediately after the last milking, the start of the non-lactating period. Lacteal secretions were collected before the start of the non-lactating period, and during the immediate postpartum period in both studies, and during the non-lactating period in Study I. Milk was cultured for mastitis pathogens and S. aureus antibody levels and somatic cell counts were determined from all samples. There was an approximate 2-week delay in the elevation in antibody levels in response to the instillation of S. aureus. Antibody levels remained elevated in cows with S. aureus intramammary infections postpartum, but were below threshold in cows where intramammary infections were cured during the non-lactating period. Antibody levels were elevated by S. hyicus intramammary infections, remained elevated for the first 12 days postpartum, but were below threshold by day 21 postpartum. Cows with incipient intramammary S. aureus infections might be misclassified as false negatives by the antibody test. However, results suggest that cows with S. hyicus intramammary infections that were not cured would not be misclassified if milk is withheld from test for the first 30 days postpartum, as recommended by the manufacturer of the test.  相似文献   

18.
The outcome of E. coli mastitis in cows ranges from mild to severe in individual animals. This study explored the hypothesis that milk from individual cows differs in its growth medium properties for E. coli, and whether possible variation could be related to specific milk constituents. To mimic the early phase of intramammary E. coli infection, a low inoculum size and a short incubation period were used. Cell-reduced, cell- and fat-free (skim) and cell- and fat-free and protein-reduced (whey) fractions were prepared from whole milk samples (n=18). Ten ml of whole milk, milk fractions and brain heart infusion broth (BHI) were inoculated with approximately 100cfu E. coli. After 6h of incubation, bacterial counts were assessed by dilution plating in triplicate. Bacterial counts in whole milk differed up to a 100-fold between cows, which was not associated with SCC. Bacterial counts were significantly higher in whey fractions than in whole milk, cell-reduced and skim fractions and variation in whey was smaller, indicating that the acid-precipitable protein fraction contains the milk constituents of major relevance for inhibition of and variation in bacterial growth. The presence of fat and cells added to bacterial growth inhibition to a lesser extent. In conclusion, in vitro growth of E. coli in milk differs substantially between individual cows within an incubation period comparable with the early phase of intramammary infection. This suggests that the growth medium properties of milk could be of importance in the pathogenesis of E. coli mastitis and subsequent outcome of disease.  相似文献   

19.
为评价复方阿莫西林乳房注入剂对泌乳期奶牛临床型乳房炎的治疗效果,在甘肃某两个牛场选择70头自然发生的临床型乳房炎奶牛进行临床试验。将患病奶牛随机分为试验组(n=36头)和对照组(n=34头)。试验用药和对照用药分别为郑州百瑞动物药业有限公司和齐鲁动物保健品有限公司提供的复方阿莫西林乳房注入剂。每个感染乳区注入3 g药物,每12 h注射1次,连续用药3 d。在用药前、停药后7 d及14 d采集各组奶牛的奶样进行细菌学检测及乳汁体细胞计数。通过临床观察、细菌清除率及体细胞计数变化对临床疗效进行评价。停药后14 d,试验组和对照组的临床治愈率分别为58.3%和61.8%,细菌总清除率分别为94.12%和93.55%。两组奶样中的SCC在治疗后均显著下降(P<0.01)。两组临床疗效无统计学差异(P>0.05),表明试验用药对奶牛临床型乳房炎具有良好的治疗效果。  相似文献   

20.
OBJECTIVE: To determine whether a combination of vaccination and extended intramammary antimicrobial treatment would eliminate chronic intramammary Staphylococcus aureus infections in lactating dairy cows. DESIGN: Randomized controlled clinical trial. ANIMALS: 50 dairy cows with chronic mastitis caused by S aureus. PROCEDURE: Cows were identified and paired within herd on the basis of days in milk, lactation number, milk production, and numbers of quarters infected. Treated cows (n=20) received 3 doses of a polyvalent S aureus bacterin on days 1, 15, and 21 of the study along with intramammary administration of pirlimycin in all 4 quarters once daily for 5 treatments (days 16 to 20). Control cows (n=23) received no treatment. Follow-up samples for bacteriologic culture were collected for at least 3 months after treatment to determine treatment success rates. RESULTS: Significantly more S aureus infections were eliminated from treated cows (8/20 [40%]), compared with control cows (2/23 [9%]). The proportion of infected quarters that yielded negative results throughout the follow-up period was also significantly higher in treated cows (13/28 [46%]) than in control cows (2/41 [5%]). CONCLUSIONS AND CLINICAL RELEVANCE: Results indicate that a combination of vaccination and antimicrobial treatment can be successful in eliminating some cases of chronic intramammary S aureus infections in dairy cattle. However, it is important to consider extended treatment protocols carefully because many cows are likely to remain infected with S aureus despite treatment and vaccination.  相似文献   

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