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1.
Two dry-cow therapy products were evaluated in seven factory-supply dairy herds in the Waikato area. A product containing neomycin sulphate and the benzathine salt of penicillin (Neopen D.C. White; Smith-Biolab) was used in five herds, and one containing benzathine cloxacillin (Orbenin, Beecham) was used in two herds. Non-treated control cows were included in each herd. Both products were effective in eliminating intramammary infections with Staphylococcus aureus, Streptococcus uberis, and Streptococcus agalactiae. Efficacy of dry-cow therapy against S. aureus was 83.8% and 85.2% respectively. Spontaneous cure rate among controls was 30.8% for S. aureus during the dry period. Spontaneous cure rate for Str. uberis was 50%, while dry-cow therapy eliminated 100% and 77.8%, respectively, for the two products. Dry-cow therapy with either product eliminated more than 90% of Str. agalactiae infections while spontaneous cure rate was only 28.6%. These results further support the effectiveness of dry-cow therapy in reducing the level of subclinical mastitis in dairy herds by shortening the duration of intramammary infections.  相似文献   

2.
Four dry-cow treatment regimens were evaluated against Staphylococcus aureus intramammary infections: 1) high persistency product at drying off and low persistency product 1 to 3 days prepartum; 2) high persistency product at drying off; 3) low persistency product 1 to 3 days prepartum; 4) untreated controls. Treatment 1 was no more efficacious (64.4%) than Treatment 2 (61.3%). Both treatments were significantly different from spontaneous recovery observed in Treatment 4 (41.2%), but not significantly different from Treatment 3 (46.9%). Dry-cow therapy reduced new S. aureus intramammary infections during the dry period by half. Prepartum treatment eliminated more than 90% of new Streptococcus uberis infections.  相似文献   

3.
Data on the infection status of cows on seven commercial dairy farms were collected over 492 full lactations. Foremilk samples were taken at an average interval of five weeks. A total of 249 streptococcal and 433 staphylococcal infections were diagnosed. Spontaneous elimination occurred in 49 per cent of all streptococcal infections and in 54 per cent of Staphylococcus aureus infections. The average duration of spontaneously eliminated infections was 10.8 weeks for Streptococcus agalactiae, 9.9 weeks for Strep dysgalactiae, 10.4 weeks for Strep uberis and 12.8 weeks for Staph aureus. The average duration of infections persisting until drying off was 19.3 weeks for Strep agalactiae, 18.7 weeks for Strep dysgalactiae, 18.5 weeks for Strep uberis and 25.2 weeks for Staph aureus. The method and rate of elimination of infection as found in this analysis are of value for estimating new infection rates and selecting quarters for dry cow therapy.  相似文献   

4.
Bacteriological examinations were made on quarter samples from cows in 35 herds over a 3 year period to monitor the response in a mastitis control program. Initially, Staphylococcus aureus predominated in 32 of the herds and the mean herd prevalence was 26%. The control measures halved this rate but there was considerable variation in response between herds. The decline occurred rapidly and there was a significant reduction (P less than 0.01) by 3 months. Streptococcus agalactiae predominated in 3 herds and the overall infection rate was 4.9%. Control measures eliminated the infection completely from most herds but reinfection occurred in 2 herds. The greatest decline occurred in the first 6 months and was significant (P less than 0.05). The measures had little effect upon Str. uberis and Str. dysgalactiae which remained fairly consistently at low levels. Initially, strains of Staph. aureus resistant to penicillin were dominant in most herds. In a minority of herds strains resistant to streptomycin predominated and in these herds there was a concurrent resistance to penicillin. These patterns did not change greatly over the control period. Resistance by Str. agalactiae to streptomycin occurred in most herds at the start of the program.  相似文献   

5.
The prophylactic use of a dry-cow antibiotic for reducing the incidence of mastitis due to Streptococcus uberis was studied in four seasonally calving dairy herds involving 378 cows. The treatment was a long-acting dry-cow antibiotic preparation administered immediately after the last milking of lactation. New intramammary infections were identified by comparing the bacteriological status of quarters at drying off with that after calving, or through manual udder palpation during the dry period. The administration of dry-cow antibiotic to uninfected quarters at drying off reduced the overall incidence of new infections with Streptococcus uberis from 12.3% for untreated quarters to 1.2% of quarters (p<0.01). The reduction was significant (p<0.01) for both dry-period and post-calving infections. The susceptibility of uninfected quarters to new infection by Streptococcus uberis appeared to be unrelated to the infection status of a cow at drying off. Clinical infections during the dry period were most prevalent (97%) in quarters identified as having open teat canals. Fewer open teat canals (p<0.05) were observed among antibiotic treated quarters over the first 4 weeks of the dry period. Treated quarters had a lower (p<0.05) incidence of new clinical infection during the ensuing lactation and lower somatic cell counts. This did not affect production levels of milk, milk fat or protein. The results clearly indicated a prophylactic benefit for the dry cow antibiotic treatment against new Streptococcus uberis infections during the dry period.  相似文献   

6.
Summary

The comparative efficacy of a product containing 500 mg benzathine cloxacillin (Orbenin D.C.), another product containing 100 mg nafcillin, 300 mg procaine benzylpenicillin and 100 mg dihydrostreptomycin (Nafpenzal D.C.) and a third product containing 250 mg cephalonium (Cepravin D. C.), in the elimination and prevention of mastitis due to gram‐positive microorganisms during the dry period was investigated in 1253 cows located in 14 herds in Israël.

Although more uniform results were observed after treatment with Nafpenzal D.C., differences were not found among the products with respect to the overall efficacy but differences among herds were rather large. The mean cure rate for Staphylococcus aureus quarter infections was 81.4 per cent. New S. aureus infections which occurred between drying off and post calving sampling time were found in 7.0 per cent of the quarters.

Dry period therapy reduced infection level with S. aureus from 13.5 per cent of quarters to 8.0 per cent. A similar proportional decrease was found in infection level due to non‐agalactiae Streptococcus quarter infections.  相似文献   

7.
Eighteen dairy herds were studied, 12 with a 12-month Dairy Herd Improvement Association herd mean somatic cell count (SCC) less than or equal to 150,000 cells/ml (low SCC) and 6 with a 12-month mean SCC greater than 700,000 cells/ml (high SCC). At the outset of the study, quarter samples for bacteriologic culture were collected (in duplicate) from all quarters of all lactating cows (whole herd culture). Subsequently, quarter milk samples for culture from all cows with clinical mastitis were collected for a period of 6 months. In the herds with low SCC, results of whole herd culture revealed low prevalence of intramammary infection attributable to all major pathogens (less than 4% of all quarters). Prevalence of infection with Streptococcus agalactiae (22.2% of all quarters) and Staphylococcus aureus (6.6% of all quarters) was significantly (P less than 0.05) higher in the herds with high SCC. Mean incidence of clinical mastitis in the herds with low SCC was 4.23 infections/100 cows/month (range, 0.42 to 10.25 infections). In the herds with high SCC, mean incidence was 2.91 infections/100 cows/month (range, 1.33 to 3.92 infections). In the herds with low SCC, infection type, as mean percentage of total clinically infected quarters sampled for culture/herd, was 0.0%, 2.2%, 12.3%, 43.5%, and 28.6% for Str agalactiae, S aureus, streptococci other than Str agalactiae, coliforms, and organisms not isolated, respectively. Respective percentages for the herds with high SCC were 41.5%, 18.3%, 12.6%, 8.0%, and 8.8%. During the study period (from April through January), incidence of clinical mastitis and clinical mastitis caused by coliform bacteria were highest in July and August for herds with low SCC.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

8.
By combining information from 2 databases, we investigated the possibility of an association between the genotype of Staphylococcus aureus causing bovine intramammary infection and dry-period cure of subclinical infection. The 1st database contained bacteriologic and cow data from a field study evaluating the efficacy in such infections of a new intramammary dry-cow therapy (DCT) containing tilmicosin phosphate, in comparison with a commercially available DCT containing benzathine cloxacillin. Isolates of S. aureus from that study were frozen and later independently analyzed by pulsed-field gel electrophoresis (PFGE) and macrorestriction DNA fingerprinting. The molecular information, summarized and published elsewhere, constituted the 2nd database. Data from 121 subclinically infected quarters of 92 cows from 40 herds were studied by univariate and multivariable regression analysis. Infection by an isolate of PFGE lineage group D was more likely than infection by an isolate of group A or F to be cured (P < 0.05). Cows infected by lineage group D had a higher linear somatic cell count score (LS) from the last Dairy Herd Improvement test before the dry period than did cows infected by the other lineage groups (P = 0.04). Although the probability of cure was significantly lower for cows with an LS at or above the mean of 5.7 for the study population (P = 0.05), when such a cow was infected with lineage group D, cure was significantly more likely (P < 0.001) than when it was infected by another lineage group. Significantly more (P = 0.02) of the infections treated with tilmicosin (74%) than of those treated with benzathine cloxacillin (53%) were cured, and significantly more (P = 0.05) of the infections by group D (81%) than of those by group A (57%) or group F (54%) were cured. However, there was no difference in cure rate for any PFGE genotype when tilmicosin phosphate was administered; when benzathine cloxacillin was administered, 87% of lineage group D isolates were eliminated, as compared with 46% of group A and 33% of group F isolates (P < 0.05). This research demonstrates that certain genotypes of S. aureus may naturally elicit a greater inflammatory response, yet be more susceptible to elimination by antibiotics in the dry period, than other genotypes.  相似文献   

9.
In this paper an outbreak of bovine mastitis in a dairy herd caused by Streptococcus group G is described. Initial identification of the organism as Streptococcus agalactiae was based upon hemolysis, esculin reaction, and CAMP reaction observed on blood agar used for bulk milk analysis. Initial therapy with a penicillin-containing, lactating cow product cured 24.4% of all streptococcal infections. Definitive serogrouping by coagglutination determined that the majority of infections were due to a weakly-hemolytic, esculin-negative Streptococcus group G. Treatment with a cephalosporin, lactating cow product was only moderately successful (54.9%). Dry-cow therapy with 300 mg cephalosporin eliminated 69.5% of refractory infections. Animals remaining infected following dry-cow therapy were culled. Histopathological study of parenchymal tissue in the lower portion of infected quarters revealed mild damage and slight involutionary changes, whereas, deep parenchymal areas appeared relatively unaffected.  相似文献   

10.
Streptococcus uberis is an important cause of mastitis in dairy cows throughout the world, particularly during the dry period, around the time of calving, and during early lactation. Strategies for controlling S. uberis mastitis have not received adequate research attention and are therefore poorly defined and inadequate. Objectives of the present study were to evaluate the efficacy of extended therapy regimens with pirlimycin for treatment of experimentally induced S. uberis intramammary infections in lactating dairy cows during early lactation and to evaluate the usefulness of the S. uberis experimental infection model for evaluating antimicrobial efficacy in dairy cows. The efficacy of extended pirlimycin intramammary therapy regimens was investigated in 103 mammary glands of 68 dairy cows that became infected following experimental challenge with S. uberis during early lactation. Cows infected with S. uberis in one or both experimentally challenged mammary glands were randomly allocated to three groups, representing three different treatment regimens with pirlimycin, including 2-day (n = 21 cows, 31 mammary quarters), 5-day (n = 21 cows, 32 quarters), and 8-day (n = 26 cows, 40 quarters). For all groups, pirlimycin was administered at a rate of 50 mg of pirlimycin hydrochloride via intramammary infusion. A cure was defined as an experimentally infected mammary gland that was treated with pirlimycin and was bacteriologically negative for the presence of S. uberis at 7, 14, 21, and 28 days after treatment. Experimental S. uberis intramammary infections were eliminated in 58.1% of the infected quarters treated with the pirlimycin 2-day regimen, 68.8% for the 5-day regimen, and 80.0% for the 8-day regimen. Significant differences (P <.05) in efficacy were observed between the 2-day and 8-day treatment regimens. The number of somatic cells in milk decreased significantly following therapy in quarters for which treatment was successful in eliminating S. uberis. However, there was no evidence to suggest that extended therapy with pirlimycin resulted in a greater reduction in somatic cell counts in milk than the 2-day treatment. The S. uberis experimental infection model was a rapid and effective means of evaluating antimicrobial efficacy during early lactation at a time when mammary glands are highly susceptible to S. uberis intramammary infection.  相似文献   

11.
The activity of a 0.5% chlorhexidine gluconate postmilking teat germicide in reducing the numbers of Staphylococcus aureus and Streptococcus agalactiae on the skin of excised teats from cows was determined. The product yielded logarithmic reductions of 4.09 and 4.10 against S aureus and Str agalactiae, respectively, compared with 3.80 and 3.81 reductions, using a 1% iodophor dip. Germicide tolerance to an organic load containing Serratia marcescens or Pseudomonas spp was also determined. Organisms were not recovered from the product 8 hours after introduction of a simulated organic load containing either species of bacteria. The germicide was further evaluated against S aureus and Str agalactiae, using experimental challenge-exposure procedures in a research dairy herd. Efficacy was 73.4% (P less than 0.001) against S aureus and 68.1% (P less than 0.005) against Str agalactiae.  相似文献   

12.
The comparative efficacy of a product containing 500 mg benzathine cloxacillin (Orbenin D.C.). another product containing 100 mg nafcillin, 300 mg procaine benzylpenicillin and 100 mg dihydrostreptomycin (Nafpenzal D.C.) and a third product containing 250 mg cephalonium (Cepravin D.C.), in the elimination and prevention of mastitis due to gram-positive microorganisms during the dry period was investigated in 1253 cows located in 14 herds in Isra?l. Although more uniform results were observed after treatment with Nafpenzal D.C. differences among herds were rather large. The mean cure rate for Staphylococcus aureus quarter infections was 81.4 per cent. New S. aureus infections which occurred between drying off and post calving sampling time were found in 7.0 per cent of the quarters. Dry period therapy reduced infection level with S. aureus from 13.5 per cent of quarters to 8.0 per cent. A similar proportional decrease was found in infection level due to non-agalactiae Streptococcus quarter infections.  相似文献   

13.
Thirty-two dairy herds, 16 with low somatic cell counts (LSCC; Dairy Herd Improvement Association 12-month mean herd SCC less than or equal to 150,000 cells/ml) and 16 with high somatic cell counts (HSCC; Dairy Herd Improvement Association 12-month mean herd SCC greater than or equal to 700,000 cells/ml) were evaluated to determine the relationship between the prevalence of mastitis in each herd and each herd's mastitis control and management practices. Once for each herd, duplicate quarter milk samples were collected from the lactating cows, a survey of herd mastitis control, milking hygiene, and management practices of each herd was performed, and milking-machine function was evaluated. Of the 16 herds with LSCC, 2 (12.5%) had Streptococcus agalactiae isolated and 7 (44%) had Staphylococcus aureus isolated. Both organisms were found in all of the herds with HSCC. In herds with LSCC, the mean percentage of quarters infected with Str agalactiae was 0.1%, the mean percentage infected with streptococci other than Str agalactiae was 1.9%, and the mean infected with S aureus was 0.7%. In herds with HSCC, 25.7% of the quarters were infected with Str agalactiae, 3.7% were infected with streptococci other than Str agalactiae, and 7.6% were infected with S aureus. A program of postmilking teat dipping and treatment of all cows at the beginning of the nonlactating period was practiced more frequently in the herds with LSCC (81.3%) than in the herds with HSCC (37.5%). Major differences were not found between the 2 groups of herds in the use of the more common milking hygiene techniques or in the maintenance and functional characteristics of the milking equipment.  相似文献   

14.
Quarter samples from twenty-five dairy herds, representing 223 herds supplying direct to Brisbane, were cultured and submitted to the Wisconsin Mastitis Test (WMT). Thirteen herds had a history of producing bulk milk with a consistently high WMT score (greater than 15 mm) and in twelve herds the WMT score was consistently low. Prevalence of infection was higher in group A herds (22.2% quarters were infected with Staphylococcus aureus or streptococci) than in group B herds (9.8% of quarters were infected). There was considerable scatter of prevalence among both groups of herds. Overall, S. aureus was found in 19% of cows and 7% of quarters, and Streptococcus agalactiae in 15% of cows and 7% of quarters. Quarters from group A herds showed a higher WMT score than those in group B herds whether infected with S. aureus, Str. agalactiae, micrococci or yielded no detectable organisms. It was concluded that regular surveys are required of the high cell count herds to monitor mastitis status in the industry.  相似文献   

15.
Four strategies for selecting cows for intramammary therapy with benzathine cloxacillin at drying off were compared in 12 Victorian dairy herds. The bacteriological status of all quarters of all (1044) cows was determined just before drying off, within 2 d of calving, and again 3 to 5 months after calving. All cases of clinical mastitis (from calving to mid-lactation) were recorded. Cows not infected at drying off were allocated randomly to 2 subgroups of approximately 350 cows each: not infected, not treated (NI-NT), or not infected, all quarters treated (NI-AT). New infection rates in the dry period (3.8% for NI-NT vs 2.1% for NI-AT) and in early lactation (4.1% for NI-NT vs 3.9% for NI-AT) were low and these differences were not significant. Incidence of clinical mastitis in early lactation was almost 50% higher for the treated group of uninfected cows compared with the untreated group (0.05 less than p less than 0.1). Cows infected in one or more quarters at drying off were split randomly into 2 subgroups of approximately 170 cows each: infected, all quarters treated (I-AT), or infected quarters treated only (I-QT). The new infection rate during the dry period was nearly 4 times higher for I-QT (15.3%) due to significantly more new infections by Staphylococcus aureus and Streptococcus uberis.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

16.
OBJECTIVE: To investigate and compare the therapeutic efficacy of dry cow agents containing either cephalonium or cloxacillin within Australian dairy herds. DESIGN: A treatment-control trial. METHODS: Milk from infected quarters of cows with high somatic cell counts in milk on eight Australian dairy farms was cultured to identify bacterial pathogens. Cows were randomly assigned to treatment groups and one group was treated with cephalonium at drying off and the other group was treated with cloxacillin at drying off. Milk samples from infected quarters were collected immediately after calving and were cultured for pathogens. The effect of treatment on bacteriological cure was examined and somatic cell counts from infected cows from the first two herd tests after calving were examined for a treatment effect. On four farms, milk samples were collected for culture from all cases of clinical mastitis identified within the first 7 days after calving. The effect of treatment upon incidence of clinical mastitis after calving was examined. RESULTS: There was no significant difference between treatments on quarter cure rates for new infections, for chronic infections and for infections with Staphylococcus aureus, Streptococcus agalactiae and Streptococcus uberis. Infected quarters treated with cephalonium had a significantly higher cure rate than quarters treated with cloxacillin when Corynebacterium bovis and Staphylococcus epidermids were included as pathogens combined (80.3% versus 70.7%). There was no significant difference between the treatments on somatic cell counts of infected cows at the first two herd tests after calving. There was no difference between treatments on the incidence of clinical mastitis in the first 7 days after calving.  相似文献   

17.
In a dairy herd with a low incidence of intrammary infections due to Streptococcus agalactiae and Staphylococcus aureus, clinical mastitis remained a serious problem despite good control of nonclinical mastitis through postmilking teat disinfection and antibiotic therapy of known infected quarters at the end of lactation. During the 2-year study, the incidence of clinical mastitis was 0.88 cases/cow-year; 32.2% were caused by streptococcal species other than Str agalactiae and 33.5% by gram-negative organisms. Among all new infections detected, 54.1% were caused by streptococcal species other than Str agalactiae and 25.7% by gram-negative bacteria. Among new infections, 41.6% occurred during the nonlactating period or within a few days of calving. Incidence of clinical mastitis was highest in the 1st month of lactation. Among 84 gram-negative infections, 42.8% were caused by Klebsiella pneumoniae, 20.2% by Escherichia coli, and 23.8% by Enterobacter spp. Among the many serotypes of K pneumoniae and E coli, none was predominant.  相似文献   

18.
A 31-year record-based retrospective study was carried out to determine the aetiology and temporal distribution of bovine clinical mastitis in smallholder dairy herds in the Dar es Salaam region of Tanzania over the period November 1971-December 2002. Laboratory information on 1964 quarter samples from 1365 cows in 281 smallholder dairy herds were retrieved, compiled and studied. Eighty-eight percent of the quarter samples were culture-positive and the predominant mastitis pathogens isolated were Staphylococcus aureus (25.7%), Streptococcus agalactiae (15.4%), Klebsiella pneumoniae (14.3%) and Escherichia coli (14.1%). Other isolates included Pseudomonas aeruginosa (7.5%), Streptococcus dysgalactiae (5.2%) and Streptococcus uberis (4.2%). Contagious mastitis pathogens were isolated from 45.6% of the culture-positive samples, whereas environmental and miscellaneous pathogens were isolated from 48.2% and 5.7%, respectively. Thirty percent of the miscellaneous mastitis pathogens were Candida species. The results demonstrate a steady increase in clinical Candida albicans mastitis. The prevalence of Candida albicans has increased from 1% in 1971 to 17.0% in November 2002. Conversely, despite some fluctuations, the prevalence of Staphylococcus aureus, Streptococcus agalactiae, E. coli and K. pneumoniae remain above 10%. The possible risk factors for these observations are discussed.  相似文献   

19.
AIMS: To assess the efficacy of a commercial intramammary preparation containing cefuroxime as a treatment for clinical mastitis in lactating dairy cows. METHODS: Clinical mastitis cases (n=440) were identified during early to mid lactation on 36 seasonally-calving commercial dairy herds in south-western Victoria, Australia, that ranged in size from 140 to 550 cows. A milk sample for bacterial culture was collected from each affected quarter prior to treatment. Cases were treated using a commercial intramammary antibiotic product containing either 250 mg cefuroxime or 200 mg cloxacillin, according to the manufacturer's recommendations, and the recommended milk with-holding period was observed. The assessment of clinical cure of each case was made by the farm owner/manager at the end of the milk with-holding period. Post-treatment milk samples were taken from clinically cured quarters at each of three consecutive milkings, commencing 7 days after the end of the milk with-holding period and submitted for bacterial culture. RESULTS: Pathogenic bacteria were isolated from 252/416 (60.6%) pre-treatment milk samples submitted from eligible cases. Streptococcus uberis was the most frequent isolate, being cultured from 31.7% of cases. Staphylococcus aureus was isolated from 18.3% of pre-treatment samples, and Esherichia coli from 7.0%. The clinical cure rate for all eligible cases was 81.7%. There was no significant difference in clinical cure rates between cases treated with cefuroxime (186/225=82.7%) and cases treated with cloxacillin (154/191=80.6%). The trial had 80% power to detect a significant difference if the actual cure rates differed by at least 12.6%. There was a superior clinical response rate (p=0.04) for mastitis cases from which E. coli was isolated that were treated with cefuroxime (18/19=95%) compared with cloxacillin 6/10=60%), but case numbers were low (n=29). The overall bacteriological cure rate for the trial was 70% (69/98 cases assessed). There was no significant difference (p=0.27) in bacteriological cure rate between cases treated with cefuroxime (42/56=75%) and cases treated with cloxacillin (27/42=64%). CONCLUSIONS: This trial demonstrated that cefuroxime was an effective intramammary treatment for clinical mastitis and had similar clinical and bacteriological cure rates to cloxacillin, an accepted industry-standard product. Activity against Gram-negative and Gram-positive bacteria was demonstrated for cefuroxime which, along with the economic benefits of less discarded milk compared with other antibiotic preparations, indicated that cefuroxime is likely to be an appropriate intramammary antibiotic for the treatment of clinical mastitis in commercial dairy herds during early to mid lactation in Victoria, Australia.  相似文献   

20.
为进一步制定奶牛乳房炎的防治措施,对天水地区6个不同奶牛场50份乳房炎奶样,进行病原分离、鉴定和药敏试验,共分离得到3类106株细菌,分别为：金黄色葡萄球菌、表皮葡萄球菌、腐生葡萄球菌、溶血葡萄球菌、无乳链球菌、乳房链球菌、停乳链球菌、大肠杆菌、沙门菌、沙雷菌和变形杆菌。金黄色葡萄球菌检出率最高,为24.5%。同时比较了不同治疗方法对奶牛乳房炎的治疗效果,认为中西医结合治疗乳房炎,其治愈率高,见效快。  相似文献   

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