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1.
Two lactational intramammary antibiotic preparations (cloxacillin and oxytetracycline) were each used to treat eight goatsby intramammary infusion in one half. The rate of release of the antibiotics was monitored by a diffusion assay based on the sensitive organism Bacillus stearothermophilus var. calidolactis. Cloxacillin was still detectable 156 hours afterthe final treatment while oxytetracycline was undetectable 108 hours following treatment. A small but significant amount of antibiotic was translocated between treated and untreated halves of the udder in both cases.  相似文献   

2.
Residue persistence in sheep milk following antibiotic therapy   总被引：2，自引：0，他引：2  
Drug residues in milk supplies may have public health implications and can interfere in the manufacture of dairy products, such as cheese. In Spain, most ewe milk production is destined for cheese making, often using raw milk. This study analyses the main factors influencing antibiotic depletion time in lactating dairy sheep. 42, Manchega ewes were distributed into three groups, each receiving a different treatment (cephalexin intramammary infusion, penicillin G intramuscular, and oxytetracycline intravenous injections). During and after the recommended withdrawal period, milk samples were taken at each milking. A microbiological inhibition test (Brilliant Black Reduction, BRT) was used to screen all samples and antibiotic withholding times were established using a logistic regression model. The response to the BRT method in milk from individual ewes treated showed that the effect of the milking order was significant (P<0.001) with the three antibiotics. However the only influence on milk yield was with the intramammary treatment (P<0.005). The BRT method was found to be very sensitive, particularly to the two beta-lactamic antibiotics.  相似文献   

3.
Thirty cows naturally infected with Brucella abortus were treated by various routes, using free or liposomal streptomycin or a combination of liposomal streptomycin and a long-acting oxytetracycline preparation. Of 21 cows treated with liposomal streptomycin alone, 3 (14%) were culture negative and 3 had 10 or fewer bacterial colonies isolated from tissues obtained at necropsy. Thirteen (62%) cows continued to shed organisms in udder secretions and were considered treatment failures. Of 9 cows that were given a combination of liposomal streptomycin and long-acting oxytetracycline, 5 (56%) were cured, 3 had 10 or fewer colonies on culture plates of tissue after necropsy and only 1 continued to shed B abortus in udder secretions after treatment. Eleven cows were given streptomycin liposomes by intramammary infusion with or without IM administration of long-acting oxytetracycline. The most effective regimen consisted of 2 intramammary infusions of streptomycin liposomes and 2 doses of oxytetracycline administered IM. Of 5 cows treated thusly, 2 were cured and all others had fewer than 10 B abortus colonies isolated from tissues obtained at necropsy.  相似文献   

4.
There is limited information on the value of antibiotic therapy for mastitis in beef cows. Effects of antibiotic treatment at weaning and the subsequent calving on calf weaning weight, milk somatic cell counts, milk components, and intramammary infection were studied in beef cows. Additionally, effects of number of infected mammary quarters, number of dry mammary quarters, type of intramammary pathogen, and parity on response variables were determined. Cows (n = 192) were randomly assigned to treatments in a 2 x 2 factorial arrangement; factors were time of treatment (weaning and after calving) and treatment (vehicle and vehicle plus antibiotic). Oxytetracycline (LA-200) or vehicle was administered intramuscularly following collection of quarter milk samples at weaning and calving. Percentage of infected cows and quarters averaged 43.4 and 16.4%, respectively, at calving and increased (P < 0.05) to 53.7 and 29.7% at weaning. Calves from cows with one or two dry quarters weighed 12.7 kg less (P < 0.05) at 90 d after calving and 18.7% less (P < 0.05) at 212 d after calving than calves from cows with no dry quarters. Calves from cows with three or four infected quarters weighed 17.5 kg less (P < 0.05) at 90 d and 25.5 kg less (P < 0.05) at weaning than calves from cows with two or fewer infected quarters. Infections by Staphylococcus aureus and coagulase-negative staphylococci were the most common and accounted for 67 and 78% of the infections. Percentages of infected cows and quarters, infections caused by S. aureus, and dry quarters increased (P < 0.05) with parity. No differences were found among antibiotic treatments for any of the response variables studied. Intramuscular oxytetracycline was not effective in the control of mastitis in beef cows under the conditions of the study.  相似文献   

5.
Mycoplasma spp. are highly contagious pathogens and intramammary Mycoplasma infection is a serious issue for the dairy industry. As there is no effective vaccine for Mycoplasma infection, control depends on good husbandry and chemo‐antibiotic therapy. In this study, antimicrobial susceptibility of Mycoplasma strains recently isolated from cases of bovine mastitis in Japan was evaluated by minimum inhibitory concentration (MIC). All Mycoplasma bovis strains were sensitive to pirlimycin, danofloxacin and enrofloxacin, but not kanamycin, oxytetracycline, tilmicosin or tylosin. M. californicum and M. bovigenitalium strains were sensitive to pirlimycin, danofloxacin, enrofloxacin, oxytetracycline, tilmicosin and tylosin, but not to kanamycin. This is the first report to describe the MIC of major antimicrobial agents for Mycoplasma species isolated from bovine mastitis in Japan.  相似文献   

6.
Ewes treated by intramammary infusion of cephapirin benzathine at the end of lactation were less likely to develop new intramammary infections by early in the next lactation. A controlled clinical trial involving 135 treated ewes and 145 untreated control ewes evaluated the prophylactic and treatment efficacy of intramammary antibiotic treatment of ewes at the time of weaning lambs. Milk samples for bacteriologic examination and identification of intramammary infections were collected at weaning of lambs and 1 to 3 weeks into the subsequent lactation. Untreated ewes were 2.6 times more likely than treated ewes to develop new intramammary infections between sampling times. Existence of an intramammary infection in one mammary gland significantly increased the risk of the other mammary gland becoming infected. Treatment also appeared to be associated with a higher cure rate of existing infections.  相似文献   

7.
The study was performed on 18 Black-and-White Lowland Breed calves with clinical signs of enzootic bronchopneumonia divided into three groups and respectively treated with oxytetracycline and meloxicam--Group I (9 animals); oxytetracycline and flunixin meglumine--Group II (3 animals); and oxytetracycline only--Group III (6 animals--control). The following observations were recorded before treatment (1st day) and two days later (3rd day): body temperature, the serum level of interferon (IFN) and tumor necrosis factor (TNF) as well as cytokine production by bronchoalveolar lavage (BAL) cells. The treatment of calves with a combination of oxytetracycline and meloxicam (Group I) and especially with oxytetracycline and flunixin meglumine (Group II) caused a significantly faster, in comparison to the control group, normalization of body temperature. Both drugs, meloxicam and especially flunixin meglumine, inhibited excessive TNF production in the organism (measured as the serum level of cytokine). Moreover, BAL cells isolated from calves treated with both NSAIDs were still able, ex vivo, to release TNF, in contrast to the control group (treated only with tetracycline) which lost the ability to produce TNF. The treatment of the calves with meloxicam and flunixin meglumine did not significantly influence the levels of IFN in sera but normalized ex vivo IFN production in BAL cells. These results suggest that the combination of meloxicam with an antibiotic or flunixin meglumine with an antibiotic which does not exert an immunosuppressive influence on the organism of calves suffering from enzootic bronchopneumonia is equally effective in the treatment of calves and superior to the antibiotic alone.  相似文献   

8.
The effect of 2 different oxytetracycline treatments in acute E. phagocytophila infected lambs was investigated. Twenty 5-month-old lambs of the Dala and Rygja breeds were used. Ten lambs were inoculated intravenously with a stabilate of an ovine E. phagocytophila strain. On the third day of fever, 4 lambs were given long-acting oxytetracycline (Terramycin prolongatum vet, Pfizer) (20 mg/kg) intramuscularly and another 4 lambs were given short-acting oxytetracycline (Terramycin vet, Pfizer) (10 mg/kg) intravenously for 5 consecutive days. The lambs were examined for the presence of Ehrlichia infection by blood smear evaluation, polymerase chain reaction (PCR) and antibody titre against E. equi. One month after the last antibiotic treatment, 250 ml citrate blood from each of these lambs were inoculated into each of 10 susceptible lambs, which were observed during the following 6 weeks. The results indicate that oxytetracycline given in the acute stage of the infection may effectively terminate the development of fever, rickettsemia and weight reduction in E. phagocytophila infected lambs. No difference was observed between the 2 treatment groups. However, at least 3 of 8 antibiotic treated lambs (37.5%) were still infected with granulocytic Ehrlichia 3 months after treatment.  相似文献   

9.
OBJECTIVE: To determine whether there would be detectable antibiotic residues in milk obtained from dairy cattle with papillomatous digital dermatitis (PDD) after topical treatment with oxytetracycline. DESIGN: Randomized controlled clinical trial. ANIMALS: 28 lactating Holstein cows with PDD. PROCEDURE: Cows were assigned to 2 treatment groups. Treatment 1 (n = 16) consisted of spraying of PDD lesions with 15 ml of a solution containing 100 mg of oxytetracycline/ml; lesions were sprayed twice daily for 7 days, using a garden sprayer. Treatment 2 (n = 12) consisted of a one-time application of a bandage that consisted of cotton soaked with 20 ml of a solution containing 100 mg of oxytetracycline/ml. Milk samples were obtained before and after treatment and assayed for tetracycline content by use of high-performance liquid chromatography and a commercially available tetracycline screening test. RESULTS: None of the cows in either treatment group had violative residues of oxytetracycline in milk samples. CONCLUSIONS AND CLINICAL RELEVANCE: Producers treating lactating cows that have PDD, via topical application of oxytetracycline solution at the concentrations reported in this study, have a low risk of causing violative antibiotic residues in milk.  相似文献   

10.
Summary Of 1500 examined Holstein cows in milk, there were 315 cows with mucopurulent discharges at the time of insemination (21%). Twenty-four hours after insemination, the infected animals randomly received no treatment (group I, control, n = 93), intrauterine infusion of 1 g oxytetracycline (group II, n = 63) and intrauterine infusion of 5 million IU procain penicillin G sodium (group III, n = 159). First service conception rate following treatment was 48.3, 49.2 and 47.7% in groups I, II and III, respectively. In conclusion, treatment with either antibiotic had no advantage relative to the control on first service conception rate.  相似文献   

11.
Pasteurella anatipestifer infection in turkeys   总被引：3，自引：0，他引：3  
In a case of excessive mortality in seven-week-old turkeys, the primary lesion at necropsy was severe fibrinous pericarditis and epicarditis. After 48 hours of incubation at 37 C, Pasteurella anatipestifer was isolated. The infection responded to antibiotic therapy with a combination of neomycin and oxytetracycline in the drinking water. The lesions suggested chlamydial infection, but cultural procedures for chlamydia were negative.  相似文献   

12.
OBJECTIVE: To examine the effectiveness of mass medication with long acting antibiotics at feedlot entry on lot-fed Australian domestic cattle during a period of high risk for bovine respiratory disease (BRD). DESIGN: Systematic allocation at feedlot entry of tilmicosin, long acting oxytetracycline or no antibiotic treatment, to cattle lot fed for the Australian domestic market. Comparisons of growth rate, disease occurrence and mortality were made between the groups at the conclusion of the feeding period. RESULTS: Cattle medicated with tilmicosin at 10 mg/kg body weight on entry to the feedlot grew 0.08 kg/d faster than cattle medicated with oxytetracycline at 20 mg/kg body weight and non-medicated cattle. There was no significant difference in growth rate between oxytetracycline medicated cattle and cattle not medicated with antibiotic at feedlot entry. Cattle medicated with tilmicosin at feedlot entry had 8 fewer cases of disease per 100 animals compared with cattle not medicated with antibiotic at feedlot entry. There was no significant difference in disease occurrence between oxytetracycline medicated cattle and those not medicated with antibiotic at feedlot entry. CONCLUSION: Mass medication with tilmicosin at feedlot entry of cattle destined for the Australian domestic market may be used to reduce disease occurrence and increase growth rate during periods of high risk for BRD.  相似文献   

13.
Twenty-four rams inoculated with Brucella ovis by conjunctival and preputial routes were treated with a long-acting oxytetracycline alone or in combination with dihydrostreptomycin sulfate. The combined treatment eliminated Brucella ovis from 11 of 12 (91.6%) treated rams. Only 4 of 12 (33.3%) rams treated with oxytetracycline alone were bacteriologically negative. Neither treatment resolved clinical epididymitis in 2 rams affected before treatment. Many rams had pathologic lesions in the epididymis and ampullae, which limited the efficacy of antibiotic treatment.  相似文献   

14.
Six groups of swine (85 animals) were fed a combination of antimicrobial drugs (sulfamethazine 100 g/ton, chlortetracycline 100 g/ton and penicillin 50 g/ton). After two weeks the antimicronial drugs were removed from the diet of two groups (28 animals). These swine were compared to four groups fed the medicated diet to determine the effect of duration of treatment and degree of animal isolation on the persistence of resistance in lactose-fermenting enteric organisms. The degree of resistance to penicillin, oxytetracycline, dihydrostreptomycin and neomycin as determined by minimum inhibitory concentrations and the incidence of resistant organisms were examined during and after antibiotic feedings. Ninety-two percent or greater of all isolates tested during and after treatment had minimum inhibitory concentrations for oxytetracycline of greater than 100 mug/ml. Thirty-two weeks after cessation of dietary antibiotic, resistance to oxytetracycline and dihydrostreptomycin remained at 100% and 89% respectively. Variation in degree of contact between swine receiving medicated feed and those receiving nonmedicated feed was not sufficient to reduce the incidence of resistance to oxytetracycline or dihydrostreptomycin in all animals. Factors influencing persistence of resistant enteric organisms are discussed. Addition of the antimicrobials to the ration resulted in significantly greater weight gains for treated animals than for the controls but did not alter feed conversion.  相似文献   

15.
A crossover study was carried out in cattle to determine the serum pharmacokinetics of a standard dose (20 mg/kg bodyweight) of oxytetracycline given either as a conventional injectable formulation or as a long acting formulation. For reference purposes, an intravenous treatment (also given at 20 mg/kg) was included in the trial protocol. A comparison of the two treatment regimes showed that the long acting formulation gave a significantly lower peak oxytetracycline serum concentration, with a significant extension of drug serum concentration. The long acting formulation also showed a longer serum half life and a significantly greater area under the curve value, calculated from 36 hours onwards, together with serum oxytetracycline concentrations which exceeded 0.5 microgram/ml for 86.8 as opposed to 51.5 hours for the conventional formulation. It is concluded that the use of the long acting formulation in cattle leads to a more sustained serum oxytetracycline concentration than does the same dose of conventional formulation.  相似文献   

16.
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   

17.
乳酸链球菌素治疗奶牛乳房炎效果观察   总被引：1，自引：0，他引：1  
乳酸链球菌素（Nisin）是由乳酸链球菌产生的合有34个氨基酸的抗菌肽,对人体无害。本研究将患临床型乳房炎奶牛92头（107个乳区）和隐性乳房炎奶牛90头（90个乳区）随机分成试验组和对照组。试验组的治疗方法是在患病乳区灌注Nisin;临床型乳房炎以庆大霉素乳房内灌注作对照,隐性乳房炎的对照组不作任何处理。临床型乳房炎的Nisin治疗组细菌学治愈率和临床治愈率分别为60．8％和90．2％,而庆大霉素治疗组则分别为44.6％和91．2％,两者无统计学差异。隐性乳房炎经Nisin治疗后,高体细胞数奶牛的数量和牛奶中NAGase的活性均显著下降,细菌转阴率提高。乳酸菌发酵试验表明,经Nisin乳房内灌注治疗临床型乳房炎后,牛奶在第36小时恢复正常发酵,而庆大霉素治疗则需要72h。  相似文献   

18.
OBJECTIVE: To determine whether results of antimicrobial susceptibility testing of bacterial pathogens isolated from the milk of dairy cows with clinical mastitis were associated with duration of clinical signs or bacteriologic cure rate following treatment with cephapirin and oxytetracycline. DESIGN: Observational study on a convenience sample. ANIMALS: 58 dairy cows with 121 episodes of clinical mastitis. PROCEDURE: Cows that only had abnormal glandular secretions were treated with cephapirin alone. Cows with an inflamed gland and abnormal glandular secretions were treated with oxytetracycline and cephapirin. Cows with systemic signs of illness, an inflamed gland, and abnormal glandular secretions were treated with oxytetracycline and flunixin meglumine and frequent stripping of the affected glands. The Kirby-Bauer method was used for antimicrobial susceptibility testing, and current guidelines were used to categorize causative bacteria as susceptible or resistant to the treatment regimen. RESULTS: Median durations of episodes of clinical mastitis caused by susceptible (n = 97) and resistant (24) bacteria were not significantly different. Bacteriologic cure rates at 14 and 28 days were similar for episodes caused by susceptible and resistant bacteria; however, for 56 episodes of clinical mastitis caused by gram-positive bacteria and treated with cephapirin alone, bacteriologic cure rate at 28 days was significantly higher for susceptible than for resistant bacteria. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that antimicrobial susceptibility testing was of no value in predicting duration of clinical signs or bacteriologic cure rate in dairy cows with mastitis, except for episodes caused by gram-positive organisms treated with intramammary administration of cephapirin alone.  相似文献   

19.
Concentrations of chloramphenicol (C M) were determined, by microbiological assay, in the milk and blood serum of 17 culled dairy cows after intramammary infusion of an approved parenteral CM product (Gloveticol) and in the milk of 16 lactating cows after treatment with two approved CM products for intramammary infusion, at dosages ranging from 1 to 30 g/cow. C M was quickly absorbed from the udder into the blood circulation; the doses of 12.5 and 25 g/cow were almost completely absorbed within 20 hours. Absorption half-life (t1/2ab) from fully functioning quarters was 57+/-18 minutes, and the t1/2ab from partially functioning quarters was 125+/-37 minutes. Mean peak serum C M concentrations were 6.1, 16.2, and 37.4 microg/ml after the cows had been infused with 5, 12.5, and 25 g, respectively. These values were considerably higher than the corresponding peak serum C M concentrations reported following intramuscular injection of equivalent doses of the drug. C M residues were not detectible microbiologically in milk from treated quarters 20 hours after treatment with 5 g or 6.25 g, and 36 hours after treatment with 15 g. Drug concentrations in the milk from the non-treated quarters were approximately 70 per cent of the corresponding serum drug levels. Serum CM concentrations of potential therapeutic value in the treatment of gram-negative bacterial infections, i.e. > 5 microg/ml, were maintained for 8 hours after cows had been infused with 12.5 g, and for 12 hours after infusion with 25 g. The implications of the improved systemic availability of C M infused by the intramammary route over the intramuscular route are discussed in terms of potential therapeutic efficacy, local irritation, and duration of drug residues.  相似文献   

20.
The neurally evoked contractile response of the upper lip muscles of horses anesthetized with halothane was used to evaluate the neuromuscular blocking property of oxytetracycline which was administered intravenously at total dose rate of 21 to 28 mg/kg. This dose rate did not alter the contractile response which had a mean control value (and standard error; SE) of 1.76 plus or minus 0.22 kg. Arterial blood pressure was not affected by these dose rates. Neuromuscular blocking effect of the antibiotic occurred when it was administered during partial neuromuscular blockade which had been induced by infusion of magnesium sulfate (0.12 or 0.16 g/kg). Moderate hypocalcemia induced by infusion of sodium oxalate did not enhance the neuromuscular blocking property of this antibiotic. Since the dose rates of the oxytetracycline preparation used had a small effect on calcium concentration of equine serum (smaller than 0.3 mg/dl), calcium binding does not seem to play a major role in the neuromuscular blocking effect of this antibiotic. It was concluded that the weak neuromuscular blocking effect of oxytetracycline is not a significant etiologic factor in the acute type of adverse reaction to this antibiotic that is occasionally encountered in horses.  相似文献   

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