oxytetracycline--anhydrous and Mastitis--Bovine

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.

Topics: Animals; Anti-Bacterial Agents; Body Weight; Cattle; Female; Incidence; Injections, Intramuscular; Mastitis, Bovine; Milk; Oklahoma; Oxytetracycline; Weaning

Bovine mastitis and mastitis control were investigated on smallholder farms in central Kenya. After an initial observational study, a clinical trial to assess the impact of three different mastitis control strategies--(1) improved udder hygiene, (2) treatment of subclinical cases, and (3) a combination of these--was conducted on 100 randomly selected farms with 332 lactating cows. Before the implementation of control measures, the milk yield was low (mean 6.5 kg/day; median 6 kg/day) and somatic cell counts (SCC) were high, with 80% and 43% of cows having milk with SCC greater than 250 x 10(3) cells/ml and 600 x 10(3) cells/ml, respectively. Infectious pathogens were also commonly isolated, with 63% of cows being positive for pathogenic bacteria. Neither intervention strategy alone had any effect on mastitis indicators or milk yield. In combination, the measures had some impact, lowering the prevalence of contagious pathogens by 18%, but this was not reflected in a significantly increased milk yield, lowered SCC or reduced incidence of clinical mastitis.

Topics: Animal Husbandry; Animals; Anti-Bacterial Agents; Cattle; Cell Count; Dairying; Female; Incidence; Kenya; Lactation; Mammary Glands, Animal; Mastitis, Bovine; Milk; Oxytetracycline; Prevalence

To determine whether antibiotic and supportive treatment would improve outcome for dairy cows with naturally developing clinical mastitis, compared with supportive treatment alone.. Randomized controlled trial.. 124 cows in one herd with 172 episodes of clinical mastitis.. Cows were examined at the onset of clinical mastitis, assigned a severity score, and randomly assigned to receive antibiotic (intramammary administration of cephapirin, i.v. administration of oxytetracycline, or both) and supportive treatment (administration of oxytocin, stripping of affected glands, and, in severely affected cows, administration of flunixin meglumine or fluids) or supportive treatment alone. Treatment was continued until 24 hours after signs of clinical mastitis resolved (clinical cure). Milk samples from affected glands were submitted for bacterial culture before initial treatment and every 2 weeks thereafter until the causative organism was no longer isolated (bacteriologic cure).. When mastitis was caused by Streptococcus spp or coliform bacteria, clinical cure rate by the tenth milking was significantly higher if antibiotics were used. Bacteriologic cure rate at 14 days was significantly higher when antibiotics were used, particularly if mastitis was caused by Streptococcus spp. Cows receiving antibiotics developed fewer subsequent episodes of clinical mastitis during the 60 days after the initial episode of mastitis and had less severe clinical disease than cows that did not.. Results suggest that, in herds in which mastitis is often caused by environmental bacteria, antibiotic and supportive treatment may result in a better outcome for cows with clinical mastitis than supportive treatment alone.

Topics: Animals; Anti-Bacterial Agents; Cattle; Cephalosporins; Cephapirin; Combined Modality Therapy; Drug Therapy, Combination; Enterobacteriaceae Infections; Female; Mastitis, Bovine; Microbial Sensitivity Tests; Oxytetracycline; Recurrence; Severity of Illness Index; Streptococcal Infections; Treatment Outcome

To determine the efficacy of intramuscular oxytetracycline as a supplemental dry cow treatment for Staphylococcus aureus mastitis, 37 Holstein cows were randomly assigned to two treatment groups: intracisternal infusion with a commercial preparation of cephapirin benzathine at drying off (20 cows) and infusion with cephapirin benzathine at drying off and intramuscular oxytetracycline at 11 mg/kg once daily on d 7, 8, 9, and 10 after drying off (17 cows). Milk samples collected 7, 14, 30, and 60 d after calving were plated for bacterial isolation within 24 h after collection and after 24 to 72 h of storage at -20 degrees C. Quarters were defined as infected if S. aureus was isolated from the fresh and frozen cultures from any one sample collected before drying off. An infected quarter was defined as cured if S. aureus was not isolated from the fresh or frozen culture from milk samples obtained following calving. The rate of cure by 30 d after calving for systemic oxytetracycline (in combination with cephapirin treatment) was 29.4% for infected quarters and 29.4% for infected cows, compared with 27.5 and 25.0%, respectively, for the cephapirin treatment only. Results including the culture at 60 d after calving were 21.2 and 22.5%, respectively, for combination therapy and cephapirin therapy only. Systemic oxytetracycline, in combination with intramammary dry cow treatment, did not improve the rate of cure for S. aureus mastitis.

Topics: Animals; Cattle; Cephapirin; Female; Infusions, Parenteral; Injections, Intramuscular; Mammary Glands, Animal; Mastitis, Bovine; Oxytetracycline; Staphylococcal Infections

Use of antibiotics without following standard guidelines is routine practice in developing countries which is giving rise to genetic divergence and increased drug resistance. The current study analyzed genetic divergence and drug resistance by

Topics: Animals; Anti-Bacterial Agents; Cattle; Female; Humans; Mastitis, Bovine; Microbial Sensitivity Tests; Milk; Oxytetracycline; Staphylococcal Infections; Staphylococcus aureus; Vancomycin

The current study was designed to characterize methicillin-resistant Staphylococcus aureus (MRSA) isolated from bovine milk, along with its response to antibiotics, and ultimately reverse its mechanism of resistance by modulation with non-antibiotics. The synergistic combination of antibiotics with NSAIDs were tested in-vivo by giving MRSA challenge to rabbits. The current study reported an overall 23.79% prevalence of MRSA. The BLAST alignment of current study sequences revealed 99% similarity with mecA gene of MRSA from NCBI database. The current study isolates were more similar to each other and also with reference sequences as compared to other mecA gene sequences from Turkey, India, and Russia. Antibiogram of MRSA isolates showed a highly resistant response to cefoxitin, amoxicillin, and gentamicin. Amoxicillin, gentamicin, tylosin, vancomycin, and ciprofloxacin elicited a significant response (p < 0.05) in combination with non-antibiotics against tested MRSA isolates. The highest zone of inhibition (ZOI) increase was noted for vancomycin in combination with flunixin meglumine (145.45%) and meloxicam (139.36%); gentamicin with flunixin meglumine (85.71%) and ciprofloxacin with ivermectin (71.13%). Synergistic behavior was observed in the combination of gentamicin with ketoprofen; sulfamethoxazole and oxytetracycline with meloxicam. Hematological analysis showed significant differences (p < 0.05) among lymphocyte count and bilirubin. On histopathological examination of skin tissue, hyperplasia of epithelium, sloughed off epidermis, hyperkeratosis, infiltration of inflammatory cells, and hemorrhages were observed. The highest cure rate was observed in case of gentamicin in combination with ketoprofen as compared to other treatment groups. The current study concluded antibiotics in combination with non-antibiotics as potential therapeutic agents for resistance modulation against MRSA. This study will help to devise treatment and control strategies against bovine mastitis. Although the prospect of using NSAIDs to manage infections caused by MRSA appears to be a promising direction, further studies should be conducted to test these medications using suitable in-vivo models in controlled clinical trials to justify their repurposing as a treatment for MRSA infections.

Topics: Amoxicillin; Animals; Anti-Bacterial Agents; Anti-Inflammatory Agents, Non-Steroidal; Bilirubin; Cattle; Cefoxitin; Ciprofloxacin; Drug Repositioning; Female; Gentamicins; Ivermectin; Ketoprofen; Mastitis, Bovine; Meloxicam; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Oxytetracycline; Rabbits; Staphylococcal Infections; Sulfamethoxazole; Tylosin; Vancomycin

Topics: Animals; Anti-Bacterial Agents; Cattle; Escherichia coli; Female; Fluoroquinolones; Goats; Humans; Macrolides; Mastitis, Bovine; Oxytetracycline; Staphylococcus; Staphylococcus aureus; Streptococcus; Tylosin

The purpose of this study was to clarify the therapeutic effects of oxytetracycline (OTC) as a first-line antibiotic in cattle with acute Escherichia coli mastitis and systemic signs. Drug susceptibility was determined by the minimum inhibitory concentration (MIC) of E. coli isolated from cows with acute E. coli mastitis (n=38). Cattle were divided into OTC-susceptible (S, n=30) and OTC-resistant (R, n=8) groups. They were further subdivided according to susceptibility to the antibiotic used as a second treatment, into susceptible-susceptible (SS, n=30), resistant-susceptible (RS, n=5), and resistant-resistant (RR, n=3) groups. Clinical signs on the day after initial treatment were compared between S and R groups as short-term indicators of treatment effects. The 28-day survival rate of cattle was then compared among SS, RS, and RR groups as a long-term indicator of treatment effects. There were no differences in clinical signs between S and R groups on the day after the first dose, but the 28-day survival rate was significantly greater in the SS group than in the RR group (P=0.04). The results demonstrated that an effective drug is essential for first-line treatment of acute coliform mastitis. However, anticipating the effectiveness of a first-line antibiotic based on clinical symptoms at the second day of treatment is impossible. It is important to build a picture of drug resistance trends in cattle herds for empirical selection of antibiotics to be administered.

Topics: Animals; Anti-Bacterial Agents; Cattle; Drug Resistance, Bacterial; Escherichia coli; Escherichia coli Infections; Female; Japan; Mastitis, Bovine; Microbial Sensitivity Tests; Oxytetracycline; Treatment Outcome

To test the non-inferiority of a novel combination intramammary product containing penicillin and cloxacillin to a reference intramammary product containing oxytetracycline, oleandomycin, neomycin and prednisolone with regard to bacteriological cure and clinical cure.. Clinical cases of mastitis were sourced from 30 spring-calving dairy farms in the Southland region of New Zealand. Affected quarters were infused three times at 24 hourly intervals with either the novel combination product containing 1 g penicillin and 200 mg cloxacillin, or a reference product containing 200 mg oxytetracycline, 100 mg oleandomycin, 100 mg neomycin and 5 mg prednisolone. Cows were enrolled when a farmer detected a case of clinical mastitis. Milk samples were collected for microbiological culture immediately before treatment (Day 0) and on Days 9, 16 and 23. Bacteriological cure was compared for 187 and 178 quarters treated with the reference and novel product, respectively, and clinical cure was compared for 235 and 223 quarters, respectively. Non-inferiority was assessed by calculating the difference in cure rates between the two products and constructing a 95% CI around the difference, using the variance inflation factor to account for herd level clustering. The non-inferiority margin was 20% for both bacteriological and clinical cure. Generalising estimating equation models were used to determine predictor variables.. The bacteriological cure percentage, adjusted to account for herd-level clustering, was 8.5 (95% CI=-1.7-21.8)% higher for quarters treated with the novel than the reference product. The adjusted clinical cure percentage was 0.3 (95% CI=-11.2-12.0)% higher for clinical quarters treated with the novel than the reference product. Bacterial species was the only covariate for bacteriological cure (p=0.003), and quarter score at enrolment (indicating udder inflammation) was the only covariate for clinical cure (p=0.032) in the multivariable models.. The novel combination product was demonstrated to be non-inferior to the reference product with regards to both bacteriological cure and clinical cure.. Clinicians treating mastitis now have access to this novel combination intramammary product, and demonstration of its non-inferiority compared to the existing reference product will provide options for treatment approaches. The novel product contains fewer antimicrobials; which are of a narrower spectrum of activity.

Topics: Animals; Anti-Infective Agents; Cattle; Cloxacillin; Drug Therapy, Combination; Female; Injections; Mammary Glands, Animal; Mastitis, Bovine; Neomycin; Oleandomycin; Oxytetracycline; Penicillins; Prednisolone; Treatment Outcome

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.

Topics: Animals; Anti-Bacterial Agents; Cattle; Clindamycin; Drug Resistance, Bacterial; Enrofloxacin; Female; Fluoroquinolones; Japan; Mastitis, Bovine; Mycoplasma; Mycoplasma Infections; Oxytetracycline; Tylosin

Antimicrobials are frequently used for treatment of bovine mastitis and few studies have examined modern treatment strategies on large US dairy farms. The objective of this study was to describe treatment practices for clinical mastitis occurring in cows on large dairy herds in Wisconsin. Treatments performed on 747 cows experiencing cases of mild, moderate, or severe symptoms of clinical mastitis were recorded on 51 Wisconsin dairy farms. Duplicate milk samples were collected from the affected quarter for microbiological analysis at the onset of clinical mastitis and 14 to 21 d after treatment ended. Cows were treated according to individual farm protocol. Drugs and doses used for treatments were recorded for each case. Among all herds, 5 intramammary (IMM) antimicrobials (amoxicillin, hetacillin, pirlimycin, ceftiofur, and cephapirin) were used to treat cows for clinical mastitis. Of 712 cows with complete treatment data, 71.6% were treated with IMM ceftiofur either solely or combined with other antimicrobials (administered either IMM or systemically). Of cows experiencing severe symptoms of clinical mastitis, 43.8% received IMM treatment concurrent with systemic antimicrobials. Of all cows treated, 23.1% received an additional secondary treatment (either IMM, systemic, or both) because of perceived lack of response to the initial treatment. The majority of IMM treatments were administered to cows with a microbiological diagnosis of no growth (34.9%) or Escherichia coli (27.2%). Half of the cows experiencing cases caused by E. coli were treated using systemic antimicrobials in contrast to only 6.8% of cows experiencing cases caused by coagulase-negative staphylococci. In conflict with FDA regulations, which do not allow extra-label treatments using sulfonamides, a total of 22 cows from 8 farms were treated with systemic sulfadimethoxine either solely or in combination with oxytetracycline. Antimicrobial drugs were used on all herds and many cows received extra-label treatments. Great opportunity exists to improve mastitis therapy on large dairy herds, but use of more diagnostic methodologies is necessary to guide treatments. Farmers and veterinarians should work together to create protocols based on the herd needs considering reduced inappropriate and excessive use of antimicrobials.

Topics: Amoxicillin; Animals; Anti-Bacterial Agents; Cattle; Cephalosporins; Cephapirin; Clindamycin; Escherichia coli; Female; Klebsiella; Logistic Models; Mammary Glands, Animal; Mastitis, Bovine; Oxytetracycline; Pasteurella; Penicillins; Staphylococcus; Streptococcus; Wisconsin

Methicillin-resistant Staphylococcus aureus (MRSA) poses a serious problem in dairy animals suffering from mastitis. In the present study, the distribution of mastitic MRSA and antibiotic resistance was studied in 107 strains of S. aureus isolated from milk samples from 195 infected udders. The characterizations pathogenic factors (adhesin and toxin genes) and antibiotic susceptibility of isolates were carried out using gene amplification and disc diffusion assays, respectively. A high prevalence of MRSA was observed in the tested isolates (13.1%). The isolates were also highly resistant to antibiotics, i.e. 36.4% were resistant to streptomycin, 33.6% to oxytetracycline, 29.9% to gentamicin and 26.2% each to chloramphenicol, pristinomycin and ciprofloxacin. A significant variation in the expression of pathogenic factors (Ig, coa and clf) was observed in these isolates. The overall distribution of adhesin genes ebp, fib, bbp, fnbB, cap5, cap8, map and cna in the isolates was found to be 69.1, 67.2, 6.5, 20.5, 60.7, 26.1, 81.3 and 8.4%, respectively. The presence of fib, fnbB, bbp and map genes was considerably greater in MRSA than in methicillin-susceptible S. aureus (MSSA) isolates. The proportions of toxin genes, namely, hlb, seb, sec, sed, seg and sei, in the isolates were found to be 94.3, 0.9, 8.4, 0.9, 10.2 and 49.5%, respectively. The proportions of agr genes I, II, III and IV were found to be 39.2, 27.1, 21.5 and 12.1%, respectively. A few isolates showed similar antibiotic-resistance patterns, which could be due to identical strains or the dissemination of the same strains among animals. These findings can be utilized in mastitis treatment programmes and antimicrobials strategies in organized herd.

Topics: Adhesins, Bacterial; Animals; Bacterial Toxins; Cattle; Chloramphenicol; Ciprofloxacin; DNA, Ribosomal; Drug Resistance, Bacterial; Female; Gentamicins; Mastitis, Bovine; Methicillin-Resistant Staphylococcus aureus; Milk; Nucleic Acid Amplification Techniques; Oligonucleotides; Oxytetracycline; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; Pristinamycin; Streptomycin; Virulence Factors

The primary objective of this study was to determine management practices concerning mastitis in Brandenburg, Germany, the prevalence of mastitis pathogens in dairy cows, and their resistance to selected antimicrobial agents. A further objective was to study the potential effect of parity and stage of lactation on the resistance of Staphylococcus aureus isolates against ampicillin. Milk samples for microbiological culture were collected from 4 groups of clinically healthy cows (first lactation, >1 lactation, >50 d in milk, and >250 d in milk; 8 cows/group) in 80 dairy herds. Resistance of gram-positive pathogens against 6 antimicrobial agents was tested using the broth microdilution method. Mastitis pathogens were isolated from 26.4% of the milk samples. Coagulase-negative staphylococci (CNS, 9.1% of quarters) and Corynebacterium bovis (7.3%) were the pathogens most frequently isolated. Among the major pathogens, Staph. aureus (5.7%) and Streptococcus uberis (1.0%) had the highest prevalence. Streptococcus agalactiae was isolated in samples from 29% of the herds. Although the prevalence of most pathogens was higher in older cows, the prevalence of CNS was higher in primiparous cows. Results of the mastitis control questionnaire showed that cows with clinical mastitis were transferred to a sick cow pen in 70% of the herds. Cephalosporins were the drug of first choice for treatment of clinical mastitis cases followed by fixed combinations of antimicrobial agents, beta-lactamase-resistant penicillins, and penicillin. Most farmers treated cows 3 to 4 times per case. Cloxacillin, alone or in combination, and penicillin were most often used for dry-cow therapy. Antimicrobial resistance of the pathogens was within the range of other reports. Resistance of Staph. aureus to ampicillin increased significantly during the first lactation. Further research is required to determine the factors that lead to the selection of Staph. aureus strains that are resistant to ampicillin during the first lactation.

Topics: Ampicillin Resistance; Animals; Anti-Infective Agents; Cattle; Cephalosporins; Cloxacillin; Corynebacterium; Drug Resistance, Microbial; Female; Germany; Lactation; Logistic Models; Mastitis, Bovine; Microbial Sensitivity Tests; Milk; Oxacillin; Oxytetracycline; Staphylococcus aureus; Streptococcus; Streptococcus agalactiae

The aims of this study were to describe antibiotic use and biosecurity practices among Washington State dairy producers and to evaluate the effectiveness of a collaborative approach to promoting judicious antibiotic use on dairy farms. In collaboration with a statewide industry group, Washington State dairy producers participated in a written, self-administered survey in 2003. They were then provided several educational interventions followed by a second written survey in 2005. Sixty-five percent (381) of dairy producers completed the 2003 survey. The most commonly cited drugs used for disease treatment were penicillin, ceftiofur, and oxytetracycline. Participants also indicated significant preventive uses with 28% using medicated milk replacer. Most producers appeared to consider intramammary infusion at dry-off to be a treatment rather than a preventative practice. Twenty-three percent of initial respondents indicated at least one extra-label use of antibiotics, yet only half routinely consulted with a veterinarian when doing so. Most agreed that using written protocols for disease treatment could reduce errors, but less than one-third had protocols. After the educational intervention there was a tendency toward reduced use of antibiotic medicated milk replacer: 51% of producers who originally reported using medicated milk replacer discontinued this practice, whereas 12% of producers began using medicated milk replacer between the 2003 and 2005 surveys. Most reported that the resources and educational materials were useful. Areas where additional work is needed include reducing the use of medicated milk replacer, increasing veterinary involvement in antibiotic use decisions, implementing treatment protocols, enhancing biosecurity, and ensuring optimal cow and calf immunity.

Topics: Animals; Animals, Newborn; Anti-Bacterial Agents; Cattle; Cattle Diseases; Cephalosporins; Colostrum; Dairying; Drug Resistance, Microbial; Female; Health Education; Health Knowledge, Attitudes, Practice; Mastitis, Bovine; Milk Substitutes; Oxytetracycline; Penicillins; Surveys and Questionnaires; Washington

The objectives of this study were to determine antimicrobial resistance patterns of Staphylococcus aureus strains isolated from bovine clinical mastitis cases and to subtype the strains by polymerase chain reaction (PCR) technique based on coagulase gene polymorphism. Two hundred sixty-five S. aureus isolates collected from individual animals in different herds (n = 235) from 1995 to 2004 were tested for susceptibility to penicillin, ampicillin, amoxicillin-clavulanate, oxacillin, oxytetracycline, enrofloxacin, kanamycin-cephalexin, and trimethoprim-sulfamethoxazole using the agar disc diffusion test. Strains were also tested for beta-lactamase production. A total of 29.8% of the strains were susceptible to all antimicrobial agents tested. The highest resistance was observed in 63.3% of the strains against beta-lactam antibiotics, penicillin and ampicillin. Oxytetracycline resistance was observed in 27.9% of the strains, either alone or in combination with beta-lactams. No resistance was detected for amoxicillin-clavulanate, oxacillin, enrofloxacin and kanamycin-cephalexin. beta-Lactamase production and resistance to beta-lactam antibiotics were usually correlated. Resistance against beta-lactams increased from 43.5% in 1995 to 58 to 77% from 1999 to 2004. One hundred twenty-five strains were examined for coagulase gene polymorphism. The isolates were subtyped into 4 types by coagulase gene-based PCR. A predominant 1000-bp PCR product was observed in 60.8% of the isolates typed. The results indicate that a few coagulase gene types of S. aureus are responsible for the majority of bovine clinical mastitis cases in one province of Central Anatolia region, Turkey.

Topics: Ampicillin Resistance; Animals; beta-Lactam Resistance; beta-Lactamases; Cattle; Coagulase; DNA, Bacterial; Drug Resistance, Bacterial; Female; Mastitis, Bovine; Microbial Sensitivity Tests; Oxytetracycline; Penicillin Resistance; Polymerase Chain Reaction; Polymorphism, Genetic; Staphylococcus aureus; Turkey

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.. Observational study on a convenience sample.. 58 dairy cows with 121 episodes of clinical mastitis.. 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.. 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.. 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.

Topics: Animals; Anti-Bacterial Agents; Cattle; Cephapirin; Combined Modality Therapy; Drug Resistance, Bacterial; Drug Therapy, Combination; Female; Gram-Positive Bacteria; Lactation; Mastitis, Bovine; Microbial Sensitivity Tests; Milk; Oxytetracycline; Time Factors; Treatment Outcome

Spring-calving multiparous Angus x Hereford cows were used to determine the efficacy of intramuscular treatment with oxytetracycline to reduce the incidence of mastitis-causing bacteria, decrease milk somatic cell counts (SCC), and increase calf growth. During 2 yr, milk samples were collected from each quarter from a total of 319 cows at 8 to 14 d after calving and at weaning, to determine the presence of bacteria and SCC. A California mastitis test (CMT) was performed on milk from each quarter of each cow at the initial sample collection. Cows with a CMT score of 1, 2, or 3 in at least one quarter, were randomly assigned to receive either an intramuscular injection of oxytetracycline (n = 63) or the control vehicle (n = 60), and cows with a CMT score of 0 or trace in all four quarters were not treated (n = 196). Calf weights were determined at birth, early lactation, and weaning. The number of somatic cells in milk and the percentage of quarters that were infected increased as CMT score increased (P < 0.01). The presence of mastitis-causing bacteria at calving increased (P < 0.05) the incidence of infection at weaning. The presence of mastitis-causing bacteria at weaning was associated with increased SCC for quarters and average SCC for cows (P < 0.01). Average SCC per cow at weaning increased (P < 0.05) as the number of infected quarters per cow increased. Treatment did not alter (P > 0.10) the percentage of cows or quarters infected with mastitis-causing bacteria or SCC of cows or quarters at weaning. Average SCC per cow was negatively correlated (P < 0.05) with calf weights at early lactation, but not with weaning weights of calves. Treatment did not influence (P > 0.10) calf weights at early lactation or at weaning. Cows with one or more dry quarters after calving had calves that weighed less at early lactation and weaning than cows with four functional quarters (P < 0.01). Intramuscular oxytetracycline treatment of beef cows that had CMT scores of 1 or greater after calving did not reduce intramammary infection rates or increase calf weights at weaning.

Topics: Animals; Animals, Suckling; Anti-Bacterial Agents; Cattle; Cell Count; Female; Injections, Intramuscular; Mastitis, Bovine; Milk; Oxytetracycline; Treatment Outcome; Weaning; Weight Gain

Topics: Animals; Antibodies, Bacterial; Cattle; Disease Outbreaks; Drug Therapy, Combination; Enzyme-Linked Immunosorbent Assay; Female; Mastitis, Bovine; Milk; Mycoplasma; Mycoplasma Infections; Northern Ireland; Oxytetracycline; Tylosin

The objective of this study was to determine the oxytetracycline residues in milk from cows with clinical mastitis dosed with two extra-label routes of oxytetracycline administration not only during antibiotic's treatment (5 days), but also six days after treatment by use of a liquid chromatography method of testing with a detection limit of 20 ppb. Both groups of animals were treated once daily for five milkings at 24-hour intervals following morning milkings. Composite milk samples (equal volumes of foremilk from each quarter) were collected during morning and afternoon milkings, mixed together (1:1), and stored until analyzed. Milk samples were analyzed just before the first treatment (0 hour) and ten times at 24-hour intervals. Residue studies in milk cows indicate that oxytetracycline passes into milk. Residues in milk were higher for the cows receiving oxytetracycline by intramammary route (Tab. I) than for the cows receiving oxytetracycline intramuscularly (Tab. II). The highest mean data were 195.68 mg/kg after intramammary infusion (Fig. 2) and 2.74 mg/kg after intramuscular injection (Fig. 3) on the 5th day of the treatment beginning. The analysis data showed that oxytetracycline persisted in milk for as long as two days after both treatments at the concentration 0.03 mg/kg versus 0.02 mg/kg, respectively. No residues were detected in milk of any animal from the 4th day of the cessation of the therapy (Fig. 1) as detected by the HPLC method.

Topics: Animals; Anti-Bacterial Agents; Cattle; Drug Residues; Female; Lactation; Mastitis, Bovine; Milk; Oxytetracycline

Efficacy of three different treatment regimens in the elimination and prevention of Staphylococcus aureus intramammary infection was studied in 106 dry cow periods. At drying off, norfloxacin nicotinate was given subcutaneously to 44 cows at 10 mg/kg, oxytetracycline-HCl was administered intramuscularly to 18 cows at 20 mg/kg, 500 mg cephapirin benzathine were infused into each udder quarter of 21 cows, and a group of 23 cows served as an untreated control. Number of existing Staphylococcus aureus intramammary infections was reduced only in the norfloxacin nicotinate treatment group. New infection rate appeared lower in the two systemic treatment groups. The percentage of infected quarters remained the same throughout the dry period in the norfloxacin treatment group but number of infected quarters increased by 33 to 85% (significant in the cephapirin group) in the other groups. Minimal inhibitory concentration of the drugs for 57 S. aureus isolates was determined. Isolates were sensitive to norfloxacin and cephapirin and moderately sensitive to oxytetracycline. Results suggest that systemic dry cow therapy using norfloxacin nicotinate, which possesses large distribution volume, long half-life, and is highly active against the pathogen involved, was more effective than the other treatments.

Topics: Animals; Cattle; Cephalosporins; Cephapirin; Female; Injections, Intramuscular; Injections, Subcutaneous; Mastitis, Bovine; Microbial Sensitivity Tests; Norfloxacin; Oxytetracycline; Random Allocation; Staphylococcal Infections; Staphylococcus aureus

Topics: Animals; Cattle; Chlortetracycline; Drug Therapy, Combination; Female; Lactation; Mastitis, Bovine; Milk; Mycoplasma Infections; Oxytetracycline; Pregnancy; Tylosin

The non-selective antibiotic treatment of dairy cows at the last milking in lactation was studied for its influence on the reduction in the occurrence of infectious processes in the udder after calving. The herd of 120 dairy cows, on an average, was housed in the K 98 cow-house and in a calving house equipped with the traditional technology. The non-selective treatment was performed in 125 dairy cows in the form of single administration of Oxymykoin foam (Galena) (70 cows) and Chronicin foam (Galena) (55 cows) after the last milking in lactation. The treatment of 53 bacteriologically positive cows with Oxymykoin foam had 86.8% therapeutic effectiveness; this indicates the excellent effectiveness of the preparation. Five additional new infections arose in this group of cows treated with Oxymykoin. The treatment of 36 bacteriologically positive cows with Chronicin foam had the effectiveness of 63.9%; in almost 2/5 of the treated cows (13 animals) the bacteria causing mastitis persisted in the post-parturient period. Eight new infections occurred in this group of treated cows. The results of the non-selective antibiotic treatment of dairy cows after the last milking in lactation prove the good effectiveness of the method reducing the percentage of infected cows in the period after calving.

Topics: Administration, Topical; Animals; Bacterial Infections; Cattle; Chloramphenicol; Female; Lactation; Mastitis, Bovine; Oxytetracycline; Pregnancy

Daily monitoring of milk over a 120-day period for bacteria and neutrophil counts revealed that following experimental E coli mastitis, five out of 28 infections resulted in the development of a long continued and recurring condition. Intermittent periods of acute inflammation were observed in the gland, pyrexia was noted, and if bacteria were isolated they were always of the same serotype as the original infecting strain. Failure to isolate bacteria and the lack of overt inflammation during periods of remission suggested that the bacteria were not in the gland cistern but within gland tissue. In one animal antibiotic therapy with a drug which was active in vitro was ineffective in vivo. However another antibiotic proved effective.

Topics: Animals; Cattle; Escherichia coli; Escherichia coli Infections; Female; Framycetin; Mastitis, Bovine; Milk; Oxytetracycline; Recurrence

Effect of six antibiotics on the hemolysin formation by 320 strains of Staphylococcus (including 112 S. aureus) and 100 strains of S. agalactiae isolated from cow udders, have been determined. Tests were performed on plates containing 5% horse red cells, but the hemolytic strains were tested on blood agar plates supplemented with 5% sheep, rabbit and calf cells in addition. One strain of S. aureus produced the rings of hemolysis around the zones of growth inhibition on the media containing the discs of penicillin, erythromycin, oxyterramycin and chloramphenicol. Another strain of S. agalactiae produced similar rings, but only on the medium supplemented with penicillin. On the calf blood agar plate, S. aureus produced the hemolytic rings only in association with streptomycin and neomycin. After five times of propagation on the nutrient agar, the hemolytic phenomenon was not reproducible. It may be suggested that in cow milk there are some inhibitors for hemolysin formation by Staphylococcus and S. agalactiae.

Topics: Animals; Anti-Bacterial Agents; Cattle; Chloramphenicol; Erythromycin; Hemolysin Proteins; Mammary Glands, Animal; Mastitis, Bovine; Oxytetracycline; Penicillins; Staphylococcus; Streptococcus agalactiae

Sensitivity of mastitis bacteria to antibiotics and chemotherapeutic agents. The author tested the following bacteria, isolated from milk: -2236 strains of streptococci (1384 of group B, 262 of group C, 62 of group D, 109 of E, 16 of F, 24 of G, 7 of H, 11 of K, 270 of L, 5 of M, 41 of N, 45 of P); 361 ungroupable streptococci; 18,481 CAMP-positve, 1,966 CAMP-negative beta-haemolytic streptococci; 5,403 CAMP-negative, non-haemolytic streptococci; 1,179 strains of staphylococci, 596 of coliforms, 477 Corynebacterium pyogenes. They were tested against penicillin, streptomycin, chloramphenicol, oxytetracycline, and some were also tested against Nifuzin, Suprazid and sulfadimidine. A high proportion of the streptococci, which were the dominant mastitis agents, was sensitive to penicillin: - 97.2% of group B, 99.2% of C, 96.3% of E, 99.6% of L, 98.7% of CAMP-positive strains, 99.6% of beta-haemolytic strains. Only 20 strains of streptococci (0.08%) were resistent to penicillin. More than half were resistent to streptomycin (52.19%) while 44.38% showed decreased sensitivity. Nearly all streptococci (98.53%) were susceptible to chloramphenicol. With oxytetracycline most CAMP-positive (96.4%) and group B streptococci (95.4%) were sensitive, but only 53.4% of groups C, G and L and 31.4% of beta-haemolytic streptococci were. Sensitivity to Nifuzin, Suprazid and sulfadimidine was variable: the proportion of streptococci sensitive to each drug was 75.32%, 58.51% and 66.05%. During the ten year period of testing (1963 to 1972) the only evidence of an increase in resistance was with oxytetracycline, involving streptococci of groups N and P, the ungroupable strains and above all the beta-haemolytic strains. 82% of the staphylococci were sensitive to penicillin, 89.6% to streptomycin, 95.5% to chloramphenicol and 96.2% to oxytetracycline. Between 1963/66 and 1972 the proportion of strains showing reduced sensitivity to penicillin rose by 28.1%. With sulphonamides, 80.4% were sensitive to Suprazid and 80.6% to sulfadimidine, showing that these drugs were less effective in vitro than antibiotics. 92% of staphylococcal strains were sensitive to Nifuzin. Among coliform bacteria the dominant pattern was sensitivity to streptomycin (96%-, chloramphenicol (97.3%), oxytetracycline (88%), Nifuzin (95%), Suprazid (92%) and sulfadimidine (91.3%). The only change between 1963 and 1972 was a 14% increase in strains resistant to oxytetracacline. Strains of Corynebacterium pyogenes wer

Topics: Animals; Anti-Bacterial Agents; Cattle; Chloramphenicol; Corynebacterium pyogenes; Escherichia; Female; Hemolysis; Mastitis, Bovine; Microbial Sensitivity Tests; Oxytetracycline; Penicillin Resistance; Penicillins; Staphylococcus; Streptococcus; Streptomycin; Sulfonamides

Topics: Aluminum; Animals; Anti-Bacterial Agents; Bacteriological Techniques; Cattle; Chlorobutanol; Chlortetracycline; Dihydrostreptomycin Sulfate; Female; Hydrocortisone; Lactation; Leukocyte Count; Mammary Glands, Animal; Mastitis, Bovine; Milk; Neomycin; Oxytetracycline; Penicillins; Pharmaceutical Vehicles; Polymyxins; Pregnancy; Stearic Acids; Sulfamerazine; Sulfates; Sulfathiazoles

Topics: Animals; Cattle; Cattle Diseases; Female; Mastitis; Mastitis, Bovine; Milk; Oxytetracycline

Topics: Animals; Cattle; Cattle Diseases; Female; Mastitis; Mastitis, Bovine; Oxytetracycline