novobiocin and Mastitis--Bovine

To determine whether treating cows with antimicrobials at the end of lactation would lower the incidence of clinical mastitis, improve milk production, and decrease somatic cell count (SCC) in the subsequent lactation.. Randomized blind field trial.. 233 Holstein cows from a single herd. All cows were in lactation 2 or greater.. Cows were randomly assigned to treatment groups. Treated cows were given procaine penicillin G and novobiocin by intramammary infusion. Control cows were not treated. Farm personnel recorded cases of clinical mastitis. Milk yield and SCC were recorded during the subsequent lactation.. Treatment did not significantly reduce the incidence of clinical mastitis when data for all cows were grouped or when data were stratified by lactation groups (lactation 2 vs lactation > or = 3) or by last SCC (< or = 500,000 cells/ml vs > 500,000 cells/ml). Somatic cell counts (first, mean of first 5, maximum of first 5) for treated and control cows were similar, and proportions of treated and control cows with SCC > 500,000 cells/ml at least once were not significantly different. Treated cows produced 179 kg (394 lb) more milk during the first 17 weeks of lactation than did control cows.. Treating cows with antimicrobials at the end of lactation increased 17-week milk production during the subsequent lactation and, at current milk prices, was financially preferable to not treating them.

Topics: Analysis of Variance; Animals; Anti-Bacterial Agents; Cattle; Cell Count; Female; Follow-Up Studies; Incidence; Lactation; Mastitis, Bovine; Milk; Mycoplasma; Mycoplasma Infections; Novobiocin; Penicillin G Procaine; Penicillins; Prevalence; Single-Blind Method; Staphylococcal Infections; Staphylococcus; Streptococcal Infections; Streptococcus; Time Factors

To determine the efficacy of intramuscular administration of ceftiofur sodium as treatment for intramammary infections attributable to Streptococcus agalactiae, compared with that for a standard treatment of intramammary infusion of penicillin/novobiocin.. Prospective, randomized, controlled trial.. 72 lactating Holstein cows with intramammary infections caused by S agalactiae from 5 commercial dairies in Michigan.. In 36 of 72 infected cows, ceftiofur was administered (2.2 mg/kg of body weight, IM, q 24 h) for 5 days; 150 mg of novobiocin and 100,000 U of procaine penicillin G was infused daily into each mammary gland of the other 36 cows for 2 days. Milk samples were collected aseptically at approximately 4 and 8 weeks after initial treatment. If cows were determined to be infected at 4 weeks after initial treatment, the treatment was repeated.. The cure rate at 4 weeks (91.7%) and at 8 weeks (96.8%) after initial treatment for the penicillin/novobiocin-treated cows was significantly (P < 0.0001) higher, compared with that of the ceftiofur-treated cows (2.8 and 9.1%, respectively). Somatic cell counts were significantly (P < 0.0001) lower in the penicillin/novobiocin-treated group after treatment.. Intramuscular administration of ceftiofur is not efficacious as a treatment to eliminate intramammary infections caused by S agalactiae and should not be used to reduce the prevalence of this organism in dairy herds.

Topics: Animals; Cattle; Cell Count; Cephalosporins; Drug Therapy, Combination; Female; Infusions, Parenteral; Injections, Intramuscular; Logistic Models; Mammary Glands, Animal; Mastitis, Bovine; Milk; Novobiocin; Penicillin G Procaine; Penicillins; Streptococcal Infections; Streptococcus agalactiae; Treatment Outcome

Topics: Animals; Cattle; Cloxacillin; Coagulase; Drug Therapy, Combination; Female; Lactation; Mastitis, Bovine; Novobiocin; Penicillins; Staphylococcal Infections

Spring calving Angus and Angus x Hereford multiparous cows were utilized to determine the effects of intramammary treatment with penicillin G procaine (200,000 IU) and novobiocin (400 mg) at the time of weaning on udder health and calf growth after the subsequent calving. Cows were stratified by age and breed and assigned randomly to receive intramammary treatment (n = 99) at weaning or as untreated controls (n = 97). Quarter milk samples were collected at weaning and at 8 to 14 d after calving. Milk samples were analyzed for somatic cell counts (SCC) and mastitis-causing bacteria. Dry cow treatment decreased (P = 0.005) the number of cows infected after calving. Treatment decreased (P = 0.04) the number of cows that developed new infections and reduced (P = 0.03) the number of quarters with mastitis-causing bacteria after calving that were infected at weaning. Somatic cell counts after calving were greatest (P = 0.008) for cows infected with Staphylococcus aureus. Treatment did not alter (P = 0.19) SCC of quarters after calving that were infected with S. aureus at weaning but reduced (P = 0.002) SCC after calving of quarters that were infected with coagulase-negative staphylococci at weaning. Body weight of calves during early lactation was increased (P = 0.006) if cows with intramammary infection were treated at weaning. Treatment of noninfected cows at weaning increased (P = 0.008) adjusted 205-d weaning weights of calves after the subsequent lactation when compared with untreated noninfected cows. We conclude that treatment of beef cows at weaning with intramammary antibiotics decreased intramammary infections after calving, improved udder health during the subsequent lactation, and increased BW gain of the calves.

Topics: Animals; Animals, Suckling; Anti-Bacterial Agents; Cattle; Female; Gram-Positive Bacteria; Gram-Positive Bacterial Infections; Lactation; Least-Squares Analysis; Mammary Glands, Animal; Mastitis, Bovine; Milk; Novobiocin; Penicillin G Procaine; Random Allocation; Weaning; Weight Gain

A study was conducted in 2 dairy research herds to determine whether prepartum therapy of heifer mammary glands with penicillin-novobiocin or pirlimycin hydrochloride was effective for reducing the percentage of heifers and mammary quarters infected with mastitis pathogens during early lactation. Almost 96% of Jersey heifers (67 of 70) and 71.3% of quarters (199 of 279) were infected 14 d before expected calving. Of the quarters infected at 14 d before expected parturition, 75% (54 of 72) were uninfected following treatment with penicillin-novobiocin; 87% (61 of 70) were uninfected following treatment with pirlimycin, and 56% (32 of 57) were uninfected in the untreated negative control group. The majority of intramammary infections in Jersey heifers were due to coagulase-negative staphylococci (61%), Streptococcus species, primarily Streptococcus uberis (19%), and Staphylococcus aureus (8%). Almost 73% of Holstein heifers (40 of 55) and 34.3% of mammary quarters (73 of 213) were infected 14 d before expected calving. Of the quarters infected at 14 d before expected parturition, 76% (19 of 25) were uninfected following treatment with penicillin-novobiocin; 59% (17 of 29) were uninfected following treatment with pirlimycin, and 26% (5 of 19) were uninfected in the untreated negative control group. The majority of intramammary infections in Holstein heifers were due to coagulase-negative staphylococci (44%) and Staph. aureus (30%). In both herds, the bacteriological cure rate was significantly higher in heifer mammary glands treated with penicillin-novobiocin or pirlimycin hydrochloride than in untreated controls. Prepartum therapy of heifer mammary glands with penicillin-novobiocin or pirlimycin hydrochloride significantly reduced the percentage of heifers and quarters infected with mastitis pathogens during early lactation.

Topics: Animals; Anti-Bacterial Agents; Cattle; Clindamycin; Drug Therapy, Combination; Female; Lactation; Mammary Glands, Animal; Mastitis, Bovine; Novobiocin; Penicillins; Pregnancy; Random Allocation; Staphylococcus; Streptococcus; Treatment Outcome

The results of three standard methods (broth dilution, agar dilution, disk diffusion) and an experimental modification of the microdilution method for determination of resistance to ampicillin, cephalotin, cloxacillin, neomycin, novobiocin, penicillin and streptomycin were compared using 151 Staphylococcus aureus isolates obtained from cases of mastitis. The accuracy of the dilution methods was compared by determination of minimum inhibition concentrations (MIC, MIC50, MIC90 and modal MIC) and by assessment of the agreement within the tolerance of +/-1 dilution step in 2-fold dilution series. The results of the dilution methods were further compared with those of the reference disk diffusion method and the strains were classified as sensitive or resistant using the interpretation criteria for human strains. The comparisons indicated that MIC characteristics and the final classification as sensitive or resistant were method-dependent. Resistance to aminoglycoside antibiotics was observed more often when using broth dilution methods, especially when the broth was supplemented with lactose.

Topics: Ampicillin; Animals; Anti-Bacterial Agents; Cattle; Cephalothin; Cloxacillin; Drug Resistance, Microbial; Female; Mastitis, Bovine; Microbial Sensitivity Tests; Neomycin; Novobiocin; Penicillins; Staphylococcal Infections; Staphylococcus aureus; Streptomycin

Dairy heifers were treated 0 to 90 d, 90 to 180 d, or 180 to 270 d prepartum with one of five different antibiotic products to determine the best time and with which product they should be treated prior to calving. Two hundred thirty-three heifers were included in the study. At the initial sampling, 56.5% of quarters were infected with some type of organism and 15.4% of quarters were infected with Staphylococcus aureus. Treatments included a cephapirin dry cow product, a penicillin-novobiocin dry cow product, a penicillin-streptomycin dry cow product, an experimental dry cow product containing tilmicosin, and a cephalonium dry cow product not available in the United States. Cure rates for the five antibiotic products indicated that all were equally effective against Staph. aureus and all were significantly more effective than the spontaneous cure rate observed in untreated control quarters. No differences in efficacy were observed due to the different treatment times prepartum. However, fewer new Staph. aureus infections occurred after treatment in the group treated at 180 to 270 d prepartum, indicating that treatment in the third trimester will reduce the chances of new intramammary infections occurring after treatment and persisting to calving.

Topics: Animals; Anti-Bacterial Agents; Cattle; Cephapirin; Drug Combinations; Female; Mastitis, Bovine; Novobiocin; Penicillins; Pregnancy; Prevalence; Staphylococcal Infections; Staphylococcus aureus; Time Factors; Treatment Outcome

The activity of novobiocin against Escherichia coli ATCC 25922 and three E. coli strains that were isolated from cases of bovine mastitis was determined in timekill studies in the presence of bovine lactoferrin. Lactoferrin alone did not affect the growth of any of the strains of E. coli. A combination of 1.0 mg/ml of lactoferrin and novobiocin at 1/16x minimum inhibitory concentration (MIC) was bactericidal for E. coli ATCC 25922. When the concentration was increased to 3.0 mg/ml of lactoferrin, novobiocin was bactericidal at 1/64x MIC. Among the mastitis strains tested, 6789 and 6806 were more susceptible to killing by novobiocin than was strain 6800. Strains 6789 and 6806 were killed when treated with novobiocin concentrations of 2, 1/2, and 1/4x MIC. When these strains were also treated with lactoferrin at 3.0 mg/ml, there was a bacteriostatic effect at novobiocin concentrations of 1/8 and 1/16x MIC for strains 6789 and 6800. Strain 6806 appeared to be more susceptible to the combination of lactoferrin and novobiocin as was evidenced by a bactericidal effect over the 24-h testing period. The combination treatment with cephapirin and lactoferrin showed that there was a synergistic bactericidal effect against all of the E. coli strains tested. These studies indicate that lactoferrin can potentiate the activity of antibiotics against Gram-negative bacteria.

Topics: Animals; Anti-Bacterial Agents; Cattle; Cephalosporins; Cephapirin; Drug Synergism; Escherichia coli; Female; Lactoferrin; Mastitis, Bovine; Microbial Sensitivity Tests; Novobiocin

Minimum inhibitory concentrations were determined for selected antimicrobial agents against 872 bacteria isolated from intramammary infections in heifers in New Zealand (n = 401) and Denmark (n = 471). These values were reported in micrograms per milliliters. Antimicrobial agents tested against isolates from New Zealand were penicillin, cloxacillin, cephapirin, ceftiofur, novobiocin, enrofloxacin, erythromycin, and pirlimycin. The minimum inhibitory concentrations that inhibit 90% of the strains tested for these antimicrobial agents with Staphylococcus aureus were 4.0, 0.5, 0.5, 2.0, 1.0, 0.25, 0.5, and 1.0, respectively. The minimum inhibitory concentration values that inhibit 90% of the strains tested against the Staphylococcus spp. ranged from 0.5 to 1.0 for all antimicrobics. The minimum inhibitory concentrations against streptococci were < or = 0.06, 0.5, 0.13, 0.13, 4.0, 1.0, 0.13, and < or = 0.06, respectively. Antimicrobial agents tested against isolates from Denmark included penicillin, ampicillin, oxacillin, cephalothin, ceftiofur, penicillin plus novobiocin, erythromycin, and pirlimycin. Against S. aureus, the minimum inhibitory concentrations were 0.13, 0.5, 0.5, 0.5, 1.0, 0.25, 0.5, and 0.5, respectively. The minimum inhibitory concentrations against Staphylococcus spp. were 0.25, 0.25, 0.5, 0.5, 1.0, < or = 0.06, 0.13, 1.0, and 0.5, respectively. The minimum inhibitory concentrations against the streptococci were < or = 0.06, 0.13, 0.5, 0.5, 1.0, < or = 0.06, 0.13, 0.5, and 0.5, respectively. Minimum inhibitory concentration values for staphylococci from New Zealand and Denmark were similar to values reported for US isolates. Streptococci from New Zealand and Denmark had lower minimum inhibitory concentration values than did US isolates. Only ceftiofur and enrofloxacin were active against the Gram-negative bacilli.

Topics: Ampicillin; Animals; Anti-Bacterial Agents; Anti-Infective Agents; Bacteria; Cattle; Cephalosporins; Clindamycin; Denmark; Enrofloxacin; Erythromycin; Female; Fluoroquinolones; Mammary Glands, Animal; Mastitis, Bovine; Microbial Sensitivity Tests; New Zealand; Novobiocin; Penicillins; Quinolones; Staphylococcus; Staphylococcus aureus

Antimicrobial susceptibility testing was conducted on a variety of mastitis pathogens. The infected quarters were subsequently treated during lactation with a commercially available product containing penicillin and novobiocin that was designed for lactating cows. Cows were treated as per the recommendations of the product manufacturer, and cures were determined by the absence of bacteria in both sets of duplicate quarter milk samples that were collected at 28 d posttreatment. Comparisons were made between the susceptibility of the bacteria and the therapeutic success or failure. All isolates tested were considered to be susceptible to the penicillin and novobiocin combination. Bacteriologic cure rates for newly acquired Staphylococcus aureus intramammary infection (IMI) (< 2 wk in duration) at 28 d posttreatment were 70%. Cure rates for chronic Staph. aureus IMI (> 4 wk duration) were much lower (35%), reaffirming previous reports of the intractable nature of chronic Staph. aureus IMI. Cure rates for subclinical IMI caused by other organisms were 90% for Streptococcus agalactiae, 91% for Streptococcus uberis, 90% for Streptococcus dysgalactiae, 77% for other Streptococcus spp., and 71% for Staphylococcus spp. other than Staph. aureus. In vitro testing was considered to be a predictor of therapy outcome for IMI caused by Staphylococcus spp., newly acquired Staph. aureus, Strep. uberis, Strep. dysgalactiae, and Strep. agalactiae, but was not considered to be a useful predictor of efficacy for chronic IMI caused by Staph. aureus.

Topics: Animals; Anti-Bacterial Agents; Cattle; Female; Lactation; Mastitis, Bovine; Microbial Sensitivity Tests; Novobiocin; Penicillins; Staphylococcus; Staphylococcus aureus; Streptococcus

The combination of penicillin and novobiocin is currently available for the treatment of bovine mastitis, but methods are not available for susceptibility testing of the combination by veterinary diagnostic laboratories. The minimum inhibitory concentration (MIC) and disk diffusion data were determined for penicillin, novobiocin, and a combination of the two in a 1:2 ratio for 225 staphylococcal, streptococcal, and Gram-negative isolates from bovine intramammary infections. Based on the drug concentrations in milk following infusion, linear regression analysis, and error rate bounding, the interpretive zone diameters selected were < or = 16 mm for resistant isolates and > or 17 mm for susceptible isolates with a disk containing 10 U of penicillin and 30 micrograms of novobiocin. Additionally, MIC breakpoints of < or = 2 micrograms/ml of penicillin and 4 micrograms/ml of novobiocin were selected to categorize isolates as susceptible and > or = 4 micrograms/ml of penicillin and 8 micrograms/ml of novobiocin were selected to categorize isolates as resistant. The MIC and disk diffusion results, as well as studies to monitor bacterial killing by antimicrobial agents over time, indicated that the combination of penicillin and novobiocin in a 1:2 ratio was more active than were the individual drugs. Kinetics of the kill curves with the penicillin and novobiocin combination (1:2 ratio) showed that the combination was bactericidal for Staphylococcus aureus and Staphylococcus xylosus.

Topics: Animals; Anti-Bacterial Agents; Cattle; Diffusion; Drug Therapy, Combination; Female; Mastitis, Bovine; Microbial Sensitivity Tests; Novobiocin; Penicillins; Staphylococcus; Streptococcus

The activity of selected antimicrobial agents was determined against strains of Staphylococcus aureus that were isolated from bovine intramammary infections and that were positive or negative for beta-lactamase. A total of 107 S. aureus strains (70 that were positive for beta-lactamase and 37 that were negative for beta-lactamase) were used in the study. Production of beta-lactamase was determined using a chromogenic cephalosporin disk method. Minimum inhibitory concentrations (MIC) for each test strain were determined using a commercially available microdilution panel. The following compounds were tested: penicillin, ampicillin, oxacillin, cephapirin, ceftiofur, penicillin plus novobiocin, erythromycin, and pirlimycin. Of the five beta-lactam compounds tested, penicillin and ampicillin were most affected by beta-lactamase activity, but oxacillin, cephapirin, and ceftiofur were not affected. Penicillin plus novobiocin also demonstrated excellent activity against strains of S. aureus that were both positive and negative for beta-lactamase. Erythromycin and pirlimycin demonstrated good activity against the S. aureus strains that were negative for beta-lactamase; 90% of the isolates had an MIC of < or = 0.5 microgram/ml (MIC90). The MIC90 for erythromycin and pirlimycin for strains that were positive for beta-lactamase was > 64.0 micrograms/ml. However, 8 strains, in addition to producing beta-lactamase, were also resistant to macrolides and lincosaminides. Recalculation of the MIC90 without these 8 strains yielded equivalent values for both erythromycin and pirlimycin with strains that were positive or negative for beta-lactamase (MIC90 < or = 0.5 microgram/ml).

Topics: Ampicillin; Animals; Anti-Bacterial Agents; beta-Lactamases; beta-Lactams; Cattle; Cephalosporins; Cephapirin; Dose-Response Relationship, Drug; Drug Resistance, Microbial; Erythromycin; Female; Mammary Glands, Animal; Mastitis, Bovine; Novobiocin; Oxacillin; Penicillins; Staphylococcal Infections; Staphylococcus aureus

Twelve dairy herds that had participated in the Pennsylvania Dairy Herd Improvement Association (DHIA) program for at least 12 months, that had a 12-month mean DHIA somatic cell count greater than 700,000 cells/ml, and that had greater than 25% of lactating cows infected with Streptococcus agalactiae participated in a herd blitz treatment program. Initially, quarter milk samples for bacteriologic culturing were collected from all lactating cows. Subsequently, all cows identified as infected with Str agalactiae were treated, using a commercial penicillin-novobiocin intramammary infusion product. In addition, a herd mastitis management program of postmilking teat dipping and treatment of all cows at the start of the nonlactating period was instituted. Thirty days after the initial herd visit, samples from all lactating cows were again cultured, and cows infected at that time were treated. Twelve months after the initial herd visit, samples from all lactating cows were again cultured. Mean prevalence of infection with Str agalactiae decreased (P less than 0.05) from 23.0% of quarters and 41.6% of cows initially to 3.4% of quarters and 9.3% of cows at 30 days and 1.6% of quarters and 4.2% of cows at 1 year. Mean herd DHIA somatic cell count decreased (P less than 0.05) from 918,000 cells/ml initially to 439,000 cells/ml at 30 days and 268,000 cells/ml at 1 year.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Cattle; Cost-Benefit Analysis; Female; Mastitis, Bovine; Novobiocin; Penicillin G Procaine; Streptococcal Infections; Streptococcus agalactiae

Cows with Staphylococcus aureus mastitis received either one or two intramammary infusions containing 100,000 U penicillin G and 150 mg novobiocin. Milk and tissue samples were obtained from each quarter. Peak mean penicillin and novobiocin concentrations from antibiotic-positive tissue samples were .013 U/mg and .06 microgram/mg, respectively, for quarters treated once. Quarters treated twice had peak mean penicillin and novobiocin concentrations of .057 U/mg and .06 microgram/mg, respectively. Viable Staphylococcus aureus were isolated intermittently from milk and tissue samples of quarters positive for penicillin and novobiocin for both treatment groups. Histological analysis of mammary parenchyma demonstrated marked decreases in luminal area and increases in connective tissue area and leukocyte infiltration in S. aureus-infected quarters compared with uninfected controls, suggesting that reduction in milk collecting space and presence of inflammatory changes may be responsible for poor drug distribution.

Topics: Animals; Biopsy; Cattle; Drug Therapy, Combination; Female; Lactation; Mammary Glands, Animal; Mastitis, Bovine; Milk; Novobiocin; Penicillin G; Pregnancy; Staphylococcal Infections; Tissue Distribution

A total of 156 dairy cows was randomly assigned to one of four groups at drying off over an 18-mo period: untreated control or intramammary treatment of each mammary quarter with either 400 mg novobiocin, 300 mg cephapirin, or 1 g dihydrostreptomycin with 1 million units penicillin. Quarter foremilk samples were aseptically collected from each cow within 1 mo of drying off and within 1 mo after parturition for bacteriological analysis. Prior to drying off, 28.7% of quarters were positive of which 46.7% were Corynebacterium bovis and 45.5% were coagulase-negative staphylococci. Reductions in infection prevalence from drying off to postpartum samplings for control, novobiocin, cephapirin, and streptomycin-penicillin groups were 13.6, 60.5, 74.4, and 35.3% of quarters. Recovery rates for C. bovis infections were 47.6, 100, 100, and 94.1%; for coagulase-negative staphylococci infections they were 72.7, 86.4, 80.0, and 100%. The cephapirin group showed the lowest new infection rate (1.3%) with coagulase-negative staphylococci compared with control (6.9%). There were no significant differences in lactation milk production among groups following dry period therapy. Results suggest that dry treatment reduces the prevalence of infections by the minor mastitis pathogens.

Topics: Animals; Cattle; Cephapirin; Corynebacterium Infections; Dihydrostreptomycin Sulfate; Drug Therapy, Combination; Female; Mammary Glands, Animal; Mastitis, Bovine; Milk; Novobiocin; Penicillin G Procaine; Postpartum Period; Pregnancy

A commercially available, penicillin-novobiocin, intramammary infusion product and a solution of procaine penicillin G (1.2 X 10(6) IU) in 10 ml of sterile saline solution were evaluated for their comparative efficacies against Streptococcus agalactiae mastitis in 3 California dairy herds. After composite milk samples from each cow in each herd were bacteriologically cultured, cows infected with S agalactiae (n = 228) were assigned randomly to 2 treatment groups. Milk samples were reevaluated bacteriologically 21 to 25 days after treatment. Both preparations were highly effective against S agalactiae in first-lactation cows and in cows scored negative or trace by use of the California Mastitis Test. Efficacy was significantly decreased in cows with California Mastitis Test scores of 1, 2, or 3. Herd and treatment were associated significantly with treatment success or failure. Most treatment failures were in one herd in cows that were given procaine penicillin G in sterile saline solution. Milk production and lactation stage were not associated with success or failure of treatment.

Topics: Animals; Cattle; Drug Combinations; Female; Infusions, Intravenous; Mastitis, Bovine; Milk; Novobiocin; Penicillin G; Penicillin G Procaine; Random Allocation; Streptococcal Infections; Streptococcus agalactiae

Eight dry cow dye/antibiotic preparations were used to determine dye and antibiotic excretion endpoints. Formulations contained 400 mg of novobiocin with 25 or 250 mg Food Drug and Cosmetic Blue No. 1 per infusion or 400 mg novobiocin plus 200,000 IU penicillin with 25, 125, or 250 mg Blue No. 1 or 2 dye per infusion. Fifty-two cows entering their second or later lactations were treated in two or four quarters. Milk was sampled postpartum and tested for residues. Dye content was determined visually and subvisually. Antibiotic content was analyzed by the cylinder plate, or Delvotest-P, or by both methods. One sample contained penicillin residues. Three samples had visual dye content of Blue No. 1. Blue No. 2 was not detected. Subvisual dye was detected for one to four milkings in most cows treated with preparations containing Blue No. 1. Cows were treated within 1 to 7 d prepartum with novobiocin plus penicillin containing 250 mg Blue No. 1. Visual dye persisted from 3 to 15 milkings postpartum and subvisual dye for one to two milkings longer. Penicillin was present in postpartum milk in five of seven cows. Novobiocin persisted in three of seven cows.

Topics: Animals; Cattle; Coloring Agents; Drug Combinations; Female; Mastitis, Bovine; Milk; Novobiocin; Penicillins

A procedure for deriving drug combinations for animal health is used to derive an optimal combination of 200 mg of novobiocin and 650,000 IU of penicillin for nonlactating cow mastitis treatment. The procedure starts with an estimated second order polynomial response surface equation. That surface is translated into a probability surface with contours called isoprobs. The isoprobs show drug amounts that have equal probability to produce maximal efficacy. Safety factors are incorporated into the probability surface via a noncentrality parameter that causes the isoprobs to expand as safety decreases, resulting in lower amounts of drug being used.

Topics: Animals; Cattle; Cattle Diseases; Drug Therapy, Combination; Female; Mastitis, Bovine; Mathematics; Novobiocin; Penicillins; Probability; Random Allocation; Staphylococcal Infections; Streptococcal Infections

Cell-free, fat-free mammary secretions were tested in vitro for ability to support growth of streptococci associated with mastitis. Secretions were obtained prior to drying off, during the dry period, at calving, and during lactation from four cow treatment groups. Treatment groups were dry cow therapy, dry cow therapy and mammary glands subjected to induced inflammation 7 d post-drying-off, no dry cow therapy and no induced inflammation, no dry cow therapy but mammary glands subjected to induced inflammation. Growth of Streptococcus uberis, Streptococcus faecalis, and Streptococcus agalactiae in secretions from nonlactating glands was unaffected by induced inflammation. Growth of Streptococcus bovis was significantly inhibited in secretion obtained 14 d after induced inflammation. Dry cow therapy had no effect on streptococcal growth in secretion obtained 7 d after therapy. Streptococcal growth was greatest in secretions from involuted glands, and there was little or no evidence for growth inhibitory factors in cell-free, fat-free secretions obtained during the dry period. Milk from lactating glands inhibited streptococcal growth, and the inhibitory factor was presumptively identified as lactoperoxidase. Apolactoferrin, immunoglobulin, or both had little effect on streptococcal growth.

Topics: Animals; Apoproteins; Bacteriological Techniques; Body Fluids; Cattle; Citrates; Citric Acid; Culture Media; Disease Susceptibility; Female; Immunoglobulins; Inflammation; Lactation; Lactoferrin; Mammary Glands, Animal; Mastitis, Bovine; Milk; Novobiocin; Pregnancy; Streptococcal Infections; Streptococcus

Staphylococcus aureus is a frequent cause of bovine mastitis worldwide. A model that may predict the efficacy of antimicrobial agents in the treatment of bovine mastitis induced by Staph. aureus was developed in lactating mice. Infection was established by the inoculation of lactating CF1 mice with Staph. aureus into the mammary gland via the teat duct. At the dose of bacteria used, 85-90% of the inoculated, untreated animals developed a nonlethal, acute mastitis within 48 h. Antibiotic treatment was administered subcutaneously or by the intramammary route. Lincosaminide antibiotics including lincomycin, clindamycin, and pirlimycin were evaluated in this system. Other compounds which have been used in therapy of bovine mastitis including novobiocin, penicillin G, ampicillin, cloxacillin and rifamycin-SV were used as reference antibiotics. Pirlimycin was the most effective of the antibiotics tested in this standardized system. Depending upon the route of administration, this novel lincosaminide was 15 to 95-fold more effective than clindamycin, three- to six-fold better than lincomycin, two- to ten-fold more effective than novobiocin, 13- to 17-times more effective than cloxacillin and 8- to 22-times better than rifamycin-SV on a weight-dose comparison. Penicillin G and ampicillin were the least effective drugs tested against mastitis induced by the beta-lactamase producing strain of Staph. aureus used in these assays. Pharmacokinetic experiments suggested that the greater effectiveness of pirlimycin compared to clindamycin and lincomycin was due to increased affinity for and prolonged retention in the mammary gland.

Topics: Animals; Anti-Bacterial Agents; Cattle; Clindamycin; Cloxacillin; Disease Models, Animal; Female; Injections; Injections, Subcutaneous; Kinetics; Lactation; Lincomycin; Lincosamides; Macrolides; Mammary Glands, Animal; Mastitis; Mastitis, Bovine; Mice; Microbial Sensitivity Tests; Novobiocin; Pregnancy; Rifamycins; Staphylococcal Infections

Dye markings of intramammary antibiotic infusions could give a dairy farmer immediate visual warning that milk contains antibiotic residue. Six dye and antibiotic preparations for lactating cows were studied for rates of dye and antibiotic milk-out. Albacillin containing 1 X 10(5) IU of penicillin plus 150 mg of novobiocin combined with 25, 125, or 250 mg of Food, Drug, and Cosmetic Blue No. 1 or No. 2 per infusion was used. Thirty cows with healthy udders producing 13.6 to 22.7 kg milk per day were treated in all quarters twice in 24 h (0500 and 1500 h). Milk samples from 14 posttreatment twice per day milkings (0500 and 1500 h) were tested for dye and antibiotic residue. Dye content was determined by a visual method and subvisually by an ion exchange resin method. No antibiotic residues were found by the cylinder plate method after the second to fourth posttreatment milkings. Antibiotic residue was detected up to the sixth milking by Delvotest-P. Depending on the dye type and its concentration, milk was visibly blue for one to four milkings. Subvisual quantities for dye were detectable by the ion exchange resin method for three to five milkings. The preparation showing the most promise for farm use contained 250 mg Blue No. 1 per infusion. Milk from cows treated with this preparation contained visually and subvisually detectable dye through three or four and five milkings, respectively. The dye persistence exceeded or coincided with the maximum antibiotic persistence in nearly all cows treated regardless of dye formulation or method of antibiotic detection.

Topics: Animals; Benzenesulfonates; Cattle; Coloring Agents; Drug Combinations; Female; Glycerides; Glycerol; Indigo Carmine; Injections; Lactation; Mammary Glands, Animal; Mastitis, Bovine; Milk; Novobiocin; Penicillin G; Penicillin G Procaine; Pregnancy

Topics: Animal Feed; Animals; Anti-Bacterial Agents; Cattle; Female; Fermentation; Hydrogen-Ion Concentration; Mastitis, Bovine; Milk; Novobiocin; Penicillin G; Temperature

Identification to species level was attempted on a collection of 954 cultures of catalase-positive, clumping-factor- and beta-haemolysin-negative Gram-positive cocci isolated from teats and milk of cows. Eighty-seven per cent of the strains were identified as Staphylococcus xylosus, S epidermidis, S sciuri, S haemolyticus, S hyicus subsp hyicus and chromogenes, S simulans and S cohnii. Nine per cent of the collection belonged to another group which could not be identified with any of the known Staphylococcus species. Many of the strains of this group and also part of the S epidermidis and S hyicus subsp chromogenes strains examined showed various degrees of growth enhancement on certain media when fatty substances were added. Only nine strains were classified as Micrococcus. A scheme for the identification of coagulase-negative staphylococci from cows' milk is proposed.

Topics: Animals; Cattle; Culture Media; Deoxyribonucleases; Hemolysin Proteins; Mammary Glands, Animal; Mastitis, Bovine; Novobiocin; Staphylococcus; Staphylococcus aureus

Infections were induced at the end of lactation in all udder quarters of 19 cows by the infusion of 0.2 mL of a 10(-4) dilution in milk of a six hour milk culture of Staphylococcus aureus, strain 305 (A.T.C.C No. 29740). Two right or two left udder quarters were infected at 15 days and the opposite two five days before the last milking of lactation. Following the last milking all four udder quarters of eight cows were treated with 400 mg novobiocin in 10 mL of 2% aluminum monosterate in peanut oil, gelled. All udder quarters of eight other cows were treated with 50 mg novobiocin in the same vehicle and the udder quarters of three cows were treated with the vehicle only. At calving, eight of 32 quarters treated with 400 mg novobiocin were still infected, as were 18 of 32 treated with 50 mg of novobiocin and all those quarters treated with vehicle only. Results were identical from udder quarters infected 15 and five days before drying off. No significant differences were found between quarters in milk yield on the last day of lactation, nor the length of the dry period. An increasing number of udder quarters were infected at calving with increase in lactation age of the cow, although the small number of cows would not allow a firm conclusion. A significant difference in results was found between front and hind udder quarters, only five of 32 front quarters were infected at calving as compared to 21 to 32 hind quarters. The method proposed was found to give essentially the same results as those from a large field trial using the same antibiotic. It should therefore be useful in evaluation trials of new antibiotic products for dry cow treatment.

Topics: Animals; Cattle; Female; Injections; Lactation; Mammary Glands, Animal; Mastitis, Bovine; Novobiocin; Pregnancy; Staphylococcal Infections; Staphylococcus aureus

Four dose levels of novobiocin (50, 200, 400, 600 mg) were compared with no drug for the intramammary treatment of Staphylococcus aureus, Streptococcus agalactiae and other streptococcal infections present in the udder of dairy cows at the initiation of the dry period. Treatment success was evaluated by comparing the microbiological status of duplicate pretreatment quarter milk samples collected at drying off with the microbiological status of duplicate quarter milk samples collected four to ten days postcalving. Infection status of 1318 cows in 75 herds in five geographic locations was determined. Treatment effects on infected cows were evaluated by least squares analysis of variance with treatment, herd, lactation number, days dry and milk production at drying off considered as variables. The dose of 400 mg novobiocin per quarter was demonstrated to be significantly more effective (P < 0.05) than no drug and significantly better than (P < 0.05) or equal to the other doses for curing infections caused by S. aureus, S. agalactiae and other streptococci. A significant reduction (P < 0.05) in the overall rate of new udder infections acquired during the dry period was observed in cows treated with >/= 200 mg novobiocin at drying off. The data supported the conclusion that the cow rather than the quarter is the appropriate experimental unit in the evaluation of intramammary mastitis treatments. Herd and lactation number were the most significant variables affecting cures.

Topics: Animals; Cattle; Female; Injections; Lactation; Mammary Glands, Animal; Mastitis, Bovine; Novobiocin; Pregnancy; Staphylococcal Infections; Streptococcal Infections

Topics: Animals; Cattle; Female; Lactation; Mastitis, Bovine; Novobiocin; Penicillins; Pregnancy

An experimental product incorporating 500,000 IU of procaine penicillin G and 600 mg of sodium novobiocin in 2% aluminum monostearate-peanut oil gel (10-ml dose) was used to treat all quarters of 56 cows which were infected in at least 1 quarter at time of final mild-out at end of lactation. Treatment was withheld from 89 cows uninfected in all quarters. Quarter infection was determined by bacteriologic culturing of milk samples collected at the last regular milking, at intervals up to final milk-out (7 or 12 days later), at calving, and 1 week later. Clearance rates against Staphylococcus aureus, Staphylococcus epidermidis, streptococci other than Streptococcus agalactiae, and coliform bacteria in treated quarters were 83, 94, 88, and 71%, respectively. Subtraction of the spontaneous clearance rate of about 50% in untreated quarters resulted in values of 35 to 45% for drug efficacy against existing staphylococcal and streptococcal infections. Prophylactic efficacy was examined. In cows entering the true nonlactating period with 1 or more quarters infected, new infection rates across the period aming quarters uninfected at the beginning were 36.0% among untreated cows and 6.3% among treated cows (P less than 0.005). The comparable rates for cows entering the nonlactating period uninfected in all quarters were 5.7 and 0%. Staphylococcus aureus and streptococci, which comprised 38.5% of new period infections among untreated cows, were completely lacking among treated cows (P less than 0.025). Within the treated group of cows, 83.1% of infected quarters were cleared, and new infection rate in the non-lactating period was 50% less than the rate among untreated cows. Because the frequency of intramammary infection in this herd was quite low at "drying-off" (10.5% of quarters), the net effect on herd health of selective therapy of cows infected at end of lactation was a reduction in total quarter infection from 19.8 to 13.6%.

Topics: Animals; Cattle; Drug Combinations; Female; Lactation; Mastitis, Bovine; Novobiocin; Penicillin G Procaine; Pregnancy; Staphylococcal Infections; Streptococcal Infections

An experimental product incorporating 500,000 IU of procaine penicillin G and 600 mg of sodium novobiocin in 2% aluminum monostearate-peanut oil gel (10-ml dose) was infused after the final milk-out at end of lactation into all 4 mammary quarters of 56 cows that were infected in at least 1 quarter. The therapeutic and prophylactic efficacies were published in the companion report. Infusion of the product in all quarters of 5 lactating cows resulted in only slight irritation. Penicillin was eliminated by the 11th milking and novobiocin by the 5th. After infusion in the dry udder, the antibiotics were no longer detectable in serous secretion after 14 days and failed to appear in urine at the earliest (7-day) sampling after administration. Neither antibiotic was detectable in the 1st postpartum milking after nonlactating periods as short as 3 weeks.

Topics: Animals; Cattle; Drug Combinations; Female; Inflammation; Lactation; Mammary Glands, Animal; Mastitis, Bovine; Novobiocin; Penicillin G Procaine; Pregnancy

Penicillin (P), novobiocin (N), and both (P-N) were evaluated in vitro against 143 clinical isolates of bovine mastitis, including, Staphylococcus aureus, Streptococcus agalactiae, Streptococcus dysgalactiae, and Streptococcus uberis. Greater antistaphylococcal activities were demonstrated with N alone and P-N than with P alone. Streptococcus spp were more susceptible to P alone than to N alone, and the effectiveness of P-N corresponded with that of P alone. In vitro, P-N had a wider spectrum of antibacterial activity than did either P or N. Similar results were also obtained in vivo, using the mouse protection test. The P-N gave a greater protection rate in mice experimentally infected with S aureus and Str agalactiae than did P or N.

Topics: Animals; Cattle; Female; Mastitis, Bovine; Mice; Novobiocin; Penicillin G; Staphylococcal Infections; Staphylococcus; Streptococcal Infections; Streptococcus; Streptococcus agalactiae

Topics: Animals; Antigens, Bacterial; Bacitracin; Cattle; Chlortetracycline; Dihydrostreptomycin Sulfate; Female; Klebsiella; Klebsiella pneumoniae; Mastitis, Bovine; Milk; Neomycin; Novobiocin; Penicillin G; Penicillin Resistance

Topics: Animals; Anti-Bacterial Agents; Cattle; Cloxacillin; Female; Framycetin; Mastitis, Bovine; Novobiocin; Penicillin G; Penicillins; Staphylococcal Infections; Streptomycin

Topics: Animals; Cattle; Cloxacillin; Female; Mastitis, Bovine; Novobiocin; Penicillin G; Staphylococcal Infections

Topics: Animals; Anti-Bacterial Agents; Cattle; Female; Lactation; Mammary Glands, Animal; Mastitis, Bovine; Novobiocin; Oxacillin; Penicillin G Procaine; Pregnancy; Pregnancy, Animal; Staphylococcus; Streptococcus

Topics: Animals; Cattle; Cloxacillin; Leucomycins; Mastitis, Bovine; Novobiocin