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This article is part of the supplement: Focus on Bovine Mastitis: knowledge into practice

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Treatment of mastitis during lactation

S Pyörälä

Author Affiliations

University of Helsinki, Faculty of Veterinary Medicine, Department of Production Animal Medicine, Pohjoinen Pikatie 800 FI-04920 Saarentaus, Finland

Irish Veterinary Journal 2009, 62(Suppl 4):S40-44  doi:10.1186/2046-0481-62-S4-S40

The electronic version of this article is the complete one and can be found online at:

Published:1 April 2009



Treatment of mastitis should be based on bacteriological diagnosis and take national and international guidelines on prudent use of antimicrobials into account. In acute mastitis, where bacteriological diagnosis is not available, treatment should be initiated based on herd data and personal experience. Rapid bacteriological diagnosis would facilitate the proper selection of the antimicrobial. Treating subclinical mastitis with antimicrobials during lactation is seldom economical, because of high treatment costs and generally poor efficacy. All mastitis treatment should be evidence-based, i.e., the efficacy of each product and treatment length should be demonstrated by scientific studies. Use of on-farm written protocols for mastitis treatment promotes a judicious use of antimicrobials and reduces the use of antimicrobials.

antibiotic; antimicrobial; bovine; intramammary; lactation; mastitis; systemic; therapy; treatment


Intramammary infection (mastitis) is the most common reason for the use of antimicrobials in dairy cows [31,17]. Antimicrobials have been used to treat mastitis for more than fifty years, but consensus about the most efficient, safe, and economical treatment is still lacking. The concept of evidence-based medicine has been introduced to veterinary medicine [3] and should apply also to treatment of mastitis. The impact on public health should be taken into account as dairy cows produce milk for consumption [33]. The aim of this article is to review current treatments of mastitis during lactation and seek for evidence-based, best practice treatment recommendations for bovine mastitis.

Pharmacokinetic and Pharmacodynamic Considerations

The bovine mammary gland is a difficult target for antimicrobial treatment. Penetration of substances into milk when administered parenterally or absorption and distribution throughout the udder when infused intramammarily (IMM) depends on their pharmacokinetic characteristics. These are lipid solubility, degree of ionization, extent of binding to serum and udder proteins, and the type of vehicle. Antimicrobial treatment of dairy cows creates residues into milk, and residue avoidance is an important aspect of mastitis treatment [55].

Pharmacodynamics of the antimicrobial is another aspect which should be considered. Milk should not interfere with antimicrobial activity. The activity of macrolides, tetracyclines and trimethoprim-sulphonamides has been shown to be reduced in milk [28,13]. Selecting a substance with a low minimum inhibitory concentraton (MIC) value for the target pathogen is preferable, particularly when the antimicrobial is administered systemically. The antimicrobial should have bactericidal rather than bacteriostatic action, because phagocytosis is impaired in the mammary gland [24].

Antimicrobial susceptibility determined in vitro has been considered as a prerequisite for treatment. However, activity in vitro does not guarantee efficacy in vivo when treating bovine mastitis. Antimicrobial resistance amongst mastitis pathogens has not yet emerged as a clinically relevant issue, but geographical regions may differ in this respect. The biggest problem is the widespread resistance of staphylococci, particularly Staphylococcus aureus, to penicillin G [38,35,20]. Cure rates for mastitis caused by penicillin-resistant strains of S. aureus seem to be inferior to those of mastitis due to penicillin-susceptible strains [59,42,50,52]. It is not known if this is due to pharmacologic problems of the drugs used, or virulence factors possibly linked to β-lactamase gene of the resistant isolates [19]. Using an in vitro β-lactamase test for determining resistance to penicillin G of staphylococci before treatment is recommended [35].

Coagulase-negative staphylococci tend to be more resistant than S. aureus and easily develop multiresistance [38,47]. Mastitis causing streptococci have remained susceptible to penicillin G, but emerging resistance to macrolides and lincosamides has been detected [38,27]. Antimicrobial susceptibility of coliform bacteria varies but normally is not a limiting factor for therapy [25,14,55].

Intramammary or Systemic Administration?

An important question regarding the treatment of mastitis is whether the antimicrobial should accumulate in the milk or in the udder tissue [9]. The target site may depend on the causative agent: streptococci are known to remain in the milk compartment, but S. aureus penetrates udder tissue and causes deep infection (Table 1). The most common route of administration of antimicrobials in mastitis is the IMM route. The advantages of this route are high concentrations of the substance achieved in the milk and low consumption of the antimicrobial as the drug is directly infused into the diseased quarter. For example, concentration of penicillin G in milk after IMM administration is 100-1000 times as high as the concentration after systemic (parenteral) administration [15,16,59,32]. A disadvantage of the IMM administration is uneven distribution throughout the udder [53,7,8] and the risk of infecting the quarter when infusing the product via the teat canal. Efficacy of IMM treatment varies according to the causative pathogen, with the best therapeutic response being shown for mastitis caused by streptococci, coagulase-negative staphylococci, and Corynebacterium spp..

Table 1. Where to target antimicrobial therapy in clinical mastitis due to different pathogens [9]

The systemic route of administration has been suggested to be more efficient than IMM for the treatment of clinical mastitis as antimicrobials theoretically have better penetration of the udder tissue by this route [59,9]. However, it is difficult to attain and maintain therapeutic concentrations in milk or udder tissue following systemic administration. Very few substances have optimal pharmacokinetic and pharmacodynamic characteristics for systemic mastitis treatment. With many commonly used broad-spectrum antimicrobials such as oxytetracycline, trimethoprim-sulphonamide and ceftiofur, it is difficult to produce and maintain therapeutic concentrations in the milk [12,23]. They have been tested for systemic treatment and prevention of mastitis with poor efficacy [10,23,7,26]. Macrolides would have ideal pharmacokinetics [16,45], but clinical studies have failed to demonstrate efficacy when used for the systemic treatment of clinical mastitis [42,36]. In streptococcal mastitis, spiramycin and tylosin have shown reasonable efficacy [42,30]. One additional problem for the bovine practitioner is that the recommended dosage for many antibiotic preparations for adult cattle may be too low when pharmacological aspects are considered, but residue studies have been carried out using the approved dosages. Repeated intramuscular injections of large volumes of antibiotics can be irritating and cannot be recommended from the animal welfare point of view [41,23].

One substance used for systemic treatment is penicillin G, which as a weak acid penetrates poorly into the mammary gland, however, due to the very low MIC values of susceptible organisms, therapeutic concentrations can be achieved in milk [15,16,60]. Penethamate is a more liphophilic penicillin G formulation and diffuses better than penicillin G procaine into milk [60]. The efficacy of systemic treatment with penicillin G or penethamate has been shown in clinical trials [21,54,42,30]. Combinations of penicillin and aminoglycosides should not be used, as there is no scientific evidence demonstrating a better efficacy for the combination [51] and aminoglycosides are known to produce long-lasting residues [22,57].

The only type of mastitis where systemic treatment would be clearly advantageous may be mastitis caused by S. aureus [52,2]. In severe mastitis due to coliform bacteria, parenteral administration of antimicrobials has been suggested to combat bacteraemia [56]. The general benefit of antimicrobial treatment in coliform mastitis has been questioned [22,40], but systemic antimicrobial treatment is recommended in cases of severe Escherichia coli mastitis with heavy bacterial growth in the udder. Fluroquinolones and cefquinome have shown efficacy in experimental trials [49,6,43,39] and ceftiofur in a clinical field trial [11]. There is no evidence that administering bactericidal antimicrobials to cows with severe coliform mastitis causes the release of massive amounts of endotoxin [5]. Finally, the antimicrobial used for systemic treatment of mastitis must be approved for dairy cattle. The availability of substances on the market differs between countries. For example, penicillin G procaine or fluoroquinolones are not approved for dairy cattle in the United States.

Treatment of Clinical Mastitis in Practice

Treatment of mastitis should be targeted towards the causative bacteria whenever possible, but in acute situations, treatment is initiated based on herd data and personal experience. Rapid or on-farm bacteriological diagnosis would facilitate the selection of the most appropriate antimicrobial. Treatment protocols and drug selection for each farm should be made by veterinarians familiar with the farm [46,55]. The use of on-farm written protocols for mastitis treatment can promote judicious use of antimicrobials [44,37]. Therapeutic response of the cows can be monitored using individual somatic cell count data if available, or using the California Mastitis Test, and with bacteriological samples in herds with contagious mastitis.

In general, the use of narrow-spectrum antimicrobials is preferable (Table 2). Prudent use guidelines have been developed which also include antimicrobial treatment of mastitis [1,37]. First choice antimicrobials for treating mastitis caused by streptococci and penicillin-susceptible staphylococci are β-lactam antimicrobials, particularly penicillin G. Broad-spectrum antimicrobials such as third or fourth generation cephalosporins should not be used as first alternatives for mastitis, as they may increase emergence of broad-spectrum β-lactam resistance. Systemic treatment is recommended in clinical mastitis due to S. aureus and in severe cases of coliform mastitis, preferably in combination with IMM treatment [2]. Too short a duration of standard treatment is probably an important reason for poor cure rates in mastitis therapy. A longer treatment improves cure rates, and duration of treatment should generally be extended in mastitis caused by S. aureus and Streptococcus uberis [42,34,4]. Clinical mastitis should be treated for at least three days; this recommended treatment duration is longer than label treatments in many countries. All mastitis treatment should be evidence based i.e., the efficacy of each product and treatment length should be demonstrated by scientific studies [3].

Table 2. Suggestions for antimicrobial treatment of clinical mastitis due to different pathogens. The availability of substance on the market mentioned in the table may differ between countries

Subclinical Mastitis

Treating subclinical mastitis with antimicrobials is generally not economical during lactation because of high treatment costs and poor efficacy. In a study with a large number of subclinical mastitis cases [58], the overall bacteriological cure rate for antimicrobial treatment was 75% and that for no treatment 68%. The marginal benefit applied for streptococcal mastitis only; in mastitis due to S. aureus, antimicrobials were equal to no treatment. Treatment of subclinical mastitis will not affect the incidence of mastitis in the herd unless other preventive measures are taken. Studies on treating cows based on high somatic cell counts have generally shown that no effect on milk production has been achieved [29,48,18] In herd problems caused by very contagious bacteria such as S. aureus or Streptococcus agalactiae treatment of subclinical mastitis is advised [55].


  1. Anonymous: Use of antimicrobial agents in animals. Report of the working group on antimicrobial agents. Ministry of Agriculture and Forestry in Finland. MAFF Publications 9. [Online] Helsinki, MAFF. [] webcite


    [Accessed February 20 2006]

  2. Barkema H, Schukken YH, Zadoks RN: Invited review: the role of cow, pathogen, and treatment regimen in the therapeutic success of bovine Staphylococcus aureus mastitis.

    J Dairy Sci 2006, 89:1877-1895. PubMed Abstract | Publisher Full Text OpenURL

  3. Cockcroft P, Holmes M: Evidence-based veterinary medicine. 1st edition. Oxford UK, Blackwell Publishing; 2003. OpenURL

  4. Deluyker HA, Van Oye SN, Boucher JF: Factors affecting cure and somatic cell count after pirlimycin treatment of subclinical mastitis in lactating cows.

    J Dairy Sci 2005, 88:604-614. PubMed Abstract | Publisher Full Text OpenURL

  5. Dosogne H, Meyer E, Sturk A, et al.: Effect of enrofloxacin treatment on plasma endotoxin during bovine Escherichia coli mastitis.

    Inflamm Res 2002, 51:201-205. PubMed Abstract | Publisher Full Text OpenURL

  6. Duenas MI, Paape MJ, Wettemann RP, et al.: Incidence of mastitis in beef cows after intramuscular administration of oxytetracycline.

    J Anim Sci 2001, 79:1996-2005. PubMed Abstract | Publisher Full Text OpenURL

  7. Ehinger AM, Kietzmann M: Tissue distribution of oxacillin and ampicillin in the isolated perfused bovine udder.

    J Vet Med A 2000, 47:157-168. Publisher Full Text OpenURL

  8. Ehinger AM, Kietzmann M: Tissue distribution of benzylpenicillin after intramammary administration in the isolated perfused bovine udder.

    J vet Pharm Therap 2000, 23:303-310. Publisher Full Text OpenURL

  9. Erskine RJ: Antibacterial therapy of clinical mastitis - part I. Drug selection. Part II Administration.

    North Am Vet Conf, Proc 2003, 13-16. OpenURL

  10. Erskine RJ, Barlett PC: Intramuscular administration of ceftiofur sodium versus intramammary infusion of penicillin/novobiocin for treatment of Streptococcus agalactiae mastitis in dairy cows.

    J Am Vet Med Assoc 1996, 208:258-260. PubMed Abstract OpenURL

  11. Erskine RJ, Barlett PC, VanLente JL, et al.: Efficacy of systemic ceftiofur for severe clinical mastitis in dairy cattle.

    J Dairy Sci 2002, 85:2571-2575. PubMed Abstract | Publisher Full Text OpenURL

  12. Erskine RJ, Wilson RC, Tyler JW, et al.: Ceftiofur distribution in serum and milk from clinically normal cows and cows with experimental Escherichia coli - induced mastitis.

    Am J Vet Res 1995, 56:481-486. PubMed Abstract OpenURL

  13. Fang W, Pyörälä S: Mastitis causing Escherichia coli: serum sensitivity and susceptibility to selected antibacterials in milk.

    J Dairy Sci 1996, 79:76-82. PubMed Abstract | Publisher Full Text OpenURL

  14. Finnish veterinary antimicrobial resistance monitoring and comsumption of antimicrobial agents. Finnish Food Safety Authority Evira [Internet] Helsinki, Multiprint [] webcite


    [Accessed January 31 2009]

  15. Franklin A, Holmberg O, Horn af Rantzien M, et al.: Effect of procaine benzylpenicillin alone or in combination with dihydrostreptomycin on udder pathogens in vitro and in experimentally infected bovine udders.

    Am J Vet Res 1984, 45:1398-1402. OpenURL

  16. Franklin A, Horn af Rantzien M, Obel N, et al.: Concentrations of penicillin, streptomycin, and spiramycin in bovine udder tissue liquids.

    Am J Vet Res 1986, 47:804-807. PubMed Abstract OpenURL

  17. Grave T, Greko C, et al.: The usage of veterinary antibacterial drugs for mastitis in cattle in Norway and Sweden during 1990-1997.

    Prev Vet Med 1999, 42:45-55. PubMed Abstract | Publisher Full Text OpenURL

  18. Hallén Sandgren C, Persson Waller K, Emanuelson U: Therapeutic effects of systemic or intramammary antimicrobial treatment of bovine subclinical mastitis during lactation.

    Vet J 2008, 175:108-117. PubMed Abstract | Publisher Full Text OpenURL

  19. Haveri M, Roslöf A, Rantala L, et al.: Virulence genes in bovine Staphylococcus aureus mastitis of different clinical characteristics and outcome.

    J Appl Microb 2005, 103:993-1000. Publisher Full Text OpenURL

  20. Hendriksen RS, Mevius DJ, Schroeter A, et al.: Prevalence of antimicrobial resistance among bacterial pathogens isolated from cattle in different European countries: 2002-2004. [] webcite

    Acta Vet Scand 2008, 50:28. PubMed Abstract | BioMed Central Full Text | PubMed Central Full Text OpenURL

  21. Jarp J, Bugge HP, Larsen S: Clinical trial of three therapeutic regimens for bovine mastitis.

    Vet Rec 1989, 124:630-634. PubMed Abstract | Publisher Full Text OpenURL

  22. Jones GF, Ward GE: Evaluation of systemic administration of gentamicin for treatment of coliform mastitis in cows.

    J Am Vet Med Assoc 1990, 197:731-735. PubMed Abstract OpenURL

  23. Kaartinen L, Löhönen K, Wiese B, et al.: Pharmacokinetics of sulphadiazine-trimethoprim in lactating dairy cows.

    Acta vet Scand 1999, 40:271-278. PubMed Abstract OpenURL

  24. Kehrli M, Harp J: Immunity in the mammary gland.

    Vet Clinics North Am - Food Animal Practice 2001, 17:495-516. OpenURL

  25. Lehtolainen T, Shpigel N, Pohjanvirta T, et al.: In vitro antimicrobial susceptibility of Escherichia coli isolates originating from clinical mastitis in Finland and Israel.

    J Dairy Sci 2003, 86:3927-3932. PubMed Abstract | Publisher Full Text OpenURL

  26. Lents CA, Wettemann RP, Paape MJ, et al.: Efficacy of intramuscular treatment of beef cows with oxytetracycline to reduce mastitis and to increase calf growth.

    J Anim Sci 2002, 80:1405-1412. PubMed Abstract | Publisher Full Text OpenURL

  27. Loch IM, Glenn K, Zadoks RN: Macrolide and lincosamide resistance genes of environmental streptococci from bovine milk.

    Vet Microb 2005, 111:133-138. Publisher Full Text OpenURL

  28. Louhi M, Inkinen K, Myllys V, et al.: Relevance of sensitivity testings (MIC) of S. aureus to predict the antibacterial action in milk.

    J Vet Med B 1992, 39:253-262. Publisher Full Text OpenURL

  29. McDermott MP, Erb HN, Natzke RP, et al.: Cost benefit analysis of lactation therapy with somatic cell counts as indications for treatment.

    J Dairy Sci 1983, 66:1198-1203. PubMed Abstract | Publisher Full Text OpenURL

  30. McDougall S, Agnew KE, Cursons R, et al.: Parenteral treatment of clinical mastitis with tylosin base or penethamate hydriodide in dairy cattle.

    J Dairy Sci 2007, 90:779-789. PubMed Abstract | Publisher Full Text OpenURL

  31. Mitchell JM, Griffiths MW, McEwen SA, et al.: Antimicrobial drug residues in milk and meat: causes, concerns, prevalence, regulations, tests and test performance.

    J Food Protect 1998, 61:742-756. OpenURL

  32. Moretain JP, Boisseau J: Excretion of penicillins and cephalexin in bovine milk following intramammary administration.

    Food Add Contamin 1989, 6:79-90. OpenURL

  33. OIE: Guidelines on the responsible and prudent use of antimicrobial agents in veterinary medicine. [] webcite


    [Accessed September 25 2008]

  34. Oliver SP, Almeida RA, Gillespie BE, et al.: Extended ceftiofur therapy for treatment of experimentally-induced Streptococcus uberis mastitis in lactating dairy cattle.

    J Dairy Sci 2004, 87:3322-3329. PubMed Abstract | Publisher Full Text OpenURL

  35. Olsen JE, Christensen H, Aarestrup FM: Diversity and evolution of blaZ from Staphylococcus aureus and coagulase-negative staphylococci.

    J Antimicrob Chemother 2006, 57:450-460. PubMed Abstract | Publisher Full Text OpenURL

  36. Owens WE, Nickerson SC, Ray CH: Efficacy of parenterally or intramammarily administered tilmicosin or ceftiofur against Staphylococcus aureus mastitis during lactation.

    J Dairy Sci 1999, 82:645-647. PubMed Abstract | Publisher Full Text OpenURL

  37. Passantino A: Ethical aspects for veterinarians regarding antimicrobial drug use in Italy.

    Int J Antimicrob Agents 2007, 29:240-244. PubMed Abstract | Publisher Full Text OpenURL

  38. Pitkälä A, Haveri M, Pyörälä S, et al.: Bovine mastitis in Finland 2001 -- prevalence, distribution of bacteria and antimicrobial resistance.

    J Dairy Sci 2004, 87:2433-2441. PubMed Abstract | Publisher Full Text OpenURL

  39. Poutrel B, Stegemann MR, Roy O, et al.: Evaluation of the efficacy of systemic danofloxacin in the treatment of induced acute Escherichia coli bovine mastitis.

    Journal of Dairy Research 2008, 75:310-318. PubMed Abstract | Publisher Full Text OpenURL

  40. Pyörälä S, Kaartinen L, Käck H, et al.: Efficacy of Two Therapy Regimes for Treatment of Experimentally Induced Escherichia coli Mastitis in the Bovine.

    J Dairy Sci 1994, 77:453-461. PubMed Abstract | Publisher Full Text OpenURL

  41. Pyörälä S, Manner E, Kesti E, et al.: Local tissue damage in cows after intramuscular injections of eight different antimicrobial agents. Brief communication.

    Acta vet Scand 1994, 35:107-110. PubMed Abstract OpenURL

  42. Pyörälä S, Pyörälä E: Efficacy of parenteral administration of three antimicrobial agents in treatment of clinical mastitis in lactating cows: 487 cases: (1989-1995).

    J Am Vet Med Assoc 1998, 212:407-412. PubMed Abstract OpenURL

  43. Rantala M, Kaartinen L, Välimäki E, et al.: Efficacy and pharmacokinetics of enrofloxacin and flunixin meglumine for treatment of cows with experimentally induced Escherichia coli mastitis.

    J vet Pharmacol Therap 2002, 25:251-258. Publisher Full Text OpenURL

  44. Raymond MJ, Wohlre RD, Call DR: Assessment and Promotion of Judicious Antibiotic Use on Dairy Farms in Washington State.

    J Dairy Sci 2006, 89:3228-3240. PubMed Abstract | Publisher Full Text OpenURL

  45. Sanders P, Moulin G, Guillot P, et al.: Pharmacokinetics of spiramycin after intravenous, intramuscular and subcutaneous administration in lactating cows.

    J vet Pharmacol Therap 1992, 15:53-61. Publisher Full Text OpenURL

  46. Sawant AA, Sordillo LM, Jayarao BM: A survey on antibiotic usage in dairy herds in Pennsylvania.

    J Dairy Sci 2005, 88:2991-2999. PubMed Abstract | Publisher Full Text OpenURL

  47. Sawant AA, Gillespie BE, Oliver SP: Antimicrobial susceptibility of coagulase-negative Staphylococcus species isolated from bovine milk.

    Vet Microb 2009, 134:73-81. Publisher Full Text OpenURL

  48. Shephard RW, Malmo J, Pfeiffer DU: A clinical trial to evaluate the effectiveness of antibiotic treatment of lactating cows with high somatic cell counts in their milk.

    Austr Vet J 2000, 78:763-768. Publisher Full Text OpenURL

  49. Shpigel NY, Levin D, Winkler M, et al.: Efficacy of cefquinome for treatment of cows with mastitis experimentally induced using Escherichia coli.

    J Dairy Sci 1997, 80:318-323. PubMed Abstract | Publisher Full Text OpenURL

  50. Sol J, Sampimon OC, Barkema HW, et al.: Factors associated with cure after therapy of clinical mastitis caused by Staphylococcus aureus.

    J Dairy Sci 2000, 83:278-284. PubMed Abstract | Publisher Full Text OpenURL

  51. Taponen S, Dredge K, Henriksson B, et al.: Efficacy of intramammary treatment with procaine penicillin G vs. procaine penicillin plus neomycin in bovine clinical mastitis caused by penicillin-susceptible, gram-positive bacteria - a double blind field study.

    J vet Pharm Therap 2002, 26:193-198. Publisher Full Text OpenURL

  52. Taponen S, Jantunen A, Pyörälä E, et al.: Efficacy of targeted five day parenteral and intramammary treatment of clinical Staphylococcus aureus mastitis caused by penicillin-susceptible or penicillin-resistant bacterial isolate.

    Acta vet Scand 2003, 44:53-62. PubMed Abstract | BioMed Central Full Text | PubMed Central Full Text OpenURL

  53. Ullberg S, Hansson E, Funke H: Distribution of penicillin in mastitic udders following intramammary injection - an autoradiographic study.

    Am J Vet Res 1958, 19:84-92. PubMed Abstract OpenURL

  54. Waage S: Comparison of two regimens for the treatment of clinical bovine mastitis caused by bacteria sensitive to penicillin.

    Vet Rec 1997, 141:616-620. PubMed Abstract OpenURL

  55. Wagner S, Erskine R: Antimicrobial drug use in bovine mastitis. In Antimicrobial Therapy in Veterinary Medicine. 4th edition. Edited by Giguère S, Prescott JD, Baggot RD, et al. Oxford, Blackwell; 2006. OpenURL

  56. Wenz JR, Barrington GM, Garry FB, et al.: Bacteraemia associated with naturally occurring acute coliform mastitis in dairy cows.

    J Am Vet Med Assoc 2001, 219:976-981. PubMed Abstract | Publisher Full Text OpenURL

  57. Whittem T, Hanlon D: Dihydrostreptomycin or streptomycin in combination with penicillin in dairy cattle therapeutics: a review and re-analysis of published data, Part 1: Clinical pharmacology.

    New Zealand Vet J 1997, 45:178-184. Publisher Full Text OpenURL

  58. Wilson DJ, Gonzalez RN, Case KL, et al.: Comparison of seven antibiotic treatments with no treatment for bacteriological efficacy against bovine mastitis pathogens.

    J Dairy Sci 1999, 82:1664-1670. PubMed Abstract | Publisher Full Text OpenURL

  59. Ziv G: Drug selection and use in mastitis: systemic vs. local therapy.

    J Am Vet Med Assoc 1980, 176:1109-1115. PubMed Abstract OpenURL

  60. Ziv G, Storper M: Intramuscular treatment of subclinical staphylococcal mastitis in lactating cows with penicillin G, methicillin and their esters.

    J vet Pharmacol Therap 1985, 8:276-283. Publisher Full Text OpenURL