DRY COW THERAPY: A COMPARATIVE FIELD TRIAL USING BENZATHINE CLOXACILLIN AND ERYTHROMYCIN By
t Veterinary
F. G.
CLEGG*,
G.
J.
HALLIDAyt AND H. HARDIE~
* Veterinary Investigation Centre, M.A.F.F., Sutton Bonington. Investigation Centre, North qf Scotland College qf Agriculture, Bucksburn, Aberdeen. tAbbott Laboratories Limited, Q.ueenborough, Kent. SUMMARY
Benzathine cloxacillin or erthromycin were used in one dairy herd for dry cow therapy and the bacteriological efficacy of these two antibiotics was compared. INTRODUCTION
Infusion of the udder of the cow with antibiotic during the dry period is considered to be an essential part of the modern control of mastitis. The indications for dry cow therapy in the control of bovine mastitis are the elimination of infections which have occurred in the previous lactations and which may have been inapparent or have persisted despite treatment, and the reduction in the number of new infections occurring during the dry period. There is no wastage of milk because of antibiotic contamination and more cows commence their period of maximum lactation free from udder infections (Kingwill et al. 1970). The value of benzathine cloxacillin in this treatment has been described and the optimum dose level established (Kingwill et al., 1967). The present trial compares the results obtained with a preparation of erythromycin and those obtained with benzathine cloxacillin. The effects of dry cow therapy in changing the incidence and character of the udder infection in a commercial herd are of interest. METHODS
A complete herd test was carried out before the commencement of the trial in August and quarter samples were examined by routine bacteriological methods. Quarter samples were also collected from individual cows 1 week before drying off, at the time of drying off, 1 week after calving, and finally 2 weeks after calving. Teat dipping was practised in the herd using an iodophor solution (5000 p.p.m. available 12 ),
BRITISH VETERINARY JOURNAL, 131, 6
The preparations were used alternately as the cows were dried off. After the last milking the teat orifices were cleaned with cotton wool soaked in 70 per cent ethanol and the quarters infused with either benzathine cloxacillin (500 mg) in slow release base* or erythromycin (600 mg) as an oily solution.t Milk samples were incubated overnight and o· I ml of milk was plated on 5 per cent sheep blood agar and Edwards' medium (5 per cent sheep blood). The plates were incubated for approximately 48 h at 37°C and organisms identified by their colonial appearance or after further biochemical and serological examinations as required. Sensitivity tests were carried out on approximately three-quarters of the isolations of Staphylococcus aureus using the Multodisk paper disc method and sensitivity test agar plates (DST Agar Oxoid); the standard disc 30-9B being used in each case. The sensitivity plates were incubated for 18 h at 37°C. At the initial herd tests 151 cows were sampled but the complete results from only 109 dry cow treatments have been recorded. The records from the other cows were either inadequate, the cow had been sold or culled, or contamination of the sample had occurred. Of the 109 cows, 57 were infused with benzathine cloxacillin and 52 with erythromycin. A quarter was regarded as infected if either of the precalving samples showed the presence of a potentially pathogenic organism. The treatment was considered successful when previously infected quarter samples failed to yield the same infections from both post-calving samples. Failure was considered to be the recovery of the same species of organism present at drying off from either of the two post-calving samples. A new infection was considered to be the presence of infection in both post-calving samples, from a quarter which had previously proved negative. The numbers of apparently successful treatments of individual quarters is shown in Table I. Successful treatment of Staph. aureus infected quarters was obtained in 72'9 per cent and 75'4 per cent for the erythromycin and benzathine cloxacillin treatments respectively. Corynebacterium bovis quarter infections were successfully treated in 88·6 per cent and 84'4 per cent of cases respectively. The other infections found at drying off were fewer in number but there was successful treatment in 100 per cent and 86 per cent respectively of the Streptococcus uberis infected quarters in both groups. New infections were found in the case of Staph. aureus in eleven quarters only, eight of which had been treated with erythromycin and three treated with benzathine cloxacillin. The sensitivity tests carried out on 93 isolates of Staph. aureus showed that no strain was resistant to either cloxacillin or erythromycin. The success in the treatment of Staph. aureus infected quarters by the dry cow treatment with benzathine cloxacillin was similar to the results obtained by Loosmore et at. (1966) when successful treatment occurred in 62 per cent of cases on ten farms and by Smith et al. (1967) who reported a success rate of 68 per cent. The successful treatment of this infection with erythromycin compares favourably with that obtained with cloxacillin . ... Orbenin Intramammary Suspension (Dry Cow) Beecham Animal Health. Erytrotil (Dry Cow) Abbott Laboratories Ltd. ! Oxoid Limited, London.
t
DR Y COW THERAPY TABLE I THE RESULTS OF THE BACTERIOLOGICAL EXAMINATION OF INDIVIDUAL QUART E R SAMPLES, NUMBERS OF SUCCESSFUL TREATMENTS FOLLOWING DRY COW THERAPY AND THE NUMBER OF NEW INFECTIONS
Treatment Erythromycin
Staph. aureus Successful Failed
Benzathine cloxacillin
Quarters
%
Quarters
%
43 16
72'9 27'1
46 15
75"4 24.6
100
Strep. uberis Successful Failed
12 0
100
12 2
86 14
Infected
12
100
14
100
C. bovis Successful Failed
78 10
Infected
88
New infections
61
100
59 8
Infected
3
88·6 I 1'4 100
81 15 96
84'4 15.6 100
Infected: either the sample collected I week before calving, or the sample collected at the time of drying off was positive. Failed: the same infection was found in one of the post-calving samples despite treatment. N ew Infection: infection found in post-calving samples from a previously uninfected quarter. Successful: both post-calving s~mples proved negative after treatment of infected quarter.
The incidence of C. bovis infection in this herd is of interest together with the high rate of successful treatment with either antibiotic or of spontaneous recovery. The organism is considered by some workers to be a low-grade pathogen and Cobb & Walley (1962) described numerous cases of mastitis associated with C. bovis. The increase in the number of Strep. uberis infected quarters in the herd followed the earlier high incidence of C. bovis in the herd. Forbes (1970) has suggested that quarters which show an induced leucocytosis due to low-grade pathogenic organisms may be more resistant to infection with pathogens, although the increased incidence of Strep. uberis could also be associated with the time of sampling following winter housing. ACKNOWLEDGEMENTS
We wish to thank Mr H. Martin, M.R.C.V.S. of the Co-operative Wholesale Society for making arrangements for the trial and Mr D. Ashmore for his technical assistance.
BRITISH VETERINARY JOURNAL, 131, 6 REFERENCES
R. W. & WALLEY, J. K. (1 962). Vet. Rec. 7.f, 101. FORBES, D. (1970) . Br. vet. J. 126,260. KINGWILL, R. G., NEAVE, F. K., DODD, F. H . & WILSON, C. D. (1967). Vet. Rec. SI, 199. KINGWILL, R. G., NEAVE, F. K., DODD, F. H., GRIFFIN, T. K., WESTGARTH, D. R. & WILSON, C. D. (1970). Vet. Rec. 8" 94. LOOSMORE, R. M., HOWELL, D., ADAMS, A. D., BARNETT, D. N. & BARR, T. F. F. (1968). Vet. Rec. 83, 358. SMITH, A., WESTGARTH, D. R., JONES, M. R ., NEAVE, F. K., DODD, F. H . & BRANDER, G. C. (1967). Vet. Rec. 8I, 504. COBB,
(Acceptedfor publication 14 J anuary 1975) Therapeutie sur vaebe seebe: une epreuve cOlDparative appliquee c1oxaci11ine benzathine et d'erthrolDycine (Clegg et al.)
a I'aide de
ResUIDe. On utilisa de la cloxacilline benzathine et de l'erothromycine sur un troupeau laitier pour therapeutie sur vache seche et on compara l'efficacite bacteriologique de ces deux antibiotiques. Behandlung der an Milchc10sigkeit leidenden Kuh: Ein vergleichender Versuch bei freigehaltenen Tieren IDit Benzathinc10xazillin und ErythrolDYcin (Clegg et al.) ZusalDlDenfassung. Benzathincloxazillin oder Erythromycin wurden zur Behandlung der an Milchlosigkeit leidenden Kuhne bei einer H erde von Milchkiihen verwendet, und ein Vergleich wurde zwischen der bakteriologischen Wirksamkeit der beiden Antibiotika angestellt. Terapeutica de vaca seca: Una prueba de caD1PO cOD1parativa en que se emple6 benzatina cloxaci1ina y ertroIDicina (Clegg et al.) ReSUIDen. Se emplearon benzatina cloxacilina 0 ertromicina en una manada de vacas lecheras para la terapeutica de vaca seca y se comparo la eficacia bacteriologica de estos dos antibioticos.
t Veterinary
F. G.
CLEGG*,
G.
J.
HALLIDAyt AND H. HARDIE~
* Veterinary Investigation Centre, M.A.F.F., Sutton Bonington. Investigation Centre, North qf Scotland College qf Agriculture, Bucksburn, Aberdeen. tAbbott Laboratories Limited, Q.ueenborough, Kent. SUMMARY
Benzathine cloxacillin or erthromycin were used in one dairy herd for dry cow therapy and the bacteriological efficacy of these two antibiotics was compared. INTRODUCTION
Infusion of the udder of the cow with antibiotic during the dry period is considered to be an essential part of the modern control of mastitis. The indications for dry cow therapy in the control of bovine mastitis are the elimination of infections which have occurred in the previous lactations and which may have been inapparent or have persisted despite treatment, and the reduction in the number of new infections occurring during the dry period. There is no wastage of milk because of antibiotic contamination and more cows commence their period of maximum lactation free from udder infections (Kingwill et al. 1970). The value of benzathine cloxacillin in this treatment has been described and the optimum dose level established (Kingwill et al., 1967). The present trial compares the results obtained with a preparation of erythromycin and those obtained with benzathine cloxacillin. The effects of dry cow therapy in changing the incidence and character of the udder infection in a commercial herd are of interest. METHODS
A complete herd test was carried out before the commencement of the trial in August and quarter samples were examined by routine bacteriological methods. Quarter samples were also collected from individual cows 1 week before drying off, at the time of drying off, 1 week after calving, and finally 2 weeks after calving. Teat dipping was practised in the herd using an iodophor solution (5000 p.p.m. available 12 ),
BRITISH VETERINARY JOURNAL, 131, 6
The preparations were used alternately as the cows were dried off. After the last milking the teat orifices were cleaned with cotton wool soaked in 70 per cent ethanol and the quarters infused with either benzathine cloxacillin (500 mg) in slow release base* or erythromycin (600 mg) as an oily solution.t Milk samples were incubated overnight and o· I ml of milk was plated on 5 per cent sheep blood agar and Edwards' medium (5 per cent sheep blood). The plates were incubated for approximately 48 h at 37°C and organisms identified by their colonial appearance or after further biochemical and serological examinations as required. Sensitivity tests were carried out on approximately three-quarters of the isolations of Staphylococcus aureus using the Multodisk paper disc method and sensitivity test agar plates (DST Agar Oxoid); the standard disc 30-9B being used in each case. The sensitivity plates were incubated for 18 h at 37°C. At the initial herd tests 151 cows were sampled but the complete results from only 109 dry cow treatments have been recorded. The records from the other cows were either inadequate, the cow had been sold or culled, or contamination of the sample had occurred. Of the 109 cows, 57 were infused with benzathine cloxacillin and 52 with erythromycin. A quarter was regarded as infected if either of the precalving samples showed the presence of a potentially pathogenic organism. The treatment was considered successful when previously infected quarter samples failed to yield the same infections from both post-calving samples. Failure was considered to be the recovery of the same species of organism present at drying off from either of the two post-calving samples. A new infection was considered to be the presence of infection in both post-calving samples, from a quarter which had previously proved negative. The numbers of apparently successful treatments of individual quarters is shown in Table I. Successful treatment of Staph. aureus infected quarters was obtained in 72'9 per cent and 75'4 per cent for the erythromycin and benzathine cloxacillin treatments respectively. Corynebacterium bovis quarter infections were successfully treated in 88·6 per cent and 84'4 per cent of cases respectively. The other infections found at drying off were fewer in number but there was successful treatment in 100 per cent and 86 per cent respectively of the Streptococcus uberis infected quarters in both groups. New infections were found in the case of Staph. aureus in eleven quarters only, eight of which had been treated with erythromycin and three treated with benzathine cloxacillin. The sensitivity tests carried out on 93 isolates of Staph. aureus showed that no strain was resistant to either cloxacillin or erythromycin. The success in the treatment of Staph. aureus infected quarters by the dry cow treatment with benzathine cloxacillin was similar to the results obtained by Loosmore et at. (1966) when successful treatment occurred in 62 per cent of cases on ten farms and by Smith et al. (1967) who reported a success rate of 68 per cent. The successful treatment of this infection with erythromycin compares favourably with that obtained with cloxacillin . ... Orbenin Intramammary Suspension (Dry Cow) Beecham Animal Health. Erytrotil (Dry Cow) Abbott Laboratories Ltd. ! Oxoid Limited, London.
t
DR Y COW THERAPY TABLE I THE RESULTS OF THE BACTERIOLOGICAL EXAMINATION OF INDIVIDUAL QUART E R SAMPLES, NUMBERS OF SUCCESSFUL TREATMENTS FOLLOWING DRY COW THERAPY AND THE NUMBER OF NEW INFECTIONS
Treatment Erythromycin
Staph. aureus Successful Failed
Benzathine cloxacillin
Quarters
%
Quarters
%
43 16
72'9 27'1
46 15
75"4 24.6
100
Strep. uberis Successful Failed
12 0
100
12 2
86 14
Infected
12
100
14
100
C. bovis Successful Failed
78 10
Infected
88
New infections
61
100
59 8
Infected
3
88·6 I 1'4 100
81 15 96
84'4 15.6 100
Infected: either the sample collected I week before calving, or the sample collected at the time of drying off was positive. Failed: the same infection was found in one of the post-calving samples despite treatment. N ew Infection: infection found in post-calving samples from a previously uninfected quarter. Successful: both post-calving s~mples proved negative after treatment of infected quarter.
The incidence of C. bovis infection in this herd is of interest together with the high rate of successful treatment with either antibiotic or of spontaneous recovery. The organism is considered by some workers to be a low-grade pathogen and Cobb & Walley (1962) described numerous cases of mastitis associated with C. bovis. The increase in the number of Strep. uberis infected quarters in the herd followed the earlier high incidence of C. bovis in the herd. Forbes (1970) has suggested that quarters which show an induced leucocytosis due to low-grade pathogenic organisms may be more resistant to infection with pathogens, although the increased incidence of Strep. uberis could also be associated with the time of sampling following winter housing. ACKNOWLEDGEMENTS
We wish to thank Mr H. Martin, M.R.C.V.S. of the Co-operative Wholesale Society for making arrangements for the trial and Mr D. Ashmore for his technical assistance.
BRITISH VETERINARY JOURNAL, 131, 6 REFERENCES
R. W. & WALLEY, J. K. (1 962). Vet. Rec. 7.f, 101. FORBES, D. (1970) . Br. vet. J. 126,260. KINGWILL, R. G., NEAVE, F. K., DODD, F. H . & WILSON, C. D. (1967). Vet. Rec. SI, 199. KINGWILL, R. G., NEAVE, F. K., DODD, F. H., GRIFFIN, T. K., WESTGARTH, D. R. & WILSON, C. D. (1970). Vet. Rec. 8" 94. LOOSMORE, R. M., HOWELL, D., ADAMS, A. D., BARNETT, D. N. & BARR, T. F. F. (1968). Vet. Rec. 83, 358. SMITH, A., WESTGARTH, D. R., JONES, M. R ., NEAVE, F. K., DODD, F. H . & BRANDER, G. C. (1967). Vet. Rec. 8I, 504. COBB,
(Acceptedfor publication 14 J anuary 1975) Therapeutie sur vaebe seebe: une epreuve cOlDparative appliquee c1oxaci11ine benzathine et d'erthrolDycine (Clegg et al.)
a I'aide de
ResUIDe. On utilisa de la cloxacilline benzathine et de l'erothromycine sur un troupeau laitier pour therapeutie sur vache seche et on compara l'efficacite bacteriologique de ces deux antibiotiques. Behandlung der an Milchc10sigkeit leidenden Kuh: Ein vergleichender Versuch bei freigehaltenen Tieren IDit Benzathinc10xazillin und ErythrolDYcin (Clegg et al.) ZusalDlDenfassung. Benzathincloxazillin oder Erythromycin wurden zur Behandlung der an Milchlosigkeit leidenden Kuhne bei einer H erde von Milchkiihen verwendet, und ein Vergleich wurde zwischen der bakteriologischen Wirksamkeit der beiden Antibiotika angestellt. Terapeutica de vaca seca: Una prueba de caD1PO cOD1parativa en que se emple6 benzatina cloxaci1ina y ertroIDicina (Clegg et al.) ReSUIDen. Se emplearon benzatina cloxacilina 0 ertromicina en una manada de vacas lecheras para la terapeutica de vaca seca y se comparo la eficacia bacteriologica de estos dos antibioticos.
