Scandinavia keeps penicillin potent
POOR treatment of mastitis may have led to the higher level of antibiotic resistance in the UK compared with Scandinavian countries.
Per Jonsson, of the College of Vet Medicine, Uppsala, Sweden, told the conference that in his home country, and much of Scandinavia, only 10-15% of Staph aureus bacteria were resistant to penicillin compared with 60% in the UK. He believed the lower resistance in Scandinavia resulted from its more effective antibiotic policy for mastitis control.
Clinical mastitis was treated with antibiotic injections, intramuscularly or intravenously, for three to five days in preference to intramammary tubes. Injections resulted in a higher concentration of antibiotics in the udder, compared with antibiotic tubes, he said. Injections had shown a 63% clinical and sub-clinical cure rate, much higher than that for tubes.
Because Scandinavian producers were not allowed to keep antibiotics on the farm, vets visited the farm to treat each case, allowing a more accurate diagnosis and treatment, said Dr Jonsson.
"The vet can check the case history, cell count and stage of lactation and diagnose what is causing the cows mastitis, after a clinical examination. A milk sample is taken by the vet after carefully washing the teat to avoid contamination."
Swedish vets could then use an on-farm diagnostic test for mastitis and/or a lab test at the vet practice.
The on-farm test proved in about 15min whether the bacteria was one that would respond to penicillin, such as Strep and Staph, or one which needed alternative treatment with broad spectrum antibiotics. The lab test was more accurate but took 24 hours to complete.
Treatment targeted at the bacteria present allowed use of narrow spectrum antibiotics at the correct dose and for the required time, said Dr Jonsson.
"Narrow spectrum antibiotics are more effective, give less risk of resistance and less disturbance of the cows normal gut flora."
As for infections caused by E coli bacteria, use of antibiotics was questionable, he added. In cases that were not severe they should be treated by frequent milking, oxytocin, intravenous fluid therapy and anti-inflammatory drugs.
Dr Jonsson suggested that Sweden had lower levels of clinical mastitis because cases there were more effectively treated. The average was 24 clinical cases per 100 cows compared with the estimate of 35 cases per 100 cows for the UK. However, treatment was expensive, he admitted.
• Use milk samples to find out what is causing mastitis.
• Injections may be more effective than tubes.
• Give full course of treatment.