Antibiotic persistence and tolerance in the lactating sheep following a course of intramammary therapy.

The commercial use of sheep for the production of milk and milk products is attractive to farmers actively diversifying their dairy interests due to the impact of the quota system. As intensification of milking increases, flock sizes will enlarge and the incidence of ovine mastitis will inevitably increase. The pharmaceutical industry and the veterinary practitioner will be required to provide advice and data upon the performance of currently available bovine intramammary preparations for the sheep. This study produces evidence to confirm that one available bovine intramammary preparation, when infused into milking sheep, produced a withholding time approximately three times as long as that defined for the cow. Following a course of three infusions over a period of 24 hours after consecutive milkings, milk was not acceptable for human consumption or for the production of cheese and yoghurts until 136 hours following the final infusion. This situation is likely to be representative of that which will occur with other intramammary products used in the ovine species following infusion with bovine intramammary preparations.

Antibiotic persistence and tolerance in the lactating goat following intramammary therapy.

Due to the impact of the dairy quota system, the commercial use of goats for the production of milk and associated products is attractive to farmers diversifying their dairy interest. Intensification of milking and the expansion of herds will inevitably increase the incidence of caprine mastitis. The pharmaceutical industry and the veterinary surgeon will be required to provide data and advice upon the performance of currently available bovine intramammary products when used in the goat. This study produced evidence that one available bovine intramammary product, when infused into the glands of milking goats, produced a withholding time approximately double that defined for the cow. Following a course of infusions after three successive milkings, milk was not available for human consumption or for the production of cheese and yoghurt until 112 hours after the final infusion. This situation is likely to be representative of that which will occur for other currently available bovine intramammaries when prescribed in the goat.

Clavulanate-potentiated amoxycillin: activity in vitro and bioavailability in the dog.

Clavulanic acid is an inhibitor of beta-lactamase (penicillinase) and when used with amoxycillin the resulting combination becomes active against most bacteria resistant to amoxycillin through production of beta-lactamase. A total of 551 bacterial isolates from dogs and cats were examined by disc sensitivity testing, which showed that there was amoxycillin resistance particularly among staphylococci (50 per cent), Klebsiella species (97 per cent) and Escherichia coli (28 per cent). A combination of potassium clavulanate and amoxycillin reduced the incidence of resistance to 0.3, 3 and 7 per cent, respectively. Minimum inhibitory concentrations were determined for a number of the isolates and showed marked reductions in the presence of potassium clavulanate. A formulation containing amoxycillin trihydrate and potassium clavulanate (4:1) was dosed to beagles at 12.5 mg/kg. Concentrations of the drugs in blood, tissue fluid and skin showed that both drugs were sufficiently well absorbed and distributed to allow a prediction of efficacy against infections caused by beta-lactamase producing bacteria.