The intramuscular administration of penethamate hydriodide over 3 consecutive days and the intramammary administration of an ampicillin/cloxacillin combination were compared in lactating cows suffering from infectious clinical mastitis in one quarter, through an open, randomized, controlled multicenter field trial. Clinical examinations were carried out on d 1 (immediately before treatment), 3, 8, 17, and 22. Milk samples were taken from affected quarters for bacteriological analysis on d 1, 17, and 22, and from all quarters for somatic cell count (SCC) determination on d 1, 8, 17, and 22. There was no significant difference in bacteriological and clinical cure rates between the 2 treatment groups. The systemic treatment with penethamate resulted more frequently in a reduction of the milk SCC below the threshold of 250,000 cells/mL. This also occurred in the adjacent quarters not affected by clinical mastitis but with an SCC above 250,000 cells/mL before treatment. These findings suggest that the parenteral treatment with penethamate provides collateral cure on the quarters of the cows affected by subclinical mastitis. The number of quarters per cow affected by clinical or subclinical mastitis should be considered when selecting an antibiotic treatment by the local or systemic route.

SummaryThis GCP(v) multi centre blinded positive controlled study investigated under field conditions the clinical efficacy, safety and palatability of meloxicam in horses suffering from musculoskeletal disorders. The efficacy of meloxicam (Metacam ® ) at the recommended dose of 0.6 mg/kg body weight administered once daily was investigated (n=100) in comparison to vedaprofen (Quadrisol ® , n=97). Lameness at a trot, walk and rest was recorded before initiation of therapy on Day 1, after a 5, 10 or 14 day treatment period and during the follow-up examination, performed 2 to 4 days after the respective last treatment. The duration of treatment (5, 10 or 14 days) was decided by the veterinarian depending on the clinical condition. Furthermore palatability and relapse rates were recorded. Significantly better results (p≤0.01) for "lameness at a trot" (primary clinical variable) after 14 days of treatment, and at the follow-up examination (p≤0.001), were found in the meloxicam group compared to the reference group. Significant differences (p≤0.05) in "lameness at walk" occurred in favour of meloxicam at the follow-up examination on Day 14. A significant superiority in lameness at a trot (p≤0.001) and walk (p≤0.01) was revealed in favour of meloxicam for the evaluation at the time point when therapy was judged no longer necessary. Fewer meloxicam cases showed relapse to lameness (p≤0.05). Furthermore, meloxicam was superior (p≤0.001) with regard to overall efficacy and palatability. No adverse events occurred in the meloxicam group compared to two cases in the reference group. The results indicate that 0.6 mg meloxicam/kg bodyweight administered orally once daily is an efficacious, safe, easy to use, and highly palatable NSAID treatment for reduction of inflammation and relief of pain associated with lameness in both acute and chronic musculoskeletal disorders and soft tissue lesions. Keywords

The long-term effects of a single dose of meloxicam (Metacam 20 mg/ml; Boehringer Ingelheim Vetmedica) in conjunction with antibiotic therapy in cattle with clinical signs of bovine respiratory disease (BRD) was evaluated in a blind, controlled, randomised study. Two hundred animals with clinical signs of brd received a single subcutaneous injection of 20 mg/kg oxytetracycline; 100 of them also received a subcutaneous injection of 0.5 mg/kg meloxicam, and the other 100 received an injection of isotonic saline. The animals were weighed before they were treated and seven, 35, 70 and 105 days later, and finally before they were slaughtered. The mean bodyweight of the meloxicam-treated animals was significantly higher from day 70 until slaughter, and the mean average daily weight gain until slaughter and the mean carcase weight of the animals treated with meloxicam were significantly higher. In the animals with lung lesions, significantly less lung tissue was affected in those that had been treated with meloxicam.

The clinical and anti-inflammatory effects of a single treatment of 0.4 mg meloxicam/kg bodyweight on pigs that had been challenged with Escherichia coli endotoxin were investigated. Significantly lower total clinical scores were recorded in pigs treated with meloxicam than in pigs treated with a placebo. Significantly higher mean serum concentrations of thromboxane B(2) were also recorded in pigs treated with a placebo for up to 24 hours after the challenge. The serum concentrations of acute phase proteins and specific antibody titres to E coli lipopolysaccharide were unaffected by the meloxicam. The meloxicam treatment was well tolerated.

Penethamate hydriodide was highly effective in killing Streptococcus uberis, Streptococcus dysgalactiae subsp. dysgalactiae and Staphylococcus aureus that internalized mammary epithelial cells. At higher concentrations (32 microg/mL to 32 mg/mL), killing rates ranged from 85% to 100%. At lower concentrations (0.032 microg/mL to 3.2 microg/mL), killing rates ranged from 0 to 80%. Results of this proof-of-concept study demonstrated that: (1) penethamate hydriodide is capable of entering mammary epithelial cells and killing intracellular mastitis pathogens without affecting mammary epithelial cell viability, (2) the in vitro model used is capable of quantifying the fate of mastitis pathogens internalized into mammary epithelial cells, and (3) this in vitro model can be used to determine the effectiveness of antibiotics at killing bacteria within the cytoplasm of mammary epithelial cells.