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.

Objective-To compare the safety and efficacy of 2 analgesic protocols (preoperative meloxicam or intraoperative ketoprofen administration) during the first 24 hours after orthopedic surgery in dogs. Study Design-Double-blind, prospective randomized clinical trial. Animals-Sixty client-owned dogs. Methods-Dogs with surgical orthopedic disorders were randomly separated into 2 groups: 30 dogs were administered 0.2 mg/kg meloxicam intravenously (IV) immediately before induction and 30 dogs were administered 2 mg/kg ketoprofen IV, 30 minutes before the end of surgery. Pain was assessed with a visual analog scale (VAS) and a cumulative pain score (CPS) preoperatively and at 30 minutes, 1, 2, 3, 4, 6, 8, and 24 hours after extubation. Selected serum biochemical variables were measured before and 24 hours after surgery and, buccal mucosal bleeding time (BMBT) and whole blood clotting time (WBCT) were measured before and 8 hours after surgery. Dogs were anesthetized with propofol and maintained on halothane in oxygen. Any complications were documented for 7 days after surgery. Results were compared between the 2 groups for significant differences in VAS scores (2-sample t-test) and in CPS (Wilcoxon's 2-sample test). Moreover, results were analyzed for significant differences in area under the curve (AUC) for VAS (2-sample t-test) and CPS (Wilcoxon's 2-sample test) among groups. To assess the effects of treatments on biochemical and coagulation functions, pre-and postoperative mean values of BMBT and WBCT were compared within both treatment groups (paired t-tests) and between both groups (2-sample t-test). Results-No significant differences in pain response or coagulation were found between meloxicamand ketoprofen-treated dogs. In both groups, alkaline phosphatase and alanine aminotransferase concentrations were significantly increased compared with baseline. No serious complications occurred. Conclusions-Preoperative administration of meloxicam is a safe and effective method of controlling postoperative pain for up to 24 hours in dogs undergoing orthopedic surgery. Clinical Relevance-Analgesia after administration of preoperative meloxicam was comparable with administration of ketoprofen at the end of the surgery. r

The dry period is acknowledged as playing a key role in mastitis epidemiology and yet surprisingly few studies have explored dry period infection dynamics in detail. The aim of this study was to investigate the dynamics of intramammary infection across a cohort of dairy herds in Europe. Five hundred and twenty-two cows were recruited from 12 farms in 6 European countries. All cows received antibiotic dry cow therapy but teat sealants were not used. All quarters of all cows were sampled for bacteriology at drying off and in the week immediately postcalving. Two ipsilateral quarters were also sampled for bacteriology in each cow 2 and 6wk after drying off. Cows were body condition scored and teats assessed for cleanliness at all sampling time points and for the presence of a keratin plug during the dry period. Other cow-level parameters such as historic somatic cell counts and milk yields before drying off were collated from farm records. Univariable and multivariable analyses were undertaken to investigate the etiology, prevalence, and dynamics of infection during the dry period and associated influential factors. In summary, environmental mastitis pathogens predominated. Although gram-positive major pathogens were typically well controlled and did not increase in prevalence across the dry period, gram-negative pathogens generally increased in prevalence. There was an increase in the number of quarters that yielded no growth across the dry period, although this was driven by minor rather than major mastitis pathogen control. Other than the presence of a gram-positive or gram-negative pathogen 6wk after drying off, the measured parameters were not influential when considering their effect on the presence of pathogens postcalving. Analysis also suggested that the early and mid dry period may be more important with respect to the timing of acquisition of infection than previously thought. We observed substantial variation in the etiology and prevalence of different pathogens on different farms with, in all cases, at least one of the 12 herds experiencing the opposite of the others with respect to increases and decreases in pathogen prevalence. Overall, this study confirms the importance of the dry period in mastitis epidemiology but highlights the importance of assessing and understanding infection dynamics on individual units. The lack of influence of the cow and quarter factors measured in this study suggests that herd and management factors may be more influential.

Cows suffering from bovine mastitis have markedly reduced milk production because of inflammation within the udder subsequent to infection and damage from bacterial toxins. Antibiotic treatment is commonly used as a preventative and therapeutic measure for bovine mastitis. The most common pathogens include Staphylococcus aureus, various streptococci (Streptococcus dysgalactiae, Streptococcus uberis), and coliforms (Escherichia coli), which can be contracted from other infected cows or from the environment. A combination of kanamycin and cefalexin (1:1.5 wt/wt) is currently used therapeutically in Europe for the treatment of bovine mastitis, although standardized methods for the in vitro determination of the susceptibility of target pathogens have not been developed. This study evaluates the appropriate broth microdilution testing criteria for kanamycin and cefalexin administered in combination and reports the development of a disk diffusion test. At a ratio of kanamycin:cefalexin relevant to that observed in milk postadministration (10:1 wt/wt), the minimum inhibitory concentrations were determined against 307 isolates of target mastitis pathogens (staphylococci, streptococci, and E. coli). Based on achievable concentrations in milk and the resulting distribution of minimum inhibitory concentrations, preliminary broth breakpoints for kanamycin/cefalexin (10:1 fixed ratio) of or=32/3.2 microg/mL resistant were applied to evaluated staphylococci, streptococci, and E. coli. Parallel testing by disk diffusion and resulting error-rate bounded analysis using a combined disk concentration of 30 microg of kanamycin and 15 microg of cefalexin resulted in the establishment of preliminary disk interpretive breakpoints of >or=20 mm susceptible, 18 to 19 mm intermediate, and