A randomized controlled field trial was performed to evaluate the efficacy of a 3-d treatment regimen with i.m. penethamate hydriodide compared with no treatment in lactating cows with subclinical mastitis. To be included, a cow had to have 2 somatic cell counts (SCC) 300,000 cells/mL at the last 3 monthly controls, 1 or more quarters with SCC >250,000 cells/mL, and the same bacterial species isolated in 2 consecutive samples 2 to 4 d apart. A total of 151 quarters from 92 cows were monitored for 2 mo following treatment. Quarter milk samples were examined for bacteriological cure (BC) and SCC at 14, 28, and 60 d after treatment. Bacteriological cure was defined as not having the same bacterial species isolated from the quarter milk samples taken at 14 and 28 d posttreatment as in the samples taken before treatment. Systemic treatment with penethamate resulted in BC in 59.5% of quarters and 52.2% of cows, compared with 16.7 and 10.9% in the untreated cows. Somatic cell count decreased significantly in the penethamate-treated cows, steadily in the case of BC and transiently when the infections persisted. This study confirms that systemic treatment of subclinical mastitis with penethamate is effective and that BC of infected quarters has a sustained positive effect on milk SCC during the 2 mo following treatment.

Integrated pest management (IPM) in agriculture animals remains undeveloped as compared to IPM in crops. With respect to the range of external nuisance arthropods that may bother farm animals, development and implementation of systematic IPM strategies are difficult to carry out. However, recurrent outbreaks of blue tongue disease in sheep and cattle, the public threats regarding the prophylactic use of veterinary insecticides and the need to preserve the efficacy of available actives have to lead the reflexion on new control strategies for arthropod pests of livestock. A recent extension of EU regulation on the use of pesticides in crops provides an opportunity to compare IPM strategies and to suggest new lines of reflection for the control of nuisance pests in ruminants under European conditions. In this paper, actions suggested by the Annex III of the Directive 2009/128/CE on Sustainable Use of Pesticides and related National Action Plans from 28 member states of the EU were reviewed from an animal production perspective by a group of veterinary entomologists. Eight lines of action have been identified and thus challenged with respect to current husbandry practices in modern European ruminant operations. Many IPM strategies for crops were identified to be unsuitable for large animals. Suggestions for implementing tools, opportunities and constraint assessment, and needs for support were also discussed. Only control of pest development sites and monitoring of harmful organisms were considered achievable in the near future; both in conjunction with the use of topical insecticides. Complementary actions such as alternatives to chemical control require further researches and industrial development. Marketing of IGR-based feed additives would be of great interest, but development of new compounds for veterinary medicines is very unlikely with respect to the European regulatory environment and associated cost of development.

Ceftiofur, a third-generation cephalosporin, is one of the most used antibiotics in dairy industry. Intramuscular injection of 1 mg/kgBW ceftiofur hydrochloride (HCl) generally results in 0 hour withdrawal time for the milk in dairy cows. Nevertheless, farmers and dairy processors occasionally complain about ceftiofur-based products in case of positive result to a commercial rapid screening test for the presence of violative residues of antimicrobials (inhibitors) in the bulk milk tank. Six lactating cows were injected with a 50 mg/ml ceftiofur HCl-based product at the dosage regimen of 1 mg/kg, intramuscularly, once a day, for five consecutive days, as per label. Milk samples were then collected just before the very last injection (T0) and then at 12, 24, 36, 48, 60, 72, 84 and 96 hours after the last injection. Individual milk samples were tested using three commercial screening test kits for inhibitor residues: DelvotestSP NT, SNAP Beta-Lactam ST Plus and ROSA MRL Beta-Lactam Test. Since bulk tank is screened in real operating conditions, samples were also diluted to 1:4, 1:10 and tested again. For the Delvotest SP NT, which lowest detected concentration is close the MRL of the ceftiofur (100 µg/kg), all results were negative. For the ROSA MRL Beta-Lactam Test and the SNAP Beta-Lactam ST Plus, several samples yielded positive and doubtful results at T0 and T12. However, after dilution to 1:10, all results were negative. Consequently, when used as officially instructed, the tested 50 mg/ml ceftiofur HCl-based injectable veterinary products are safe, and milk should be free of violative residues of ceftiofur. With consideration to the low specificity and the low positive predictive value of commercial screening tests, positive reactions of the bulk milk should be interpreted as false positive or another risky usage of β-lactam-based medicines in the farm must be investigated.

K99. In this multi-centre, randomised, blinded study, adult cows vaccinated with a trivalent vaccine marketed for years (Rotavec™ Corona, MSD Animal Health -RC) prior to last parturition were revaccinated 12-15 months later, prior to the upcoming parturition, with either a single injection of a recently marketed vaccine (Bovigen™ Scour, Virbac -BS), or RC. The aim of this trial was to verify whether BS is not inferior to RC for the stimulation of the immune response and the passive transfer to calves in these conditions. A total of 136 multiparous dairy cows, from 5 different herds and located in 3 countries (France, UK and Germany) were enrolled in the study. Sixty-five cows were vaccinated with BS and 71 with RC. Antibody levels, measured by competitive ELISA and represented as percentage of inhibition (PI), were assessed in the cow's serum (on the day of vaccination: D0 and on days 21, 42 and at calving), in the colostrum and in the serum of calves in the first week of life. Differences in means of PI between groups and the 95% confidence interval (CI) were calculated. The non-inferiority threshold was set at −10%. The relationships between antibody levels in the colostrum and the vaccination-calving interval (VCI) or the inter-booster vaccination interval (IBVI) were also analysed.All the lower margins of the 95% CI of the difference in means of PI, in all samples and for the 3 pathogens assessed, were above −10%. This result shows that BS is not inferior to RC for the stimulation of the immune response against BoRV, BoCV and E. coli K99 and the passive transfer of immunity to calves when this vaccine is administered to their dams previously vaccinated with RC. Furthermore, no correlation was found between PI values in the colostrum and the VCI or IBVI. The ratio of animals with a PI ≥ 95% in the colostrum, among cows with similar intervals, was not significantly different between groups, for all antigens tested.Therefore, this study shows that a single injection of the heterologous vaccine BS can be used as a booster in cattle previously vaccinated with RC.

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