No abstract

There is still no conclusive evidence relevant to the etiopathogenesis of RAS. Routine hematological screening and tests for serum iron, folic acid, and vitamin B12 deficiencies should be assessed in all patients with RAS.

Summary Reasons for performing study: Danofloxacin is a fluoroquinolone developed for veterinary medicine showing an excellent activity. However, danofloxacin pharmacokinetics profile have not been studied in horses previously. Objective: To study the pharmacokinetics following i.v., i.m. and intragastric (i.g.) administration of 1.25 mg/kg bwt danofloxacin to 6 healthy horses. Methods: A cross‐over design was used in 3 phases (2 times 2 × 2), with 2 washout periods of 15 days (n = 6). Danofloxacin (18%) was administered by i.v. and i.m. routes at single doses of 1.25 mg/kg bwt. For i.g. administration an oral solution was prepared and administered via nasogastric tube. Danofloxacin concentrations were determined by HPLC assay with fluorescence detection. Tolerability at the the site of i.m. injection was monitored by creatine kinase (CK) activity. Results: Danofloxacin plasma concentration vs. time data after i.v. and i.g. administration could best be described by a 2‐compartment open model. The disposition of i.m. administered danofloxacin was best described by a one‐compartment model. The terminal half‐lives for i.v., i.m. and i.g. routes were 6.31, 5.36 and 4.74 h, respectively. Clearance value after i.v. dosing was 0.34 l/kg bwt/h. After i.m. administration, absolute bioavailability was mean ± s.d. 88.48 ± 11.10% and Cmax was 0.35 ± 0.05 mg/l. After i.g. administration, absolute bioavailability was 22.36 ± 6.84% and Cmax 0.21 ± 0.07 mg/l. CK activity following i.m. dosing increased 3‐fold over pre‐injection levels 12 h after dosing and subsequently approached (but did not reach) normal values at 72 h post dose. Conclusions: Systemic danofloxacin exposure achieved in horses following i.m. administration was consistent with the predicted blood levels needed for a positive therapeutic outcome for many equine infections. Conversely, danofloxacin utility by the i.g. route was limited by low bioavailability. Tolerability associated with i.m. administration was high. Potential relevance: Pharmacokinetics, blood levels and good tolerability of i.v. and i.m. administration of danofloxacin in horses indicates that it is likely to be effective for treating sensitive bacterial infections.

Data suggest that difloxacin is likely to be effective for treating susceptible bacterial infections in horses.

The aim of this work was to measure serum concentrations of dehydroepiandrosterone, androstenedione, testosterone and 17β-oestradiol in horses with various diseases and after surgery. We hypothesize that diseases and castration could potentially affect concentrations of steroid reproductive hormones. Blood samples were obtained from six groups of horses comprising a total of 119 horses (75 males and 44 females, 5-15 years old) with laminitis, acute abdominal syndrome, acute diseases, chronic diseases, after castration and healthy control. Hormone concentrations in serum were determined for each group using competitive enzyme immunoassay. Significant increases compared to control were found for dehydroepiandrosterone in horses with castration (P < 0.01), acute abdominal syndrome and acute diseases (P < 0.05). Besides, significant increases were observed for androstenedione in horses with laminitis, castration and acute diseases (P < 0.01), and in acute abdominal syndrome and chronic diseases (P < 0.05). Significant increases were also found for testosterone in horses with castration (P < 0.01) and with laminitis, acute abdominal syndrome and chronic diseases (P < 0.05). The lowest values of testosterone were found in the control group. Compared to control, 17b-oestradiol serum concentrations showed significant decreases (P < 0.01) in horses with laminitis, acute abdominal syndrome, acute and chronic diseases. Significant differences (P < 0.05) for the four studied hormones were found between males and females in each group. Our results showed that there were significant differences in steroid reproductive hormone concentrations in diseased horses and in those after surgery, compared to controls. Equine, steroid reproductive hormone levels, serum, EIA No detailed comparative data are available on steroid reproductive hormone concentrations in horses with various diseases and after surgery. We hypothesize that these pathological situations or surgery could potentially affect concentrations of steroid reproductive hormones. In fact, the response of the hypothalamic-pituitary-adrenal (HPA) axis and adrenal medulla has been assessed in horses with various diseases and following surgery (Ayala et al. 2011). Several HPA axis components are modulated by gonadal steroids and pregnolone is the precursor to cortisol and cortisone (Figueiredo et al. 2002). The aim of the present study was to measure serum concentrations of steroid reproductive hormones in horses with various diseases (acute and chronic) or after surgery, whilst avoiding the potential influence of other factors (time of sampling, transport, therapy and season), and to provide data for assessing the relationship between disease and reproductive endocrine system activity. Materials and Methods A total of 95 Spanish-bred horses diseased or referred for castration (Table 1) admitted to the Veterinary Clinical Hospital of the University of Murcia in Spain were studied, in addition to 24 horses in the control group. Only clinical cases admitted during morning hours...