2015 ACVIM Forum Research Abstract Program

In conclusion, SPL placement in the upper eyelid was associated with fewer complications, use of antimicrobials appeared protective against complications and plasma should only be administered when indicated as it increased the likelihood if complications. Placental steroids have been suggested as useful diagnostic markers for pregnancy loss in mares; however, there are few controlled studies that have examined changes in steroids in mares with placentitis. The objectives were to compare plasma concentrations of estradiol 17b and estrone sulfate in mares with placentitis with gestationally age-matched control mares. Pregnant mares (260-280d of gestation) were allocated to a control group (n = 17) and to a group with experimentally induced placentitis (n = 17). Induction of placentitis was achieved via intracervical inoculation of Streptococcus equi ssp zooepidemicus. Plasma was collected at inoculation for mares in the placentitis group or commence for control mares (day = 0), and then daily until abortion or for 12 days post inoculation (DPI). Estrone sulfate concentration was determined by ELISA, whereas estradiol 17b was determined by a chemiluminescence immunoassay. Data were analyzed by mixed models, for DPI and for days from abortion (DFA) for the different steroids. Mares with experimentally induced placentitis aborted within 5-25 DPI. There were significant effects of time (DPI, P < 0.0001; DFA P = 0.0008) and time by group interactions (DPI or DFA P < 0.001) for the concentrations of estradiol 17-b. Concentrations of estradiol 17-b were significantly reduced at 4 DPI and at -2 DFA (P < 0.05). Analyses of estrone sulfate revealed effects of time (DPI P < 0.003; DFA P = 0.01) and time by group interactions (DPI P = 0.002; DFA P < 0.0001). Estrone sulfate concentrations were significantly reduced 6 and 7 DPI and on the day of abortion (0 DFA) for mares with experimentally induced placentitis. Concentrations of estrogens changed significantly in mares with experimentally induced ascending placentitis. Vaccination of horses and foals with WNV and EEE vaccines might illicit an IgM antibody response that could interfere with the capture ELISA diagnostic test, especially if horses and foals are tested after vaccination. The hypothesis of this study is that horses and foals vaccinated with a multivalent vaccine containing WN and EEE antigens will not elicit an IgM antibody response of >1:400.