Combined thickness of the uterus and placenta (CTUP) as indicator of placentitis in Thoroughbred mares

Abstract

Significant financial losses caused by ascending placentitis, frequently caused by bacterial infection in mares with poor perineal conformation, have stimulated interest in improved diagnostic and treatment tools. This study was designed to determine whether or not the presence of histologically evident placentitis was related to previously diagnosed thickened CTUP (combined thickness of the uterus and the placenta). During 30 days prior to their expected foaling date, 333 pregnant mares were examined on a single occasion. CTUP was obtained using transrectal ultrasonography. All parturitions were assisted and after foaling, the fetal membranes were weighed and macroscopically examined. Samples of allantochorion near the cervical star or from any area with macroscopical alterations were submitted to histological evaluation. A mare was considered with placentitis when the presence of neutrophils was detected outside the blood vessels after the complete examination of the slide. The data were analyzed by logistic regression with a statistical significance of P < 0.05. Only 3.9% of the mares suffered from ascending placentitis as demonstrated by the infiltration of neutrophils in the chorioallantoic tissues near the cervical star. No differences in mean values of CTUP were observed in mares with and without placentitis. All deliveries were eutocic and seven foals died within 24 h of birth. Five of these were born from mares with placentitis. In conclusion CTUP is not a good indicator of ascending placentitis during the final month of gestation in Thoroughbred mares.

Ascenderende placentitis bij de merrie

“…In some studies (Morris et al, 2007;Bailey et al, 2010;Löf et al, 2014), no different CTUP measures between mares with or without placentitis were seen, which led the authors to the conclusion that CTUP is not a good indicator of ascending placentitis during the final month of gestation in Thoroughbred mares (Löf et al, 2014). However, if an increase in CTUP is seen, a degree of placental insufficiency may be present (Cummins et al, 2008), but also other reasons of thickened placenta should be considered (e.g.…”

“…In the event of ascending placentitis, a thickened, discolored, edematous or even ulcerated chorioallantois is present at the level of the cervical star (Platt, 1975b;Mays et al, 2002) (Figure 1). Gross lesions at macroscopic inspection are not specific, as they may be absent in the event of placentitis or be caused by other diseases, as in cases of cervical pool necrosis (Löf et al, 2014). Furthermore, the ultrasonographic feature of a thickened placenta is not correlated with the total weight of the placenta after expulsion (Löf et al, 2014); however, a heavier placenta may be caused by inflammation and should be sampled for histology to exclude placentitis.…”

“…In the majority of cases, the affected mares are pluriparous and may have anatomic defects of the genital tract, such as pneumo-or urovagina and/or cervical incompetence (Platt, 1975b;LeBlanc, 2010;Löf et al, 2014). No breed predisposition has been noted.…”