Artificial insemination (AI) involving the placing of frozen-thawed semen directly into the jenny uterine body is associated with very low pregnancy rates. This might be because of an exacerbation of the acute response of the endometrium to sperm, as seen in mares with persistent induced mating
endometritis. Pregnancy rates can be increased in such mares, however, by including anti-inflammatory treatments in the insemination protocol (Bucca S, Carli A, Buckley T, Dolci G, Fogarty U. The use of
dexamethasone administered to mares at breeding time in the modulation of persistent mating induced
endometritis. Theriogenology 2008;70:1093-100; Rojer H, Aurich C. Treatment of persistent mating-induced
endometritis in mares with the non-
steroid anti-inflammatory
drug vedaprofen. Reprod Domest Anim 2010;45:e458-60). To investigate the
endometritis caused by the use of frozen-thawed semen in jennies, and to assess the response to
ketoprofen treatment, endometrial cytological samples and biopsies from six healthy jennies were examined in a crossover design experiment. Samples were taken from jennies in estrus (E; control) and at 6 hours after AI with or without
ketoprofen (+K and -K, respectively).
Ketoprofen was administered iv 24 hours before and for 4 days after insemination (total = 2.2 mg/kg/24 hours for 5 days). All animals showed a severe inflammatory response to semen deposition. Polymorphonuclear neutrophil numbers in the cytological smears and biopsies differed significantly between the +K and E animals. No significant differences were recorded, however, between the +K and -K treatments. Eosinophils were observed in all sample types from all groups; these cells appear to be a feature of the normal jenny endometrium. Slight
fibrosis was observed in some biopsies, but no significant relationship with
inflammation was found. Intense
cyclooxygenase-2 (COX-2) immunohistochemical labeling was detected in the -K biopsies. Less intense labeling was seen in those of the +K animals, and mainly localized in the stratum compactum. No differences in COX-2 labeling were observed between the +K and E animals. Plasma concentrations of
ketoprofen remained detectable until 2 hours after administration, after which the compound was rapidly eliminated. In summary, jennies are susceptible to
endometritis after insemination with frozen-thawed semen.
Ketoprofen reduces this
inflammation by inhibiting COX-2; no reduction in the number of polymorphonuclear neutrophils occurs. The physiological and pharmacological characteristics of jennies should be taken into account when designing treatments for acute
endometritis aimed at enhancing pregnancy rates after insemination with frozen-thawed sperm.