Changes in the endometrium of the cow after intrauterine administration of different drugs

32 young and healthy cows each received a single intrauterine treatment with one of the following solutions: Lugol's solution, Vetedine, Lorasol, Lotagen, Aureomycin, and normal saline solution as a control. Endometrial biopsies were taken immediately before application and at days 1, 3, 6, 10, 15, 20 and 30 thereafter. On day 1, degenerative and inflammatory reactions could already be observed in all groups, with the exception of the control group. The intensity of the lesions varied, not only between treatment groups but also to a lesser extent between individuals within groups. Degeneration and inflammatory reaction found in the subepithelial stromal tissues were more distinct than those seen in the epithelia. Lorasol caused the most severe degenerative changes, regarding the depth of degeneration into the tissue, as well as the intensity of the inflammatory reaction. Lugol's solution also showed a high degree of change, followed by Lotagen and Vetedine showing moderate change, respectively. Reaction to the antibiotic treatment with Aureomycin was only slight. The regeneration time of these lesions was proportional to the intensity of the induced changes, amounting to 10-15 days for Lorasol and 3-6 days for Aureomycin, respectively. The clinical significance of these findings is discussed.