Influence of Induced Uterine Infection at Various Stages of the Estrous Cycle on the Corpus Luteum of the Ewe

Abstract

Inflammation was induced by injecting a suspension of E. coli into the lumen of a uterine horn adjacent to an ovary containing a corpus luteum to study the effect on corpus luteum lifespan. Some ewes were infected on day 1, 3, 5, 7 or 9 and killed 6 days later. Other ewes were infected on day 9, 11, 13 or 15 and killed at estrus or day 21, whichever occurred earliest. Corpus luteum development was inhibited and CL regression hastened following infection induced on days 1 through 7. Uterine infection induced on day 9 did not cause luteolysis. Estrous cycles were not lengthened when infection was induced on day 9, 13 or 15, but cycle lengths were prolonged in some ewes infected on day 11.