INVITRO EXPOSURE OF BOVINE MORULAE TO UREAPLASMA-DIVERSUM

  • 1 April 1987
    • journal article
    • research article
    • Vol. 51  (2) , 198-203
Abstract
Ureaplasma diversum has been associated with infertility in the cow experimentally and in naturally occurring cases. However, the pathogenic mechanism is undetermined. The purpose of this study was to determine whether ureaplasmas are pathogenic for bovine morulae in vitro. Twenty-one morulae were recovered from three superovulated, mature, Holstein cows six or seven days postestrus. The embryos were divided into three groups (A,B,C) and incubated for 16 hours at 37.degree. C in humidified air with 10% CO2. Group A was incubated in embryo culture medium alone, Group B was incubated in culture medium with sterile ureaplasma broth added and Group C was incubated in culture medium containing 1.7 .times. 106 colony forming units U. diversum strain 2312. After incubation, the morulae were examined using an electron microscope. Structures morphologically identical to U. diversum were present on the outer surface of the zonae pellucidae of all the morulae exposed to the organism and none were present on the unexposed control embryos. No other morphological differences were observed in either the ureaplasma-exposed embryos or the two groups of control embryos. U. diversum was isolated from three of the five embryos incubated in culture medium with sterile ureaplasma broth added. These three embryos were recovered from one donor cow which cultured positive for U. diversum from the vulva and flush fluid. This finding suggests that the contaminating organisms entered the embryo culture wells either in the embryo collections medium or attached to the embryos. It was concluded that U. diversum strain 2312 attached to the outer surface of the bovine zona pellucida, U. diversum strain 2312 was not pathogenic for bovine morulae and embryos may be contaminated with ureaplasmas when flushed from a cow with vulvar colonization.