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EFFECT OF INTRAVAGINAL MAP-IMPREGNATED SPONGES AND PMS ON MERINO EWES DURING THE BREEDING SEASON:

II. A BACTERIOLOGICAL INVESTIGATION

E. M. VAN TONDER, G. MARINCOWITZ  and T. F. W. BOLTON, Veterinary Investigation Centre, Middelburg, Cape Province

 

ABSTRACT

A bacteriological examination was conducted on vaginal specimens taken from 36 Merino ewes immediately before insertion of a 60 mg 6 a methyl - 17 a acetoxyprogesterone (MAP) impregnated sponge and again 14 days later, immediately after the removal of the sponge. At the latter stage, 24 of these ewes also received a subcutaneous injection of 250 or 500 I.U. pregnant mare serum (PMS) to improve synchronized oestrus and ovulation. Similar specimens were taken simultaneously from an untreated group of 12 ewes. All 48 ewes were mated at the occurrence of oestrus and slaughtered four to five weeks later when specimens of the uterus were taken.

Corynebacterium renale was the most common organism present in specimens taken before insertion of the sponges, but was totally absent after removal of the sponges. Micrococcus spp. isolated from the uterus could be due to contamination. The bacteriological picture of the vagina varied considerably between individual animals and the two sampling periods. A definite increase was observed in cultures containing intestinal organisms, especially of the Alcaligenes spp. This was attributed to introduction by the speculum and a possible resistance to the antiseptic cream.

No difference in embryonic loss was observed between ewes with positive and negative bacterial growth on cultures at the removal of the sponge. The higher embryonic loss in ewes with positive cultures in the group additionally injected with 500 I.U. PMS can rather be attributed to the acknowledged consequences of superovulation.

A higher leucocyte count in vaginal smears in treated ewes was not related to bacterial growth on cultures, but presumably to the resultant effect of irritation in the vagina by the sponge and the leucocyte stimulating effect of the progestagen in the sponge.

 

Published

South African journal agricultural science 11