Cervical mucus characteristics of clover-affected ewes after ovariectomy

THERIOGENOLOGY CERVICAL MDCXJSCBARACTERISTICS OF CLOVER-AFFECTED EWES AFTER OVARIECTOMY N.R. Adams, Division of Animal Health, CSIRO, Private Bag, Wembley, W.A. 6014. The permanent infertility in ewes after prolonged grazing on oestrogenic clover pasture is associated with changes in cervical histology and an abnormal, low-spinbarkheit mucus. This experiment was carried out to see whether such mucus could be reproduced by oestrogenic stimulation of such ewes.4 months after ovariectomy. Ten clover-affected and 12 control ewes from groups previously shown to vary in mucus spinbarkheit (1) were treated with 10 mg progesterone daily for 10 days, and 48 hours later equal subgroups of affected and control ewes were treated with either 15 or 25 ug oestradiol benzoate (ODB). Cervical mucus samples were collected by pipette 24 hours after ODB treatment (1). This experiment was repeated so that each ewe had received each dose of ODB. As seen in Table I, there were no significant differences between affected and control ewes in total amount of mucus, spinbarkheit, or the proportion of dry matter at either dose of ODB. TABLE I.

Dose

Characteristics of cervical mucus (means + S.E.M.) produced after ODB treatment of clover-affected and control ewes.

of

Spinbarkheit (mm)

ODB

Ewes

25 pg

clover-affected control

15 pg

clover-affected control

Total wet wt.(g)

Dry matter !%of total)

65 + 16 57 T15 -

0.39+0.09 0.24TO.01 -

2.0 + 0.2 2.0 + 0.3

455 8 46 + 12

O-26+0.09 0.13+0.03 -

2.4 f. 0.2 2.4 + 0.6

After the study 7 clover-affected and 5 control ewes were killed and their cervixes compared histologically with those taken from 5 affected and 5 control ewes prior to ovariectomy. There were significantly more segments of tubular glands cut in cross-section in the lamina propria of affected ewes, and ovariectomy had not resulted in any change. The failure to detect any difference between affected and control ewes in the mucus response to ODB was surprising. The results suggest that the histological changes in the cervix of clover-affected ewes are not necessarily associated with the production of abnormal mucus. REFERENCE (1)

Adams, N.R. Cervical mucus changes in infertile ewes previously exposed to oestrogenic subterranean clover. Res. Vet. Sci. -21: 59-63 (1916).

OCTOBER

1977

VOL. 8 NO. 4

187