1¾«6 From: "I.M. JOYCE"
Date: Tue, 7 Apr 1998 16:08:48 GMT0BST
Subject: RE: bST and its effect in superovulation of sheep

> I am not surprised to learn that bST didn't seem to affect the superovulatory
> response in ewes in terms of ovulation rate. Several studies (Gong et al.,
> Anim. Reprod. Sci. 1996, 41: 13-26; Eckery et al., J. Anim. Sci. 1994, 72:
> 2425-2430; Joyce et al., J. Reprod. Fertil. Abstract Series 1996, 17: abstract
> 33) have already shown that bST treatment does not increase total number of
> antral follicles and/or superovulatory response in ewes. This is unlike in
> cattle where bST can increase the total number of antral follicles and
> therefore pretreatment with bST significantly enhances superovulatory
> response (Gong et al., Theriogenology 1996, 45: 611-622). Nevertheless,
> bST might still have an effect on the quality of response (in terms of
> transferability of embryos recovered) in ewes, as already demonstrated in cattle
> (Kuehner et al., Theriogenology 1993, 40: 1003-1013; Gong et al., Theriogenology
> 1996, 45: 611-622). Has anybody looked at this in ewes already?
>
> Jin Gong


Dear Jin and anyone else who is reading:

We have looked at embryo quality in a fairly small sample of
hemi-ovariectomised GH-treated ewes. Frankly the results were rather
ambiguous. The number of transferable (Grades 1 to 3) embryos was
non-sig. increased from 2.9 to 5.7; however, this appeared to be due
to 3/10 ewes in the control group but only 1/10 ewes in the
GH group having a zero fertilisation rate. All a bit inconclusive and
very much requiring a larger scale study I'm afraid. However, I would
be interested in peoples comments on whether GH treatment might
possibly be expected to improve embryo quality through an action on
the uterine environment, as well as through an effect on the oocyte
(for which, as I recall, there is some in vitro evidence).

Anyway, I'm glad to see you survived NOW98 with your inquisitiveness
intact.

Ieuan Joyce
(Universities of Leeds and Nottingham)


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Date: Tue, 7 Apr 1998 16:08:48 GMT0BST
Subject: RE: bST and its ef