Time of ovulation in cattle following treatment with a prostaglandin analogue (PG), PG with LH-RH, or intravaginal silastic coils impregnated with progesterone (PRID)

Cumming, I. A.; Baxter, Robert W.; White, MB; McPhee, S. R.; Sullivan, Andrea

doi:10.1016/0093-691x(77)90146-7

Cited by 5 publications

(1 citation statement)

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“…Many aspects of ovarian function can be controlled or modified with hormone treatments; the luteal phase can be shortened by treatment with prostaglandins or artificially extended with progesterone (see Hansel & Convey, 1983), superovulation can be induced with exogenous gonadotrophins (see Moor et al, 1984), and the timing of the preovulatory LH surge (Fernández-Limia et al, 1977) and ovulation (Cumming et al, 1977) can be advanced with LHRH or its agonists. However, to define the role of gonadotrophins in the control of ovarian function more clearly, their endogenous secretion must be suppressed.…”

Section: Discussionmentioning

confidence: 99%

Effects of an LHRH antagonist on gonadotrophin and oestradiol secretion, follicular development, oestrus and ovulation in Holstein heifers

Rieger¹,

Roberge²,

Coy³

et al. 1989

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Mature cyclic Holstein heifers were given a luteolytic dose of cloprostenol followed by two i.v. injections, 12 h apart, of various doses of [Ac-D-Nal1, D-p-Cl-Phe2, D-Trp3, D-Arg6, D-Ala10]-LHRH, beginning either at the time of first observation of behavioural oestrus, or 48 h after the cloprostenol injection. When treatment began at the first observation of oestrus, the time of ovulation, as determined by ultrasonic echography, was significantly delayed by total doses of 0.8 mg or more of the antagonist. When given at 48 and 60 h after cloprostenol injection, a total dose of 1.5 mg of the antagonist significantly delayed the growth of the ovulating follicle, the onset of oestrus, the preovulatory surges of oestradiol, LH and FSH, and ovulation. It is concluded that the LHRH antagonist can effectively suppress endogenous LH secretion and may therefore be useful in the study of follicular development, ovulation, and other events in the oestrous cycle of the cow.

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Section: Discussionmentioning

confidence: 99%