The effects of GnRH analogue (buserelin) or hCG (Chorulon) on Day 12 of pregnancy on ovarian function, plasma hormone concentrations, conceptus growth and placentation in ewes and ewe lambs

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dc.contributor.author Beck, Neil F. G.
dc.contributor.author Khalid, M.
dc.contributor.author Khan, T. H.
dc.date.accessioned 2009-12-03T16:41:00Z
dc.date.available 2009-12-03T16:41:00Z
dc.date.issued 2007-12
dc.identifier.citation Beck , N F G , Khalid , M & Khan , T H 2007 , ' The effects of GnRH analogue (buserelin) or hCG (Chorulon) on Day 12 of pregnancy on ovarian function, plasma hormone concentrations, conceptus growth and placentation in ewes and ewe lambs ' Animal Reproduction Science , pp. 3-4 . en
dc.identifier.issn 1873-2232
dc.identifier.other PURE: 141480
dc.identifier.other dspace: 2160/3769
dc.identifier.uri http://hdl.handle.net/2160/3769
dc.description Khan, T. H., Beck, N. F. G., Khalid, M. (2007). The effects of GnRH analogue (buserelin) or hCG (Chorulon) on Day 12 of pregnancy on ovarian function, plasma hormone concentrations, conceptus growth and placentation in ewes and ewe lambs. Animal Reproduction Science, 102, (3-4), 247-257. en
dc.description.abstract The objectives of this study were to determine the effect of GnRH analogue (buserelin) or human chorionic gonadotrophin (hCG, Chorulon) treatment on Day 12 of pregnancy on ovarian function, plasma hormone concentrations, conceptus growth and placentation in ewes and ewe lambs. After oestrus synchronization with progestagen sponges and eCG, all the animals were mated with fertile rams. Both ewes and ewe lambs (20 per treatment group) were given either normal saline or 4 μg GnRH or 200 IU hCG on Day 12 post-mating. Pre- and post-treatment plasma hormone concentrations were determined in seven pregnant animals per treatment group in samples collected 1 h before and 0, 2, 4, 6, 8, 24, 48 and 72 h after treatment. Overall mean progesterone concentrations were higher (P <0.001) in ewes as compared with ewe lambs in saline-treated controls. GnRH or hCG treatment increased (P <0.001) mean plasma progesterone concentrations in both age groups, however, post-treatment concentrations were significantly (P <0.05) higher in ewes than in ewe lambs. Oestradiol concentrations were similar in the two control groups. In ewes, but not in ewe lambs, both GnRH and hCG treatments significantly (P <0.05) increased the mean oestradiol concentrations above pre-treatment levels. Moreover, post-treatment oestradiol concentrations in GnRH- and hCG-treated animals were significantly (P <0.05) higher than those in the saline-treated controls. LH release in response to GnRH treatment was greater (P <0.05) in ewes than in ewe lambs, whereas FSH release in ewes was less (P <0.05) than that of ewe lambs. The effects of GnRH or hCG on conceptus growth and placentation was determined at slaughter on Day 25. In ewes, GnRH treatment increased (P <0.05) luteal weight, amniotic sac width and length, and crown-rump length compared with controls, but had no effect on these parameters in ewe lambs. In ewes, hCG treatment also enhanced (P <0.05) luteal weight, amniotic sac width and length, crown-rump length, embryo weight and number of placentomes as compared with controls. In ewe lambs, there was no difference (P <0.05) between hCG and control groups in luteal weight, embryo weight and amniotic sac width but crown-rump length, amniotic sac length and the number of placentomes forming the placenta were greater (P <0.05). In conclusion, GnRH or hCG treatment on Day 12 of pregnancy can increase ovarian function, conceptus growth and placental attachment in ewes. However, these treatments were less effective in ewe lambs. en
dc.format.extent 2 en
dc.language.iso eng
dc.relation.ispartof Animal Reproduction Science en
dc.title The effects of GnRH analogue (buserelin) or hCG (Chorulon) on Day 12 of pregnancy on ovarian function, plasma hormone concentrations, conceptus growth and placentation in ewes and ewe lambs en
dc.type Text en
dc.type.publicationtype Article (Journal) en
dc.identifier.doi http://dx.doi.org/10.1016/j.anireprosci.2006.11.007
dc.contributor.institution Institute of Biological, Environmental and Rural Sciences en
dc.description.status Peer reviewed en


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