title: Fetal growth and reproductive performance in ewes administered GnRH agonist on day 12 post-mating.
abstract: Reproductive performance and fetal growth was determined in GnRH (4 microg synthetic GnRH agonist, Receptal) administered (i.m.) to ewes on day 12 post-mating (n = 103) compared to control ewes (n = 97) during the breeding season. Plasma progesterone and LH concentrations were analyzed. A total of 13 ewes was slaughtered on day 45 of pregnancy (six from control, seven from GnRH treated groups). GnRH administration on day 12 post-mating increased plasma progesterone concentration (4.39+/-0.25 ng/ml) compared to control group (3.43+/-0.15 ng/ml) on days 13-15 post-mating (P < 0.01). GnRH administration also increased plasma LH concentration between 1 and 4 h after GnRH administration (P < 0.01). Pregnancy rate was higher in GnRH treated group (84%) than control (66%) group (P < 0.05). The ewes in GnRH administered group had more twins (P < 0.05) than those in control group. The ovarian weights (P < 0.05) and the number of corpora lutea (CL) (P < 0.01) were greater in ewes slaughtered on day 45 of pregnancy in GnRH treated group than those in control group. GnRH administration on day 12 post-mating did not have any effect on products of conception at day 45 of pregnancy except on crown-rump length (CRL) of fetuses and cotyledon weight. CRL of fetuses and cotyledon weight in GnRH treated group was higher than those in control group (P < 0.05). In conclusion GnRH administration improved reproductive performance of ewes when administered on day 12 post-mating probably through its beneficial effect on embryo survival by enhancing luteal function, but not through stimulating fetal growth.
authors.affiliation: Ondokuz Mayis Universitesi, Ziraat Fakultesi, Kurupelit, 55139 Samsun, Turkey. makifcam@omu.edu.tr
authors.forename: Mehmet Akif
authors.initials: MA
authors.lastname: Cam
authors.forename: Mehmet
authors.initials: M
authors.lastname: Kuran
authors.forename: Sedat
authors.initials: S
authors.lastname: Yildiz
authors.forename: Erdogan
authors.initials: E
authors.lastname: Selcuk
mesh_terms: D000818:Animals; D004622:Embryo, Mammalian / Q000187:drug effects / Q000502:physiology; D005314:Embryonic and Fetal Development / Q000187:drug effects* / Q000502:physiology; D005260:Female; D005300:Fertility Agents, Female / Q000008:administration & dosage / Q000819:agonists; D007987:Gonadotropin-Releasing Hormone / Q000008:administration & dosage* / Q000819:agonists*; D007273:Injections, Intramuscular / Q000662:veterinary; D008098:Litter Size / Q000187:drug effects; D007986:Luteinizing Hormone / Q000097:blood; D010053:Ovary / Q000033:anatomy & histology / Q000187:drug effects; D011247:Pregnancy; D011374:Progesterone / Q000097:blood; D011897:Random Allocation; D012098:Reproduction / Q000187:drug effects* / Q000502:physiology; D012756:Sheep / Q000502:physiology*
chemical_list: D005300:Fertility Agents, Female; D007987:Gonadotropin-Releasing Hormone; D011374:Progesterone; D007986:Luteinizing Hormone