title: Exogenous progesterone and embryo survival in Booroola-cross ewes.
abstract: To investigate if exogenous progesterone improves embryo survival, 209 multiparous Booroola Merino x South Australian Merino ewes, heterozygous for the F gene (F+) were allocated to seven treatment groups and inseminated at a synchronized oestrus. Six groups received progesterone from controlled internal drug release G dispensers on the following days after ovulation: 4-7, 4-11, 4-14, 7-11, 7-14 and 11-14. Concentration of peripheral progesterone increased (P less than 0.05) in most supplemented groups, but there were no significant differences in pregnancy rates between treatments. However, the number of fetuses per pregnancy was increased for progesterone treatments starting on Day 4 (Days 4-7, 4-11 and 4-14 combined v. control; P less than 0.05) and for all supplemented treatments compared with the control (P less than 0.05).
authors.affiliation: Department of Agriculture, Turretfield Research Centre, Rosedale, Australia.
authors.forename: D O
authors.initials: DO
authors.lastname: Kleemann
authors.forename: S K
authors.initials: SK
authors.lastname: Walker
authors.forename: R J
authors.initials: RJ
authors.lastname: Grimson
authors.forename: D H
authors.initials: DH
authors.lastname: Smith
authors.forename: T I
authors.initials: TI
authors.lastname: Grosser
authors.forename: R F
authors.initials: RF
authors.lastname: Seamark
mesh_terms: D000818:Animals; D004343:Drug Implants; D004622:Embryo, Mammalian / Q000187:drug effects*; D005260:Female; D005313:Fetal Death / Q000517:prevention & control; D008098:Litter Size / Q000187:drug effects; D008183:Luteal Phase / Q000187:drug effects / Q000502:physiology; D011247:Pregnancy; D011374:Progesterone / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D012756:Sheep
chemical_list: D004343:Drug Implants; D011374:Progesterone