Concentrations of gonadotropins, estradiol and progesterone in sows selected on an index of ovulation rate and embryo survival

The objective of this study was to determine concentrations of follicle sti mulating hormone (FSH), luteinizing hormone (LH), progesterone (P-4) and 17 beta-esuadiol (E-2) in sows from a line selected on an index which emphasi zed ovulation rate (Select) and from a control Line. A further classificati on of the sows in each line was made according to the estimated number of o vulations during an estrous cycle. Sows in the Select line were ranked into a high (HI) or low group (LI) when their estimated number of ovulations we re 25 or more and 14 to 15, respectively. Sows of the control line were cla ssified into groups as high (HC) or low (LC) when the estimated values for ovulation rate were 14-15 and 8-9 ovulations, respectively. Bleed samples w ere collected every 11 h during a complete estrous cycle and samples were a nalyzed for concentrations of FSH and LH. Samples collected every 24 h were assayed for P-4 and E-2, Mean concentrations of FSH, LH, P-4 and E-2 did n ot differ (P > 0.10) between lines or between HI and LI or HC and LC groups . Selection of pigs for ovulation rate and embryonal survival did not affec t concentrations of FSH, LH, P-4 and E-2 in sows during the estrous cycle. (C) 1998 Elsevier Science B.V. All rights reserved.