Steroid hormones profile during an ovarian synchronization procedure in different age categories of red deer hinds (Cervus elaphus L.)

Abstract

The objective of the present study was to compare estradiol/progesterone ratios of different age categories of red deer hinds and use it as a predictor of estrus synchronization success and consequently conception rate. To accomplish this we used 38 red deer hinds to establish serum progesterone and estradiol levels in young (21 animals), mature (10 animals) and old (7 animals) hinds during the estrus synchronization procedure (transvaginal/cervical AI). The following estrus synchronization was used: at the start of the experiment each hind received a controlled intravaginal drug-releasing device (CIDR, Pharmacia&Upjohn, New Zealand) containing 0.3 g of progesterone. The device was removed on day 11, simultaneously with an application of 250 IU of Pregnant Mare Serum Gonadotropin (PMSG, Folligon® Intervet International, Boxmeer, Holland). Transvaginal/ cervical AI (artificial insemination) was performed 48 hours after CIDR withdrawal (day 13). Blood samples were obtained from the jugular vein using a Venoject® vacutainer without an anticoagulant for hormonal tests on the same experimental day (0, 11th and 13th day). A statistically (p<0.01) higher progesterone level was found in young hinds on the 11th day after controlled intravaginal drug-releasing device insertion. A significantly higher (p<0.01) estrogen level was observed in the young in regard to mature and old hinds on the expected day of estrus (13th day). Estradiol/progesterone ratios showed a statistically significant difference (p<0.01) on insemination day (13th day) between old and young hinds (98.67 : 46.59) and between old and mature hinds (98.67 : 51.79). Out of a total of 38 hinds only 9 had their offspring, 6 of the young and 3 of the mature hinds.