201 RED DEER (CERVUS ELAPHUS) CALVES BORN FROM IN VITRO-PRODUCED BLASTOCYSTS FERTILIZED AND CULTURED IN DEER SYNTHETIC OVIDUCT FLUID

Abstract

Deer Synthetic Oviduct Fluid medium (DSOF;; Berg and Asher 2003 Theriogenology 59, 189–205), based upon the composition of red deer oviduct fluid, has been shown to support routine in vitro fertilization and blastocyst development (15%) of in vitro-matured red deer oocytes without the use of somatic cell co-culture or serum supplementation. However, pregnancy establishment and fetal survival remained to be determined. The objectives of this study were to transfer in vitro red deer blastocysts produced by the DSOF culture system, follow fetal survival through calving and investigate trans-cervical embryo transfer for red deer. Red deer hinds of mixed age were synchronized using a 12-day CIDR (Pharmacia & Upjohn, Auckland, NZ) synchrony program (Berg DK et al. 2002 Ani. Reprod. Sci. 70, 85–98). Onset of estrus was synchronized to the day of IVF and embryos were transferred 7 days later. in vitro red deer blastocysts were produced after aspirating oocytes from abattoir-sourced ovaries. Selected COCs were matured and fertilized and presumptive zygotes cultured in vitro (Berg and Asher 2003 Theriogenology 59, 189–205) with modified Ca²⁺ concentrations: 3.0 mM and 1.5 mM for early and late DSOF, respectively. in vitro blastocyst development was 14.7% (21/143) on Day 7 and 22.4% (32/143) on Day 8. Ten blastocysts (grade 1 and 2) were selected for transfer on Day 7 (post-IVF) and placed into Emcare embryo holding medium (ICPbio, Auckland, NZ). Blastocysts were loaded into 0.25-cc straws (n = 5) or tom cat catheters (n = 5) and transported to the Ruakura Deer Unit at 25°C. Hinds were restrained and sedated as described for OPU (Berg and Asher 2003 Theriogenology 59, 189–205) and an attempt was made to pass a cattle transfer pistolette through the cervix. If unsuccessful, the hind underwent laparoscopic uterine transfer. Serial serum progesterone values diagnosed pregnancies at Day 21 and fetal survival was determined using rectal ultrasonography on Day 35, 45, 60 and 90. Seven single-embryo transfers were completed;; 2 of 5 trans-cervical attempts and 5 using the laparoscopic method. Serum progesterone levels confirmed 57% (4/7) of the hinds were pregnant on Day 21;; 2/2 (100%) from trans-cervical and 2/5 (40%) from laparoscopic transfers. No pregnancy losses occurred after Day 21. Four calves, 1 male and 3 female, were born unassisted after 230 to 233 days of gestation. Birth weights ranged from 7.3 to 10 kg. Our results indicate that in vitro red deer blastocysts produced using the DSOF culture system can establish pregnancies after transfer and result in normal healthy calves.