Embryo transfer

Day 6 blastocysts cultured in MU2+Max were placed in 3 mL of manipulation medium (9.50 g TCM-199, 0.05 g NaHCO₃, 0.75 g HEPES, 1.76 g NaCl, 3.00 g BSA, 1 mL gentamicin, 1000 mL Milli Q H₂O) with 5 μM PS48 in polystyrene tubes (BD Biosciences, San Jose, CA). After being transported at 37°C to the University of Missouri Swine Research Complex, 40 blastocysts were loaded into a tomcat catheter and surgically transferred into the ampullary-isthmic junction of a cycling gilt on day 3 of her estrous cycle. Pregnancy was determined by heat checking and monitoring by ultrasound after day 25. Surrogates were checked weekly until farrowing. Sexes and birth weights were recorded.