The Storage of Fertilized Sheep Ova At 5°C

Abstract

Fertilized day-2 (1-4 cells) and day-5 (morulae) sheep ova were cooled at a rate of 0·25 or 1·0 degC/min to 5°C then stored at 5°C for intervals between 10 min and 6 hr, after which they were cultured in vitro for two days at 37· 5°C. Storage had no effect upon subsequent development in culture. Of 103 day-2 ova, 75 (73 %) developed to eight cells and 57 of 88 (65 %) day-5 ova developed to blastocysts. There were no effects of age of ovum, cooling rate, or duration of storage on development in culture.