Table 1. Developmental ability of cold-vitrified embryos by embryo transfer.

Stored period (h)	Two-cell embryos	Number of recipients	Number oftransferred embryos	Number of live pups (%)
72	Cold	4	80	35 (43.8 ± 4.8)
	Vitrified-Cold	4	80	34 (42.5 ± 22.2)
	Cold-Vitrified	3	60	27 (45.0 ± 10.0)
96	Cold	7	140	36 (25.7 ± 9.8)
	Vitrified-Cold	4	80	25 (31.3 ± 16.5)
	Cold-Vitrified	4	78	17 (21.8 ± 6.2)

Two-cell embryos were transferred to each oviduct of the recipient mice (18–20 embryos/recipient), and the number of pups was recorded after 19 days. The birth rate was calculated as follows: (Number of pups/Number of transferred two-cell embryos) × 100. Results are expressed as the mean ± SD (n=3–7).