Table 2. Development after transfer of day 6.5–8 bovine embryos frozen in 1.36 M glycerol or 1.36 M glycerol –1.25 M sucrose in phosphate buffer saline.

Temperature a (°C)	Cryoprotectant
	1.36 M glycerol in PBS		1.36 M glycerol –0.25 M sucrose in PBS
	(diluted before transfer)		(transferred without dilution)
	No. of frozen-thawed embryos	No. of pregnancies (%)	No. of frozen-thawed embryos	No. of pregnancies (%)
–25	16	2 (12.5)	27	14 (51.8)
–35	24	10 (41.7)	11	2 (18.2)
Total	40	12 (30.0)	38	16 (42.1)

^a Temperature at which samples were plunged into liquid nitrogen. PBS: phosphate buffer saline. From Massip et al. (1987) [30].