Direct transfer of bovine embryos frozen-thawed in the presence of propylene glycol or ethylene glycol under on-farm conditions in an integrated embryo transfer program.

An integrated bovine embryo transfer program was conducted in collaboration with 11 Japanese prefectural livestock experiment stations. The program was conducted to evaluate the practicability of the direct transfer method for bovine embryos frozen-thawed in the presence of propylene glycol (PG) or ethylene glycol (EG) under on-farm conditions. Embryos at the compacted morula to expanded blastocyst stages were collected from superovulated donors on Day 7 or 8 after estrus and equilibrated in 1.

In vitro and in vivo survival of frozen-thawed bovine oocytes after IVF, nuclear transfer, and parthenogenetic activation.

Cryopreservation of bovine oocytes would be beneficial both for nuclear transfer and for preservation efforts. The overall objective of this study was to evaluate the viability as well as the cryodamage to the nucleus vs. cytoplasm of bovine oocytes following freezing-thawing of oocytes at immature (GV) and matured (MII) stages using in vitro fertilization (IVF), parthenogenetic activation, or nuclear transfer assays.

Endocrine profiles and embryo quality in superovulated Japanese Black cattle.

The relationships between plasma concentrations of progesterone (P4), estradiol-17beta (E2) and lutenizing hormone (LH) and embryo yield and quality were examined in 40 superovulated Japanese Black cattle. The results indicated that the ovarian function, especially the function of corpus luteum on the first treatment day, is an important factor for reliable superovulation in cattle. The levels of plasma E2 and LH at estrus were related to embryo yield and quality.

Plasma progesterone profiles and embryo quality in superovulated Japanese Black cattle.

The relationship between plasma progesterone (P(4)) levels before and after superovulation treatment and embryo yield and quality was examined in Japanese Black cattle. It is concluded that a plasma P(4) level at the start of follicle stimulating hormone (FSH) injections is related to embryo quality. The P(4) level of over 3.