Time-lapse videomicrographic observations of blastocyst hatching in cattle.

Morphological changes of cultured bovine blastocysts during hatching were observed using time-lapse videomicrography in order to investigate the patterns of the hatching process that occurred in the blastocysts and to determine whether the hatching patterns differed between blastocysts developed from fresh and cryopreserved embryos. Compacted morulae (CMs) were collected from superovulation-treated Japanese Black and Holstein dairy cattle and cultured in a medium in a CO(2) culture chamber equipped with an inverted microscope at 38.5 C.

Biological and immunological characteristics of porcine follicle-stimulating hormone chemically modified with a polyethylene glycol derivative.

Porcine follicle-stimulating hormone (pFSH) was chemically modified with a polyethylene glycol (PEG) derivative to form PEGylated pFSH. The hormone was conjugated with a succinimidyl ester of methoxy PEG propionic acid (mPEG-SPA) at stoichiometric molar ratios of 1:0, 1:1, 1:3, 1:10, 1:30 and 1:100. The molecular weight of PEGylated pFSH increased depending on the stoichiometry of the conjugation reaction.

The effect of pretreatment with different doses of GnRH to synchronize follicular wave on superstimulation of follicular growth in dairy cattle.

The objective of this study was to evaluate the efficiency of gonadotropin releasing hormone (GnRH) and GnRH doses in synchronizing follicular wave emergence as a pretreatment for superovulation in cattle. Fourteen Holstein-Friesian cows 6 days from estrus were randomly assigned to receive 100 microg (n=4), 50 microg (n=5), or 25 microg (n=5) of GnRH. Superovulation was induced with injections of porcine FSH (pFSH) twice daily, decreasing the dose (total 42 AU) over 5 days beginning 2.