Normal development following in vitro fertilization in the cow

Area of Science:

• Veterinary Science
• Reproductive Biology
• Embryology

Background:

• In vitro fertilization (IVF) in cattle requires efficient oocyte maturation and sperm capacitation techniques.
• Previous methods lacked repeatability and consistent success rates for bovine embryo production.

Purpose of the Study:

• To establish a repeatable in vitro fertilization procedure for bovine oocytes.
• To assess the viability and developmental potential of in vitro fertilized bovine embryos.
• To identify key factors for successful bovine IVF.

Main Methods:

• Oocytes were retrieved from ovarian follicles or oviducts after hormonal stimulation (pregnant mare's serum gonadotropin and prostaglandin F2 alpha).
• Sperm capacitation involved incubation, high ionic strength treatment, and incubation in defined medium before insemination.
• Frozen bull semen was utilized in some experiments.

Main Results:

• Fertilization rates varied by bull and oocyte source, with up to 62.9% fertilization of tubal oocytes achieved.
• In vitro development progressed to the 8-cell stage.
• A normal bull calf was born following the transfer of a 4-cell stage embryo derived from in vitro fertilization.

Conclusions:

• The developed procedure is repeatable for bovine oocyte fertilization in vitro.
• Vigorous progressive sperm motility and acrosome integrity are crucial for successful IVF.
• The birth of a normal calf confirms the potential of this IVF technique for cattle reproduction.