Embryo recovery, evaluation, storage and transfer in goats

Abstract

Embryo recovery, manipulation and preservation (frozen at −196°C) with cryoprotective agents like glycerol or dimethyl sulfoxide make future transfer of genetic resources possible. Survival of embryos has been better for those beyond the two-cell stage of development. Positioning transferred embryos in the oviduct or uterus, and ovaries with functional corpora lutea (CL) in the recipient doe are factors affecting successful implantation. Techniques in embryo recovery, temporary storage, longterm preservation of goat embryos, and methods of transfer for successful pregnancy in goats are reviewed. It is concluded that over 70% of fertilized ova can be surgically recovered from most superovulated does using exogenous hormones like equine anterior pituitary extract (HAP) or follicle stimulating hormone (FSH). Embryos, after microscopic morphological evaluation, can be temporarily stored cultured in bicarbonate or phosphate buffer saline medium enriched with homologous goat serum, for 2–3 d at below 10°C, or indefinitely at −196°C in liquid nitrogen. Successful transfer with good embryo survival has to take into consideration the stage of development (2–3 d post fertilization; 2–12-cell stage), rate of ovulation or state of CL of recipients and place of deposition of embryos relative to CL.