Definition, objectives of Veterinary Embryology and its relations with other subjects. Gametogenesis: germ cells, oogenesis and spermatogenesis, meiosis. From ovulation to the implant: notes on the ovarian cycle, fertilization, cleavage and formation of the morula and blastocyst. Formation of the bilaminar and trilaminar germ disk. Origin and formation of the mesoderm and notochord.The ectoderm and its main derivatives.The endoderm and its main derivatives. The mesoderm and its main derivatives. Placenta and fetal adnexa: chorion, amnion, allantois, yolk sac, umbilical cord. Structure, function and classification of placentas.