Feed and forage toxicants affecting embryo survival and fetal development.

Early embryonic and fetal development in mammals is sensitive to deficiencies and excesses of specific nutrients and toxicants. Operating directly and/or indirectly, these deficiencies and excesses can result in embryonic death or, in less severe circumstances, disruption of normal embryo and fetal growth. This paper explores the threats posed by feed and forage toxicants to the developing embryo and their impact on early programming of fetal development. Using significant examples, we consider the relevance of temporal sensitivities during early development in utero, and their implications for the morphology and functional competence of specific organs and tissues.