Early embryonic mortality in modern dairy cows: Causes, consequences and remedies

Lactating dairy cows experience a temporary infertility syndrome. There is a multiplicity of factors contributing to early and late embryonic losses. Some of these factors begin within the postpartum period in association with dynamic metabolic and condition changes of the cow. Other factors include uterine health, as the cow enters the breeding period. Programming the preovulatory period with optimal recruitment and growth of the follicle influences subsequent quality, viability and survival of the embryo via direct effects associated with quality of the oocyte and indirectly via endocrine regulation (i.e., follicle and corpus luteum function) of the oviduct and uterus. The maternal-embryo unit appears to be responsive to reproductive management as well as pharmaceutical and nutraceutical programs to enhance pregnancy rates.