New Technologies for Manipulating Bovine Reproduction

Abstract

The reproductive process is a continuum of events that occur cyclically throughout the life of an animal, starting with fertilization, and continuing through embryonic and fetal development, parturition, the neonatal development period (including lactation), puberty, ovulation, and establishment of pregnancy once again. A number of malfunctions and technological interventions can be superimposed on this sequence, including post-partum anestrus, such technologies of selective breeding as artificial insemination and embryo transfer, and such management techniques as inducing twin pregnancies and decreasing intervals between calving. Many aspects of reproduction can be manipulated: induction of parturition, lactation, puberty, ovulation, twinning, abortion, etc. Detection of ovulation, diagnosis of pregnancy, and determining or manipulating the sex of offspring also are of obvious value. In addition, many things can go wrong in the reproductive process, including mastitis, dystocia, venereal disease, embryonic death, cystic ovaries, and dozens of other pathological conditions.

Many approaches exist for manipulating reproduction and dealing with reproductive pathology, including more or less new technologies. I have chosen to concentrate on three items. The first is getting the cow pregnant; the second, in vitro oogenesis; and the third, adding genes to embryos.