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Through studies conducted at the LSU AgCenter’s Reproductive Biology Center (RBC), we have shown that beef bull semen processed and frozen from the 1960s is still as viable and produces similar pregnancy rates in beef females as semen processed in 2003. We also found that differences in animal temperament prior to artificial insemination (AI) is not associated with AI pregnancy rates.
We are evaluating the procedure laser-assisted zona hatching in experiments using frozen-thawed bovine embryos to determine if recipient pregnancy rates of in vivo-derived, frozen-thawed bovine embryos can be improved.
Studies on white-tailed deer have shown that pregnancy rates following synchronization of estrus and AI average 55 percent. Also, this laboratory has shown that semen from the testicles of hunter-killed bucks can be harvested, frozen, stored and thawed at a later date to produce viable offspring. Using this approach will allow us to preserve superior genetics for future use.
Somatic cell nuclear transfer, or cloning, is an important technique that has the potential of significantly impacting many aspects of animal production. Cloning can be used to enhance the propagation of superior animals and is the method of choice for the introduction of new genetic components into the genome of domestic animals. Scientists at the RBC are engaged in a number of experiments to improve the efficiency of this procedure in order to enhance its application in animal production and biomedical science. Pig and cattle somatic stem cells derived from fat have been isolated and culture conditions have been defined as an efficient source of cells from adult animals to be used as donor cells in the cloning procedure.
We are engaged in a number of studies to understand at a molecular level what determines the developmental competency of an oocyte and what factors determine how an embryo’s genetic program is expressed during development. By understanding how fertilization and normal development are regulated, we can develop procedures and management practices to reduce reproductive failure. Epigenetics is a process by which the expression of genes is controlled. Epigenetic modifications are passed on from one cell generation to the next. We are studying how these modifications can be altered in cells and embryos during development. The goal of this research is to determine methods to control these modifications such that embryos produced by assisted reproductive techniques develop to term at a higher rate and yield healthier animals.
