Objective:
Evaluation of post-thaw motility and fertility of cryopreserved Angus semen frozen that had been collected and stored from the 1960¿s through 2004/2005.

Approach:
Semen collected and cryopreserved from 25 Angus bulls in one of three time periods (1960-1975, 1976-1990, and 1991-2005) will be used to inseminate 180 cows at the Louisiana State University (LSU) Agricultural Research Center. Prior to insemination various post-thaw analysis of the semen will be performed at the National Center for Genetic Resources Preservation (NCGRP), National Animal Germplasm Program (NAGP) and at LSU. Upon determining the fertility rate for the time treatments statistical analysis will be conducted to evaluate the effect of storage time on fertility level. Additionally, LSU will perform in-vitro fertilization studies with the semen samples. NAGP will perform analysis exploring the ability to predict fertility using various motion characteristics of the sperm.