Date of this Version
Frozen gene pools (semen or embryos) can provide a safe place for the storage of genetic material for many generations. Cranes (Grus spp.) are one of many species in need of gene pool protection. Of the seven species and four subspecies considered rare or endangered (Archibald et al. 1981), two, the whooping crane (G. americana) and the Mississippi sandhill crane (G. canadensis pulla), are part of captive propagation projects at the Patuxent Wildlife Research Center in Laurel, Maryland. Greater sandhill crane (G. c. tabida) semen cryopreservation, under study at Patuxent since 1976 (Sexton and Gee 1978; Gee and Sexton 1979, 1980), indicated a need to reevaluate semen diluents and cryoprotectant levels.
The present paper summarizes experiments that were designed to determine the effects of semen diluents and cryoprotectant levels on viability of frozen-thawed crane semen, sperm damage before freezing and after thawing, and techniques that would result in increased numbers of fertile eggs and progeny from cranes inseminated with frozen-thawed semen.