Submitted to: Swine Improvement Federation Proceedings
Publication Type: Proceedings
Publication Acceptance Date: December 3, 2005
Publication Date: December 3, 2005
Citation: Blackburn, H.D., Welsh, C.S., Stewart, T. 2005. U.s. swine genetic resources and the national animal germplasm program. Swine Improvement Federation Proceedings. Interpretive Summary: A collection of germplasm for 16 breeds of pigs has been established by the National Animal Germplasm Program (NAGP). This collection serves as a source of genetic diversity for the industry and a source of germplasm that can be used to reconstitute breeds in the event of an industry or national emergency. To date, from 0.5 to 109% of the collection goals have been achieved among the targeted breeds. In developing the national collection a procedure has been developed to select boars within a breed based upon their genetic relationship to other boars. Such an approach helps guide the collection process. While process has been made in initiating collections, significant efforts need to be made over the next five years to provide the necessary genetic security for all swine populations.
Technical Abstract: The National Animal Germplasm Program (NAGP) has begun to develop cryopreserved germplasm collection for all U.S. swine breeds. In developing these collections the inbreeding trends for pig breeds have been computed. As of 2004, average breed inbreeding levels ranged between 5% and 6% for Duroc, Yorkshire and Hampshire breeds. These levels are similar in magnitude to Holstein and Jersey dairy cattle and indicate that genetic diversity is in decline for the three pig breeds. To capture the existing genetic diversity and develop a collection of germplasm that can be utilized to re-introduce genetic variation the NAGP has initiated the development of germplasm collections for 16 swine breeds and 12 industry lines. For each breed a minimum collection goal of 18,750 .5 ml straws and 100 boars was established. A procedure for selecting boars for the collection has been derived by using pedigree records to calculate genetic relationships, clustering like individuals (based upon the computed relationship coefficient), and selecting individual boars from each cluster. Across the 16 breeds the size of the collections range from 0.5 to 109% of the targeted quantity. Over the next five years breed and line collections will be further developed; a better understanding of swine genetic diversity (and how to use that diversity) will be determined; and, more effective cryopreservation protocols for semen and embryos will be developed.