NATIONAL ANIMAL GERMPLASM PROGRAM (NAGP)
Location: Plant And Animal Genetic Resources Preservation Research Unit
Title: Inseminating fresh or cryopreserved semen for maximum efficiency: implications for gene banks and industry
Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 19, 2009
Publication Date: October 1, 2009
Citation: Blackburn, H.D., Silversides, F., Purdy, P.H. 2009. Inseminating fresh or cryopreserved semen for maximum efficiency: implications for gene banks and industry. Poultry Science. 88:2192-2198.
Interpretive Summary: Developing germplasm collections in gene banks for animal genetic resources requires establishing germplasm collection goals, that consider capturing the genetic diversity of the population in question and the amount of germplasm required for reconstitution of the population or for other purposes. This is particularly important for chicken populations where routine use of cryopreserved semen in minimal. To achieve greater understanding this experiment evaluated the effective duration of a single insemination of rooster sperm (fresh and frozen-thawed) using an econometric approach. Results indicated that fertility with fresh semen reached a maximum efficiency at 6 days and an effective window can last up to 11 days. For cryopreserved semen inseminated intramagnally, maximum efficiency occurred at 8 days post-insemination, and the effective window of for fertile egg production lasted till 17 days past-insemination. These results were extended to compute the quantity of germplasm required to provide a 150% back-up of germplasm for population reconstitution. Using this information it was determined that the quantity of germplasm stored to conserve a chicken breed could be reduced by approximately 80% when compared to the FAO projections (386 vs 2,454 0.5 ml straws, respectively).
Developing germplasm collections in gene banks for animal genetic resources requires establishing germplasm collection goals, that consider capturing the genetic diversity of the population in question and the amount of germplasm required for reconstitution of the population or for other purposes. Computing collection goals for chickens is complicated by the need to account for the number of multiple eggs obtained per insemination. To address this issue fertility data were used in conjunction with econometric procedures determining production efficiency and diminishing returns. Experimental treatments consisted of inseminating fresh semen intravaginally (FIV), frozen-thawed semen inseminated intramagnally (FTIM), and frozen-thawed semen inseminated intravaginally (FTIV). Analysis revealed that the maximum efficiency for a single insemination was at post insemination day 6, 8, and 3 for FIV, FTIM, and FTIV, respectively. Furthermore, additional benefit from a single insemination can be garnered by continuing to collect and incubate eggs to day 11, 17, and 11 for FIV, FTIM, and FTIV, respectively. The ramifications of these results are profound when placed in the context of germplasm collection for genebanks. By using the FTIM treatment the number of germplasm samples needed to secure a chicken breed, at the 150% level, can be reduced from the FAO projection of 2,454 to 386 straws (0.5 ml). This represents a substantial reduction in collection, processing and storage costs for gene banks.