A retrospective study on effects of storage time of liquid boar semen on reproductive performance in Norwegian swine.

The objective of this retrospective field study was to determine the effects of storing, for up to 62 h, heterospermic and homospermic semen in the short-term extender Beltsville thawing solution (BTS), on reproductive performance in Norwegian swine of four different breed combinations. The study was based on fertility records after single or double inseminations with semen collected at an AI station in Norway from January 1998 to June 2001. Increasing the duration of storage of homospermic semen, but not heterospermic semen, from an interval of 4-14 h to an interval of 52-62 h, was associated with a 0.5 piglet reduction in litter size. There were differences in reproductive performance among breed combinations that appeared to be associated with duration of semen storage. In conclusion, prolonged semen storage decreased reproductive performance; the extent varied among breeds and was prevented by the use of heterospermic versus homospermic semen.