Research conducted at Texas Tech University compared single vs. multiple insemination of gilts in an outdoor unit.

Researcher John McGlone reported the farrowing rate for gilts bred with multiple inseminations was 83%, as compared to 54% with single inseminations. However, the total number of pigs born was greater by two pigs per litter for gilts mated with a single insemination. Overall, the multiple inseminations produced more pigs per weaning group.

A newly established herd of 375 PIC Camborough Line 22 gilts was used in the study. A group of 150 gilts received a single dose of semen 24 hours after first being observed in standing estrus. The other 225 gilts were inseminated from two to five times, starting 12 hours after they were first observed in estrus.

The total number of pigs born was 12.2 pigs/litter for single insemination and 10.2 pigs/litter for gilts bred with multiple inseminations. McGlone found that total productivity was greater for gilts given multiple inseminations. For 100 gilts mated, single insemination would result in 659 pigs compared to 844 pigs from gilts given multiple inseminations, a reflection of their higher farrowing rates.

Researcher: John McGlone, Texas Tech University. Phone McGlone at (806) 742-2826 or e-mail