Replacement rate needs careful management. Ensure herd parity is correct. Genetics Heterosis on maternal side may account for 1 pig per litter. Sows with large litters will tend to produce large litters next time. Diseases Ensure vaccination against Parvo good.
Swine influenza reduces litter size.
Implantation occurs at 14 days. Mating management Cross-serving. Light patterns The service area in particular needs to be well lit and have a 16 hours on and 8 hours off on a time clock. 500 Lux required.