Enhancing Litter Size


Age of gilt at first mating

Gilts should be 210 days

Weight of gilt at first mating

130 -140 kg

Condition of gilt at first mating

20 mm backfat.  Feed young gilts well to build up body condition

Which Oestrus in the gilt

Ideally after 2nd oestrus.  Note essential to meet batch breeding targets.  Mark gilts in each week with a different colour.

Nutrition of gilt from 95 kg

Ad lib feeding up to first mating.  Note floor feeding may not provide all gilts in group with ad lib feeding

With crated gilts it may be necessary to feed twice a day to maximise feed intake prior to first mating

Gestation feeding the pregnant gilt

Limit to a condition score of 3.5 or this will create a second litter size drop

Maximising lactation feed intake

10 kg by day 18 of lactation.  Ensure water supply excellent.  Ensure farrowing room cool enough.

Weaning to service

Maximise to service increase protein ie fish meal.

Possibly keep the sow in the crate and move the piglets and then feed another lactation feed.  Do not feed in morning, move and feed in evening

Post-service feeding

Controversial - standard advice 2.5 kg 14% protein 18 MJ 1% lysine for the first 14 days.  May be more critical - first 72 hours post-service

Feed quality

Mycotoxins can reduce litter size -  increase mummified

Vitamin A injectable

1 million units at time of weaning in sows and 5 days prior to service in gilts (15 days after last recorded heat).  Retinol Palmitate used.

Lactation length

Greater than 17 days.  Note gilts greater than 19 days.


Minimise drop-outs from herd to 10% per parity.  Parity 3-5 most productive.  Replacement rate needs careful management.  Ensure herd parity is correct. 


Heterosis on maternal side may account for 1 pig per litter.  Sows with large litters will tend to produce large litters next time.  Specific - Meishan effects


Ensure vaccination against Parvo is up-to-date.  Swine influenza reduces litter size.  Enterovirus and other viruses may reduce total born, decrease livebirths, increase mummified and stillbirths


Move at service or at 28 days once confirmed pregnant.  Implantation occurs at approximately 14 days.  Do not move or stress females from 7 to 21 days.  If crates are used, ensure gilts are accustomed to the crate for at least 10 days prior to mating

Air quality

Air temperature 16-18•C.  No draughts.

Boar fertility

Note Swine influenza and heat stress (infection and environment)

AI quality

Note long life extenders may results in bacterial contamination issues.  Note boar age also affects litter size.

Mating management

Cross-serving.  Two services. Natural service and AI.   Good polite stockpeople.  Pooled semen .  Watch “breeder fatigue”

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.

Maximise gilt litter

To maximise lifetime performance.  Use gilts as foster mum

Farrowing management

Reduced stillbirths and accurate stillbirths/pre-weaning mortality

Post-service environment

Provide quite post-service management to allow sows to sleep post-mating.