Maternal conditioning effect: How sows use chemically coded messages to communicate with their piglets to improve feeding behaviours

Sows can communicate with piglets through chemically-coded messages, known as volatiles.

Some of these chemicals originate in maternal diets and can be transferred through maternal fluids such as amniotic fluid, colostrum, milk, faeces and carpal gland fluids, to influence piglets’ feed intake and behaviours. 


This research will identify whether volatiles in feed from grains and pulses have different transfer efficiencies into sows’ amniotic fluid and milk, and any subsequent effect on feed intake behaviour of piglets.

This could lead to the modification of maternal diets, allowing piglets to overcome neophobia (fear of new foods) to help with the weaning transition.

This international collaboration of animal scientists would be part of a PhD studentship funded by the Australian Research Council.

Plan of work

Sixty indoor-reared sows and their piglets will be used. Sows will be provided a low or high sensory profile diet in the final third of gestation and then will be given one of four four diets from a week before farrowing until four weeks after: 

  • low sensory profile diet (L1); 
  • L1 with volatile booster (L1+); 
  • high sensory profile diet (L2); 
  • L2 with volatile booster (L2+). 

All sows will be weighed and body condition scored and will have blood, carpal gland fluid, urine and faecal samples taken when entering the farrowing house. Eight sows per treatment will have blood, carpal gland fluid, urine, milk and faecal samples taken and on days 5 and 12 after farrowing. Amniotic fluid and colostrum will also be collected at farrowing.

All piglets will be weighed and 3 piglets per litter (from the same 32 sows) will have umbilical blood and cord collected and a rectal swab taken using sterile cotton swabs.  

Two, 12 and 21 days after birth, the same 3 piglets per litter will have a faecal swab taken. After weaning, 80 piglets per treatment, from one production batch only, will be housed in pens of five and allocated to one of four diets, matching what their sows had received.

Four days after weaning, 2 pigs per pen will have blood, rectal and saliva samples collected. Ten and 14 days after weaning the same pigs will have saliva and rectal samples collected, respectively. All pigs will be health checked daily. Feed intake and body weight gain will be recorded for 14 days after weaning, then all pigs will return to the commercial herd. 

Animal welfare

Pigs will be housed on a commercial farm that meets current UK legislation and standard husbandry practices. Pigs will be health checked daily and medicated as appropriate. Regulated procedures will be carried out by Home Office-trained technicians to ensure comfort and minimise stress. 

Three Rs


Given the potential benefit of the sow diets to commercially housed piglets, they are the only appropriate species option and replicating commercial housing is required. 


The number of animals used for sampling has been calculated using a power analysis to estimate the smallest sample size needed to give a statistically significant and conclusive results.


Sampling methods chosen are the most appropriate method to measure the transfer of volatiles from sows to the piglets. 

Non-technical summary

Read maternal conditioning effect: How sows use chemically coded messages to communicate with their piglets to improve feeding behaviours non-technical summary (PDF).

This PDF may not be suitable for users of assistive technology. If you need an accessible version please email

Related links