Cross fostering is a recommended practice used to even up litter sizes and piglet birthweights after farrowing. If piglets then start to fall behind, they will often be swapped with a stronger piglet from another litter, or a new litter is created for the fading piglets. However, every time piglets are mixed with new litter mates, it takes time for them to re-establish the suckling hierarchy, and it can result in a lack of feed intake and reduced performance.

Swapping whole litters will reduce the stress normally experienced by the piglets from being moved and mixed with a group of new litter mates, whilst providing the weaker piglets the opportunity to recover through improved milk intake.

The Process

• Move the whole litter when it contains a number of piglets that are showing signs of reduced viability, onto a sow which is milking well
• The receiving sow must either be a young sow or previously have been a foster sow and she must be suckling a strong and uniform litter
• Move the strong litter to the sow from which the poorer litter came
• After the swap, the sows will follow their normal feed curves

A strong uniform litter can encourage a sow that is showing signs of poor milk production to start producing milk again.

Remember

• The age gap between the two litters must not exceed four days
• There must be the same number of piglets in both litters
• All the piglets must be healthy
• The swap between the litters must be direct, e.g. the sows should not be without piglets for an extended period
• After the swap give special treatment to the poorer litter, e.g. an extra heat lamp, a squirt of piglet booster etc.

As soon as there are signs of reduced performance and or more piglets are falling behind, the litter swap should be carried out.

The swap is likely to fail if:

• The swap is too late; the piglets in the poor litter may be too weak to suckle
• The sow with the poor litter is ill
• The poor litter is ill
• The sow has poor mothering ability and does not let piglets suckle
• The litter is restless because the sow is unwilling to let them suckle

Vigilance is key for litter swapping to be a successful management tool.

A successful swap will lead to more uniform piglets, improved piglet performance and reduced mortality.

Reference documents

• Action for Productivity 14: Newborn Management
• Action for Productivity 17: Colostrum: Food for Life

December 2014