Why add a foster piglet?
So the system can reflect every thing that actualy happens on the farm. If the animal was shifted inside the breeding or anyother fase S4 must contain the information.
May I foster a piglet while adding a weaning?
Yes, you can fill this info on the weaning screen. But if you use the Genetic module, this option does not exist, is an earlier and separated step, to guarantee the control of each individuo.
What is a Nurse Sow?
A nurse sow is a sow that has already weaned it's litter, became empty, is lactating and foster on some other sow's piglets.
Why to add a nurse sow?
Several reasons led to add a nurse sow:
A sow has farrowed a litter so big that it cannot feed it all, therefore you foster off to another sow some piglets to make sure it's all well fed;
The sow farrowed a litter and died after or during the farrow or before the weaning, the litter will be fostered by a nurse sow.
This matter will be handled according to the reality of each farm.
Obs: when a sow is milk dry or died during farrow it's necessary to foster foo the whole litter, therefore S4 add automaticly a null weaning, lowering the weaning rate. However once the nurse sow foster on the litter, it's weaning will rebalance the weaning rate.