It is possible to find a sow if you have her ID-number or to find the ID-number of a sow if you only have her sow number 

Go to “Sows/boars”, “Animal”, “PigVision” and choose “1. Breeding stock”: 




Then you must add the column for ID-number. In the green filter line above “Number” you can search for the sow number and then find the ID-number and the other way around.