Identification marks and health marks are the oval-shaped markings found on food products of animal origin in the European Community, required by European Union food safety regulations. It identifies the processing establishment that produced and packaged the product and that is therefore responsible for its hygiene status.
The identification and health marks are not an indication for the specific origin of a particular piece of food by themselves, as they do not encode the location of the farm that provided the initial raw product or livestock
https://en.wikipedia.org/wiki/EC_identification_and_health_marks
Long story short: They tell you where the yoghurt was produced, but not where the cow producing the milk was living.