Patent No. EP2833909 (titled "Pcv/Mycoplasma Hyopneumoniae/Prrs Combination Vaccine") was filed by Zoetis on Apr 3, 2013. The application was issued on Feb 6, 2019.

Patent oppositions filed by competitors challenge the validity of a granted patent. These oppositions are typically based on claims of prior art, lack of novelty, or non-obviousness. They are a key part of the process for determining a patent's strength and enforceability.
The dossier documents provide a comprehensive record of the patent's prosecution history - including filings, correspondence, and decisions made by patent offices - and are crucial for understanding the patent's legal journey and any challenges it may have faced during examination.