The Treaty of Lisbon, which entered into force on the 1st of December 2009 amends the current founding treaties, i.e. the Treaty on European Union (EU Treaty), which will retain its name; and the Treaty Establishing the European Community (EC Treaty), which will be renamed as the Treaty on the Functioning of the European Union (TFEU).
Title II of TFEU lists some key principles the Union should respect. Here an Article 13 has been introduced with the Lisbon Treaty. It states that: "In formulating and implementing the Union's agriculture, fisheries, transport, internal market, research and technological development and space policies, the Union and the Member States shall, since animals are sentient beings, pay full regard to the welfare requirements of animals, while respecting the legislative or administrative provisions and customs of the Member States relating in particular to religious rites, cultural traditions and regional heritage."
This puts animal welfare on equal footing with other key principles mentioned in the same title i.e. promote gender equality, guarantee social protection, protect human health, combat discrimination, promote sustainable development, ensure consumer protection, protect personal data.
It needs, however, to be noted that the European Union operates under the principles of conferred competences and subsidiarity. So competences not conferred upon the Union in the Treaties remain with the Member States and under the principle of subsidiarity, in areas that do not fall within its exclusive competence, the Union shall act only if and in so far as the objectives cannot be sufficiently achieved by the Member States (Article 1, 4 and 5 of the EU Treaty). As a consequence certain topics of animal protection remain under the responsibility of the Member States (e.g. the use of animals in competitions, shows, cultural or sporting events and the management of stray dogs).