Where does animal cruelty begin?

This question cannot be answered in general.

The Animal Protection Act (TSchG) regulates cruelty to animals in Art. 26. According to this, anyone who intentionally or negligently mistreats, neglects, unnecessarily overexerts or otherwise disregards the dignity of an animal commits cruelty to animals in the legal sense. Anyone who kills an animal in agony or wantonly, organizes fights between animals in which animals are tortured or killed, inflicts avoidable pain, suffering, damage or fear on an animal in the course of animal experiments, or abandons or leaves an animal behind in order to get rid of it, also commits cruelty to animals.
In addition to cruelty to animals within the meaning of Art. 26 of the TschG, a number of other acts are also punishable, which are referred to by the TschG as "other offences". These include, for example, breeding, transporting, slaughtering, conducting animal experiments and other interventions on animals, or producing, breeding, keeping, using or trading in genetically modified animals in violation of the regulations. In addition, the Animal Protection Ordinance (TSchV) contains an extensive catalog of prohibited acts, broken down by animal species.
If a perpetrator violates the general regulations or the additional special regulations for certain animal species such as dogs or cats, he is liable to prosecution.

Anyone who observes a grievance should first research the relevant legal situation and relevant laws for the specific case and the animal species in question. In many cases, a discussion with the animal owner can also bring about a significant change.

Anyone wishing to report animal cruelty can file a criminal complaint with the police or directly with the cantonal veterinary office. A report of animal cruelty can be filed by anyone - involvement in the situation in question is not necessary.