Summary: The Pennsylvania Emergency Management Agency (PEMA) is the agency in charge of emergency response in the state. The issue of animals in disaster are dealt with in Emergency Support Function #11 - Agriculture and Natural Resources Annex (2019).
The Pennsylvania Emergency Management Agency (PEMA) is the agency responsible for disaster response and coordination. In the Commonwealth Emergency Operations Plan of 2019, several Emergency Support Functions (ESFs) are listed (plan available at https://www.pema.pa.gov/Preparedness/Planning/Pages/default.aspx).
Emergency Support Function #11, the Agriculture and Natural Resources Annex, states as two of its purposes are to "[p]rovide bulk food supplies; monitor animal feed and food production facilities and the health of livestock and food crops; coordinate animal safety/sheltering; protect natural, cultural, and historic resources."
Specific plan requirements begin on page 66 of the attached pdf.