NYS PENAL LAW 120.05
120.05 Assault in the second degree
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3. With intent to prevent a peace officer, police officer, a fireman,
including a fireman acting as a paramedic or emergency medical
technician administering first aid in the course of performance of duty
as such fireman, an emergency medical service paramedic or emergency
medical service technician, or medical or related personnel in a
hospital emergency department, from performing a lawful duty, by means
including releasing or failing to control an animal under circumstances
evincing the actor`s intent that the animal obstruct the lawful activity
of such peace officer, police officer, fireman, paramedic or technician,
he causes physical injury to such peace officer, police officer,
fireman, paramedic, technician or medical or related personnel in a
hospital emergency department;
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Assault in the second degree is a class D felony.
If they actually cause physical harm then it's a class-C felony.
http://ypdcrime.com/penal.law/article120.htm