Severus Sanctus Endelechius (or Endelechus) was the writer of De Mortibus Boum (or Bovum), i.e. On the Deaths of Cattle.
It is a poem belonging to the classical bucolic tradition, but also concerned with Christian apologetics. It mentions a cattle plague, which has been identified as rinderpest. Another title is Carmen bucolicum de virtute signi crucis domini.
He has been identified with a rhetorician Severus who was a friend of Paulinus of Nola known as Severus Rhetor. He probably lived towards the end of the 4th century.
References
Severus Sanctus Endelechius Wikipedia(Text) CC BY-SA