The top leader is called the 'alpha' in canine behavioral science, followed by 'beta,' 'gamma,' and so on.
Literal
Top leader [topic-は] dog [possessive-の] behavioral-science [at-では] 'alpha' [quotative-と] called, below 'beta' 'gamma' [quotative-と] continues.
Explains pack hierarchy terminology. 行動学 (behavioral science) is an academic compound. ~と呼ばれ uses the passive to introduce the term. 以下 (below/following) introduces the rest of the hierarchy. The sentence bridges Western scientific terminology with Japanese explanation.