“Holy Bovines” comes from “Holy God”, meaning intense surprise. Some people believe that using the name of God is unrespectful in this situations, so other people started using “Holy Cow” as a mock up because of the the close sound. “Holy Bovines” is just a comical derivative, and I would not use it unless writing a comic strip…
H-O-R-S-E is a variation of basketball. See http://en.wikipedia.org/wiki/Variations_of_basketball