Well most guard dogs start of with barking at the intruder, so when you say that they can't startle the game i can only think of a tosa inu wich are silent  fighters but

aren't the preffered color.

i' am from the region where the belgian malinois originated and i am amazed by these dog and i know what they are capable of ,  but personaly i think they are a bit on the small side 

kind regards