I can only speak of the tests ive done on these dogs in my lab.... It increases the volume of seminal fluid(not prostatic or presperm although those usually contain trace amount of viable sperm also just not nearly as much) while maintaining the same amount of sperm per ml... make sense?
Say a dog has 90million for a count... but only gives u 5ml. Using Trib the same dog will give u 90mil, but 10ml. IMO volume plays a big part when doing an AI.