George- None of us can tell you the answer to that because we weren't there. He could have seen the baby as a toy due to not being properly introduced, or a ton of other possibilities.

While I agree with some of the things Cesar Millan teaches (Like giving dogs more exercise) For the most part I really disagree with his methods. They can often do much more harm than good, he's hurt a few dogs on his show, and there are much safer ways to go about things. Also, a lot of the "success" he has is actually learned helplessness.

Here are a few interesting reads about the subject of Cesar Milan and dominance training...

From Veterinarian, animal behaviorist, and dog trainer, Dr. Ian Dunbar:
The dog trainer's trainer

Veterinarian/animal behaviorist, Dr. Sophia Yin:
The Dominance Controversy | Philosophy | Dr. Sophia Yin, DVM, MS

Dr. Karen Becker:
The Alpha Dog Myth (Part 2): Abandoning the Dominance Theory

VCA Animal Hospitals:
Dog Behavior and Training - Dominance, Alpha, and Pack Leadership - What Does It Really Mean? | VCA Animal Hospitals

Association of Professional Dog Trainers:
Dominance Myths and Dog Training Realities

Pat Miller, CBCC-KA, CPDT-KA, CDBC:
De-Bunking the "Alpha Dog" Theory - Whole Dog Journal Article

Lisa Mullinax, CPDT-KSA:
Dog Whisperer, Dog Psychology and Cesar Millan

Association of Pet Behaviour Counsellors:
Why Won't Dominance Die? | Association of Pet Behaviour Counsellors

Lisa Mullinax, CPDT-KSA:
Cesar Millan - The Dog Whisperer: Critics Answers

There are also some really great videos out there.