As for the 'Ted Talks' I kind of ignored them for a number of reasons:
1. No reason to believe that they're peer reviewed.
2. Audio would be incredibly rude where I was at the time.
3. I'm a visual learner - listening to youtube lectures is painful for me.
4. My conclusion from the earlier 3 was that the latter 3 would be more the same. On reaching home, I confirmed this.
Anyways, some more articles on antibiotic growth promotion:
It improves growth, but not enough to justify the cost in chickens grown in clean & sanitary environments
The Mode of Growth Promotion by Antibiotics
The European ban on growth-promoting antibiotics and emerging consequences for human and animal health. link
Alternatives to Antibiotic Use for Growth Promotion in Animal Husbandry link
Effect of Abolishment of the Use of Antimicrobial Agents for Growth Promotion on Occurrence of Antimicrobial Resistance in Fecal Enterococci from Food Animals in Denmark link
Antibiotic Usage in Animals link
Conclusion: The cattle industry isn't feeding billions of dollars of antibiotics to their animals for fun.