So covering the cows half in white paint, halved the number of bites?

Seems like a large number of flaws in this study:

1. This wasn't 100% so maybe flies avoided the painted cows and just went to bite the non painted cows in the study. Would this work if the whole herd was painted? I know from personal experience that the best mosquito repellant is to bring a "city slicker" as bait but you need DEET if one isn't available.

2. Maybe it's the paint and if you cover the entire cow the flies stay away entirely?

3. How long did this experiment run? Once they horseflies get hungry or ending their season, they get more aggressive (they are getting aggressive right now in Ontario)