This needs more testing for a more accurate result.
All of these attempts used the yellow dog.

Number of Wins/Number of attempts with that message

Ruff! Oh, yeah! I feel unstoppable.:   1/1
Ruff! My four paws feel lighter than:  3/3
Ruff! Today, I feel like I can win...: 7/8
Ruff! I'm here for my wife and child:  5/7
Ruff! Today I should do pretty well:  5/12
Rrr-Ruff! I feel like I could win but: 0/5
Rrr-Ruff! I should do all right!:      0/2
Rrr-Ruff! I don't feel much different: 0/6
Rrr-Ruff! I can't predict the future:  0/2
Hoo-whine bad message:                0/18

In Japanese version: Both 1st and 2nd place counts as a win.

ワン！ …オレ、今日けっこういけそうだなぁ: 6/14
ワン！ 今日は、足がいつもより軽い！: 2/2
ワン！ 今日の私は、勝てる気がする…: 6/7
ワン！ …妻と子供のために負けるわけにはいかない!: 1/1
ワン！ うーん、調子よさそうだ…！負ける気がしない: 4/4