My dog doesn't eat!

My dog doesn't really eat a lot since all the time !! During his last visit to the vet, we saw he lost weight a lot. The vet advised me to feed him with dry dog food for baby, richer and more palatable. 
The vet gave me various samples. The cats love. Grrr  And my dog ​​seems to eat a little better. Sometimes I give him in my hand. If somebody has advices for me, to feed a dog who isn't greedy ..I want to listen to these advices ... 

Bill, my dog ...

 

Samples - food baby dog