I recently had my dog spayed and found out from her pre-surgery blood work that her liver enzymes were a little higher than the upper limit of what they consider normal for most dogs. However, my vet wasn't worried because he said that this is considered normal for Jack Russell. I haven't heard this anywhere else though so I'm not sure what to think. Anyway, I have read other places that commercial dog foods are difficult for dogs to digest and that puts a strain on their liver. So, I have started making her food at home with Sojos "Europa" dried veggies mixed with raw meat/fish oil/ yogurt etc. She's much happier with this food anyway. I'm going to have her get blood work again and see if anything is changed.