Everyone is 100% entitled to their opinion but no one should be pushing their opinions as "FACT" when there are articles and research that says otherwise.
The article by the vet was published probably over a year ago on her Facebook page so I am not going to spend countless hours of my time trying to find it but there are plenty of other articles available.
Here is one from 2018 from Dr. Becker, a separate article from what I was referring to:
Repawsitory
October 8, 2018
For the sake of health, we don't eat diets of entirely processed foods; neither should our dogs. Yes, we can mix processed and fresh foods, even raw, together!
There's this idea out there that to feed fresh (including cooked) foods, but especially raw, that you have to go all in and completely give up the commercial processed foods or you are going to make your dog ill.
We won't get into where that idea originated or why it became so entrenched, but there is a common-sense movement, growing every day, that encourages the feeding of fresh and raw foods even if you can not, or don't want to, give up the processed pet foods entirely.
In particular, the movement encourages the feeding of 20% fresh into a processed diet. Why 20%? Because that small of an amount is where you start to see health benefits, but that amount is not going to mess with the balance being provided by a good quality processed diet. Everyone can do 20% no matter their need for affordability and convenience, or their knowledge level for balancing a diet. It is an obtainable goal where going all fresh / raw may not be for some.
Of course, fresh feeders are hoping that this 20% will be a toe-in-the-door and that you'll become keen to learn about how you can go more and more fresh and still provide your dog with a balanced diet.
But, the notion that mixing processed and fresh is bad for the dog persists out there putting forth that the dog's gastric pH is affected by the consumption of processed foods and therefore unable to properly digest the fresh and raw foods, especially if bone is fed.
Yet, dogs have been eating fresh and kibble since kibble first came into being. Many dogs are fed diets that include kibble and raw. Not everyone bought into the kibble marketing gimmick which was aimed at getting pet owners to give up the table scraps and feed only kibble and only their particular brand of kibble. Many people still fed fresh on top of, or in addition to kibble. Despite the all-fresh or all-raw backlash, many dogs continue to be fed combination diets to no ill effects.
Sure, transitional GI upset can occur whenever a dog switches up to something new, especially a dog who has been mostly fed the same thing day in and out. It can even happen when you change brands or protein sources from kibble to kibble. You can deal with GI disruption by having some organic canned pumpkin on hand and some slippery elm is always handy too. You can also avoid or minimize it by doing a slow transition to anything new going into the bowl, and holding back further increases until the GI system is normal again before proceeding with greater proportions of the new food. (Below, there's a link to a great article on transitioning.)
My own dogs eat a fresh food diet with no kibble, but can eat whatever whenever ---we have no GI issues whatsoever even switching up within the same day. It is a matter of what they get used to and getting them from a static gut to a more dynamic one.
Of course, dogs are individuals and you always need to feed the individual dog before you at the bowl, dealing with their tolerances and preferences, but again, slow transitions over to the fresh-adds or entirely fresh meals can help dogs unaccustomed to having fresh foods added to their bowl, and can allow you to identify what ingredient it is that does not agree with your dog.
Bone is another big one that holds people back from freshening up the bowl. There is information out there that says the bone will not be properly digested by a "kibble gut". Personally, even if I believed that to be entirely true, it would not hold me back from adding fresh; I'd just make adjustments for that by feeding meals that included bones or ground bone separately from those that included kibble, even on different days. Many are simply fearful of the idea of feeding whole bones at all, and doing so does come with some thought and precautions required, but you can feed a fresh or raw diet without feeding whole bone by feeding ground or supplements. When freshening up the processed bowl by just 20%, you need not even include any bone at all. So, don't be held back by bone.
But, we're people and dogs are dogs, right? And the choices we make for feeding are very individual ones. So, go out and learn all you can before you decide to forego the benefits of adding fresh to a processed diet because you are feeling the pressure to feed all raw, all fresh, or none at all.
And more articles:
Yes, you can mix raw and dry dog food but how? Problems can arises when you lump a whole lot of fresh meat into the dogs dietā¦
dogsfirst.ie
To answer the question simply: yes, you can. Perhaps youāve heard otherwise, or there are some caveats. Thatās what this article will get into.
www.fetchingfoods.com
canine.care
Cut through the confusion surrounding raw and kibble dog food; our authoritative guide explains the safety of mixing both for your pup.
www.wefeedraw.com
So again, you can believe the 2 shouldn't be mixed at all but you should not be stating that your opinion is a FACT.