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Why am I supposed to mix foods when I switch pet foods?


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  1. Dianne

    When Royal Canin switched their sensitive stomache prescription food from chicken base to pork based without any warning, it makes one wonder how serious they are about their insistence of a gradual switchover. Do puppies get their initial gut flora from their moms? If so, wouldn’t it mean that if the mother is only fed one food, that the puppies start out with a disadvantage in the gut area?

    1. Peter

      What a dreadful, dangerous, and “insensitive” (no pun) tack for a pet food manufacturer to take.

      My understanding is that the population of fauna within the cat or dog’s intestinal tract changes over time, to “adjust” to the food(s) presented. If a dog or cat is fed the same food for long periods (“my cat won’t eat anything but…”), the animal’s gut adjusts by maintaining only the bacteria that is “necessary” (my words). Unneeded (good) bacteria simply dies off. So if the pet guardian switches foods– even to a “better” or “super premium” food– the animal can or even will get “sick” since s/he does not have the proper range of bacteria to digest the food. The frustrated pet guardian reacts “my cat/dog can’t stand or can’t tolerate” X-brand, and returns to the old food. So many people, particularly with “fussy” cats, get into this cycle.

  2. Caron

    Excellent article. Thank you. My 19 year-old cat Pearl developed chronic diarrhea after a bout with an intestinal bug. Her blood work was fine so the vet suggested metronidazole and probiotics.

    The problem was also that Pearl was losing her appetite. They had no real solutions for that.

    I tried many different canned foods and even cooked, but she just didn’t want much.

    So I went back to grinding whole chickens and livers and feeding her a raw diet. Her appetite gradually improved and her stools are now normal.

    I wish the vet schools weren’t controlled by Science Diet, Royal Canin, etc because a whole lot of folks can’t afford a holistic veterinarian and what they teach about nutrition is garbage, just like a lot of their food.

    And when people think their car is being fussy, I’m sure it’s because they’re feeding garbage foods and the cat just wants fresh, real food.

  3. Carol D.

    One thing you didn’t mention is the possibility of whip worm, it is more widely spread than many thing and rarely drops eggs. The symptoms you mentioned are whip worm symptoms. They also cause a “dry” strip of hair down the back with the tips that curl up – but usually after the problem is pretty bad. Lass of appetite, a roached up topline and tummy cramps are also included. Whip worms attach to the walls of the intestines and can cause leaky gut syndrome, fenbendazole is the first thing I reach for when I have a dog that shows those symptoms. I am retired now, but was a long time dog show breeder and exhibitor and became quite familiar with this problem. One of our good show dog oriented veterinarians told us that, because the eggs are persistent in the environment, the vast majority of the dog show grounds have them and he felt 90% of the show dogs would have them. They are easy and safe to treat and hard to diagnose, so I like to increase awareness. Thanks for the work you do regarding dog foods and their how unsafe they are.

  4. Nancy

    A species appropriate diet plus a holistic veterinary team does wonders. As do traditional chinese herbs and acupuncture for more persistent cases.

  5. Paul

    Great article. I have often wondered why healthy dogs would have such problems switching food. It’s because the quality of their food is so bad. I feed my dogs real, human grade food and have never had these problems. Thanks Kathy.

  6. Dianne

    My dog has rather bad allergies and I have actually had more luck with control by feeding different foods at every meal. Contrary to what most any vet dealing with allergies will tell you.

  7. Caron

    Whatever you need to do to stay safe, is fine with me Susan. I can’t tell you how much I appreciate you and your work.

  8. Hannie

    My Lab never has the same bag of kibble twice (except maybe months apart). I have two bags open at any given time & she has one in the morn & the other in the evening. She has never had any kind of digestive upset from switching food. I don’t trust any commercial food enough to give it to her all the time so I constantly switch around. She is a very health 11 yo who still loves to chase her tennis ball……not as much as she once did but she still loves to run. I believe that switching dry food & home cooking the rest is the best thing you can do for your dog. I do know people that have fed the same kibble for yrs & won’t believe me when I tell them to switch to another brand. Next most important thing is exercise…….even small dogs need exercise……

    1. Hannie

      Susan…….why did that video wind up in the middle of my comment & cut some of it off? I have no idea who posted that video but it wasn’t me & it took out some of my post……

  9. Virginia

    I have always ignored employees of pet food stores’ warnings directing me to mix the new and old food
    together rather than feeding the new food all at once. I buy healthful food for my dogs and they have
    never had any problems with sudden food changes. I have 2 healthy race bred whippets who, at 12 and 13 are still running faster than any non sighthounds. I agree with Hannie’s post.

  10. Michele

    You mentioned fermented goats milk. What are the benefits of this. I thought dogs should not have dairy?

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