Judging the Biological Value of Dog Food Protein


Judging a Dog Food's Protein Quality

Feathers. Beaks. Hooves. What do these three types of body parts all have in common?

They each contain a high amount of protein.

Yet unfortunately, it’s mostly unusable protein — protein that’s nearly impossible for a dog to digest.

High Protein May Not
Mean High Quality

Just because a particular dog food boasts a high protein content doesn’t necessarily mean the protein is beneficial.

That’s because a product’s stated protein percentage can ignore a very important factor — its nutritional value to the dog.

Biological value is a scientific way to compare the nutritional worth of different protein ingredients. It’s a measure of a protein’s ability to supply amino acids — especially the 10 essential amino acids.

And to supply them in the appropriate proportions.1

Biological value (BV) uses a number to represent how nutritious a protein is to the animal.

BV = (protein used/protein available) x 100

In other words, the higher a protein’s biological value — the more usable it is to the animal.

The Incredible Egg

Due to their near perfect usability, chicken eggs are used as the official benchmark by which all other proteins are judged.  So, eggs are assigned a reference biological value of 100.

Take a look at the following table2.  And notice the substantial difference in protein usability of these typical ingredients


From this table, it’s easy to conclude…

Animal protein can be expected to demonstrate a notably higher biological value than vegetable protein1

That’s why it’s crucial to check a dog food’s list of ingredients and judge the product’s dominant source of protein. Otherwise, you could be depriving your pet of better nutrition.


  1. “Nutrition for the Adult Dog”, Virginia-Maryland Regional College of Veterinary Medicine, Client Information Handout
  2. Palika, Liz, The Consumers Guide to Dog Food, New York, Howell Book House, 1996
  3. “Nutrition for the Adult Dog”, Virginia-Maryland Regional College of Veterinary Medicine, Client Information Handout
  • Ame

    Make sure your dogs food is GMO free. I fed my beautiful dog Walmart food kibbles and he started passing blood all over the house huge puddles. I took him to vet and she said it was the food cost me $350 my poor baby almost died. This. Is what the walmartsclosingdown shoppers look like because of the GMO food they sell. https://uploads.disquscdn.com/images/be370151ce40b0eaf423fda2aff57f1b57cfb0eb7c6a30f04c0c549325f3fd28.jpg

  • John Smith

    it is supposed to be Cheese, I think.

  • Bobby dog

    Yes, thanks for posting. I was looking for my info on the subject and I can’t find what file I bookmarked it under. It is an easily understood explanation.

  • Crazy4cats

    Thank you. Great article. Have you ever contacted a company and ask them what their food’s digestibility rating is?

  • Bobby dog

    It always boils down to math. Good thing you had a little practice this afternoon!! 😉

  • Crazy4dogs
  • Crazy4cats

    This chart was recently brought up on another thread. I’m curious does a high biological value equal high digestability?

  • Elana

    Hey, I have a 2 year old Dalmatian. She eats Zignature Trout and Fish, and I feed her 2 1/2 cups per day. Her weight is perfect, skin and coat is great, and no urinary stones. Purine and protein levels are different, stay away from game animals. Hope this helps!!

  • KC Etcetera

    Hello, I have a 1 1/2 dalmatian, I am mostly looking for low purine dog food, and as far as I know most people associate low protein and low purine.. I am actually feeding my Dal with the Hills c/d urinary tract health, but my dog doesn’t have any crystals nor stones, and as I can see the list of ingredients starts with whole grain corn? Is there anything else better than this food that I am paying 110$ per bag? I have to give him 5-6 cups of it as I can’t keep weight on him …?

  • Tracie

    Eggs have a Bio Value of 100 way better source of quality protein (as long as you leave the yolk part out once in awhile due to being very high in cholesterol)

  • Tracie

    Dogs can develop severe inflamation of the pancreas from greasey treats like this, once a month for puppies and best avoided in older dogs.. A piece of human grade boiled meat or egg whites once in awhile is good enough for an older dog – people overfeed their animals junk treats!!

  • Tracie

    NEVER buy anything thats the cheapest, you only get what you pay for and your poor dog doesnt want to get stuck eating f*cking garbage its whole life!! The dog went from neglectful owner to… come on get smart and do your research!!!

  • Dori

    Love your answer Labs. LMAO, you are so right.

  • LabsRawesome

    To answer your question, the white long things in Ol’roy Kibble Chunks and Chews are garbage. The whole ingredient list is garbage. Please get your dogs a better food. You don’t have to spend a lot. Maybe $10 to $15 more per bag. Walmart carries some pretty good foods. Rachael Ray Zero Grain, Evolve, Pure Balance.

  • stephen

    all I can say to not have arguments is dog food is like person food we don’t know what we are eating either or what it is made of if everything was safe we wouldn’t have inspections on everything so for my question does anyone know what the white things are called in the bag of kibble n chucks

  • Cyndi

    Pedigree is not much better, if you look at the review on this site. Spend a few more dollars and get Pure Balance, canned or dry. It is also sold at Walmart. Or better yet, if you can afford it, look at all the 4 or 5 star foods and find one & feed something even better quality to your new pooch.

  • kmaero1

    don’t mean to butt in but I haven’t had a dog since I was a kid (but I recently rescued one from a neglectful owner.) I went and bought the cheapest stuff at walmart which was ol’ roys.(we fed our dog right off the table his whole life) Took her to the vet and she asked what I was going to feed her(since the former owners were still feeding her puppy-type dog food and she’s 2 1/2 and 85 lbs) She said “throw it away- it has no nutritional value.” It’s crab bait now and they seem to like it. She said spend the dollar more and buy pedigree if you’re on a tight budget.

  • stephen

    ol’ roys kibble n chunks

  • Dori

    Which specific dog food are you asking about?

  • stephen

    what is the white long things called that is in it my dogs love those things

  • Shawna

    Not sure why you got a down vote??

    For those reading — the test Dr. Dodds does is for food intolerances and it is a saliva test not a blood test and can be done at your vet’s clinic and sent to Dr. Dodds for analysis.. Dr. Dodds test does not test for all foods. But for those it does test, like guest above, I’ve heard it is accurate.

    “Blood tests” for food allergies are likely to produce false positives and false negatives and therefore are not very reliable. This is a different test than Dr. Dodds test though.

  • guest

    hi! for the one wondering about blood tests for food allergies yes dr. jean dodds from hemopet does this test and they are right on target. look her up on line a small fee to do this but so worth it hope this helps.

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  • Costco’s dog food is manufactured by Diamond Pet which is all made in the US http://www.diamondpet.com/faq/. So they would be the ones to contact if you wanted further information.

  • Bill

    Dr Mike, are you comfortable in your assertion that protein from feathers (!!) is not useful for a dog? I recently learned that feather meal (hydrolyzed under heat and pressure) is used in feed for cattle and chickens. In other words, is the objection more than aesthetic? I’d make the same point about chicken meal in dog food which is made from chicken “frames.” Is it bad nutritionally? Thanks.


  • doggonefedup

    pig ears are full of pig fat. Better known as lard. Lard has a very long shelf life and is used as a preservative. Lard is also the best land based source of long chain omega 3’s, 6’s & 9’s. And since pig ears are mostly skin they are also a high protein treat. Not to mention the chewing action helps clean their teeth. So as long as they are not loaded with additives during the drying process pig ears are a very healthy treat for dogs.

  • zendawg11

    Pig ears are full of grease and unhealthy for dogs to digest. There are much healthier ways to reward your dog.

  • BryanV21

    Pig ears are fine if they come from a reliable source and are all natural, meaning there is nothing added to them (preservatives, etc). My store has sold them before (currently out of ’em).

    Yes, they are high in fat, but then again… so are most treats. Coconut oil is very high in fat, but it’s anti-fungal properties make it great not only as a treat but to rub on things like hot spots.

    Just like any treat you have to give them correctly.

  • Alison Frank

     Another treat to avoid is those pig ears and pig snouts –high fat content, and who knows what poisonous preservatives have been used. My old guy LOVES them, they’re easier on his teeth, but they  give him diarrhea. Also, watch out! — often they originally come from China but are distributed in your own country by a middleman, unbeknownst. That’s what happens here in Italy, anyway.
      Chicken liver is good for training treats. I boil it then further dry it out in the oven so it’s not slimy. Break it into bits, and you suddenly have a Mensa dog!

  • Lilikoiqueen

    Been doing lots of research on the web about dog food.
    I have 4 rescues, 3 of whom are seniors, one is a German Shepherd. I suspect the GS has lately been exhibiting signs of IBS, necessitating changes in diet. I also have a dog with allergies. I see that Costco’s food has pretty good ratings for nutrition, just curious where the ingredients come from, as the label says “distrubuted by” not where the food is made.
    I’m totally NOT getting any more treats or foods made in or ingredients coming from China (check out “jerky treats” killing dogs). Best solution I found is to get chicken strips for humans, or if you dog can tolerate the coating, chicken nuggets for humans, made in the USA. I’m very leery of corn, soy or wheat proteins not only because they are suspected allergens but also because of the GMO issues with corn and soy. Also give shrimp to cats in lieu of junk food kitty treats for cats. The amazing thing is that the ingredients are purer and the cost per pound/ounce of both alternates for pet treats are also way cheaper. IE-$2 per pound for chicken nuggets, vs. $5.+ per pound for jerky treats, and the shrimp is cheaper than cat treats.

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  • Shawna

    Kmuscat ~~ http://www.dogaware.com is an EXCELLENT site chalk full of information on home preparing diets for kidney disease dogs.  Mary Straus, the owner of the site, had a kd dog and is (or at least was) a moderator on one of the kidney disease Yahoo forums.  And, she is a nutritionist.

    Lew Olson of b-naturals.com is also a good source of info.

    By the way — dogs with kidney disease do not need to be on a low protein diet until the later stages of the disease.  In fact, lowering the protein too early in the disease can even be harmful.  My dog Audrey (pictured in my avatar) was born with kidney disease and will be 6 years old the end of June.  She has been on a high protein, raw diet since weaning and is still in excellent health.

  • Kmuscat

    I’m looking to make my own low protein dogfood for my dog who has some kidney disease.  She was put on Hills Prescription Diet Renal and does not like it too much.  if I make my own food I want to make sure she is getting all the nutrients plus still have low protein.  Right now I am adding a little chicken to the dogfood but I’d like to get her off that as I’ve heard a few things about Hills that aren’t so good.  Any suggestions?

  • Hi Shawna and Victoria,

    Aside from a previous chart in a previous article posted by Dr. T. J. Dunn (and one I can no longer find on the Net), it’s important to remember that the biological value of any ingredient is species dependent.

    And almost all the BV figures available appear to be based upon human physiology.

    If any of you come across with a reliable paper or study which includes accurate BV stats for dogs (or cats), please post a link here.


  • Shawna

    Victoria ~~ the biological value (per the below linked website) is 60.  Corn gluten meal would be the same as it is the same amino acids from protein just in a concentrated amount.


    I see Mike’s chart is slightly different from the linked one.. Either way, the BV would be the same as whole corn.

  • victoria

    Mike, do you know what the biological value of corn gluten meal is? I cant seem to find it anywhere. 

  • Hi Mike P,

    Currently, he’s eating a kibble containing 38% protein (dry matter) and topped with a wet food at about 40%.

    But we do switch the dinners around.

  • Mike P

    Mike S what is the protein % you feed your Bailey?Just curious…


    …for got to mention, their weights are good and stool is good, but poodle seems to have a hard time ‘getting it out’. (good consistency, just struggles) I want my girls to be healthy and comfortable, and I worry that sometimes they ride the fence.

  • Hi Sharon… Sounds like you’ve got quite a variety there. In most cases, breed-specific dog foods are of questionable value and are probably unnecessary. Unfortunately, due to the biological uniqueness of each pet, I cannot provide customized diet recommendations for each reader.

    For more help, please check out my reviews and visit our FAQ page. Look for the topic, “Help Me Choose a Dog Food”. Or check back for a possible response from one of our other readers.


    Hi, I have been feeding my dogs THK Keen with various meats like boiled chicken, or cooked ground buffalo or boiled fresh caught salmon. The thing is, they do pretty good with their diets, but they are very different dogs. One is a three year old Malti-poo and the other is a ten year old toy poodle. The ten year old is thriving, but I think she needs more of something, I just can’t figure out what. They get fed abt a 1/4 cup each in the morning and the same at night, with a few small meat treats in btwn, but the poodle wakes up some mornings with a ferociously growling stomach and just wants to eat grass, like she’s in some sort of daze. The Malti-poo will eat, but I think she’s bored with her diet. There are always SG Bark at the Moon crunchies out, which the Malti will eat regularly, but the poodle will only eat them in a what seems a light bout of starvation, and I dont think she really chews them! Any ideas on what might do better given the breeds and ages and reactions?

  • Scarlett’s Mom

    If you are looking for an egg based dog food Royal Canine (vet prescription) makes one. My Westie has bleeding ulcers so she cannot eat any meats. This meal is the mildest form of protein for allergic dogs and she has been doing well on it.

    Since she loves fish, I cook a scrambled egg in the microwave (no oils) and mix a tablespoon or so of baked catfish in it for flavor. Fresh water catfish has virtually no oil in it so its very mild.

    Hope this helps.

  • Barbara Eckert

    I cook our dogs’ daily lunch diet (veggies, brown rice, chicken, one or two crushed garlic cloves) plus they have dry By Nature Organic Chicken supplemented. Eggs are added to the cooked diet 2X/week. Our Cocker experienced irritating hot spots 2 consecutive summers and the vet gave me a prescription which didn’t seem to help. I did some reading on the web and found out carrots and sweet potatoes could be the culprit so I omitted those from their diet. Scooter has not had the hot spots since then, however, he has been itching badly and continuously licks his right paw. I’m thinking the culprit might be spring weeds or something popping up in the lawn, any suggestions? This just started about a month ago when the weeds appeared.

  • Hi Gina… I’m not aware of such a problem with eggs and vitamins. I take my own human vitamins with my eggs every morning.

  • Gina

    I have been feeding my Great Pyrenese puppy 4-5 duck eggs a day mixed in with her Exclusive Lg. Breed puppy food. She is growing great her fur is so soft shiny and beautiful, but then I read the post about the eggs being bad for absorbtion of some vitimins. Should this be cause for me to worry if she seems to be doing fine. I have been feeding her this everyday since we got her at 8 weeks old and she is now 4 1/2 months old….Help I only want what is best for my gal..G

  • Hi Buddy’s Mom… The fact Buddy is doing so well on your vet’s prescription food, I’d be reluctant to make the switch to a meat-rich diet without considerable forethought or professional help. I’m sure there are a number of hypoallergenic or limited ingredient products that might help.

    Unfortunately, since I’m not a veterinarian, I cannot provide specific health advice or product recommendations. Please see our FAQ page and our reviews for more information. Or check back for a possible response from one of our other readers. Wish I could be more help.

  • Buddys Mom

    Hi Mike:
    My cock a poo had suffered from many hot spots and was dragging his rear end often. Since my primary physican’s only solution was cortisone shots, I consulted a doggie dermatologist at the Univ of Penn veterinary clinic. He advised since there is no blood test for food allergies, an elimination diet would at least be a starting point. Although it was difficult to determine an exact allergy, the dermatologist’s recommendation was Purina HA (soy) food. Buddy has been on this diet for several years and we have been able to determine that beef may be his true allergen. Therefore, I supplement his diet with bits of chicken, an egg here and there and at times some salmon. It has recently come to my attention that this food is not very well rated. Since Buddy is now eight years old, I would like to transition to an option that he can tolerate with more nutritional value. Any suggestions how to go about this?

  • Hi Theresa… Since each dog responds to a particular food in its own unique way, it would be impossible for me to assure you feeding any specific product would help control your dogs’ allergies. Unfortunately, I cannot provide customized product recommendations for each reader. For more information, please check out my reviews and visit our FAQ page. Look for the topic, “Help Me Choose a Dog Food”. Or check back for a possible response from one of our other readers. Wish I could be more help.

  • Theresa

    Hi Mike
    I have adopted two beautiful Saint Bernards and I have been feeding them for the last two years Acana Dog Food. They were first on Orjien but protien levels to high. I have them on Grasslands. They do well but tend to lick them selves. I’m not sure if it’s because we live in Las Vegas or if it’s coming from the food. I went to the vet and they say there is no such thing as giving a dog a blood test for food allegries. Is there something you can recommend, that helps my babies with this problem. They have some many probotics and digestive enzy. out there don’t know what to trust. Also I’m looking for a good dog treat (grain free) not made in china.
    Please help. I’m at my witts end…..Sincerely, Theresa

  • Hi Roger… Unfortunately, there’s very little information available for pets. That’s because biological value can be a controversial representation of a protein’s true value. A more up-to-date (yet still controversial) method is known as the Protein Digestibility Corrected Amino Acid Score (PDCAAS).

    PDCAAS is a technique for judging the protein quality of a food and is based upon both the amino acid requirements of an animal and its ability to digest it. But unfortunately, only in humans.

  • Roger Prows

    Do you have a full table of biological values anywhere?

  • Molly D.

    Just a comment to follow up on Boxer’s previous post from Jan 3rd… dogs shouldn’t eat alot of raw egg whites as they contain a glycoprotein called Avidin, which binds to biotin (a B vitamin) preventing it’s absoption. They also contain inhibitors of the digestive enzyme Trypsin, which helps to break down and digest proteins.

    The yolk is the nutrient rich and beneficial part off the egg, and can be eaten raw.

    I often feed my dogs fresh chicken and duck eggs but I soft boil them (Trypsin inhibitors are destroyed by heat and light cooking cuts Avidin by about one third). I don’t even worry if I can’t fully peel the soft boiled eggs, the dogs will eat bits of the shells too.

  • Hi Rafael… Since gluten contains the protein portion of a corn kernel, it is certainly possible for a dog to be allergic to this ingredient.

  • refael franco

    HI Mike
    i talk with my friend about corn free
    i want to know if i see “corn gluten meal” and talk with the service customer they told me thats the food is corn free and the corn gluten is just for protein and this is safe use for allergic dogs (to corn) . what you think ?
    regards franco

  • Why not just feed real eggs? They are cheap and easy to feed (raw or boiled).

  • Jonathan

    Ah good point. One other thing… Is there any dog foods that begin with fresh chicken, have no chicken meal or plant based protein boosters, but contain a respectable amount of meat protein? It seems like it should be possible, they would just have to use a substantial amount of fresh chicken meat. That’s a problem I have with fresh chicken… we know that fresh chicken loses water weight when cooked, but how do we know that the manufacturer simply isn’t just using a huge amount of it so that even after cooking, it’s still the true main ingredient?

  • Hi Jonathan… That does sound like a good idea but unfortunately I’m not aware of any recipe like this. I’d imagine kibbling or canning an egg-based product might prove a bit of a challenge.

  • Jonathan

    Is there any dog foods that use only eggs as their protein source? It would seem that would be even better than chicken meal considering the BV of eggs.

  • dean

    it is so stressful to read the lable on dog food’s. i believe our dog’s are what they eat.i look at my dog’s then look at other people dog’s and i know mine are very healthy just by the skin and coat and those clear bright eye’s and how happy they are. i have a yorkie and he is very calm but very active and my toy mini schanuzer is a picture of health… we have recently adopted 3 new 4 legged kids due to two families out of work and moving out of state it has only been about one week and the new 4 legged kids are looking much better and it’s all about the food. i make home made food and use home made with halo’s dry formula on the new kids… they came with no food to make it easy on the new food given but they all had no tummy issue’s at this food. and i can say i feel like i am giving them a new start to health and a longer life as well as being happy or they would have been turned into the animal shelter i fell man or animal we are what we eat and the dog company that uses by-products need to stop and if they make dog food should make food not left over hulls of whta food was and use what a dog or cat live on not get by on until they get sick from no food as a whole but fill up the bag with too many vitamin’s/ minerals in some a over load. that is why i made my pets food and that is why i am using halo for the new kid’s along with my home made food i don’t know if they will be put compeletly on home made yet or not i did not want to change what they ate the new kids but i trust halo in fact i do not know what the two families feed these new adopted dog’s but their coats were just awful and in only a few day’s it is starting to shine so that is what food is about. working from the inside out. i wish the dog food companies would go out of business that use left over junk i will never buy junk by-products, ever. food is just that food and not only that but what a dog needs not just to fill it up.just do your research and research more and more even at what goes on the table for humans as well.something needs to change in the food business period.heathy is what everyone is wanting.thank you very much