A topic of perpetual debate and passionate opinion's amongst raw feeders. The "Prey Model Raw (PMR)" diet. Is it good? Is it bad? Do people even really understand it?
To start, I'm going to rewind a bit back to when I personally started my journey into learning how to feed my pets a homemade raw diet. I was not involved in any forms of social media when I started my journey. Yeah, I may have been that old person who thought it was all silly and I had no interest in it. I only became involved in social media with my creation of Rawpetsrule to help others feed their pets better. Of course I now am beyond grateful to have made the amazing friends I have through my social media, but holy crap am I glad I wasn't relying on social media to educate me on raw feeding basics. There are now more than ever so many conflicting "right ways" and "must do it this way" ideals out there and they often don't line up... at all! All of this makes it extremely frustrating and down right difficult for someone new just looking for guidance. It's like you need to pick your "team" and follow their rules. God forbid you think about an idea that falls outside your chosen teams ways of doing things. If you haven't experienced this then consider yourself lucky because I get the pleasure of hearing stories from people ALL the time that have been basically stressed out or even insulted to the point they think " we all be crazy" and abandon the idea of feeding raw altogether. That saddens me and quite frankly piss's me off! It shouldn't be this way.
Now, prey model raw.
This is one very popular method of putting together a homemade raw diet. The problem I see is this method has literally morphed before my eyes over time within the raw feeding community as a whole. I initially learned to feed this way BUT for one, it was more commonly called the "franken-prey" model of feeding. The same 80/10/10 was outlined but was emphasized much more that this set of percentages was just a GUIDLINE, not a rule. The premise of the diet was to most closely recreate what an entire animal would be composed of using a variety of piece's and parts from different sources. The whole ideal came about for feeing this way is based off the averages of what a whole animal contains. Assuming that, you know nature, Mother Nature if you will, knows far better than us what is correct. Quite frankly as a person who follows what I feel is a healthy mix of science based and nature based ideals I most definitely agree nature doesn't get it wrong. However humans certainly do! What started out as a guideline to create the components of a whole animal, AKA franken-prey, is now regularly being simply referred to as the "ratio diet". People are too often trying to follow the percentages to a T, like it's a law rather than being the guideline it was intended to be. Expanding the model to 80/10/5/5 to emphasize that liver and an additional organ need be fed is also now much more common. Great! Except animals contain more than 2 organs and many people will never deviate from this example, again treating the guidelines as a rule. Thus one area where this method can go wrong and gets labeled as a "bad" diet.
There are issues if your going to follow a prey model diet strictly. By strictly, I mean you feed only meat and only in these exact proportions, switching protein sources minimally and occasionally. But this dose NOT mean this model can't be worked within and fed to healthy adult dogs, cats, & ferrets. All of which I feed and all of which I offer franken-prey style meals in their food rotation. You simply need to break free of the strict 80/10/10 prison - it IS flawed! The whole reason people can & do make claims that ratio diets are "bad" is because when analyzed against outlined nutritional standards ( most commonly NRC guidelines) these diets usually fall short in a few common areas. Often having both extreme lows and highs in make up as well as unfavorable mineral interactions. As someone who analyzes diets I can confidently say making a few modifications to a prey model diet can improve it immensely. Also, I will point out that most people feeding PMR diets are not feeding the same thing day in and day out. So, simply analyzing a single meal fed is not giving an accurate depiction of the entire diet being fed, and we are often feeding items that no nutritional data has been established for. Just because the USDA dose not have info on what's in a duck head you shouldn't feed it??
That's ridiculous! Of course you should!
Let's Break Down This Diet!
The first area of the diet I'll address is liver. This model says to feed 5% liver. Ok, but all liver is not created equal. Ruminant livers (beef, lamb, goat, venison ect.) are high copper livers. These livers contain a much higher amount of copper. The low copper livers would be your chicken, turkey, & pork livers. Pork liver is actually unique in itself as even though USDA nutritional data will show copper as being present due to unique circumstances pork liver as far as our dogs & cats are concerned has zero bioavailable copper. So feeding a straight 5% liver can be improved on.
Here's how I do it: If feeding a liver that falls in the high copper category feed it at no more than 2-3% . This still gives you more than enough vit A but keeps copper from going through the roof.
If feeding a low copper liver you can feed at 5%. If feeding pork liver your best result comes from halving the portion of pork liver with a high copper liver ( 2.5% pork & 2.5% high copper liver).
The other organ, this model says feed 5%. Ok, I just generally disagree with this. Why? Because if your following the above suggestions on liver then you certainly can feed more than 5% of other organs. Other organ can refer to may things! Brain and kidney, for example, offer very different things to the diet. Organs can be more challenging to source and therefore, many people have only one or two that they always use. The most ideal situation is to remember this model is attempting to recreate an entire animal and feed small portions of each ( kidney, spleen, pancreas, brain, testes ect..) not necessarily in each meal but over the week in appropriate proportions to the "animal". If your selection is limited, most diets when analyzed do hold up nutritionally when this other organ is increased at least some from the standardized 5%, how much is dependent on the overall diet and the individual pets tolerance. What I'm getting at is don't think your cap HAS to be a strict 5% it can be more & often benefits the diet to be more. Also use more than one, no need to stop at one only.
The edible bone. Oh how this element of the diet tends to make people crazy! The prey model diet says 10% bone ( this refers to the bone on its own) . The calculating by raw feeders to come up with how much of a chicken neck or a duck foot is 10% bone is enough to cause some people to throw in the towel! People tend to overcomplicate this area more than any other. But before I even address how to figure out how much, is 10% bone the rule? No, it's a guideline! In fact if I break down the ratios in NRC meals I have formulated the happy spot is more like 12-15% bone for dogs and a bit less for cats. And guess what the type of bone you use makes a difference! So to this point I highly suggest if your following this model to utilize more than one bone source. You also don't need to meticulously cut and trim every bone in item you feed to the gram to fit your percentage. Some days it can go over, some days it can be under, unless your massively going far above or below consistently it all works itself out in the end. I will also point out that the commonly used bone in cut percentages are also to be used as a guideline. Use your eyes and look at the cut you are holding, if guide says a duck neck is 50% bone but the one your holding is extra large or small and looks visually to be more/less.... then it is more/less! Again, guidelines are not rules so don't obsess! Ultimately nature is going to dictate the meat: bone ratio in each & every animal and it won't be as neat & tidy/precise as we'd like it to be.
The muscle meat portion. This model says to feed 80%. This in itself is misleading. To many people this simply means any meat will fit without consideration of it's classification. Within this meat group, we have skeletal meats, tendons & ligaments, all the non secreting organs, the skin & cartilage (ears & tracheas), hearts, tongues...the list goes on! You ideally should not limit yourself to any one of these meat items in excess or exclude any if you can get them. These are all parts to the whole animal and all have different things to offer. Keeping in mind again, what proportion would these be in the animal as a whole? There's your guide. A decent guideline is to make at least 25%-30% of this non secreting organs (lungs, hearts, gizzards ect.) and to vary the skeletal muscle you use. In poultry breast & thigh are very different, in pork - loin and shoulder are different, utilize as many as you can. Different cuts from the same animal are going to offer different nutrients. Don't get stuck on one if your feeding this model. Again, go back to visualizing what would be in the animal as a whole.
The other issues this model of feeding can present will mostly be in part because we can do our best to recreate an animal but we can't do the job as well as nature has. We also are often using factory farmed animals. These meat sources present their own set of challenges/issues. I'm not getting into that here but in a nutshell just know for example a wild rabbit and a farmed rabbit are NOT equal, not even close!
What can you do to improve? For this you need to think beyond the model. Even your most varied diet will still have holes to fill. This too though can be remedied with a few intentional additions. Most commonly these will include items like:
1. Fish - for adequate omega 3's & vitamin D
2. Oysters - zinc is a common low, and even if its close or met it tends to get the short end of the stick when it comes to mineral interactions, more is almost always needed. There are other options than oysters but oysters are easiest.
3. Mussels- specifically blue mussels are often needed to boost manganese. Green tripe also provides it so a combination of the two works well or sufficient of either.
4. Seeds - seeds can be a source of healthful fats and are the easiest way to fulfil vitamin E , specifically sunflower seeds. A naturally derived E oil can also be used.
5. Eggs - these add a whole slue of things to the diet and I always recommend adding eggs - duck, chicken, quail ect. Eggs are great!
6. Nutritional yeast - this is more common in cat diets than dog diets due to their RA for specific B vitamins but this is a great source of B vitamins if you are not feeding sufficient sources ( pork is great, other red meats are good too). Plus its a nice flavor enhancing "seasoning" to add. B vitamins are water soluble and need be filled daily.
7. Fiber - fur & feathers are the preferred fiber source to the carnivore. If you can feed them- do it! If not your pet may require a fiber source in vegetation or use of something like psyllium husk.
8. Iodine- its going to be low in part because its not reported for many foodstuffs that it is known to be in. But you can fulfil it with a food like kelp or even salt if the diet permits it.
These are the most common places the PMR diet can fall short in. This is not to say, depending on what exactly you choose to feed that there may be more. Then there are also a long list of beneficial "extras" that will also make your diet just that much better. That list is far too long to get into here. But a word to the wise- understand why you are adding something don't simply do it because you see it in another bowl on social media. Add foods with a purpose!
So, the prey model diet, is it a picture of perfection? No. Is it a "dangerous" or "bad" way to feed? I still say NO as long as you have an understanding of where and what you might be lacking you can most certainly meet your pets needs AND do so in a more relaxed and natural way. I think people are often surprised to hear me say this because I do formulate NRC balanced diets. Yes, I do. I take care and attention to detail when formulating a diet for a client because it would be irresponsible of me to not make sure a meal will 100% meet a pets needs and be as "perfect" as it can be on paper. BUT my own pets eat recipes I create sometimes, eat PMR based on how I do it outlined here sometimes, and my pets all also eat whole prey meals regularly. I don't adhere to any one set of "rules".
Here's the thing, nutrition and the guidelines within it, regardless of how you tackle it are not carved in stone. No one has all the answers, because all the answers are not out there to be known! We have guidelines to follow - yes NRC guidelines are still just guidelines. Guidelines that were created in response to the need for standards to create "complete and balanced" foods available to the masses. Let's just be clear complete and balanced is a marketing term above all else. No species on this planet "needs" to eat something perfect on paper every single time it eats - this is a humanized ideal. We like things to be perfect when in fact the perfection of nature is that perfection simply dose not exist!
With that said, you do YOU & happy healthy feeding!