For yourself, maybe, for your pets, absolutely not. Cats are strict carnivores[1], and dogs, while they can survive on a veg diet, it is not what they evolved to consume[2].
Your friends are literally killing their pets. Please either inform them and make sure they stop it, or inform the local humane society/animal shelter and get them taken away.
Noondip's now deleted comment was as follows:
Another excellent reason to go vegan, both for yourself and your pets. I'm not an authority on this, but my friends have bragged about their cats and dogs alike living a healthy, happy life on a plant-based diet.
I can't speak for cats, but it's certainly possible for dogs to do fine on a vegetarian diet. I know several dog owners who do this. You may have to do blood work, and be more observant about their health.
Note: Dogs, not cats, and vegetarian, not vegan.
I notice you were careful to make these distinctions in your first paragraph, but then (IMHO) went too far with "Your friends are literally killing their pets."
That is, there are several nutrients that cats have completely lost the ability to manufacture in their own tissues which are only found in animal sources (and whole animals, certain things are only found in certain tissues).
Vegan or vegetarian diets for cats have to be heavily supplemented with nutrients which are either animal-derived or entirely synthetic (and the type of people who want to feed their cats vegan food are also the type of people who have big problems with synthetic chemistry as food).
Dogs (and humans) do a bad job at manufacturing many nutrients with animal sources, where cats don't do it at all, we just do it poorly. Supplementation and careful diet design make it possible to thrive on plant-based food.
If you tried making your own plant-based cat food without a chemistry lab and a PhD, you'd be literally killing your cat.
If you tried to make your own plant-based dog food (or baby food) you'd probably end up with huge risks of malnourishment, but it's still possible with careful monitoring.
Cats are another matter. Unlike most other animals, they cannot biosynthesize taurine; they must find it in their diet, and it's mostly found in meat and meat products. As such, cats are obligate carnivores -- they cannot survive on a vegan or vegetarian diet.
Linking two articles without any authors cited is hardly a compelling argument. I'm also quite sure dogs did not evolve to eat canned dog food laden with broken beaks, brain, spinal cord tissue, bones, lungs, intestinal tracts from slaughterhouse wastes of dead, dying, diseased or disabled animals, not to mention other contaminants such as PCBs and heavy metals.
You may be surprised to know they DO work for a local animal rescue, and take great care of their beloved animals. Whether their dogs and cats are 100% vegan is unknown to me, which is why I said they're fed a mostly plant-based diet, surely with nutrient fortified supplements. What's clear is they are keeping healthy and happy animals without feeding them meat and commercial dog food exclusively. I removed my original comment as to not misinform pet owners.
Spinal cords, marrow, organs (especially brains) tend to be very nutrious in fact. When given a choice, most wild animals will preffer what we call the waste.
There is a theory that falconry developed in part because birds of prey will first eat the nutritious parts of prey (i.e. the spinal cords, marrow, organs, etc.) leaving the muscle for the very last. Since humans largely prefer the muscle, it forms the basis for a lovely friendship.
Hell, the wolves dogs are descended for preferentially go for the dead, dying, diseased, and disabled animals (and the young). They're easier and safer to hunt.
>> broken beaks, brain, spinal cord tissue, bones, lungs, intestinal tracts from slaughterhouse wastes of dead, dying, diseased or disabled animals
>I'm no zoologist, but this seems exactly the kind of thing that a carnivorous/omnivorous wild animal would happily eat.
it is just pretty naive pastoral picture that many fall victims to. To start - beaks, feathers, hoofs, horns and many other pieces the cats/dogs wouldn't eat naturally. The second, most important - that stuff is flooded with strong chemicals to avoid perishing until it reaches the pet food manufacturer. This isn't preservatives from your canned food. It is basically unregulated industrial toxic stuff. And thus it ends up in the stomachs of the cats and dogs. And thus the epidemic of various autoimmune and cancer diseases.
What on earth makes you think that brains, lungs, intestinal tracts, and bones are unappetizing to dogs?
It's irritating enough that people have conditioned themselves to believe that farmers raise pork chops, not pigs. Skillfully prepared, offal meats are delicious, and also a central part of the cuisines of many cultures.
But to suggest that a dog has a problem eating offal? Too much.
HN is not an academic paper. If you have an issue with the information in the articles, then please put forth some criticisms rather than weak appeals to authority.
Im also quite sure dogs did not evolve to eat canned dog food laden with broken beaks, brain, spinal cord tissue, bones, lungs, intestinal tracts from slaughterhouse wastes of dead, dying, diseased or disabled animals
It's funny you say that, because dogs/wolves are considered scavengers. So... yeah, they kind of did. (Though apparently, the domesticated dog has a better ability to process starch - helps when you're living with humans who use it as a staple)
The whole thing about cats being strict or obligate carnivores is because they've lost the ability to, for example, synthesize vitamin A from beta carotene. They can't process carbs as well because they have little to no need to do so. Their digestive tract is short, and their gut fauna isn't meant to process plant matter, so most of it goes through untouched.
What I'm getting at is, forcing your personal choices on a pet is a pretty awful thing to do, shelter work, supplements, or otherwise. Your friends might be nice people who mean well and love their pets, but they are dangerously uneducated in this matter.
Leaving aside the comments that others have made (i.e. carnivores love offal) there's also a wide range of alternatives to canned pet food that do not require forcing an unnatural diet upon the animal. I used to feed my cat kangaroo meat, for instance, which is mostly sourced from wild animals.
Dogs are omnivorous scavengers - they eat almost anything, including the 'disgusting' stuff you listed. It's disgusting to us, but not to dogs. I used to have a dog that would eagerly hunt out and consume cat shit when I took her for walks, for example.
[1]: http://www.petmd.com/cat/nutrition/evr_ct_cat_nutritional_ne...
[2]: http://rawfed.com/myths/omnivores.html
Your friends are literally killing their pets. Please either inform them and make sure they stop it, or inform the local humane society/animal shelter and get them taken away.
Noondip's now deleted comment was as follows:
Another excellent reason to go vegan, both for yourself and your pets. I'm not an authority on this, but my friends have bragged about their cats and dogs alike living a healthy, happy life on a plant-based diet.