# cannibal cows **URL:** \ **Category:** Factual Questions\ **Created:** [March 20, 2007, 1:00am UTC](https://boards.straightdope.com/t/cannibal-cows/396653 "2007-03-20T01:00:49Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![solkoe](https://avatars.discourse-cdn.com/v4/letter/s/919ad9/32.png) [@solkoe](https://boards.straightdope.com/u/solkoe)\ **Post date:** [March 20, 2007, 1:00am UTC](https://boards.straightdope.com/t/cannibal-cows/396653/1 "2007-03-20T01:00:49Z")
Which would give a cow more energy, a kilo of human flesh or a kilo of plant material? Can we assume that a cow has the enzymes to digests human flesh? ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [March 20, 2007, 1:03am UTC](https://boards.straightdope.com/t/cannibal-cows/396653/2 "2007-03-20T01:03:53Z")
[Chicken](http://today.reuters.com/news/articlenews.aspx?type=oddlyEnoughNews&storyid=2007-03-07T154121Z_01_SP257122_RTRUKOC_0_US-INDIA-COW.xml). ---
**Author:** ![Shagnasty](https://avatars.discourse-cdn.com/v4/letter/s/9dc877/32.png) [@Shagnasty](https://boards.straightdope.com/u/Shagnasty)\ **Post date:** [March 20, 2007, 1:05am UTC](https://boards.straightdope.com/t/cannibal-cows/396653/3 "2007-03-20T01:05:23Z")
Assuming that they could process it (but you seem to stipulate that), it is no contest. Meat blows away grass in terms of calories. ---
**Author:** ![guizot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/guizot/32/3636_2.png) [@guizot](https://boards.straightdope.com/u/guizot)\ **Post date:** [March 20, 2007, 1:11am UTC](https://boards.straightdope.com/t/cannibal-cows/396653/4 "2007-03-20T01:11:56Z")
Don’t they give cows rendered cow flesh already? ---
**Author:** ![solkoe](https://avatars.discourse-cdn.com/v4/letter/s/919ad9/32.png) [@solkoe](https://boards.straightdope.com/u/solkoe)\ **Post date:** [March 20, 2007, 1:26am UTC](https://boards.straightdope.com/t/cannibal-cows/396653/5 "2007-03-20T01:26:25Z")
[QUOTE=Shagnasty] Assuming that they could process it (but you seem to stipulate that), it is no contest. Meat blows away grass in terms of calories. [/QUOTE] I was looking for the factual answer. Can a cow digest the meat? I think they can. I know they can digest cellulose but I believe it is very inefficient for them to do so. On the other hand, cellulose is glucose. Once it is digested, there is a big energy gain for them. As I remember, glucose is a larger energy molecule than protein. ---
**Author:** ![Yllaria](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/yllaria/32/3452_2.png) [@Yllaria](https://boards.straightdope.com/u/Yllaria)\ **Post date:** [March 20, 2007, 2:36am UTC](https://boards.straightdope.com/t/cannibal-cows/396653/6 "2007-03-20T02:36:40Z")
You have to remember that a cow’s first stomach is an anaerobic digester. So the question isn’t only, can the cow eventually digest the meat, but also, will the meat disrupt the microbial consortium in the first stomach? There are three (at least) types of microbes working together: hydrolyzers (which break down the cellulose), acid formers (which form acetic acid from the breakdown products) and methanogens (which shift the acetic acid to methane). It’s a complex dance between all of them and the cow. Don’t know what the answer is, but I’m pleased to be ignorant at a higher level. Oh, did you know that the ag folks who were first looking into suppressing the production of methane by cows were doing so as a way to increase feed efficiency? Any carbon atom from the feed that gets released as methane (by burps, not farts - another common misconception) is an atom that hasn’t gone into the building of cow meat. When global warming became a concern all those ag researchers said, “hey! look! new food source!” (Most of the researchers I’ve know have spent at least a third of their time writing grants to try to fund next year’s research.) Also, what the cow digests in the subsequent stomachs is part half-digested grass, part acetic acid, and part microbe bodies. Microbes eat grass, microbes grow, cows swallow and digest microbes. So they can digest the protein in the microbes, at least. ---
**Author:** ![groman](https://avatars.discourse-cdn.com/v4/letter/g/73ab20/32.png) [@groman](https://boards.straightdope.com/u/groman)\ **Post date:** [March 20, 2007, 2:43am UTC](https://boards.straightdope.com/t/cannibal-cows/396653/7 "2007-03-20T02:43:30Z")
[QUOTE=solkoe] I was looking for the factual answer. Can a cow digest the meat? I think they can. I know they can digest cellulose but I believe it is very inefficient for them to do so. On the other hand, cellulose is glucose. Once it is digested, there is a big energy gain for them. As I remember, glucose is a larger energy molecule than protein. [/QUOTE] Both sugars and proteins have 4 kcal per digested gram. To get a pound of digestible protein from meat a human being needs to eat a little over a pound of 100% lean meat. To get a pound of digestible sugars from unprocessed vegetation a human being will probably need to eat more than is actually possible. Now, this can be represented as X kcal/lb of meat and Y kcal/lb of unprocessed vegetation. It is clear that for humans X is significantly higher than Y. You are asking if **for cows** is X still higher than Y despite less adaptations to eat meat and more adaptations to eat plants, is my understanding correct? I don’t actually have an answer (although my guess would be yes, X is still higher, but there might be other reasons cows shouldn’t eat meat even if available, like gastric distress and most meat generally trying to fight back when eaten), but I’m hoping this can clarify it for other posters. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [March 20, 2007, 2:45am UTC](https://boards.straightdope.com/t/cannibal-cows/396653/8 "2007-03-20T02:45:19Z")
[QUOTE=solkoe] I was looking for the factual answer. [/QUOTE] Ok. A cannibal cow would eat other _cows_, not humans. ---
**Author:** ![Sage\_Rat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sage_rat/32/399_2.png) [@Sage\_Rat](https://boards.straightdope.com/u/Sage_Rat)\ **Post date:** [March 20, 2007, 3:44am UTC](https://boards.straightdope.com/t/cannibal-cows/396653/9 "2007-03-20T03:44:01Z")
[QUOTE=Q.E.D.] Ok. A cannibal cow would eat other _cows_, not humans. [/QUOTE] Homotarian? Humanitarian? [sings] It was a one eyed one horned flying purple homotarian! [sings] ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [March 20, 2007, 3:45am UTC](https://boards.straightdope.com/t/cannibal-cows/396653/10 "2007-03-20T03:45:55Z")
[QUOTE=Sage Rat] Homotarian? [/QUOTE] Homivore. 😃 ---
**Author:** ![dynamitedave](https://avatars.discourse-cdn.com/v4/letter/d/ed655f/32.png) [@dynamitedave](https://boards.straightdope.com/u/dynamitedave)\ **Post date:** [March 20, 2007, 6:35am UTC](https://boards.straightdope.com/t/cannibal-cows/396653/11 "2007-03-20T06:35:38Z")
Well, I’ve watched cows eat their afterbirth. Can’t say why, or even if they’re aware of what they’re doing, perhaps the cow thinks the afterbirth is a fresh born calf and is trying to clean said calf. As far as I can remember it’s only when the afterbirth expels straight after giving birth some go for it, if it’s a couple of days before it’s expeled, the cow doesn’t seem interested. So, some cows eat meat already, just not human 😃 > [@](#): > > Don’t they give cows rendered cow flesh already? I thinks that’s been stopped because of BSE, but I’m willing to be corrected. My cattle were only fed pasture based feed: grass, silage, hay, turnips. ---
**Author:** ![dynamitedave](https://avatars.discourse-cdn.com/v4/letter/d/ed655f/32.png) [@dynamitedave](https://boards.straightdope.com/u/dynamitedave)\ **Post date:** [March 20, 2007, 7:56am UTC](https://boards.straightdope.com/t/cannibal-cows/396653/12 "2007-03-20T07:56:39Z")
[QUOTE=Q.E.D.] Homivore. 😃 [/QUOTE] [Movie trailer](http://www.blacksheep-themovie.com/) tonight 😃 Almost fits the OP :eek: ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [March 20, 2007, 9:23am UTC](https://boards.straightdope.com/t/cannibal-cows/396653/13 "2007-03-20T09:23:22Z")
[QUOTE=dynamitedave] Well, I’ve watched cows eat their afterbirth. Can’t say why, or even if they’re aware of what they’re doing, [/QUOTE] Horses & other equines do this also. The generally accepted reason is that it protects the herd, because leaving a bloody afterbirth would attract predators with its smell. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [March 20, 2007, 10:40am UTC](https://boards.straightdope.com/t/cannibal-cows/396653/14 "2007-03-20T10:40:03Z")
[QUOTE=dynamitedave] I thinks that’s been stopped because of BSE, but I’m willing to be corrected. My cattle were only fed pasture based feed: grass, silage, hay, turnips. [/QUOTE] I’m sure the feeding of animals on protein derived from their own species (or indeed their own family or order, possibly) is banned, but cattle are routinely fed animal protein in the form of processed fish meal. ---
**Author:** ![solkoe](https://avatars.discourse-cdn.com/v4/letter/s/919ad9/32.png) [@solkoe](https://boards.straightdope.com/u/solkoe)\ **Post date:** [March 20, 2007, 10:09pm UTC](https://boards.straightdope.com/t/cannibal-cows/396653/15 "2007-03-20T22:09:28Z")
[QUOTE=t-bonham@scc.net] Horses & other equines do this also. The generally accepted reason is that it protects the herd, because leaving a bloody afterbirth would attract predators with its smell. [/QUOTE] I thought it was instinctual in all mammalian species because the hormones in the afterbirth stimulate lactation (humans? - some people eat their afterbirth). ---
**Author:** ![si\_blakely](https://avatars.discourse-cdn.com/v4/letter/s/d9b06d/32.png) [@si\_blakely](https://boards.straightdope.com/u/si_blakely)\ **Post date:** [March 20, 2007, 10:24pm UTC](https://boards.straightdope.com/t/cannibal-cows/396653/16 "2007-03-20T22:24:43Z")
[QUOTE=Mangetout] I’m sure the feeding of animals on protein derived from their own species (or indeed their own family or order, possibly) is banned, but cattle are routinely fed animal protein in the form of processed fish meal. [/QUOTE] Given that one of the speculative sources of BSE was _scrapie_ (a sheep prion disease) from rendered sheep meal, most mammalian products are off the bovine menu. Of course, has anyone asked the question - do fish get prion diseases? I think cows should eat grass and corn, myself. And drink beer, too. Why can’t I get NZ beef in the UK? Si ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [March 20, 2007, 11:10pm UTC](https://boards.straightdope.com/t/cannibal-cows/396653/17 "2007-03-20T23:10:03Z")
[QUOTE=solkoe] I thought it was instinctual in all mammalian species because the hormones in the afterbirth stimulate lactation (humans? - some people eat their afterbirth). [/QUOTE] No, lactation has started some time before. Dropping wax and dripping milk from the mare’s teats is a common sign of imminent birth. Obviously, in a successful traveling-herd species, the milk would have to be already produced and ready for the foal to suck right after birth. After that, it is the sucking of the foal and emptying of the teats that keeps lactation happening. Until the foal is weaned, mares will keep producing milk. (Though the hormones of pregnancy will affect this – the mares body starts to concentrate on the new, unborn foal. Most mares will start to refuse to allow a foal to suck, if they haven’t been weaned by this time.) ---
**Author:** ![dynamitedave](https://avatars.discourse-cdn.com/v4/letter/d/ed655f/32.png) [@dynamitedave](https://boards.straightdope.com/u/dynamitedave)\ **Post date:** [March 21, 2007, 5:25am UTC](https://boards.straightdope.com/t/cannibal-cows/396653/18 "2007-03-21T05:25:22Z")
[QUOTE=si\_blakely] Why can’t I get NZ beef in the UK? Si [/QUOTE] After much digging, I ended up [here](http://www.nzmeatboard.org/main.cfm?id=32) The EU has given NZ a quota of 1300 tonnes yearly (big freaking deal) of “High Quality Beef” :rolleyes: [QUOTE=long boring list of definitions] High Quality Beef means meat covered by CN codes 0201 20 90, 0201 30, 0202 20 90, 0202 30, 0206 10 95 and 0206 29 91 as defined in Commission Regulation (EC) No. 936/97: “High-quality beef originating in New Zealand meeting the following definition: Selected chilled or frozen premium beef cuts derived from exclusively pasture grazed bovine animals which do not have more than four permanent incisor teeth in wear, the carcases of which have a dressed weight of not more than 325 kilograms, a compact appearance with a good eye, of meat of light and uniform colour and adequate but not excessive fat cover. All cuts will be vacuum packaged and referred to as “high-quality beef”. [/QUOTE] ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [March 21, 2007, 8:01am UTC](https://boards.straightdope.com/t/cannibal-cows/396653/19 "2007-03-21T08:01:23Z")
[QUOTE=solkoe] Which would give a cow more energy, a kilo of human flesh or a kilo of plant material? [/quote] A kg of grass, no competition. Contrary to what Shagnasty said grass contains far more calories than meat. Grass is mostly cellulose, which is just a long chain sugar. It represents more energy than an equivalent mass of table sugar. In contrast protein contains fewer claories and far, far fewer biologically available calories. That’s why even an omnivore like a person will starve to death if fed a diet of lean meat. > [@](#): > > Can we assume that a cow has the enzymes to digests human flesh? The enzymes aren’t the problem. Cows manufacture protease enzymes, they are also home to numerous microbes that produce proteases. The problems are that the meat is a pollutant, and that the meat has to run the gauntlet of protein starved microbes first. To deal with the pollution issue, a cow is just a big microbial fermenation vat on legs. If you feed meat into a fermentation vat you can get some really nasty microbes growing. The biggest problem is Botulinum which will thrive if it gets into the a rumen loaded with fat. Cow dies within hours. The next problem is that the microbes in a cows rumen are chronically short of protein. They have evolved to strip any protein they recieve as soon as they can. If you feed a cow meat, or even just a high protein feed source, the microbes glut themsleves on protein and then start producing some nasty wastes, including organic acids and urea. That causes liver and kidney damage as well as scouring, which is basically a flushing of the intestinal tract. Not pretty and not a good way to take in calories. Cattle and other ruminants do eat meat naturally, even in the wild, but they do so primarily as a protein or mineral supplement. They don’t eat it in huge quantities as an energy source. ---
**Author:** ![Malacandra](https://avatars.discourse-cdn.com/v4/letter/m/45deac/32.png) [@Malacandra](https://boards.straightdope.com/u/Malacandra)\ **Post date:** [March 21, 2007, 10:02am UTC](https://boards.straightdope.com/t/cannibal-cows/396653/20 "2007-03-21T10:02:53Z")
[QUOTE=Q.E.D.] Homivore. 😃 [/QUOTE] Anthropophage. (adv: “anthropophagous”) [Next page](https://boards.straightdope.com/t/cannibal-cows/396653.md?page=2)