Animals Per Calorie
A typical cow produces 7,557 liters of milk Average UK Milk Yield, which equates to about 4.7 million kcal per cow per year Whole Milk. The average cow lives 5 years How long does the average dairy cow live? for about 24 million kcal per cow. However, this cow typically has calves during her three milking years and (assuming as table population), two of them will be culled (in expectation), reducing our estimate to about 7.9 million kcal per life.
The average cow yields 490 pounds of trimmed beef How Much Meat Can You Expect from a Fed Steer?. At about 798 kcal/lb Ground Beef (90% Lean / 10% Fat), that's 391,020 kcal/cow.
A pig yields around 180 pounds of edible meat How Much Meat From a Pig, which amounts to about 187,200 kcal/pig Calories in Pulled Pork Plain (No Sauce)
The average hen lays about 530 eggs The Number of Eggs Given by a Chicken in Its Life Cycle. At 74 kcal/egg 1 Large Egg, that's 39,220 kcal/hen.
Salmon vary widely in size, but yield (very roughly) 14 pounds of meat each How many pounds of fillets can you get from a whole salmon?, equating to about 10,092 kcal/fish ATLANTIC SALMON FILLET. However, farmed salmon are often feed food made from other fish; I'm ignoring this because it's complicated.
The average chicken yields yields about 0.85 pounds of edible meat and skin Cost and Yield Comparisons of Ready-to-Cook Chicken Products, which is about 589 kcal/chicken Chicken breast, grilled - 3oz.
The average blue crab yields about 2.25 oz of meat Preparing Blue Crab: A Seafood Delicacy, equating to about 53 kcal/crabHow Many Calories in Crab Meat?. In short, we haves
If you think that the problem with eating animals is the fact that they suffer beforehand, then you are probably more interested with the suffering per year Age of animals slaughtered:
If, on the other hand, you think the problem is the fact that we are cutting animals' lives short, then you probably care more about the calories per day-of-life lost:
Of course, difficult questions still remain. Which of these animals deserve moral weight. Alternatively, how much moral weight do each of these animals deserve? Are these animals living in equally bad conditions?
These are not negligible questions. For instance, a naive approach of valuing animals proportional to the mass of their brains would cause a cow to be valued 111 times as much as a chicken per day Reflective Disequilibrium - moving eggs directly below milk in our three tables. You may want to use neuron counts instead, but then the African Elephant beats out humans; if you switch to counting neurons in the cerebral cortex, then the long-finned pilot whale beats us out List of animals by number of neurons - neither of these seem intuitive to me, but that may just be my human-bias speaking.
[ I've later learned that a similar analysis was done by Brian Tomasik Tomasik. I've also done some work trying to scale suffering by measures of cognition (brain mass, neuron counts, synapse counts) and at some point I may end up putting that up here; in the mean time see Sandhoefner. See also How Much Suffering is in the Standard American Diet? An Ethical Diet: What are the impacts of our food choices?. ]
Cost and Yield Comparisons of Ready-to-Cook Chicken Products. Retrieved from https://aglifesciences.tamu.edu/posc/wp-content/uploads/sites/20/2012/08/l-2290.pdf
Agriculture and Horticulture Development Board. Average UK Milk Yield. Retrieved from https://dairy.ahdb.org.uk/market-information/farming-data/milk-yield/average-milk-yield/#.W41njJNKgWo
Alberta Milk. How long does the average dairy cow live?. Retrieved from https://albertamilk.com/ask-dairy-farmer/how-long-does-the-average-dairy-cow-live/
Aussie Abattoirs. Age of animals slaughtered. Retrieved from https://www.aussieabattoirs.com/facts/age-slaughtered
Donald E Sweat. Preparing Blue Crab: A Seafood Delicacy. Retrieved from https://edis.ifas.ufl.edu/sg078
Issa Waters. How Much Meat From a Pig. Retrieved from https://lovelivegrow.com/how-much-meat-from-a-pig/
Janet Renee. How Many Calories Are in Grilled or Baked Salmon Steak?. Retrieved from https://www.livestrong.com/article/298045-how-many-calories-are-in-grilled-or-baked-salmon-steak/
List of animals by number of neurons. (2017, April 4). In Wikipedia. Retrieved 20:34, May 22, 2017, from https://en.wikipedia.org/w/index.php?title=List_of_animals_by_number_of_neurons&oldid=773795588
Marx Foods. How many pounds of fillets can you get from a whole salmon?. Retrieved from https://www.askmarxfoods.com/pounds-of-fillets-from-whole-salmon/
Melodie Anne. How Many Calories in Crab Meat?. Retrieved from https://www.livestrong.com/article/305760-how-many-calories-in-crab-meat/
Mom.me. The Number of Eggs Given by a Chicken in Its Life Cycle. Retrieved from https://animals.mom.me/number-eggs-given-chicken-its-life-cycle-9646.html
Reflective Disequilibrium. How are brain mass (and neurons) distributed among humans and the major farmed land animals?. Retrieved from https://reflectivedisequilibrium.blogspot.com/2013/09/how-is-brain-mass-distributed-among.html
Rosie Nold. How Much Meat Can You Expect from a Fed Steer?. Retrieved from https://igrow.org/livestock/beef/how-much-meat-can-you-expect-from-a-fed-steer/
fatsecret. 1 Large Egg. Retrieved from https://www.fatsecret.com/calories-nutrition/generic/egg-whole-raw?portionid=11206
fatsecret. Ground Beef (90% Lean / 10% Fat). Retrieved from https://www.fatsecret.com/calories-nutrition/usda/ground-beef-(90%25-lean---10%25-fat)?portionid=41288&portionamount=1.000
fatsecret. Whole Milk. Retrieved from https://www.fatsecret.com/calories-nutrition/generic/milk-cows-fluid-whole
myfitnesspal. Calories in Pulled Pork Plain (No Sauce). Retrieved from https://www.myfitnesspal.com/food/calories/generic-pulled-pork-plain-no-sauce-446411497?v2=false
nutrionix. Chicken breast, grilled - 3oz. Retrieved from https://www.nutritionix.com/i/usda/chicken-breast-grilled-3-oz/463d623797fd4d0a9f16ffe2
ATLANTIC SALMON FILLET 8 OZ, SKINLESS, PBO 421348. Trident Seafoods. https://www.tridentseafoods.com/browse/food-service-products/atlantic-salmon-fillet-8-oz-skinless-pbo-421348/
Tomasik, B. (2018). How Much Direct Suffering Is Caused by Various Animal Foods?. https://reducing-suffering.org/how-much-direct-suffering-is-caused-by-various-animal-foods/
Sandhoefner, E. Farm Animal Suffering Comparisons. http://sandhoefner.github.io/animal_suffering_calculator
Hurford, P. How Much Suffering is in the Standard American Diet?. Everyday Utilitarian. http://everydayutilitarian.com/essays/how-much-suffering-is-in-the-standard-american-diet/
Peters, D. (2016). An Ethical Diet: What are the impacts of our food choices?. http://ethical.diet/