Less termination of life based on numbers or some version of (sentience * number of individuals)? I find it hard to believe the sheer number of individual insects killed during harvest could match the killing of one cow, calorie for calorie.
Also, what if we increase the calories of the animal we choose to slaughter, say we start raising massive whale-sized animals instead, would that tip the scales?
It takes 20 to 40 plant calories to raise one calorie of beef. So slaughtering a cow kills 20 to 40 times the number of lives as eating plants directly.
Significant input costs per animal calorie means there's an order of magnitude or more insects being killed to raise the animal that you ultimately end up eating, to get the same calories you'd have gotten just eating the plant sources.
If anything, I would expect the number of insects, small mammals, etc. killed by harvesting animal feed to be higher than that of harvesting crops grown for people, on a caloric basis.
Also, what if we increase the calories of the animal we choose to slaughter, say we start raising massive whale-sized animals instead, would that tip the scales?