

“In these prisons animals are born and remain there until they are killed off. The question is whether or not this system connected to the breeding system that grows animals in an abnormal way by aborting bones in order to transform them to mere meat and a bulk of fat—whereas earlier (before 1848) animals remained active by staying in free air as much as possible—will ultimately result in serious deterioration of life force?..Characterized by precocity, in entirety sickliness, want of bones, a lot of development of fat and flesh etc. All these are artificial products. Disgusting!”
Karl Marx, Ecological Notebooks

Vigour/vitality might be a better english TL. In the German, he writes Lebenskraft