My understanding is that it increases the risk of an infection spreading - any agent that survives the slaughter/cooking process could infect a much larger numb

My understanding is that it increases the risk of an infection spreading - any agent that survives the slaughter/cooking process could infect a much larger number of animals. See the BSE epidemic we had in the UK a number of years ago: https://en.wikipedia.org/wiki/Bovine_spongiform_encephalopathy#Epidemic_in_British_cattle https://en.wikipedia.org/wiki/Bovine_spongiform_encephalopat...