Various functional forms for brain-weighting wild insects and farmed land animals favor the former

Summary: Some people have offered guesses or intuitions that when comparing animals with very different nervous system scales, they should be weighted by the logarithm or square root of neural capacity, while also taking the view that the impacts of animal agriculture on wild insects are not much greater than the impacts on farmed land animals. Considering these functional forms, and linear weighting with number of neurons, it appears they assign a much greater total weight to wild insect populations affected by agricultural land use than to the land animals being farmed. This suggests a revision of some combination of the weighting schemes and evaluations of agricultural impacts.

Some considerations for prioritization within animal agriculture

Summary: Conflicting rationales have been offered to prioritize reduction of particular sectors of factory farming and animal agriculture, and I review a selection of these. Cattle make the largest contribution to climate change, and cattle raised for meat create the greatest demand for agricultural land use. Smaller chickens and farmed fish are much more numerous. Taking still more numerous wild animals into account would suggest that cattle farming has the largest impact, positive or negative. Taking neural capacity into account favors attention to large farmed animals, but this measure is still dominated by wild animals. Mental abilities such as learning and social intelligence do not seem to have strong implications between chickens and cattle. An alternative perspective is that focus should be on changes in human attitudes, efforts, and organizations, as these contribute to further change.

Trends in farmed animal life-years per kg and per human in the United States

Summary: Selective breeding, drugs, and altered diets have greatly increased the quantity of milk, meat, and eggs produced per year of farmed animal life for multiple species, creating side effects that lowered the quality of life of farmed animals, and increasing consumption through lower prices. In the United States it appears that for some agricultural industries productivity increases since 1950 might have reduced farmed animal-years enough to outweigh the effect of falling prices. These include dairy, beef, and eggs. However, total animal-years of chickens raised for meat, the most populous farmed land animal, increased dramatically in total and per capita, despite a severalfold reduction in chicken-years per kg of meat sold. Increases in production efficiency may reduce demand for farmed animal-years in some mature developed country markets, while increasing demand in larger emerging markets. Further analysis using detailed income and price elasticity information, as well as welfare effects of overbreeding, could estimate net effects of technological change on animal welfare.