The alternative animal product arena is complex and quite varied. Some plant-based alternative meat products are derived entirely from plants. Other entrepreneurs are using cultivated cells of animal origin to derive a product structurally similar to meat and milk and comprised of animal proteins. Many of these endeavors use a combination of both approaches with the plant-based product providing filler for the cultivated meat or milk product. Most of the discussion around alternative meats has focused on bovine alternatives because of the iconic position of cattle in many climate and sustainability discussions. A considerable amount of capital has been raised based on the
 envisioned market share of these products, although estimates vary widely, and the high profile initial public offering of Beyond Meat shares in May 2019 which saw share prices soar from $75 to $235, has this year seen share prices plummet to about one-tenth of that highest price. Proponents of alternative meats suggest these production systems are more sustainable based on anticipatory greenhouse gas emission (GHG) and land use life-cycle assessment (LCA)/kilogram (kg) of product, as compared to LCA metrics for ruminant meat. Much of the rationale
 invokes a simplistic narrative around GHG/kg of protein. The GHG “sustainability” metric will invariably reflect poorly on ruminants as they are uniquely able to digest cellulose through their rumen microbes, and the methanogens produces methane which is a potent but short-lived greenhouse gas. And because ruminants are typically grazing in marginal land unsuitable for producing crops, they also have a high land use m2/kg of protein. However, there is no reason to conclude that food production on well-managed pasture and rangeland is, a priori, less sustainable than food production of well-managed arable cropland. Moreover, the other sustainability externalities of ruminant meat production systems such as the provision of ecosystem services and biodiversity conservation, the consumption of inedible food waste and cellulose, manure, transportation, contributions to the livelihoods and food security of 1.3 billion livestock keepers, the fact that meat provides nutrients in addition to protein, and that existing harvesting systems utilize everything but the “moo” are often ignored or simply disregarded.