• usernamesAreTricky@lemmy.mlOP
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    1 year ago

    Grass-fed production doesn’t really scale, so there’s not much way around consumption changes here. It also comes with a side effect of raising methane emissions

    We model a nationwide transition [in the US] from grain- to grass-finishing systems using demographics of present-day beef cattle. In order to produce the same quantity of beef as the present-day system, we find that a nationwide shift to exclusively grass-fed beef would require increasing the national cattle herd from 77 to 100 million cattle, an increase of 30%. We also find that the current pastureland grass resource can support only 27% of the current beef supply (27 million cattle), an amount 30% smaller than prior estimates

    […]

    If beef consumption is not reduced and is instead satisfied by greater imports of grass-fed beef, a switch to purely grass-fed systems would likely result in higher environmental costs, including higher overall methane emissions. Thus, only reductions in beef consumption can guarantee reductions in the environmental impact of US food systems.

    Taken together, an exclusively grass-fed beef cattle herd would raise the United States’ total methane emissions by approximately 8%.

    https://iopscience.iop.org/article/10.1088/1748-9326/aad401/pdf

    • TheButtonJustSpins@infosec.pub
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      1 year ago

      To be fair, pasture raised is more expensive, so people would eat less beef. I don’t think it’s fair to talk about scaling current consumption.

    • abraxas@lemmy.ml
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      1 year ago

      You say that, but it’s not really just about grass-feeding. Cows are already fed almost 90% inedible crop materials that would be getting disposed of anyway. We could be doing better, but cattle’s food source is sorta the wrong focus.

      And as much methane is in manure, it’s better for the environment (including GHG) than synthetic fertilizers.

      The real answer is changing our meat/vegetable balance AND improve the process AND continue to improve humane regulations (and those 3 goals often synergize with each other).

      • usernamesAreTricky@lemmy.mlOP
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        1 year ago

        The % that’s edible is not as relevant as the fact that it still takes much more human-edible feed

        1 kg of meat requires 2.8 kg of human-edible feed for ruminants and 3.2 for monogastrics

        https://www.sciencedirect.com/science/article/abs/pii/S2211912416300013

        Synthetic fertilizer usage is greatly reduced by eating plants directly even compared to the best-case use of animal manure

        Thus, shifting from animal to plant sources of protein can substantially reduce fertilizer requirements, even with maximal use of animal manure

        https://www.sciencedirect.com/science/article/abs/pii/S0921344922006528

        • abraxas@lemmy.ml
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          1 year ago

          The % that’s edible is not as relevant as the fact that it still takes much more human-edible feed

          Not really. Definitely not if you consider the nutritional quality of the meat. And that’s beef, the worst example. (Feed to meat conversion from 6x to 25x, the higher number generally for free-range). Chickens are only x2 in ideal situations (closer to 5x when free-range since their calorie intake is not as well-managed). And from a health viewpoint, 100kcal of chicken is a better-balanced calorie than 200kcal of feed

          But that is before accounting for the fact that about 165 of those feed kcals are inedible, meaning you’re trading around 35 edible kcals of corn for 100 edible kcals of chicken. Would you agree from a purely health and efficiency point of view (leaving out ethics), that 35 edible calories of a “non-nutritional grain” for 100 edible calories of a protein superfood is a pretty fair trade?