This whole "if cows eat seaweed that'll vastly reduce their carbon footprint" is based on a single study with 12 cows.
If you take into consideration that especially small, never replicated studies often don't hold up to scrunity the next thing to do is not to ask how to produce the seaweed. The next reasonable step would be to try to replicate this study in a larger sample (and probably also with a larger variety of cow breeds).
This whole "if cows eat seaweed that'll vastly reduce their carbon footprint" is based on a single study with 12 cows.
If you take into consideration that especially small, never replicated studies often don't hold up to scrunity the next thing to do is not to ask how to produce the seaweed. The next reasonable step would be to try to replicate this study in a larger sample (and probably also with a larger variety of cow breeds).