“…With development of economical, low CH 4 concentration enrichment technologies still in their infancy (NORCE Norwegian Research Centre 2020, Wang et al, 2020, Yang et al, 2022, developing local ventilation techniques at the animal level capable of extracting breath CH 4 from cows before air mixing could be an option. In fact, a large body of literature already confirm that measured CH 4 concentrations close to cattle nostrils, as well as in enclosers such as feed bins and respiratory chambers ranged from 300 to 1500 ppm, compared to indoor CH 4 values of 15 to 201 ppm in naturally ventilated cattle barns (López-Paredes et al, 2020, van Breukelen et al, 2023, Teye et al, 2008, Blaise et al, 2018, Sorg et al, 2017, De Haas et al, 2019.…”