Methane conversion rate (% GE) by species and feed situation.
Cattle feedlot (>90% concentrate): 3.0%.
Sheep: a single 6.7%, irrespective of feed quality (no body-weight split).
Source
Mixed across editions.
Sheep 6.7% and goats 5.5% are the 2019 Refinement, Vol 4, Ch 10, Table 10.13 (Updated).
Cattle and buffalo 6.5% on pasture/range and mixed rations are the 2006 Guidelines Table 10.12, which gives 6.5% for every non-feedlot cattle and buffalo class. The 2019 Refinement's Table 10.12 (Updated) resolves cattle and buffalo Ym by production level and feed digestibility instead: 5.7 / 6.0 / 6.3 / 6.5 for dairy cows by yield class, 7.0 for >75 percent forage non-dairy, 6.3 for mixed rations, 4.0 for grain feedlots and 3.0 for steam-flaked-corn feedlots. The stored feedlot 3.0% is therefore the 2006 ">=90 percent concentrate" value, which in the 2019 Refinement applies only to the steam-flaked-corn case.
Camels 5.0% appears in no IPCC table. Both editions instead direct compilers to reuse the other-cattle or buffalo Ym for camels, which would be 6.5%. Assumed, unverified. Tracked in whep#601.
Examples
ipcc_2019_ym
#> # A tibble: 8 × 4
#> category feed_situation ym_percent ym_uncertainty
#> <chr> <chr> <dbl> <dbl>
#> 1 Cattle Pasture/Range 6.5 1
#> 2 Cattle Mixed 6.5 1
#> 3 Cattle Feedlot (>90% conc.) 3 1
#> 4 Buffalo Pasture/Range 6.5 1
#> 5 Buffalo Mixed 6.5 1
#> 6 Sheep All 6.7 1
#> 7 Goats All 5.5 1
#> 8 Camels All 5 1