Summary

Several comparison tests of GreenFeed with chambers and SF6 have been completed by independent colleagues. GreenFeed predicted emissions were not different than those measured in chambers or with the SF6 technique in all but one comparison (P < 0.10). Three indirect comparisons and studies of sensitivity of the GreenFeed method have also been presented, the result are summarized below.

 

Direct Comparisons

 CattleReference MethodDietReference
(g/d)
GreenFeed
(g/d)
% DiffP 
Dorich et al. 2015Holstein CSF6TMR4674680%>0.10
Hammond et al.
2013 (exp 1)
Holstein HChambersmaize/ryegrass silage 215198-8%>0.10
Hammond et al.
2013 (exp 2)
Holstein HChambersforage mixtures209208-1%>0.10
Hammond et al.
2013 (exp 3)
Holstein HSF6pasture186163-12%<0.00
Waghorn et al.
2011
Friesian HChambersrestricted DMI,
grass silage
133146-10%>0.10
Waghorn et al.
2011
(CO2 measures)
Friesian HChambersrestricted DMI,
grass silage
51235082-1%>0.10
Zimmerman et al.
2013 (diet 1)
Angus CSF6pasture2772915%>0.10
Zimmerman et al.
2013 (diet 2)
Angus CSF6pasture2873149%>0.10
DAFF (2012)Short-Horn C/HChambersThe CH4 yields (g CH4/kg dry matter intake) were very similar between the two systems.

 

Indirect Comparisons

 CattleDietResult
Huhtanen et al. 2013Swiss red, LCDMI measured,
grass silage
CH4 emissions were similar to values derived from respiration chambers in cows fed similar diets. The system has potential to rank the animals according to CH4 and energy efficiency.
Waghorn et al. 2013Friesian, LCCH4 calculated,
grass pasture
"There was a positive correlation between GreenFeed and calculated measurement of CH4 emission (R2 = 0.72; P = 0.004)"
Velazco et al. 2013Composite SteersSensitivity to Changes in diet"the short-term measures were able to detect significant nitrate-derived methane mitigation"
H = Holstein, C = Cow, LC = Lactating Cow