ghg-inventory-1990-2013

Table 5.2.3
New Zealand’s implied emission factors for enteric fermentation
from 1990 to 2013
Year
Dairy cattle (kg CH 4
per animal per
annum)
Non-dairy cattle
(kg CH 4 per animal
per annum)
Sheep, all (kg
CH 4 per animal
per annum)
Deer (kg CH 4
per animal
per annum)
1990 69.2 50.0 9.6 17.0
1991 72.2 51.4 9.9 17.6
1992 72.7 52.2 9.9 18.4
1993 73.7 53.0 10.1 18.8
1994 72.3 53.4 10.2 18.3
1995 72.0 52.9 10.0 19.2
1996 74.3 54.7 10.5 19.6
1997 75.2 55.6 10.9 19.8
1998 73.1 55.7 10.9 19.8
1999 74.6 54.4 10.9 19.9
2000 76.2 56.4 11.3 20.2
2001 77.1 57.4 11.3 20.2
2002 76.6 57.2 11.4 20.3
2003 79.5 56.8 11.5 20.1
2004 78.3 57.8 11.8 20.6
2005 78.8 58.4 11.9 20.9
2006 78.6 59.5 11.7 21.2
2007 77.6 58.1 11.3 21.2
2008 76.5 57.4 11.5 21.4
2009 77.0 57.8 11.9 21.6
2010 78.9 57.6 11.5 21.6
2011 80.0 58.5 11.9 21.7
2012 79.9 59.3 12.1 21.8
2013 80.2 58.5 11.9 21.2
Emissions from minor livestock categories
A Tier 1 approach is adopted for the minor livestock categories of goats, horses, swine,
alpaca and mules and asses, using either IPCC (2006) default emission factors (horses,
alpaca and mules and asses) or New Zealand country-specific emission factors (goats and
swine). These minor species comprised less than 0.2 per cent of total enteric CH 4
emissions in 2013. The populations of goats, horses, pigs, alpacas and mules and asses
are reported using the statistics and assumptions described in section 5.1.4.
Goats: From 1990 to 2009, the population declined from 1,062,900 to 82,229. Most of
the decline in the herd was in the non-milking goat population. New Zealand uses a
country-specific emission factor for enteric fermentation of 7.4 kg CH 4 /head for 1990 and
8.5 kg CH 4 /head for 2009 based on the differing population characteristics for those two
years (Lassey, 2011). For the intermediate years between 1990 and 2009 and for 2010 to
2013, the emission factor was calculated based on the goat population, with the
assumption that the dairy goat population has remained in a near constant numbers over
time while the rest of the goat population has declined.
Swine: New Zealand uses a country-specific emission factor of 1.06 kg CH 4 /head/year,
which was derived from the IPCC (1996) Tier 2 methodology using a country-specific
value for gross energy intake of 26.9 MJ per animal per day (Hill, 2012). The value of
gross energy intake (GEI) and the composition of the swine diet are based on a survey of
144 New Zealand’s Greenhouse Gas Inventory 1990–2013