@conference {60971,
	title = {The variation in methane emissions from sheep and cattle is not explained by the chemical composition of ryegrass},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {69},
	year = {2009},
	month = {Jun},
	pages = {174-178},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {A data base of over 3,000 ruminant methane emission records from individual animals used to compile New Zealand{\textquoteright}s greenhouse gas inventory, shows substantial variation in CH4 yields (g/kg dry matter intake (DMI)) within and between forage types. Multiple regression analyses were undertaken using datasets from sheep and cattle fed fresh ryegrass to determine the extent to which variation in CH4 yields could be explained by ryegrass chemical composition. Methane was measured using the SF6 marker dilution technique with sheep and cattle, and also directly by respiration calorimetry from sheep. Data from sheep showed a similar average CH4 yield from both techniques, but there was more variation in SF6 data (23.4 {\textpm} 5.73) than from calorimetry (23.1 {\textpm} 2.89). Cattle CH4 yields averaged 19.1 {\textpm} 3.70 g/kg DMI. Multiple regression analysis of sheep data showed pasture chemical composition accounted for <2\% of the variation determined by SF6 and 20\% of the variation from calorimetry. Only 13\% of the variation in yield from cattle was explained by ryegrass composition, so the majority of variance (>80\%) was not explained. We suggest the variation in CH4 emissions is affected by digestive characteristics of individual animals, and interactions with forage physical and chemical components. },
	issn = {1176-5283},
	author = {Hammond KJ and Muetzel S and Waghorn GC and Pinares-Patino CS and Burke JL and Hoskin SO}
}
@conference {42043,
	title = {Comparative methane emissions from cattle, red deer and sheep},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {68},
	year = {2008},
	month = {Jan},
	pages = {59-62},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Brisbane, Australia},
	abstract = {Methane (CH4) production (g CH4/d) and yields (g CH4/kg dry matter intake (DMI)) from groups of 11 non-lactating dairy cattle, sheep and red deer were compared in January and June of 2007. During each period, methane emissions measured using the SF6 tracer technique, were measured over four days following 10 days of acclimatisation. All animals were individually housed in metabolism cages and fed ensiled lucerne chaff at a rate of 1.2 times estimated energy requirements according to Australian feeding standards. Total daily methane production from cattle (140.4 g CH4/day) was greater than deer (31.5 g CH4/day) which was greater than sheep (18.3 g CH4/day) (P<0.001) and methane yield from cattle (20.6 g CH4/kg DMI) was greater than sheep (18.4 g CH4/kg DMI) which was greater than deer (16.5 g CH4/kg DMI) (P<0.001). A significant interaction of species by season was driven by the higher methane production and yield of cattle in winter compared with summer (P<0.001). The findings of this experiment show that methane emissions can differ between ruminant species at the same time on the same diet. Reasons for these differences are yet to be elucidated. },
	issn = {1176-5283},
	author = {Swainson NM and Hoskin SO and Clark H and Pinares-Patino CS and Brookes IM}
}
@conference {41780,
	title = {A versatile sheep respiration chamber system for measurement of methane emission},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {68},
	year = {2008},
	month = {Jan},
	pages = {29-30},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Brisbane, Australia},
	abstract = {Globally, the single most important source of greenhouse gas emissions from grazing systems is enteric methane (CH4) arising as a by-product of the fermentation of feed in the reticulo-rumen of ruminants (Clark et al., 2005). Methane is implicated in global warming and in countries where livestock constitutes a major emission source such as New Zealand, international commitments are driving research to develop emission reduction technologies, for which accurate measurements of CH4 emissions are ...Continued },
	issn = {1176-5283},
	author = {Pinares-Patino CS and Lovejoy P and Hunt C and Martin R and Molano G and Waghorn GC and Clark H}
}
@conference {41770,
	title = {Evaluation of the sulphur hexafluoride tracer technique for methane emission measurement in forage-fed sheep},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {67},
	year = {2007},
	month = {Jan},
	pages = {431-435},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Wanaka},
	abstract = {The aim of this study was to evaluate the sulphur hexafluoride (SF6) tracer technique for methane (CH4) emission measurement in sheep. Methane emissions from ten Romney sheep were individually measured both by the SF6tracer ({\textquoteleft}tracer CH4{\textquoteright}) and by the indirect calorimetry chamber ({\textquoteleft}calorimetric CH4{\textquoteright}) techniques while fed on lucerne hay. The tracer technique involved the use of permeation tubes with pre-calibrated permeation rates ({\textquoteleft}pre-calibrated PR{\textquoteright}) of SF6. The {\textquoteleft}tracer CH4{\textquoteright} measurements were carried out for 5 days in digestibility crates housed within a covered yard. Sheep were transferred to calorimetry chambers for 3 days acclimatisation, followed by measurement of CH4emission for 3 days. Permeation tubes were recovered at the end of the animal trial and their {\textquoteleft}post-recovery PR{\textquoteright} determined after subsequent weighing for a 6-month period. Although the {\textquoteleft}tracer CH4{\textquoteright} was slightly lower (by 4\%) and had larger variation than the {\textquoteleft}calorimetric CH4{\textquoteright} values (18.8{\textpm}0.4 vs. 19.5{\textpm}0.6), the two measurement techniques did not differ significantly (P>0.05) in their CH4emission estimates. The {\textquoteleft}post-recovery PR{\textquoteright} was not different (P>0.05) from their {\textquoteleft}pre-calibrated PR{\textquoteright} values, and they were highly correlated to each other (r=0.98, P<0.0001). It is concluded that the tracer technique provides a reliablealternative method for CH4measurement in forage-fed sheep.},
	issn = {1176-5283},
	author = {Pinares-Patino CS and Holmes CW and Lassey KR and Ulyatt MJ}
}
