DOMESTIC OFFSETS INTEGRITY COMMITTEE

C/- DOIC Secretariat

GPO Box 854

CANBERRA ACT 2601

The Hon Yvette D’Ath MP

Parliamentary Secretary for

Climate Change, Industry and Innovation

Parliament House

CANBERRA ACT 2600

Dear Mrs D’Ath

The Domestic Offsets Integrity Committee has considered the following activity proposed for inclusion on the Positive List under the Carbon Farming Initiative:

·  Reducing emissions from ruminant livestock by feeding nitrate supplements.

The Committee considers that this proposed activity is suitable for inclusion on the Positive List for the reasons provided in the Statement of Reasons.

The Committee notes that there is potential for toxicity issues to arise in association with this activity in certain circumstances. This issue can and should be addressed through any methodology developed for this activity.

Yours sincerely

AJ Press
Chair
Domestic Offsets Integrity Committee
May 2013

STATEMENT OF REASONS

The Domestic Offsets Integrity Committee considers that the following activity is suitable for inclusion on the Positive List for the reasons outlined below.

Reducing emissions from ruminant livestock by feeding nitrate supplements.

Background

Nitrates are mineral based supplements and when used as feed supplements for livestock can be calcium, potassium, or ammonium based. Nitrate supplements allow some microbes in the rumen to outcompete methane-forming microbes ensuring less methane is produced[1],[2],[3].

When first introduced into an animal’s diet, or in large quantities, nitrate supplements have the potential to be toxic, and sometimes fatal. However, several studies have found that slow introduction over an adaptation period overcomes toxicity risks[4]. In one study, a16day adaptation period was sufficient to allow the rumen microbes to adjust to nitrates[5].

The Committee notes that any methodology for this activity would need to ensure that projects are carried out in such a way as to ensure there is no detrimental impact on livestock.

Nitrate supplements can replace the feeding of urea, which promotes methane-forming microbes. Urea is typically fed to livestock when there is poor quality pasture, for example during the dry season. Urea affects rumen microbes, allowing feed to be more easily digested and more feed to be eaten. Urea also has the potential to be toxic. Potential health effects have been addressed by feeding urea in a lick block, which reduces the amount that livestock can consume.

Because of the unappealing taste, feeding nitrate supplements may cause livestock to eat less[6]. This can be addressed by also feeding the livestock grain. A high carbohydrate feed, such as grains, can counteract the effects of a reduced feed intake and toxicity if necessary[7].

Reasons for advice

There is clear evidence the use of nitrates reduces methane emissions from livestock.[8],[9] Studies have shown that supplementing feed with nitrates can reduce methane emissions from cattle and sheep by more than 20 per cent[10]. In some cases beef cattle fed a diet including nitrate were found to have a one third reduction in methane emissions compared to cattle with feed supplemented by urea or other diets[11].

Feeding nitrate supplements to livestock is not common practice. Research identifying the potential benefits of nitrate feed supplementation is relatively recent and there is a range of barriers to the uptake of the practice. Products that enable nitrate supplements to be fed to cattle safely have yet to be commercialised. Farmers are likely to prefer to use urea rather than nitrates because urea has greater nutritional density, is less costly and easier to transport. Further, farmers may remain concerned about toxicity notwithstanding evidence that this can be avoided.

[1] J.V. Nolan et al, Effects of dietary nitrate on fermentation, methane production and digesta kinetics in sheep, Animal Production Science 50:801-806, 2010.

[2] R.A. Leng, The potential of feeding nitrate to reduce enteric methane production in ruminants, 2008. www.penambulbooks.com/Papers%20&%20Presentations.htm

[3] L. Li, J. Davis, J. Nolan and R. Hegarty, An initial investigation on rumen fermentation pattern and methane emission of sheep offered diets containing urea or nitrate as the nitrogen source, Animal Production Science 52(7): 653-658, 2012.

[4] R.A. Leng and T.R. Preston, Further considerations of the potential of nitrate as a high affinity electron acceptor to lower enteric methane production in ruminants, Livestock Research for Rural Development 22 (12), 2010.

[5] R.B.A. Hulshof et al, Dietary nitrate supplementation reduces methane emission in beef cattle fed sugarcane-based diets, Journal of Animal Science, 2012.

[6] Hulshof et al, Dietary nitrate supplementation, p.1.

[7] S. Robson, Nitrate and nitrite poisoning in livestock, Primefacts: Profitable and sustainable primary industries, 2007, http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0006/111003/nitrate-and-nitrite-poisoning-in-livestock.pdf, pp2-3.

[8] C. Grainger and Beauchemin K.A. 2011, Can enteric methane emissions from ruminants be lowered without lowering their production? Animal Feed Science and Technology, 166-167, 308-320.

[9] R.J. Eckard, C.Grainger and C.A.M de Klein, Options for the abatement of methane and nitrous oxide from ruminant production: A review, Livestock science 130, 2010, 47-56.

[10] Leng, Further considerations of the potential of nitrate, 2010.

[11] Hulshof et al, Dietary nitrate supplementation, 2012.