Beef footprint study's NZ relevance questioned
New Zealand experts have questioned the relevance of a new study that highlights beef farming's high environmental impact.
The study, which is based on US farming systems, said beef required 28 times more land, 11 times more water, five times more greenhouse gas emissions, and six times more fertiliser when compared with dairy, poultry, pork and egg production.
While it was a fair reflection of US beef systems, it could not be so easily translated to New Zealand's pasture-based farming, AgResearch scientist Stewart Ledgard said.
Ledgard is the principal scientist of AgResearch's nutrient management and environmental footprinting team.
While most US beef cattle began life on pastures, the vast majority were finished in giant feedlots where they were fed irrigated crops.
Those crops consumed a lot of water and nitrogen fertiliser. The land those crops occupied could be used more efficiently for feed for other livestock or food for human consumption.
"In New Zealand we don't have big feedlot systems, especially now with dairying occupying the easier and flat land."
Most New Zealand beef cattle were farmed on a permanent pasture system on hill country.
"That land isn't suitable for growing crops and it couldn't be harvested anyway," Ledgard said. "There isn't that transferability factor."
Its only alternative land use was other stock classes such as sheep and deer, or forestry.
"It's a sensible use of our hill country resources," Ledgard said. "The only alternative we have is to put it into trees."
The authors published their research in the Proceedings of the National Academy of Sciences of the United States of America journal.
The study said that livestock-based food production was "an important and pervasive way" that humans impacted the environment.
"It causes about one-fifth of global greenhouse gas emissions, and is the key land user and source of water pollution by nutrient overabundance," its authors said. "It also competes with biodiversity, and promotes species extinctions."
Statistics from Beef+Lamb New Zealand showed that as of June, 2013, beef cattle numbers were 3.7 million, of which one million were beef breeding cows and heifers.
Total beef and veal production for the year to September, 2013, was 628,000 tonnes. Around half of beef and veal exports from New Zealand is destined for the US market.
A similar study was under way in New Zealand. However, this work looked at the environmental impact of protein production rather than beef, Ledgard said.
He co-authored a 2012 study that investigated exported New Zealand beef's greenhouse gas footprint.
It concluded that the total greenhouse gas footprint was calculated at 2.2-kilogram CO2-equivalents for a 100-gram portion of beef.
That equated to 90.3 per cent for the on-farm stage, 2.1 per cent for meat processing, 4.2 per cent for transportation, and 3.3 per cent for consumption.
On farm, the largest contributors to emissions were the natural processes associated with cattle consuming pasture. These processes include methane from rumen digestion of pasture via belching, (62 per cent of the total footprint) and nitrous oxide from animal excreta on soil (17 per cent of total footprint).
The average kilogram of New Zealand beef had a relatively low carbon footprint compared with other countries. This was largely due to about half of New Zealand's beef being sourced by the dairy industry where it is used as manufacturing beef.
"That has a very efficient carbon footprint - more efficient than traditional beef because it doesn't need a breeding cow producing a calf to grow it because it's a byproduct of the cow."
Lincoln University's Professor Caroline Saunders said similar work had already shown the environmental impact of ruminant animals.
"It's well known, so I don't know what is new that has been added here."
It was also known that a diet that included meat had higher emissions than a vegetarian diet.
Those who opt out of a meat diet often forgot that there were limited options for the hill country land beef was farmed on.
"They tend to talk about it in a global sense - we'll feed more people, but to be honest, it's not easily an alternative."
Saunders said people needed a balanced diet that could include meat.
"Meat from sources such as New Zealand produced meat is using our international resources effectively."