Farmer's Weekly (South Africa)
Global Farming
Savvy livestock farmers can lower greenhouse gas emissions and reduce the carbon footprint of their enterprises while boosting profits.
In 2006, a report by the Food and Agriculture Organization of the United Nations shocked the world’s agricultural and agro-processing industries. Titled Livestock’s Long Shadow, it alleged that livestock, largely through methane emissions, were the major producers of greenhouse gases. Since then, it has become clear that the report had exaggerated the role of livestock in this regard, particularly when compared with the transport industry. Newer methodology has resulted in much lower estimates for the greenhouse gases (GHGs) produced by farm animals.
Nonetheless, it is true that ruminants are the major culprits of methane emissions. Expressed as kilograms of carbon dioxide per kilogram of food protein, beef cattle, small ruminants and dairy cattle produce significantly more GHGs than monogastric animals such as poultry and pigs.
Ruminant food production is also seen as an inefficient way of converting plant protein and energy to food protein and energy. Dairy and beef cattle produce far less protein per kilogram of plant protein used than non-ruminants do.
On the other hand, ruminants convert parts of plants that are not edible for humans into nutritional food, and this is the basis for a different way of looking at livestock production.
An alternative measurement
In a paper delivered at the 2018 International Dairy Federation World Dairy Summit, French scientist JL Peyraud recommended an alternative method of determining protein-use efficiency by ruminants.
Humans and livestock compete for food and feed from plant production, but the competition is only for the human-edible parts of plants. If one excludes the parts that humans cannot eat, such as the parts of grain used in animal feed, livestock farming is not the inefficient food producer that a simple food:kilogram of feed comparison indicates. Based on animal protein produced per kilogram of edible plant protein used, grassland production systems are more efficient than grain-based intensive systems.
In South Africa and elsewhere, ruminants graze lands unsuited to crop production. It is estimated that 25% of the world’s animal production is derived from permanent grasslands and rangelands. Grassland production also produces healthier food with a higher percentage of important fatty acids such as omega-3 and a lower percentage of saturated fatty acids.
This said, enteric fermentation by ruminants produces methane, which is 28 times more environmentally harmful than carbon dioxide. But this can be mitigated.
‘ use crop residue and food waste to produce food’
A 2014 Agricultural Research Council study found differences between various cattle breeds and even between individual cattle of the same breed. And there are already breeding plans that include methane production as a breeding trait.
Good animal husbandry, which results in higher production from the same resources, the proper use of manure, and improved crop management through minimum tillage and crop rotation, can also help lower total carbon footprint.
Dr Martin Scholten from the Wageningen University in the Netherlands has introduced the concept of ‘circularity’ in livestock production. Farmers should focus on resource efficiency rather than production efficiency and use all produced agrobiomass, including crop residues, food waste and manure, to produce food. This would reduce the industry’s various footprints.
Implications for South Africa
A carbon tax already exists for the motor industry. While agriculture is exempt from this tax, there is no guarantee it will remain so. There are many new ways to mitigate carbon footprints internationally; South Africa’s scientists would do well to study these.
Apart from anything else, it makes economic sense for farmers to limit carbon and other footprints. For example, those who adapt biological farming methods save on fertiliser and other chemicals.