Breeding for optimal efficiency yields greener dairy herds

A recent report published by the Food and Agriculture Organization of the United Nations shows that the global dairy industry is already part of the solution to address climate change. However, dairy farmers need to accelerate their current efforts by continuing to improve production efficiency.

One of the most effective greenhouse gas mitigation strategies is to increase animal productivity, which can be achieved, amongst others, through better herd management and improved genetic selection.

The growth of the world population, which is expected to increase from the current total of about 7,6 billion people to 8,6 billion in 2030, 9,8 billion in 2050 and more than 11,2 billion in 2100, has left farmers with the responsibility to increase the supply of food in order to meet demand, which is set to double by 2050.

As is the case for every agricultural industry, this growth will provide opportunities and challenges for the dairy sector.

According to a report published earlier this year by the Food and Agriculture Organization of the United Nations (FAO) and the Global Dairy Platform, more than 80% of the world’s population, or about six billion people, regularly consume dairy products.

The report, ‘Climate change and the global dairy cattle sector: The role of the dairy sector in a low-carbon future’, states that the challenges for the dairy sector include bringing milk to the consumer at competitive prices, while also contending with changing weather patterns, changing market dynamics and dairy prices.

At the same time, dairy farmers also have to adapt their operations in line with the growing emphasis on sustainability, as well as on consumers’ growing concerns about the environment, animal welfare and the quality of their food.

Emission intensity
According to the report, livestock products are responsible for more greenhouse gas (GHG) emissions than most other food sources.

“In dairy production, emissions are the result of various complex biological processes, [such as] methane from enteric fermentation, [during which] methane is produced as a by-product of the digestion process,” the FAO report states.

Additional methane and nitrous oxide emissions occur throughout the process of managing livestock manure, and other emissions include carbon dioxide largely associated with energy use throughout the production process, such as milking for example, as well as the production and transport of inputs such as feed.

The study also shows the global dairy industry’s GHG emissions increased 18% between 2005 and 2015. However, over this period, overall milk production has grown 30%.

“The trends in absolute emissions reflect changes in animal numbers as well as changes in the production efficiency within the sector,” the report states.

Between 2005 and 2015, the global dairy herd increased 11% and average global milk yield increased 15%. According to the report, without efficiency improvements, total GHG emissions from the dairy sector would have increased 38%.

Emission intensities, measured as GHG produced per kilogram of milk, have declined almost 11% over the period, due largely to improved animal productivity and better management.

However, the report says there is a distinct difference in emission intensities between regions. In developed dairy regions, emission intensity is generally lowest, with ranges between 1,3kg and 1,4kg CO₂-equivalent per kilogram milk, while developing dairy regions such as South Asia, sub-Saharan Africa, West Asia and North Africa have recorded higher emission intensities, with ranges between 4,1kg and 6,7kg CO₂-equivalent per kilogram milk.

Increasing efficiency
The large variations that occur in emission intensity between, and also within, regions can, according to the report, be explained by differences in management practices, and implies that the potential exists to reduce GHG emissions in all regions.

While the emission intensity of milk has declined, this reduction has been offset by the increased overall growth in milk output.

The FAO report states that increased livestock productivity (milk yield/head of cattle), with considerable variability between regions, has resulted in increased individual cow feed intake to meet higher energy demands, which, in turn, has resulted in higher emission rates per cow and increased methane (see Table 1) and nitrous oxide (N2O) emissions per animal.

Table 1: Methane (CH4) released by dairy cattle versus milk produced
Region CH4 (kg) released/ animal/year Average milk yield (kilograms/animal/year)
2005 2015 2005 2015
North America 111 116,6 8 899 9 864
Central and South America 82,2 84,6 1 668 1 947
Russia 64,2 71,8 3 000 4 146
Western Europe 76,3 80,9 6 287 6 957
Eastern Europe 71,2 81,7 3 921 5 005
Oceania 72,3 81,4 4 274 4 659
East Asia 69,5 69,1 2 915 2 907
South Asia 60,8 62,1 979 1 388
Sub-Saharan Africa 46,1 46,4 464 457
West Asia and North Africa 68,2 72,8 1 240 1 830

 

“Since enteric fermentation contributes more than half to total emissions, this area represents a potential opportunity for mitigation. Emissions associated with feed production point to a potentially applicable strategy for reducing the GHG emission intensity of milk, [namely] improving feed conversion efficiency, defined as the amount of feed input for producing a given quantity of milk,” the report states.

For example, an analysis by the FAO and the Global Dairy Platform shows that more of the feed consumed by animals is used for production than for maintenance, and as such, higher milk production, which has largely been driven by increasing milk yields per cow, has contributed towards lowering emission intensities.

“Higher milk yields imply a shift of the cow’s metabolism in favour of milk production and reproduction rather than maintenance, contributing to lower emission intensities,” the report states.

Moreover, the industry has also seen a continued increase in productivity and reductions in emission intensities driven by efficiency gains in areas such as nutrition, genetics, reproductive performance, disease control, and improved fertiliser practices and enhanced management at herd and animal level.

However, studies have shown that there is a definite tipping point after which increased efficiency is no longer associated with a reduction in emissions.

“Gains in saved GHG emissions through increased milk yield is marginal for milk production systems with milk yields above 5 000kg of milk/cow per year. The inflection point for this relationship is approximately 1 200kg of milk/cow per year.

“This is the milk yield that should be the minimum performance targeted for sector-wide maximum reduction of intensity globally,” the report states. It further suggests that the largest reduction potential for increased milk yield is in systems that yield below 2 000kg/cow per year.

Reducing emissions
The report offers mitigation options that, according to the FAO and the Global Dairy Platform, are consistent with improving on-farm efficiency and profitability.

It states that enhancing animal productivity has several dimensions, including “feeding, reproduction, health, genetics and overall management of the animal operation”.

In many parts of the world, according to the report, the single most effective GHG mitigation strategy is increasing animal productivity. Some of the practices and technologies the report promotes include:

  • Feed and feeding management: Increasing feed efficiency by optimising the energy and protein content in feed, and by using precision feeding techniques to match animal requirements with dietary nutrient supply. Farmers should use more locally produced feed, and source low-emission feeds, as well as store more carbon in the soil through better grassland management.
  • Manure management: Improving manure collection, storage and utilisation. By using cow manure in biogas systems, it is possible to reduce emissions of GHGs associated with the storage of manure. Farmers should also improve the quality of fertiliser and replace fossil fuel energy sources with alternative energy sources.
    Switching from raw to composted manures can also greatly reduce emissions.
  • Fertiliser management: Optimising consumption relative to need. Lowering manure application rates and incorporating manure into the soil can reduce emissions while maintaining farm productivity. Farmers should apply fertiliser at the optimum time, using the best technology.
  • On-farm energy usage: Reducing fossil fuel energy use, while increasing the use of sustainable energy.
  • Animal health and husbandry: Improving the management of herd structures to reduce the number of non-productive animals. Improved animal and herd fertility and reproduction is an effective approach to reduce emissions per unit of milk and increase dairy profitability. Farmers should also reduce the prevalence of diseases and parasites; healthy animals are more productive, and thus produce lower emissions per unit of output. The genetic potential of animals should also be improved through planned crossbreeding or selection within breeds, and proper nutrition.

Read the full report at fao.org