• Uses mainly renewable resources and has minimal impact on the environment
• Has happy and healthy dairy cows that use minimal amounts of antimicrobials
• Is profitable because it produces healthy and nutritious animal proteins, both now and in the future.

Sustainable dairy farming has many different elements that are all interrelated.

The carbon footprint of a dairy farm is mainly related to the production of greenhouse gasses. Greenhouse emissions can come directly from the cow or can be related to the farm operations. A clear example of the latter is the CO2 which is produced because the farm uses fossil fuels to produce energy. Another less well-known example is the use of fertilizer. About 2% of the global fossil energy sources are being used for the production of fertilizer every year.

Cows on a dairy farm produce 3 different greenhouse gasses, carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4):

• Cows produce a lot of carbon dioxide, but this is a circular process: plants use CO2 and water to produce sugars and oxygen, the cow uses these plants and oxygen to produce energy and CO2 (see Figure 1). Most of the CO2 emission of a dairy farm comes from the farming operations.
• Nitrous oxide is mainly released when manure is injected into the soil.
• When the feed the cow eats is fermented in the rumen, there is enteric production of methane. Most of this enteric methane is expelled through belching. A small percentage of enteric methane is produced in the cow’s large intestine and then expelled. Next to enteric production of methane, there is also production of methane via manure after this manure has been produced by the cow. The problem with methane is that the greenhouse gas effect is 34 times bigger than the greenhouse gas effect of CO2

Several strategies to reduce greenhouse gas emissions of a dairy farm exist. Most of them are based on increasing the efficiency of production, resulting in an increase of lifetime production and income over feed costs of the farm. It is also possible to influence the rumen fermentation with feed additives in such a way that carbon emission shifts away from methane. Lastly, there are ways to reduce methane emission from manure.

Most of the health problems on a dairy farm are directly or indirectly related to poor transition to lactation. Poor transition management of dairy cows increases the incidence of metritis, mastitis and lameness. These problems are responsible for a large proportion of the use of antibiotics on a dairy farm. Thus, reducing transition problems in dairy cows does not only improve efficiency of production, leading to a reduction of methane emission per kg of milk produced, it also can result in a significant reduction of antimicrobial use.

• Significant reductions of methane emission per litre of milk produced can be achieved by reducing the age at first calving, increasing the production per lactation as well as the number of lactations per cow. Each of these improvements will result in an increase of profitability of the farm.
• Many of the disease problems on a dairy farm are related to problems with the transition to lactation. Optimising transition management of dairy cows will result in a reduction of the incidence of disease and a reduction of veterinary costs. Healthy animals are also more efficient and thus more profitable.
• Reducing the emissions from manure means that the manure will be more suitable for biogas production with a higher yield of biogas from the same amount of manure. Secondly, the manure will maintain more of its value to fertilise land, opening the possibility to reduce the purchases of artificial fertilizer. With the current prices of energy and artificial fertilizer, this has a huge potential for cost saving on the dairy farm.