Skip to 0 minutes and 16 secondsLet us assume that on average a cow produces around 350 litres of methane and 26 litres of milk per day.
Skip to 0 minutes and 28 secondsWhen a cow is sick and needs veterinary treatment the milk she produces must be thrown away. So if she is unlucky and suffers from two causes of severe mastitis during her lactation, then her milk will need discarding for roughly 28 days. A cow only produces milk for 10 months per year. So the milk which must be thrown away when she is sick with mastitis would account for a loss of 728 litres of milk per year. Nearly a 10% loss in profit for the farmer from this cow. This shows how important cow health is from a financial perspective.
Skip to 1 minute and 6 secondsEven when a cow is sick, it still produces around 350 litres of methane every day. For one lactation, which lasts around 10 months or 300 days, a cow will produce around 105,000 litres of methane. So if we look at the production of methane per unit milk, a healthy cow produces 13.1 litres of methane per litre of milk over the course of her lactation. Where as a sick cow produces 14.4 litres of methane per litre of milk because of the sickness.
Skip to 1 minute and 38 secondsThis means that the sick cow also produces 10% more methane per litre of milk than a healthy cow. It is also possible to improve the efficiency of a cow through her diet.
Skip to 1 minute and 52 secondsTo produce 26 litres of milk per day on a normal diet, a cow requires around 20 kilos of feed in dry weighed, costing, say, £ 4 On this diet, a cow would produce 350 litres of methane per day or 13.5 litres of methane per litre of milk.
Skip to 2 minutes and 14 secondsA more efficient diet, reaching a high digestibility, however, could require only 19 kilos of feed to produce the same 26 litres of milk per day for only £3.80 If this diet also led to a 5% decrease in methane production, the cow would produce only 332.5 litres of methane per day or 12.8 litres of methane per litre of milk. So by improving the diet you have a healthier cow, produce less methane, and save money on feed. Another way to improve the efficiency of a cow is by keeping her for more lactations. In the first two years of a cow's life, before she gives birth to her first calf, she will not produce milk, but she will still produce methane.
Skip to 3 minutes and 2 secondsImagine there are two cows. The first cow is culled after three lactations at five years of age. The second cow is culled after six lactations at eight years of age. Throughout her life the first cow will end up producing more methane per litre of milk than the second cow because the period during which she produces no milk is relatively longer than in second cow. Provided the productivity of the cow remains high with age, this approach is something to consider when trying to reduce the environmental impact of the dairy industry.
How to measure the effects of mitigation
In this short animation we want to show you how mitigation efforts and changes in farming practice can be measured, using dairy farming as an example. Please note that the numbers used in this animation are used for illustrative purposes only and may differ in real life.
This animation was created by Clara Kightley and Sophie McDonnell, undergraduate students from the University of Reading’s Typography and Graphic Communication department.
© University of Reading