More Milk, Less Methane in Mixed Pastures?

Research team conducts meta-analysis on the potential of diverse pasture lands for dairy farming.

Allowing dairy cows to graze on fresh grass in open pastures for a significant proportion of the year seems more natural and sustainable. And there are proven advantages for the environment: stable grasslands promote biodiversity, protect the soil, and support carbon storage. However, farms face challenges as they are heavily dependent on the weather and the time of the year. Farming is more productive when the pastures have a wide variety of different grasses, herbs and legumes, such as clover and chicory. A research team at the University of Göttingen has analysed this strategy using a meta-analysis of a number of studies. The analysis showed that the diversity of pastureland has no effect on milk production or on emissions of the greenhouse gas methane, which cows emit mainly when they burp. However, a higher proportion of legumes can promote milk production. The results were published in the journal Food and Energy Security.

In this meta-analysis of 16 studies, the researchers compared grasslands with diverse vegetation and less species-rich pastureland and considered the effects on milk production and methane emissions, as well as the nutritional value of the feed. The fact that no clear correlations could be identified may be due to methodological reasons, as lead author Dr Martin Komainda at Göttingen University’s Institute of Grassland Science explains: “Ten of the studies lasted ten days or less. However, the productivity and nutritional value of grassland areas fluctuate within seasons and between years. To better account for this, more year-round and multi-year studies are needed.” Plant species that could affect methane emissions were also rarely found in the pastures studied.

Read More: University of Gottingen

Jersey cows – which were the breed studied in the meta-analysis – grazing in a pasture (Photo Credit: Martin Komainda)