Interpretive Summary: Forb-based pastures more effective for reducing the environmental impact of pasture-based dairy farming
By Anne ZInn
Despite only contributing 1.3% of the total national greenhouse gas emissions, dairy production in the United States has come under scrutiny as the concerts of the environmental effects of maintaining ruminant livestock on pasture grows. Therefore, maintaining high-performing pastures while preserving the environment is that primary target of pasture-based dairy farming. A recent study published in the Journal of Animal Science investigated the effects of changing the forage base in spring from grass-clover pastures to forb or legume-based pastures on milk yield, nitrogen utilization, and methane emissions of Jersey cows. The research team hypothesized that specialized forb- and legume-based pastures would maintain their high nutritive value as compared to grass-clover pastures during late-spring and summer and would therefore support greater milk production with less environmental pollution.
Results of this study suggest that incorporating legume- and forb-based pastures offers a viable option to manage pastures as evidenced by greater milk yield, more efficient rumen fermentation, and, in forb-based pastures specifically, less environmental pollution potential as compared to the classical clover pasture. The results also indicated that forb and legume pastures have the potential for maintaining high milk yields, especially when the nutritive quality of grasses is poor due to accumulation of low-quality forage. As a whole, the tendency for less greenhouse gas emissions and improved nitrogen use efficiency with forb-based pastures means improved environmental efficiency over legume-based pastures. The conclusion that can be drawn is that including forb-based pastures that contain chicory and plantain in the feed-base of dairy cows may be more effective for reducing the environmental impact of pasture-based dairy farming than legume and traditional clover pastures while still maintaining their high nutritive value.
The full paper will soon be available on the Journal of Animal Science website.