Interpretive Summary: Impact of forage diversity on forage productivity, nutritive value, beef cattle performance, and enteric methane emissions

By: Dr. Emily Taylor

In recent years the beef industry has been targeted as a primary contributor to global warming. More specifically, this includes methane (CH4) production from the grazing sector, and therefore, researchers are working to mitigate the CH4 production in grazing environments. The current study aimed to examine forage productivity, nutritional value, animal performance, and enteric CH4 emissions of two common Midwest grazing mixtures that include a simple (SIMP) alfalfa:orchardgrass mixture and a complex (COMP) forage mixture. They hypothesized that the COMP forage mixture would increase forage productivity, improve forage nutritional value, and reduce enteric methane emissions. 

Over three consecutive grazing seasons, researchers observed that forage availability did not differ between treatments; however, it tended to be lower in 2018 than in 2019 and 2020. In 2018, crude protein and acid detergent fiber content were significantly lower in COMP compared with SIMP. In 2018 and 2019, dry matter digestibility was higher in the COMP treatment. Animal performance was not different between treatments. Methane production tended to be lower in the COMP treatment, but no difference was observed in emission intensity. 

In conclusion, this experiment did not prove that this complex forage mixture yielded improved forage productivity, animal performance, or reduced emissions intensity. It does, however, serve to supplement the shortage of literature examining animal emissions when grazing complex forage mixtures. The authors suggest more research is needed to test other producer-relevant mixtures.

This article is available in the Journal of Animal Science.