“Sea-feed” for beef heifers: AAFC biologist finds seaweed is helping to lower methane emissions in cattle

The research team from Agriculture and Agri-Food Canada’s (AAFC) Nappan Research Farm in Nova Scotia swapped the mineral supplements of their beef heifers for something a bit more salty: seaweed!

AAFC research biologist John Duynisveld has been working at the Nappan Research Farm for many years and will often team-up with other researchers on projects. When Dr. Ghader Manafiazar from Dalhousie Agriculture Campus received funding from the Prince Edward Island’s Climate Challenge Fund to study whether feeding kelp (a type of seaweed) as a supplement to cattle would reduce their methane emissions, he asked John to lend his expertise to the project. John agreed and the 2 teams got to work! John’s study focused on how kelp supplemented diets impact pregnant beef heifers at the AAFC Nappan Research Farm, while the Dalhousie research team also began testing their pregnant dairy cows.

"Seaweed is a natural biofilter, so we were predicting that positive nutritional qualities in the kelp would have a positive impact on the herd. However, what we really wanted to understand was how much of an impact the seaweed will have, so we would be able to say to producers 'this is a better alternative because of ‘these’ benefits.'"

- Dr. John Duynisveld, research biologist, Agriculture and Agri-Food Canada

Now entering the emission testing chamber

In August of 2023, John and his team began phase one of the study at the Maritime Beef Council’s testing station. During this phase, they measured the heifers’ feed intake, growth rate, as well as fetal growth and development. Four groups of heifers each received a different amount of the ground kelp supplement in their diet; no kelp, low kelp, medium kelp, and high kelp. In addition to quantifying methane emissions, by varying the amount of supplement and comparing those results with the kelp-free diet, the team could measure:

• if increased kelp supplements led to less feed being eaten by the heifers; and
• if there were differences in growth of the heifers depending on how much kelp was included in their feed.

The team collected the animal's weight, performed ultrasounds and took blood samples on a bi-weekly basis to evaluate the health of the heifers and monitor whether the seaweed had an impact on the fetus.

For the second phase of the study, the heifers were moved back to the Nappan Research Farm for the winter where they were placed into methane measurement chambers, owned by the Maritime Beef Council. The heifers were rotated through 4 chambers where their methane emissions were measured for 24-hour intervals. The research team then repeated the rotation process a second time to collect a second methane measurement from each heifer.

"Each chamber is a plexiglass headbox that is connected to vacuum pumps. Only the heifers’ heads were placed in the headbox to allow them to stand up, lay down, eat, drink, and see each other through the boxes. There is also a special hood that went over their neck and was velcroed to the outside of the headbox, to help reduce air leaking from the headbox chamber. When the heifer burped, the gas would travel into a machine that measured the levels of methane output. After the scientists completed their measurement sessions, the testing was done, and the heifers were returned to the barn at the Nappan Research Farm to wait for their babies to be born."

- Dr. John Duynisveld, research biologist, Agriculture and Agri-Food Canada

Seaweed showed significant impact on methane emissions in beef heifers

Over the winter, John and the team analyzed the impact of kelp supplementation on the beef heifers and their methane emissions. Preliminary results from the team indicated that heifers who received the higher amounts of kelp in their diet led to a 11 to 15% reduction in methane emissions compared to the beef heifers that received little to no kelp. While the full analysis of this research is still being evaluated, early signs show that there was no significant impact on feed intake or animal growth rate. The fetal growth rate data is expected to be available in the near future.

"The industry is looking to reduce its methane emissions by 30% by 2030. Our findings show that feeding beef cattle kelp is a significant way that farmers can help reduce methane emissions."

- Dr. John Duynisveld, research biologist, Agriculture and Agri-Food Canada

Now that the research on this project has ended, Living Lab – Prince Edward Island, led by the East Prince Agri-Environment Association with funding from AAFC, is incorporating these findings into their activities. Farmers, in collaboration with researchers and other partners, are co-developing, testing and evaluating this practice, working together to make continued improvements and making sure it is practical and feasible for adoption on the farm. This time, the impact on methane emissions when including seaweed in the diets of beef and dairy cattle is being evaluated on farms, in a real-world, large-scale setting.

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Related information

• Kentville Research and Development Centre
• Agricultural Climate Solutions – Living Labs