Maine organic dairy producers’ receptiveness to seaweed supplementation and effect of Chondrus crispus on enteric methane emissions in lactating cows

Authors: REYES, DIANA - University Of New Hampshire; MEREDITH, JENNIFER - Colby College; PURO, LEAH - Consultant; BERRY, KATHERINE - Consultant; KERSBERGEN, RICHARD - University Of Maine; Soder, Kathy; QUIGLEY, CHARLOTTE - Bigelow Laboratory For Ocean Sciences; DONIHUE, MICHAEL - Colby College; COX, DORN - Consultant; PRICE, NICHOLE - Bigelow Laboratory For Ocean Sciences; BRITO, ANDRE - University Of New Hampshire

Submitted to: Frontiers in Veterinary Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/19/2023
Publication Date: N/A
Citation: N/A

Interpretive Summary: There is a growing interest in utilizing seaweed in dairy cow diets for mitigating enteric methane emissions. However, large-scale adoption depends on technical and financial factors, as well as validation from pilot studies. A survey was developed to identify barriers and drivers towards the adoption of feeding seaweed by dairy producers. All survey respondents were familiar with seaweed, and 34% were already users. Farmers who were willing to pay 0.64 USD/cow/d on average for a methane-reducing feed also stated the need for co-benefits in terms of cattle health and performance as a requirement for adoption. For the second part of this research, a case study was conducted on an organic dairy in Maine to investigate the effect of seaweed on methane emissions and milk production. Feeding seaweed decreased methane production in lactating dairy cows by 13.9% compared with no seaweed. Milk yield and composition were not affected by feeding seaweed. Farmer receptiveness to methane inhibiting seaweed feeds will not only be dependent on purchase price, but also on co-benefits and simplicity of integration into existing feed practices

Technical Abstract: There is a growing interest in utilizing seaweed in ruminant diets for mitigating enteric methane (CH4) emissions while improving animal health. Chondrus crispus is a red seaweed that grows in the Gulf of Maine (United States) and has shown to suppress CH4 production in vitro. Organic dairy producers in Maine are currently feeding seaweed due to herd health promoting benefits. However, large-scale adoption depends on technical and financial factors, as well as validation from pilot studies. Therefore, a survey was developed to identify barriers and drivers towards the adoption of CH4-reducing algal-based feeds. All survey respondents (35, 54% response rate) were familiar with seaweed, and 34% were already users. Producers who were willing to pay 0.64 USD/cow/d on average for a CH4-reducing algal-based feed, also stated the need for co-benefits in terms of cattle health and performance as a requirement for adoption. Concurrently, a randomized complete block design study was conducted to investigate the effect of C. crispus on enteric CH4 emissions and milk production in a typical Maine organic dairy farm. Twenty-two organically certified cows averaging 29 ± 6.8 kg of milk/d were blocked and randomly assigned to a control diet without C. crispus (0CC), or with 6% [dry matter (DM) basis] C. crispus (6CC). Samples were collected on the last week of the 2-wk covariate period, and wk 3, 5, 8, and 10 after initiation of treatments. Gaseous emissions were measured using a GreenFeed unit. Data were analyzed using the MIXED procedure of SAS with repeated measures. Feeding 6CC decreased enteric CH4 production by 13.9% compared with 0CC (401 vs. 466 g/d). Further, milk yield (mean = 27.1), CH4 intensity (mean = 15.2 g of CH4/kg of energy corrected milk), and concentrations (mean = 3.84 and 3.10%, respectively) and yields (mean = 1.06 and 0.86 kg/d, respectively) of milk fat and true protein were not affected by diet. In summary, producer receptiveness to CH4-reducing algal-based feeds will not only be dependent on purchase price, but also on co-benefits and simplicity of integration into existing feed practices. Likewise, feeding C. crispus at 6% of the diet DM decreased CH4 production in dairy cows by 13.9% without negative effects on milk yield and composition.