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

Diana C Reyes; Jennifer Meredith; Leah Puro; Katherine Berry; Richard Kersbergen; Kathy J Soder; Charlotte Quigley; Michael Donihue; Dorn Cox; Nichole N Price; Andre F Brito

doi:10.3389/fvets.2023.1153097

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

Front Vet Sci. 2023 Jul 6:10:1153097. doi: 10.3389/fvets.2023.1153097. eCollection 2023.

Authors

Affiliations

¹ Department of Agriculture, Nutrition, and Food Systems, University of New Hampshire, Durham, NH, United States.
² Department of Economics, Colby College, Waterville, ME, United States.
³ Wolfe's Neck Center for the Agriculture and the Environment, Freeport, ME, United States.
⁴ Cooperative Extension, University of Maine, Orono, ME, United States.
⁵ USDA-ARS, Pasture Systems and Watershed Management Research Unit, University Park, PA, United States.
⁶ Bigelow Laboratory for Ocean Sciences, East Boothbay, ME, United States.

Abstract

Introduction: 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.

Methods: A survey was developed to identify barriers and drivers towards the adoption of CH₄-reducing algal-based feeds. 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 Holstein and Jersey cows averaging 29 ± 6.8 kg of milk/d and 150 ± 69 days in milk, 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 for a total of 12 weeks. Gaseous emissions were measured using a GreenFeed unit. Data were analyzed using the MIXED procedure of SAS with repeated measures over time.

Results: All survey respondents (n = 35; 54% response rate) were familiar with seaweeds as feed, 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. Feeding 6CC decreased enteric CH₄ production by 13.9% compared with 0CC (401 vs. 466 g/d). Further, milk yield (mean = 27.1 kg/d), CH₄ intensity (mean = 15.2 g of CH₄/kg of energy corrected milk), and concentrations and yields of milk fat and true protein were not affected by treatments.

Discussion: 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. 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. Identifying the bioactive compounds in C. crispus is critical to understand the effect of this red seaweed on mitigating enteric CH₄ emissions in dairy cows.

Keywords: alternative feed; greenhouse gases; milk quality; mitigation; survey.