Ten dairy producers include forage brassicas into the diets of 750 grazing cattle, resulting in a reduction of 10.4 kg methane per cow and 780 kg methane per farm annually. Farmers reduce feeding costs by $1.50/cow/day and $6,750/farm/year by extending the fall grazing season by 2 months.
Forage-based dairy systems have been targeted due to greater methane to gross energy intake ratio compared with confinement systems. Moreover, winter feeding costs are constantly increasing, reducing the farm profitability during times of low to no pasture production. Therefore, in order to maintain both economic and environmental sustainability of their farms, producers need alternate forage options to extend the fall grazing season, while maintaining productivity and decreasing enteric methane emission and promoting environmental stewardship.
The utilization of forage brassicas in a dairy grazing management plan will offer producers a high quality feedstuff and a 60-day longer fall grazing season, while decreasing on-farm enteric methane emissions. The project team will conduct in vitro experiments, establish field plots and conduct a grazing experiment to determine the animal performance and methane mitigation potential of forage brassica species. These experiments will provide the project team with science-based recommendations for use of individual brassica species on northeastern dairy farms. By educating producers on forage brassicas, we are giving them forage options to best develop an economic and environmentally sustainable production model for many years to come.
We hypothesize that brassicas will produce superior animal performance while emitting less methane per cow compared with annual ryegrass. Foliar glucosinolate concentration will be positively correlated with methane output reduction.
Year 1: (field plot and continuous culture fermentor studies)- Three forage brassicas were used and included: ‘Inspiration’ Spring Canola, ‘Appin’ Forage Turnip, ‘Barsica’ Forage Rape. ‘KB Supreme’. Annual Ryegrass was used as an annual grass control.
Year 2- Lactating dairy cows were grazed on either: 1) brassica treatment plus perennial pasture, or 2) perennial pasture only (control).
In August 2016, 16 plots were established and assigned 1 of 4 treatments (4 replications) in a completely-randomized block design. Treatments were be seeded at 4.5 kg/ha (brassicas) and 16.5 kg/ha (ryegrass) into a prepared seedbed located at the Russell E. Larson Agricultural Research Center at Rock Springs, Pennsylvania Furnace, PA.
Measurements were taken for forage quality, foliar nitrate-N, forage yield, rising plate meter (RPM), and foliar glucosinolate concentration every two weeks. Fall sampling ended when weather no longer permitted forage growth. Spring sampling began at forage green-up and continued until forages reached full maturity (seed-head appearance). Forage samples were sent to Dairy One Forage Analysis Laboratory (Ithaca, NY) for determination of crude protein, fiber fractions, and nitrate-N. Glucosinolate concentration of freeze-dried forages were determined through high performance liquid chromatography using an ultra aqueous C18 column (Restek Corp., Bellefonte, PA). A 4-unit continuous culture system designed to simulate ruminal digestion and outflow to the small intestine was used in a Latin-square design to evaluate ruminal fermentation and methane output for each forage treatment. Fermentors were operated for four, 10-day periods (7-day adjustment and 3-day sampling). Each fermentor was fed 75 g of dry matter per day (22.5 g brassica and 22.5 g orchardgrass) in four equal feedings. On days 8 – 10, effluent samples were collected for analysis of nutrient digestibility and methane output will be determined using a modification of methods described by Soder et al. (2012).
In July 2018, 6, 1.25-acre paddocks were planted at the UNH Organic Dairy. Three pastures were planted to annual ryegrass and three pastures planted to turnips. Turnips were chosen based on nutritive value and in vitro methane mitigation data from the forage plot study in Year 1. Approximately 45 days after planting, 20 multiparious lactating cows were blocked based on milk production and randomly assigned to one of two groups. Each group of 10 cows grazed a pure stand of brassica or annual ryegrass for approximately 12 hrs per day (after afternoon milking until morning milking). All cattle were turned out as one group into a perennial cool-season grass pasture during the day and baleage was offered at milking. Baleage and grass pasture was adjusted so that brassicas did not exceed 50% of the daily dry matter intake, in order to prevent possible adverse effects on milk, milk production, and cattle health. Pastures were rotated daily, so that each pasture was grazed once every three days. The length of the grazing season was dependent on forage growth, which was approximately 6 weeks long in 2018. Pasture intake was determined by feeding an indigestible marker. Animals had ad libitum access to water at all times.
Body condition score and weight, forage yield and quality, foliar glucosinolate concentration were determined every 14 days. Forage samples were sent to Dairy One Forage Analysis Laboratory (Ithaca, NY) for determination of crude protein, fiber fractions, and nitrate-N. Glucosinolate concentration of freeze-dried forages were determined through high performance liquid chromatography using an ultra aqueous C18 column (Restek Corp., Bellefonte, PA; 6). Milk production was monitored twice daily and milk composition including fatty acid analysis was determined three times a week. Blood, urine, and fecal samples were collected every 14 days and analyzed for glucosinolate concentrations and pasture intake determination. Additionally, an economic analysis of costs and profits associated with grazing brassicas will be performed after the second year of data collection in 2019, where forage treatments will be repeated. After the second year of data collection is completed in 2019, forage characteristics, methane, glucosinolate concentration, animal performance, and economic data will be analyzed using Proc Mixed of SAS (Statistical Analysis Software, Carey, NC) using a Repeated Measures statement. Means separation will be determined using the LSMeans statement with α = 0.05. Additional regression analysis on the variation in methane output will be conducted and correlation coefficients for significant variables calculated using the Reg and Corr procedures of SAS.
The grazing study at UNH was replanted and repeated for a second year of data collection. Laboratory analysis of samples is ongoing.
Year 1 (2016):
Continuous culture fermentor study was completed- manuscript is currently under peer review with a scientific journal. Additionally, a second manuscript is currently under review that outlines an improved methodology for detecting individual glucosinolates in brassicas, which will have application in future research to determine which individual glucosinolates may impact animal health and performance.
The forage plot study data collection is complete. Data summarization and manuscript preparation in progress.
A second manuscript is currently under review that outlines an improved methodology for detecting individual glucosinolates in brassicas, which will have application in future research to determine which individual glucosinolates may impact animal health and performance.
Year 2 (2017):
UNH study- forage brassicas were interseeded into an existing perennial pasture in fall 2017 at the UNH Organic Dairy. However, stand establishment was poor. We will repeat the experiment in fall 2018, only this time we will kill off the perennial pasture to establish the brassicas. Even though the first seeding was not successful, this information is important because farmers are interested in maintaining perennial pastures but adding brassicas to those swards for extended grazing. This will help us develop improved recommendations for establishing brassicas.
An invited symposium presentation was given by Dr. Dillard on brassica grazing at the national American Society of Animal Science conference held in Baltimore, MD in July, 2017.
Year 3 (2018):
UNH study- forage brassicas were seeded onto a prepared soil surface in fall 2018 at the UNH Organic dairy. Brassica pastures were grazed in fall of 2018, culminating in December. Data is being summarized. The grazing study will be repeated in fall 2019.
Continuous culture fermentor study manuscript is published. Dillard, S.L., A.I. Roca-Fernández, M.D. Rubano, K.R. Elkin, and K.J. Soder. 2018. Enteric methane production and ruminal fermentation of forage brassica diets fed in continuous culture. J. Anim. Sci. 96:1362-1374. doi.org/10.1093/jas/sky030. Dillard-Brassica-CCF-CH4-JAS-2018.
A symposium manuscript was published in the Journal of Animal Science that summarized the invited presentation at the American Society of Animal Science conference given by Dr. Dillard in 2017. doi.org/10.3168/jds.2016-11510. Dillard-et-al-Brassica-Symp-Paper-JAS-2018
The forage plot study data collection was completed in 2017 and data analyses completed in early 2018. The manuscript is currently being prepared by Dr. Billman for submission to a peer-reviewed journal.
Manuscript outlining an improved methodology for detecting individual glucosinolates in brassicas is being revised for re-submission to another journal.
Year 4 (2019):
The UNH grazing study was repeated for a 2nd year.
The forage plot study was accepted by Applied Animal Science in 2019 with expected publication date of 2020. Dillard, S.L., E.D. Billman, and K.J. Soder. 2020. Assessment of forage brassica species for fall grazing systems. Appl. Anim. Sci. (in press).
An oral presentation was given by Dr. Eric Billman (post doc) at the American Society of Animal Science in Austin, TX (Jul 2019). Billman, E.D., S.L. Dillard, and K.J. Soder. Brassicas as an alternative forage in the northeastern United States. Proceedings of the ASAS-CSAS annual meeting, Austin, TX. Jul 8-11, 2019. 2019.
A poster was presented by Dr. Eric Billman at the Northeast Pasture Consortium meeting in Grantville, PA (Feb 2019). Billman, E., S.L. Dillard, and K.J. Soder. Forage brassicas: Extending the grazing season with an alternative forage. Proceedings of the 2019 NE Pasture Consortium meeting, Feb 19-20, 2019, Grantville, PA. 2019.
Preliminary results of this research found that forage brassicas are well-adapted to forage-animal production systems in the northeastern United States. The in vitro fermentation study found that all forage brassicas species tested (forage rape, canola, and turnip) significantly reduced ruminant methane emissions to < 1% when fed at 50% DMI compared to a common cool-season winter annual in the region, annual ryegrass, which had methane emissions of 3-5%. The agronomic field trial also found that fall forage availability/dry matter yield for all three brassica species was more than twice that of annual ryegrass. This was irrespective of harvest timing and stage of plant growth. Forage nutritive value of the brassicas was also consistently greater in net energy concentration, and lower in indigestible fiber concentration than ryegrass, and was also not affected by time of harvest. Additionally, the greater DM yield of the brassicas provided substantially greater amounts of available nutrient yields to any potential grazing livestock. However, producers should be cautioned over the abundant sulfur concentrations in the plants, as they are indicative of elevated glucosinolates that could cause animal health concerns if consumed in excess. This was confirmed by the in vitro feeding trial, which found that the diets containing 50% of the forage brassicas, particularly turnip, contained 5 – 20 mg of glucosinolate compounds/g DM fed. Therefore, it is recommended that producers who implement forage brassicas into their livestock rations limit brassicas to 50% DMI to maximize production and reduce risk of overconsumption of glucosinolates for best results.
Extension Educator cooperators (Dr. Jessica Williamson and Mat Haan) will disseminate information via webinars, written material, and will incorporate results of this project into their recommendations to grazing farmers.
A webinar was presented by Dr. Leanne Dillard on forage brassicas in 2017.
Written material (fact sheet, trade journal articles, peer-reviewed journal articles) are in progress or forthcoming as this project progresses. Brassica-Fact-Sheet-2018 Dillard-Prog-Forage-Grower-Cover-Crops-Sept-2017
A farmer field day was held in Oct. 2016. On-farm field day held on the use of brassicas (including a demo plot of brassicas on a dairy farm). https://www.facebook.com/events/384258408660221/
Research presented at the 2017 American Society of Animal Science annual meeting.
Research presented at the 2017 American Forage and Grassland Council annual meeting.
Research presented at the 2017 Northeast Pasture Consortium meeting.
Research presented at the 2017 American Society of Agronomy Conference.
Research presented at the 2019 Northeast Pasture Consortium meeting.
Research presented at the 2019 American Society of Animal Science meeting.
Twenty farmers in PA participate in focus group interviews to help project team assess their knowledge about current brassica use.
Farmers were interviewed orally and with the use of a survey on knowledge, interest and questions regarding use of brassicas in grazing systems.
This data was summarized to help develop products, including a webinar, fact sheet, and trade journal article. Product development will continue during the life of the study.
Based on focus groups, online, printed, and technical journal articles are written to address agronomic and grazing management practices of use forage brassicas in dairy production
To date, 1 fact sheet, 1 trade journal article (Progressive Forage Grower) and 1 webinar have been deployed (all documented in products) to disseminate information to farmers.
Two peer-reviewed journal articles are accepted for publication, with another in preparation.
Three hundred cattle producers learn about the uses of forage brassicas in dairy cattle production via articles in technical journals, online media, or printed media sources written and submitted by project team.
A fact sheet was developed and disseminated at field days (including our brassica field day), pasture walks, and large ag events such as Ag Progress Days (near State College, PA) where 50,000 people attend this 3-day event.
The fact sheet is available on the Northeast Pasture Consortium website (www.grazingguide.net)
Several presentations were made to producer groups.
One hundred dairy producers and extension educators attend live or view a recorded webinar discussing agronomic, grazing, and environmental stewardship of forage brassicas in dairy production through the Penn State Extension Grazing Guides for Dairy Systems Webinar Series. Attendees will be asked to fill out a survey (including contact information) to determine any current or future brassica interest and stored feed costs
A webinar on forage brassicas was presented by Dr. Leanne Dillard in Jan 2017 (documented in products). Approximately 25 participants viewed the webinar live. The webinar was also recorded and is available online for addition dissemination.
Two hundred dairy producers and extension educators learn about brassica research at the USDA-ARS booth at AG Progress Days. Attendees will be asked to fill out a survey (including contact information) to determine any current or future brassica interest and stored feed costs.
A demonstration plot of various forage brassicas was planted and displayed at Ag Progress Days (near State College, PA) where 50,000 people attend this 3-day event. Information was disseminated, including our fact sheet. Investigators were present to answer questions. Surveys were collected from farmers.
Forty famers learn about methane mitigation potential (Year 1 results), planting, fertilization, grazing management, and soil health benefits of forage brassicas at field day/grazing demonstration conducted at producer farm located in Lebanon County, Pennsylvania. Attendees will be asked to fill out a survey (including contact information) to determine any current or future brassica interest and stored feed
A brassica field day was held at Blue Mountain View Farm on Oct 19, 2017. A demonstration field of forage brassicas was available for viewing during the pasture walk. Dr. Kathy Soder (USDA-ARS), Dr. Jessica Williamson (PSU), Mat Haan (PSU), and Matt Bomgardner (farmer host) presented information on establishment, management and challenges of forage brassicas, animal health and production, and economics of forage brassicas. Surveys were collected as well.
Project team follows up with contacts from articles, webinars, field days, and referrals and identifies twenty farmers that are interested in including forage brassicas on their farm
This milestone is ongoing as information is collected from and disseminated to farmers.
Ten of these twenty farmers utilize grazed forage brassicas (at least 1 acre/4 grazing cows) in their production system for the first time and submit establishment and grazing management plan to project team.
Ongoing milestone- too early in the project to have results for this one.
Project team follows up with primary beneficiaries identified in Milestone 7 in order to ascertain success and pitfalls of establishment and grazing of forage brassicas in a pasture-based dairy system
As with Milestones 7 and 8, this milestone is ongoing.
Milestone Activities and Participation Summary
Made farmers aware of importance of cover crops such as brassicas, and how they can benefit soils, crops as well as be used for grazing.
Provided information on potential brassica mixtures to plant under various climates and conditions.
Performance Target Outcomes
Plant brassicas after crops to improve soil health, crop and animal productivity, and reduce methane emissions
Decreased feed costs, increased crop and animal productivity