Forage-based approaches for improving profitability and ecosystem services of dairy farms in New Hampshire and Pennsylvania

Forage-based approaches for improving profitability and ecosystem services of dairy farms in New Hampshire and Pennsylvania

Summary

University of New Hampshire (UNH) site:

UNH Agronomic Research Component (Experiment 1):

We completed the third year of the annual forage crop (AFC) field experiment at the UNH Kingman Research Farm in Madbury, NH. The field experiment involves planting monocultures and mixtures of AFC that are intended to be available for grazing or harvest during one of three target periods during the forage growing season: early spring, summer, and fall.

The spring-available treatments were established in fall 2015 (harvested in spring 2016) and included monocultures of winter wheat, winter triticale, barley, cereal rye, hairy vetch, and a mixture containing all five spring-available species, each planted at 1/5 rate.

The summer-available treatments were established in June 2016 and included monocultures of BMR sorghum, buckwheat, teff, millet, oats, chickling vetch, and a mixture containing all six summer-available species, each planted at 1/6 rate.

The fall-available treatments were established in July 2016 and included monocultures of forage radish, oats, rape, wheat, triticale, sunn hemp, and a mixture containing all six fall-available species, each planted at 1/6 rate.

In October 2016, we also established the final round of the spring-available treatments. These treatments will be harvested in spring 2017. All treatments were assigned randomly within four blocks and established with a plot drill. Each target period also included a “super mixture” which contained all of the 14 AFC species used in the experiment as well as a fallow treatment which was not planted with AFC in order to assess the relative level of weed suppression associated with each AFC treatment. Our third year of data and samples collection include biomass production measurements, forage nutrient profile, and soil analyses.

UNH Animal Research Component (Experiment 2):

The two short-term grazing studies were completed the UNH Burley-Demeritt Organic Dairy

Research Farm is located in Lee, NH. The objective of these studies were to determine the impact of AFC on milk yield and composition in grazing dairy cows during the spring and summer, as well as AFC effects on milk fatty acids and rumen microbiota profile. For two seasons (2015 and 2016), we have had problems establishing the fall species (brassicas, rye, etc.) for fall grazing due to droughts in the region.

Outreach/Education Component:

We conducted two focus group interviews with organic dairy farmers in the Northeast (NH and VT) to better understand farmers’ perspectives about high-forage dairy diets and the inclusion of AFC in their forage cropping systems. Our team also presented project results in scientific and farmer-oriented events locally, nationally, and internationally, and set up an on-farm AFC demonstration site in collaboration with a NH organic dairy farmer.

Pennsylvania State University (PSU) site:

PSU Agronomic Research Component (Experiment 1):

A field experiment was established in fall 2013 to examine the impact of fall cover crops on forage yield, forage quality, and soil health. Fall treatments include no cover, spring oats, spring oats/triticale, rye, two triticale treatments, and winter barley. Fall treatments included no cover, spring oats, spring oats/triticale, rye, two triticale treatments, and winter barley. Corn has been planted following the no cover, oats, triticale, and rye treatments. Forage sorghums have been planted following the later soft dough harvest treatments. We also have established a small forage sorghum study to evaluate two varieties, seeding rates, and nitrogen levels. All these trials are complete.

PSU Animal Research Component (Experiment 2):

Two trials were conducted to evaluate the effect of inclusion of AFC in dairy diets on animal productivity, digestibility, enteric methane emissions, and income over feed costs (IOFC) in lactating dairy cows. Both trials were replicated 3 x 3 Latin square designs with 12 cows each.

Outreach/Education Component:

We have been working with two dairy farmers in PA who have set up demonstration trials to investigate the potential of AFC as dairy forage for lactating cows. We also presented project results in scientific and farmer-oriented events locally and nationally.

Objectives/Performance Targets

Performance target: Compared to the previous year, 60 farmers milking 5,000 cows enhance IOFC by $0.50/cow/day after replacing expensive grain with AFC, generating cumulative profit of approximately $5,000 per farm as a result of 120-days’ worth of forage surplus.

The project outreach and research components progressed as planned. Surveys, focus group interviews, and outreach activities such as presentations, videos, and popular-press articles have been delivered. Demonstration research sites in commercial farms have been set up in PA and NH. Winter, spring, and summer outreach events were conducted. Agronomic and animal research experiments are completed (except 2017 spring harvesting for UNH Experiment 1) in both sites and results are being reported.

Accomplishments/Milestones

The forage production season in the Northeast is relatively short due to the region’s long winters and short growing season. Here, and in other northern regions, the short grazing season is often further constrained by a “summer slump” period when hot and dry weather conditions reduce the productivity of perennial cool-season grasses.

Critical periods of low forage productivity and availability—early spring, mid-summer, and late fall—represent potential niches that could be filled by annual forage crops grown as monocultures or mixtures. Such crops could supplement forage availability during periods of deficiency, effectively extending the forage production and grazing seasons and thereby reducing the need for purchasing off-farm feeds.

Mixtures are included in the study to determine whether there may be benefits, in terms of productivity, stability, quality, or weed suppression compared to the same species grown as monocultures. Specific information about the outreach and research components of the project are presented below:

UNH Site:

Agronomic Research Component:

Overview: We completed the third year of the AFC field experiment at the UNH Kingman Research Farm located in Madbury, NH (UNH Experiment 1). The field experiment involves planting monocultures and mixtures AFC that are intended to be available for grazing or harvest during one of three target periods during the forage growing season: early spring, summer, and fall. The spring-available treatments were established in fall 2015 and included monocultures of winter wheat, winter triticale, barley, cereal rye, hairy vetch, and a mixture containing all five spring-available species, each planted at 1/5 rate.

The summer-available treatments were established in May 2016 and included monocultures of BMR sorghum, buckwheat, teff, millet, oats, chickling vetch, and a mixture containing all six summer-available species, each planted at 1/6 rate.

The fall-available treatments were established in July 2016 and included monocultures of forage radish, oats, rape, wheat, triticale, sunn hemp, and a mixture containing all six fall-available species, each planted at 1/6 rate.

In October 2016, we also established the final round of the spring-available treatments. These treatments will be harvested in spring 2017. All treatments were assigned randomly within four blocks and established with a plot drill. Each target period also included a “super mixture” which contained all of the 14 AFC species used in the experiment as well as a fallow treatment which was not planted with AFC in order to assess the relative level of weed suppression associated with each AFC treatment.

Methods: Data collected from each set of treatments consist of AFC dry biomass and weed dry biomass. Data were collected by clipping to a height of 5 cm all aboveground plant material from multiple 0.25 m² quadrants placed within the inner portion of each plot. Clipped material was sorted to species and dried to constant biomass at 60^oC and then weighed.

We assessed AFC biomass at three time periods spaced approximately two-weeks apart. The rationale for this sampling approach was to better quantify potential tradeoffs in forage dry matter and nutritional quality that may occur over the growing season across the different AFC treatments and to better assess the season extension potential of the treatments (particularly for the spring- and fall-available treatments). This sampling methodology will be carried out for the remainder of the study.

After weighing, forage samples were ground and will be analyzed for nutritional quality. For the summer-available treatments, we also quantified forage regrowth in the clipped areas of each plot approximately three weeks after each initial harvest period. These data will provide insight into which AFC may provide opportunities for additional forage production following an initial harvest or grazing event and the degree to which time of initial harvest/grazing affects regrowth potential. We are reporting some preliminary results about forage production and quality from our 2015 experiments (2016_Forage Tables). Samples and data from the 2016 season are currently being processed.

During the spring (only one harvest done), wheat showed the greatest biomass production and hairy vetch and barley the least. Forage quality was relatively good across all spring-available AFC. During the summer, buckwheat was the most productive, but with least forage quality. During the fall, forage radish and canola were the greatest biomass-producing forages, whereas triticale has the least biomass production. As expected, forage biomass production increased and nutritional quality decreased with delaying of harvesting during the summer and fall seasons.

Animal Research Component:

The two short-term grazing studies were completed the UNH Burley-Demeritt Organic Dairy

At the Research Farm located in Lee, NH: The objective of these studies were to determine the impact of AFC on milk yield and composition in grazing dairy cows during the spring and summer, as well as AFC effects on milk fatty acids and rumen microbiota profile. For two seasons (2015 and 2016), we have had problems establishing the fall species (brassicas, rye, etc.) for fall grazing due to droughts in the region. e will try to establish the fall-available AFC for grazing for the third time this coming fall 2017.

Rumeb archaea population study: In the Northeastern U.S., biomass of cool-season grasses is decreased in early spring. One potential solution is to provide AFC, such as small grains, in addition to cool-season grasses to lactating dairy cows.

The objectives of this study were to: 1) determine if AF consumption would alter the rumen archaeal populations, densities, and diversities and 2) identify correlations between rumen archaeal, bacterial, and protozoal taxa in lactating dairy cows. A 21d experiment with eight cows consuming cool-season grasses (control, CON) and eight cows consuming cool-season grasses plus AFC was performed.

During days 18-21, AF comprised 7.3% of the diet, reached maturity, and were lower in quality than the cool-season grasses. Rumen archaeal densities and diversity measures did not differ by group. Relative abundances of Methanobrevibacter (Mbr) millerae were greater in AFC (11.2%) cows than CON (8.5%) cows, while abundances of Mbr. ruminantium were lower in AFC (9.3%) than CON (13.9%) cows. More correlations were identified between archaea and bacteria of the phylum Firmicutes than between protozoa. Mbr. ruminantium was positively correlated to the bacterial family Ruminococcaceae. These results suggest that AF consumption changes the relative abundance of prevalent rumen archaea and that archaea may have specific and nonspecific relationships with bacteria and protozoa, respectively.

Milk and rumen microbiota fatty acid profile spring study: In the Northeast, early spring is characterized by decreased pasture mass. This is especially important to organic dairy farmers who must provide 120 days of grazing to their cows. Bioactive fatty acids (FA), such as branched-chain (BCFA) and unsaturated FA found in milk have been linked to human health benefits.

The purpose of this study was to determine if consumption of a mixture of spring annual forages, wheat, rye, barley, triticale, and hairy vetch strip-tilled in consortium with cool-season grasses and legumes alter the rumen environment (i.e., microbial fatty acids (FA) and taxa, and volatile FA) and enhances contents of milk bioactive FA from 16 lactating organically-certified Jersey dairy cows.

Cows consumed either a control (CON; traditional grass/legume pasture mixture), or AFC with cool-season grass pasture for a 21-day period. Total mixed ration comprised 57% of the dry matter intake (DMI). The estimated DMI of AFC was 1.7 kg/d (7.3% of total DMI). Intakes of total omega-3 FA were greater in AFC-fed than CON-fed cows, while total omega-6 FA and oleic acid intakes were greater from CON-fed cows. No differences were observed in rumen VFA, protozoal cell FA or taxa, while few differences were observed in bacterial cell FA and taxa. Milk concentration of iso-15:0 per serving of whole milk was greater and total BCFA tended to be greater in CON-fed cows than in AFC-fed cows.

Milk content of oleic acid per serving was lower in AFC-fed cows than CON-fed cows, while contents of de novo FA (i.e., 10:0, 12:0, and 14:0) per serving were greatest in AFC-fed. Our findings demonstrated the challenges of using AFC as a dietary strategy to increase milk bioactive FA and that postruminal FA synthesis likely influenced the milk FA contents.

Milk and rumen microbiota fatty acid profile summer study: In the Northeast U.S., there is interest in feeding AFC, such as cereal and broadleaf forages, to dairy cows when cool-season perennial grass growth is decreased during the summer. The purpose of the study was to determine if rumen microbial community structures and fatty acid (FA) and milk FA contents, differed between cows offered cool-season grass-legume pasture (control group, CON) or cool-season grass-legume pasture 30% strip-tilled with AFC (buckwheat, chickling vetch, oat).

A 21-day experiment was conducted with 16 Jersey cows (n = 8 CON, n= 8 AF). AFC-fed cows had lower dry matter intakes (DMI) of starch on pasture than CON-fed cows. AFC were an estimated 5.7% of the total DMI. Dietary FA intakes did not differ between AFC and CON-fed cows. The AFC buckwheat and chickling vetch contained lower NDF contents in comparison to cool season grasses. Protozoal and bacterial cell proportions of PUFA and rumen biohydrogenation intermediates (e.g., 18:1 trans isomers) and abundances of major protozoal (e.g., Entodonium) and bacterial taxa (e.g., Prevotella) did not differ between treatment groups. Milk de novo FA contents (g FA/kg milk) were greater in AFC than CON-fed cows, but did not differ by serving whole milk. Contents of palmitic acid (16:0) per serving were greater from AFC than CON cows. Our findings suggest that milk FA contents were altered through an alternative feeding strategy without impacting major rumen microbial cell membrane FA and taxa.

Outreach/Education Component:

Focus group interviews: Two focus group meetings were conducted with organic dairy farmers from New Hampshire and Vermont. The focus group meeting in New Hampshire was held in Lebanon (February, 2016) with 8 farmer participants. The focus group meeting in Vermont was held in (January, 2016) with 14 farmer participants. The focus groups were conducted to better understand farmers’ perspectives about high-forage dairy diets and the inclusion of AFC in their forage cropping systems. Results from the focus groups are being currently analyzed, and will be used to design surveys and workshops.

Forage workshop: We organized a section about annual forage crops production and pasture management during the 2016 Northeast Pasture Consortium Annual Meeting held in Freeport, ME (March, 2016). Our workshop agenda was: Session 6 – Transitioning dairy cows to a no grain or high forage diet – Moderator, Andre Brito. Speakers: Sabrina Greenwood (Assistant Professor, Department of Animal Science, University of Vermont, Burlington, VT) – “Milk production and health of grazing dairy cows”; Jessica Williamson (Forage Extension Specialist, Department of Plant Science, The Pennsylvania State University, University Park, PA) – Annual forage crops: Overcoming challenges and maximizing opportunities for improved productivity”; Sarah Flack (Sarah Flack Consulting, 5455 Duffy Hill Rd, Enosburg Falls, VT) – “Zero grain dairy: Lessons learned from farm successes and disasters.”

UNH field days: We presented project results during the field days held during fall 2016 at the Fairchild Dairy Teaching and Research Center (Durham, NH) and Woodman Farm (Madbury, NH).

Presentations at scientific meetings: We present project results during the National Agronomy and Weed Sciences Annual Meetings, National American Animal and Dairy Science Annual Meeting, 7th International Weed Science Congress, 2016 Organic Agriculture Research Symposium, and 2016 Northeast Pasture Consortium.

PSU Site:

Agronomic Research Component:

A field experiment was established in fall 2013 to examine the impact of fall cover crops on forage yield, forage quality, and soil health. Fall treatments included no cover, spring oats, spring oats/triticale, rye, two triticale treatments, and winter barley. Corn has been planted following the no cover, oats, triticale, and rye treatments. Forage sorghums have been planted following the later soft dough harvest treatments. We also have established a small forage sorghum study to evaluate two varieties, seeding rates, and nitrogen levels. All these trials have been completed to date and data are being analyzed.

Animal Research Component:

Feeding trial 1: Double cropping and increasing crop diversity could improve dairy farm economic and environmental sustainability. In this experiment, corn silage was partially replaced with 2 alternative forages, brown midrib-6 brachytic dwarf forage sorghum (Sorghum bicolor) or fall-grown oat (Avena sativa) silage in the diet of lactating dairy cows. We investigated the effect on dry matter (DM) intake, milk yield, milk components and fatty acid profile, apparent total tract nutrient digestibility, nitrogen utilization, enteric methane emissions, and income over feed cost along with in situ DM and neutral detergent fiber disappearance of the forages.

Sorghum was grown in the summer and harvested in the milk stage. Oats were grown in the fall and harvested in the boot stage. Compared with corn silage, neutral detergent fiber and acid detergent fiber concentrations were higher in the alternative forages. Lignin content was highest for sorghum silage, intermediate for corn silage, and lowest for oat silage. The alternative forages had less than 1% starch compared to the approximately 35% starch in the corn silage. Ruminal in situ DM effective degradability was similar for corn silage and oat silage, but lower for sorghum silage.

Diets with the alternative forages were fed in a replicated 3 × 3 Latin square design experiment with 3 28-day periods and 12 Holstein cows. The control diet contained 44% (DM basis) corn silage. In the other 2 diets, sorghum or oat silages were included at 10% of dietary DM, replacing corn silage. Sorghum silage inclusion slightly decreased DM intake, milk yield, and milk protein content, but increased milk fat and maintained energy corrected milk yield similar to the control. Oat silage had no effect on dry matter intake, milk production or components compared with the control. The oat silage diet increased apparent total tract digestibility of dietary nutrients, except starch, whereas the sorghum diet slightly decreased DM, organic matter, crude protein, and starch digestibility. Cows consuming the oat silage diet had higher milk urea nitrogen and urinary urea nitrogen concentrations. Milk nitrogen efficiency was decreased by the sorghum diet. Diet did not affect enteric methane or carbon dioxide emissions. This study shows that oat silage can partially replace corn silage at 10% of the diet DM with no effect on milk yield. Brown midrib sorghum silage harvested at the milk stage may decrease dry matter intake and milk yield in dairy cows.

Feeding trial 2: The objective of this experiment was to partially replace corn silage with 2 alternative forages, wheat (Triticum aestivum) or triticale (× Triticosecale) silages, at 10% of the diet dry matter (DM) and investigate the effects on dairy cow productivity, nutrient utilization, enteric methane emissions, and farm income over feed costs. Wheat and triticale were planted in the fall as cover crops and harvested in the spring at the boot stage.

Neutral- and acid-detergent fiber and lignin concentrations were higher in the wheat and triticale silages compared with corn silage. The forages had similar ruminal in situ effective degradability of DM. Both cover crop silages had 1% starch or less compared with the approximately 35% starch in corn silage. Diets with the cover crop silages were fed in a replicated 3 × 3 Latin square design experiment with 3 28-day periods and 12 Holstein cows.. The control diet contained 44% (DM basis) corn silage. In the other 2 diets, wheat or triticale silages were included at 10% of dietary DM, replacing corn silage.

Dry matter intake was not affected by diet, but both wheat and triticale silage decreased yield of milk (41.4 ± 5.18, 41.2 ± 5.18 vs. 42.7 ± 5.18 kg/d) and milk components, compared with corn silage. Milk fat from cows fed the alternative forage diets contained higher concentrations of 4:0, 6:0, 8:0, and 18:0 and tended to have lower concentrations of total trans fatty acids. Apparent total tract digestibility of DM and organic matter was decreased in the wheat silage diet, and digestibility of neutral-and acid-detergent fiber was increased in the triticale silage diet.

The wheat and triticale silage diets resulted in higher excretion of urinary urea, higher MUN, and lower milk N efficiency, compared with the corn silage diet. Diet had no effect on enteric methane emission, whereas carbon dioxide emission was decreased by both wheat and triticale silage. This study showed that, at milk production around 42 kg/d, wheat silage and triticale silage can partially replace corn silage DM and not affect DM intake, but milk yield may decrease slightly. For dairy farms in need of more forage, triticale or wheat double cropped with corn silage may be an appropriate cropping strategy.

IOFC (corn silage and oat silage): The economic outcome of the use of alternative forages is critical for their adoption. The IOFC of corn silage (CS) and oat silage (OS) were comparable at $9.49 and $9.43/cow/d, respectively (data not presented in tables). The sorghum silage (SS) diet resulted in slightly lower IOFC, $9.32/cow/d. A disadvantage in double cropping fall oats in central Pennsylvania is that they must be planted in mid-August to yield well. To plant at that time, a short season corn (< 85 d relative maturity) must be used. Short season corn usually has a decreased yield compared with longer season varieties and this raises corn crop production costs. The SS diet had the lowest IOFC due to a lower milk yield and a lower BMR sorghum crop yield even though input costs were lower.

When we ran the IOFC analysis with a 65 milking cow dairy, we had to account for rental costs of additional acreage to produce the necessary forage due to the low yield from a late planting date. Sorghum would have an advantage of using less irrigation water, but irrigation is not very common in the northeastern U.S and, therefore, was not included in the IOFC analysis. Sorghum can perform better than corn silage on soils with low water holding capacity which would positively affect the IOFC of SS. Using a scenario of a higher yield of 13.4 t/ha that would be more typical with a proper planting, we found the IOFC of SS to increase to $9.43/cow/d. This is equal to the OS scenario and only $0.06/cow/d lower than the CS scenario. The reported results are only a model and individual farm results would vary, but they do demonstrate that, financially, these forages deserve consideration in dairy farm crop rotations and lactating cow feeding programs.

IOFC (corn silage, wheat silage and triticale silage): The IOFC of CS was $11.05 and decreased to $10.39 and $10.26 for wheat silage (WS) and TS, respectively. Decreased per acre corn silage yield due to later corn planting and decreased milk yield caused the decrease in IOFC for WS and TS. The higher IOFC for WS over TS was due to the numerically higher milk yield and milk components resulting in higher calculated income. The WS and TS diets were not least cost formulations and did not fully utilize the protein value of the alternative forages as indicated by the higher MUN and urinary urea nitrogen losses. Likely, the supplemental protein content of WS and TS could be decreased to lower costs of on-farm rations.

Outreach/Education Component:

Forage workshop: We organized a workshop about AFC at the Penn State Dairy Nutrition Conference (November, 2016).

Presentations at scientific meetings: We present project results during the National Agronomy and Weed Sciences Annual Meetings, National American Animal and Dairy Science Annual Meeting, and 2016 Northeast Pasture Consortium.

Field days: We conducted two field days that were attended by 20 farmers each.  One was at the Biddle farm in Blair County and the other at the Miller farm in Lebanon County. The discussions were summarized in our Field Crop News here: http://extension.psu.edu/plants/crops/news/2016/08/triticale-and-fall-cover-crop-management. This was also emailed to over 1,000 dairy producers. It was reprinted in a national publication, No-till Farmer  https://www.no-tillfarmer.com/articles/6028-triticale-and-fall-cover-crop-management. One of our farms was featured in American Agriculturist in February: http://www.americanagriculturist.com/story-tills-enough-build-healthy-soils-9-136338.  his article was posted on Kings Agriseeds website as well:  http://www.kingsagriseeds.com/blog/wp-content/uploads/2014/03/No-till-Not-Enough-American-Agriculturalist-Feb-2016.pdf.

Video: Our triticale video as part of the project now has over 11,000 views:  https://www.youtube.com/watch?v=HiPjrL4vVcw&feature=youtu.be

Impacts and Contributions/Outcomes

Our team are engaging dairy farmers in New Hampshire, Pennsylvania, and other northeastern states in a research and educational program to enhance the utilization of AFC in their dairy enterprises. We actively participated in several outreach efforts presenting project results in farmer- and scientific oriented venues, while conducting workshops and focus group interviews, developing on-farm demonstration sites in four dairy farms in New Hampshire and Pennsylvania, and production of videos. Most of the agronomic and animal research components have been completed to date. As a result of our integrated research and educational approach, farmers are able to make informed decisions about how to incorporate AFC in their forage cropping systems, while changing management practices to improve farm profitability.

Collaborators: