Final Report for ONE12-160
Project Information
There is little documented adoption of mob grazing by dairy producers as of yet because it is such a new practice. The intent of this research is more to help dairy producers understand that there is not a very large difference between what these graziers are doing and intensively managed grazing farms. Popular press articles present conflicting information to what we observed.
Four dairy farms participated in a study designed to describe a technique called “mob grazing”. All of the farms were certified organic and forage based operations, using little grain or mixed TMR (total mixed ration). We have learned that most dairy farmers call mob grazing, “tall” grazing”, or another term being used is ultra-high stock density grazing (UHSD) grazing. The cattle are grazing taller, slightly more mature pastures and leaving greater grass residuals, while the farmers are still striving for high quality forage. Forage height at grazing averaged 9 inches across the farms in 2012 and 14.5 inches across 3 farms in 2013. Averaged across all farms, cows consumed 46 and 45% of total available DM in 2012 and 2013, respectively. We did not find that this was “superior” nutrition. Pasture crude protein (CP) ranged from 14.2 to 32.2% and neutral detergent fiber (NDF) ranged from 33.6 to 60.0% across all farms and throughout the grazing seasons.
Despite different grazing styles, forage heights as well as nutrient content were fairly similar between MiG reported by Sanderson et al. (2006)1 and the current study. This would suggest that UHSD grazing systems adopted by dairy graziers in Pennsylvania and New York are not drastically different from MiG; rather, they are slight modifications of the MiG system adapted to their individual farms.
Each farm has resource challenges and opportunities that impact their ability to use this practice. Grass was measured for forage quality, height and botanical composition, number of cows grazing and paddock size. A survey tool was developed to interview farmers for their practices.
|
Table 1. Summary of Practices |
Farm 1 |
Farm 2 |
Farm 3 |
Farm 4 |
|
Farm description |
|
|
|
|
|
Acres of pasture |
620 |
240 |
260 |
200 |
|
No. milk cows |
270 |
60 |
235 |
145 |
|
Pasture allotment |
|
|
|
|
|
Pasture size, acre |
1 |
2-4 |
2-2.5 |
1 |
|
Cows/pasture |
135 |
50 |
245 |
145 |
|
Pasture size/cow/d, acres |
0.03 |
0.06-0.08 |
0.02 |
0.01-0.02 |
|
Grazing cycle |
28-30 d |
When rested |
18-24 inch |
35 d |
|
Forage remaining |
30% |
30-50% |
30-40% |
40% |
|
Moves per day |
1 |
2-5 |
2 |
2 |
|
Hours on pasture |
20 |
20 |
20 |
20 |
|
Distance to barn, miles |
0.19 |
0.04 – 1.50 |
0.11 – 0.50 |
0.04 -0.75 |
|
Supplemental feeding |
|
|
|
|
|
Stored feeds, if any |
Hay |
Silage |
Hay + Silage |
Silage +Baleage |
|
Graze in winter? |
If weather permits |
Until Dec. |
No |
No |
1Sanderson, M. A., K. J. Soder, N. Brzesinski, F. Taube, K. Klement, L. D. Muller, and M. Wachendorf. 2006. Sward structure of simple and complex mixtures of temperate forages. Agron. J. 98:238–244.
Information was disseminated to farm producers through farmers meetings, along with peer reviewed and farmer trade publications and websites and handouts developed. From a field day, participant evaluations (n=26) showed that 85% (N=22) learned “a moderate amount” or “a great deal”. Fourteen farmers said they would make changes on their farms, including monitoring forage height, monitor days of rotation in paddocks and move animals more frequently. Sixteen farm advisors said they increased their understanding of tall grazing and increased their ability to talk to farmers about tall grazing.
Introduction:
Five Northeastern dairy farms were recruited and 4 participated in a study designed to describe a technique called “mob grazing”. We have since learned that most dairy farmers call mob grazing, “tall grazing”. Another term that can be used to describe this system is “ultra-high stock density grazing” or UHSD grazing. The cattle are grazing taller, slightly more mature pastures and leaving greater grass residuals, while the farmers are still striving for high quality forage. Each farm has resource challenges and opportunities that impact their ability to use this practice. Our goal was to collect data and later interview the producers to understand their management goals and practices. The case studies have been developed for use in Extension/Outreach with dairy producers and other graziers.
The goal of this project was to create “snapshots” or case studies of dairy producers using UHSD grazing as a production technique. In the growing season of 2012, our goal was to recruit dairy farms for the study, collect data, interview farmers and document the activity. We also took measurements for two grazing rotations in the spring of 2013.
In 2013, a field day was conducted on one of the farms involved in the study, with 3 additional farmers invited to participate as speakers. All 4 farmers were involved in farmer’s panel discussion and an additional pasture walk in the afternoon. We also took an informal survey of all participants and asked them to make their own definition of “mob grazing”, which we then summarized.
The data has been summarized for use in peer reviewed articles and posters and distributed to some farmer “popular press” and electronic newsletters. A list of outreach methods, including study circles, fact sheets and popular press is summarized in the section, “Outreach and Milestones”.
The overall goal of this project is to help other dairy producers understand the opportunities and challenges to adopting UHSD grazing as a practice. Trends may also help researchers understand what they can do to develop more controlled studies in the future.
Note: It was not a goal of this project, but all of the five farms were certified organic and forage based operations, using little grain or mixed TMR (total mixed ration). However, this technique is not exclusive to certified organic dairies.
Cooperators
Research
Case studies are used to describe what innovative farmers are doing to adapt “UHSD grazing” techniques to a dairy farm. Data was derived from the following methods:
-Farmer Interviews: Face to face and phone interviews were conducted in 2012. Areas discussed with farmers included farm information, milk production, pasture management, supplemental feeding and housing, economics, environment and community. The interview for each farmer took approximately 1.5 hours. Information was summarized in an Excel spreadsheet.
-Pasture Sampling: Pastures were sampled in 2012 and 2013. At each farm, one paddock was sampled at each rotation before cattle grazed the paddock (“pre-grazing”). Measurements taken included grass height, paddock size and cow number, pasture nutritional analysis, pasture botanical composition, sward stratification by mass measurement.
- Basic soil test (pH, N, P2O5, K20, Mg, Ca, Zn, Cu, S) including organic matter through The Penn State Ag Analytical Services, State College, PA.
Four organically certified dairy farms (3 in Pennsylvania and 1 in New York) participated in this study. The dairy farmers selected were selfdescribed UHSD graziers and were initially surveyed to capture their
experience and management practices. In June 2012, one pasture on each farm was identified to be the sample pasture. The pastures selected had been managed under UHSD grazing before this grazing season and were representative of pastureland on each farm. Farm and pasture management information was gathered using a detailed survey given to each farmer to describe intended grazing management practices and animal production.
Farm visits occurred each time the study pastures were grazed from June to November of 2012 and from April to June of 2013. Sampling encompassed 2 yr to capture data from all months throughout the grazing season, because project funding did not become available until June of 2012 and delayed the initiation of sampling early in the grazing season. Data collected during each farm visit, immediately before grazing, included number of cows grazing, measurements of pregrazed forage height, canopy stratification, botanical composition, and samples for forage-quality analyses.
Forage samples were plucked by hand to the approximate height the cows were grazing from representative spots within the pasture (n = 20), composited, and frozen before shipment to an independent laboratory for analysis of nutrient content (Dairy One Forage Analysis Laboratory, Ithaca, NY). Forage height was recorded on a diagonal transect of the sample pasture using a meter stick at 25 points. Stratification of the forage canopy was measured by the herbage-gripping stratification method described by Barthram et al. (2000) to estimate the vertical level at which cows were consuming the most forage and to document forage utilization. This method uses rubber-lined, narrow boards (50 × 5 × 1 cm) that are inserted into the sward at ground level and then clamped together capturing a section of forage that is then clipped off at ground level. This section of forage was placed on a template and cut every 7 cm, with the 0- to 5-cm section discarded because of contamination of forage sample with soils. The forage from each vertical level was dried in a forced-air oven at 60°C for 48 h and weighed for DM content. Five stratification clippings were taken from both pregrazed and postgrazed areas within the sampling pasture. Botanical composition was estimated twice during the 2012 grazing seasons for all farms, once for 2 farms in 2013, twice for 1 farm in 2013, and was not recorded for 1 farm in 2013. Botanical compositions of the pastures were estimated visually using the step-point method at 50 points within the sample pasture (Little and Frensham, 1993). In May 2013, 6 soil cores (20 cm deep) were taken along a diagonal transect from within the sample pasture on each farm. The cores were composited, and a subsample was sent for nutrient analyses and OM content (Ag Analytical Lab, University Park, PA). Monthly historic (1981–2010) precipitation averages and total monthly accumulated precipitation were acquired from the closest available National Climatic Center weather stations (www.ncdc.noaa. gov; accessed July 23, 2013), located 8 to 48 km from the Pennsylvania and New York farms that participated in this study.
Forage height, canopy stratification, botanical composition, and forage quality data were transferred to Microsoft Excel files and summarized. Forage quality was analyzed using the MIXED procedure of SAS (SAS Institute Inc., Cary, NC), with month as fixed effect, farm as random, and least squares means reported. Differences in forage-quality measures were considered significant at P < 0.05.
For a detailed discussion of the project including refernces, please refer to the publication, “Case Study: Dairies Using Self-Described Ultra-High Stocking Density Grazing in the Northeastern U.S.”, The Professional Animal Scientist 30 (2014):366–374 in the attachments to this article.
Experience Helps:
All participants had been using managed intensive grazing (MIG) before adopting UHSD grazing. They are experienced pasture managers. Several mentioned they adopted grazing over 20 years ago (late 1980’s to the mid-1990’s). They have been trying to use some variation of UHSD for 2-8 years. Their responses for making this change ranged from labor and machinery savings, continuing to provide a forage diet to cows, thought of as “natural” and matching the productivity of the soil to a forage cropping system.
Our conclusion is that experienced graziers are more likely to be able to make this shift as they have developed the skills to produce forage quality, monitor forage quantity and have worked to improve their soil quality.
Forage Quality Was Variable and Acceptable
Does UHSD grazing in dairies give superior results for pastures? We did not find that this was “superior” nutrition. See the document, Figure 1 . Forage Analysis 2012-2013 attached below.
Pasture crude protein (CP) ranged from 14.2 to 32.2% and neutral detergent fiber (NDF) ranged from 33.6 to 60.0% across all farms and throughout the grazing seasons. These variations likely reflect differences in botanical composition and seasonal effects on forage quality and emphasize the importance of regular forage-quality testing of pastures.
Forage quality increased (P <0.05) from June to September 2012, as characterized by an increase in CP and net energy lactation (NEl) and a decrease in NDF (Figure 1). The increase in forage quality may be a result of the pasture being in a less mature stage of growth at each successive grazing. From April to June of 2013 forage quality decreased (P < 0.05) and coincided with the increase in environmental temperature, typical for that time of year. The increase in forage quality throughout the grazing season is favorable for meeting the nutritional requirements of lactating dairy cows; however, altering forage quality and maturity through repeated grazing may also be achieved through MiG, where the goal is to maintain forage in the vegetative state. It is important to note that CP and NDF values of forage from pastures managed with self-described UHSD grazing were within range of previously published values from MiG-managed pastures in Pennsylvania and New York (Kolver and Muller, 1998; Soder and Muller, 2007).
However, NEl values were observed to be slightly lower in this study compared with those reported by Soder and Muller (2007) and Kolver and Muller (1998). Much of the current information available on UHSD grazing refers to beef cattle grazing rangeland (Savory and Parsons, 1980; Judy, 2008) in contrast to pastures in the northeastern United States where soils, climate, and forages are much different With UHSD grazing where more mature forages are fed, overestimating nutrient intake can quickly affect profitability in grazing dairy systems; therefore, a high level of management is needed to successfully transition to a UHSD grazing system.
Dry Matter Production-How Does Increased Forage Height Balance with Forage Quality
Is more more dry matter (DM) produced because these dairy farmers are grazing tall?
Forage height at grazing averaged 9 inches across the farms in 2012 and 14.5 inches across 3 farms in 2013. The shorter grazing height observed in 2012 is likely related to less total forage availability due to below-normal precipitation in Pennsylvania and New York, especially early in the grazing season. The forage heights at grazing observed in this study were slightly taller than those recommended for MiG systems for dairy herds in the northeastern United States (6 inches; Sullivan et al., 2000) to maintain high forage quality and optimize utilization.
As plants mature, the leaf to-stem ratio changes, favoring more stems and less leaves (Ball et al.,2007). Leaves provide higher-quality feed compared with stems, and young green leaves have greater forage quality compared with old dead stems; therefore, current MiG recommendations are to keep available forage in a leafy state throughout the grazing season to ensure optimal nutritional quality of forage.
Graziers using any grazing management practice must establish a balance between total available forage and forage quality to ensure optimum milk production. The UHSD grazing strategy results in greater forage availability, but forage quality may be reduced. Matching the nutrient requirements of the animals with nutrients available from the forage may be where some dairy farmers have fallen short with UHSD grazing as they learn the art of this grazing system to balance available nutrients without negatively affecting productivity in any aspect of the system (animal, forage, soil).
Dry Mater Production-What Were the Cows Selectively Eating?
Averaged across all farms, cows consumed 46 and 45% of total available DM in 2012 and 2013, respectively. See the document, Figure 2.Percent of Stratified Layer Consumed, 2012 and 2013 From 4 Farms in the attachments.
The percent of stratified layers consumed during 2012 and 2013 are shown in Figure 2. As expected, the most forage was consumed from the upper layers of the forage canopy where there would be a greater proportion of vegetative leaves, as opposed to the layers closer to the ground that would contain older leaves, dead material, and stem. Cows consumed an average 75% of forage from layers 13 inches and higher and an average of 49% from layers below 13 inches, averaged across farms.
Despite different grazing styles, forage heights as well as nutrient content were fairly similar between MiG reported by Sanderson et al. (2006) and the current study. This would suggest that UHSD grazing systems adopted by dairy graziers in Pennsylvania and New York are not drastically different from MiG; rather, they are slight modifications of the MiG system adapted to their individual farms.
Stocking Rate Comparison and Trampling, Forage Rest
Stocking density ranged from 44,128 lbs. /acre to 337,437 lbs. /acre, across the farms. These stocking densities were generally lower than indicated by proponents of this grazing method with beef cattle (100,080 to 500,403 lbs. /acre; Judy, 2008). This may be due to several reasons, including slight modification of (but not complete deviation from) traditional MiG practices regarding stocking densities of lactating dairy cows, or less forage available than in some of the beef models where regrowth periods are much longer.
We did not have the resources or time to evaluate soil bulk density with this study and it may need further examination. Savory and Parsons (1980) suggested that animal effect through hoof action of dense populations of animals improves water penetration of the soil and increases plant succession in Africa. However, a review of the literature by Holechek et al. (2000) examined various studies conducted with short duration grazing on semiarid rangeland conditions with beef cattle and sheep in the Great Plains and concluded that the hoof action of livestock grazing in high-animal-density situations may actually lower water infiltration (increase bulk density of soils) and increase erosion of rangeland soils.
Soil characteristics in the Great Plains differ from the temperate northeastern United States, which often contain clay and shale soils that may have increased compaction issues with high levels of hoof action (Ball et al., 2007). Additionally, the greater levels of precipitation found in the northeastern United States compared with the above studies may result in pugging and mudding of pastures with high levels of hoof action.
Descriptions of UHSD grazing under midwestern United States beef grazing systems have indicated periods of forage rest ranging from 25 to 150 d (Judy, 2008), with short rotations occurring early in the growing season when forage regrowth is rapid and the long rotations occurring later in the season, as ensuring that the plants are fully “rested” and the roots fully regrown is the ultimate goal. The farmers participating in the current study all noted that unusually dry conditions in 2012, coupled with the summer slump, or seasonal decrease in forage growth, required them to return to the sample pastures sooner than anticipated.
Traditional recommended forage rest periods (dependent on environment) to maximize forage yield and quality for some species under MiG systems during periods of rapid growth include 15 to 30 d for orchardgrass, fescue, and grazing alfalfas and 7 to 20 d for clovers (Ball et al., 2007).
Longer rest periods between grazing will allow greater amounts of available forage to accumulate through regrowth; however, as forage becomes more mature, increased lignin and cellulose content limit intake and digestibility (Van Soest, 1994). Furthermore, forage leaves have an approximate lifespan of 30 to 60 d, and over time the rate of leaf tissue loss to aging and decomposition increases, resulting in a high proportion of dead leaves in an ungrazed pasture (Ball et al., 2007).
Tall Grazing Field Day
On June 11, a successful field day demonstrated how tall grazing could be adapted to grazing dairy farms. The sustainable event was held at Spring Creek Farm, Wernersville, PA, with fifty people in attendance. Components of the field day included: pasture walk, panel discussion of farmers involved in the study, afternoon pasture walk with discussion about grazing profitability. The objective of the field day was to communicate applied research results to farmers and service providers about a study conducted on 4 farms in the Northeast in regards to UHSD grazing. A pasture walk was held in the morning and a study circle session in the afternoon, followed by another pasture walk in the afternoon.
Evaluations (n=26) showed that 85% (N=22) learned “a moderate amount” or “a great deal”. Fourteen farmers said they would make changes on their farms, including monitoring forage height, monitor days of rotation in paddocks and move animals more frequently. Sixteen farm advisors said they increased their understanding of tall grazing and increased their ability to talk to farmers about tall grazing.
An outcome of the meeting was to collect and compile a list of definitions by attendees of mob grazing. See the list of comments in attachments.
A comment from an attendee associated with agricultural industry: “Good session and was highly needed as many farmers misapplied this concept and lost a lot of dollars.”
A follow-up from an attendee, as a result of profitability information presented by Penn State Extension and an experienced grazier said: “At some point organic production may be an option if I continue to push for low input. But I need good financial info before making such a change. I have listened to many organic grazing producers speak, but they don't talk much about the financials and instead say they're successful based on their happiness in life. I have a lot of debt per cow and it would be nice to know profit per acre, profit per cow, and other financial ratios.”
The meeting was a collaborative event with USDA-Ag Research Service, the Pennsylvania Association for Sustainable Agriculture (PASA) and Spring Creek Farm, Wernersville, PA.
Dairy and Forage Study Circle
The Southeast Pennsylvania Organic Field Crop Growers had a study circle on March 10, 2014 with a variety of forage topics for organic dairy producers, including “Tall Grazing on Dairies”. Fifteen participants attended. Thirteen producers responded to the question about adapting tall grazing to their operations. Of the 13 producers, two said they are already using the practice and three said they plan to start to use the practice, while the remaining 8 said it does not apply to my operation (they likely were not dairy farmers).
Service Providers:
A seed industry owner in Pennsylvania took the preliminary research presented at the field day and presented it at a sustainable agriculture conference in Maryland in 2013. He added the USDA fact sheet to his Company’s website.
Education & Outreach Activities and Participation Summary
Participation Summary:
Extension and Outreach
Please note: Poster, Field Day Handouts and "The Definitions of Mob Grazing" are included in the 2013 Annual Report.
-Field Day-A “Tall Grazing Field Day” was held in June 2013 with 50 attendees on a cooperating farm, plus handout with 2012 results.
-Study Circle, “Dairy and Forages” held March 19, 2014 with 15 people in attendance for the Penn State Southeastern Organic Field Crop Growers Network
Fact sheet, “Case Study: Dairies Using Ultra-high Stocking Density Grazing in the Northeastern U.S. distributed to extension educators and NRCS specialists for their use and distribution.
Posters:
Two scientific posters were developed and used at the 2013 Northeast Pasture Consortium (February in New Hampshire) and the American Dairy Science Society Meeting in July in Indianapolis, IN and one extension research poster was displayed at the Extension Galaxy Meeting in Pittsburgh, PA in September and at the 2014 Northeast Pasture Consortium, State College, PA.
Peer Reviewed Journal Articles
-A.N. Hafla, PAS, K.J. Soder, PAS, M. Hautau, M.D. Rubano, B. Moyer, R. Stoudt. “Case Study: Dairies Using Self-Described Ultra-High Stocking Density Grazing in the Northeastern U.S.”.
-Joint Abstracts of the American Dairy Science and Society of Animal Science, Case study: dairies utilizing ultra-high stock density grazing in the Northeast
http://www.ars.usda.gov/research/publications/publications.htm?SEQ_NO_115=291048
Extension and Farm Popular Press Literature
-Penn State Field Crop News
A summary of the field day and the fall 2012 results for the Penn State Field Crop News, which reaches over 1700 farmers and agri-businesses.
http://extension.psu.edu/plants/crops/news/2013/06/tall-grazing-field-day-follow-up
The follow-up article on the final results for the Penn State Field Crop Newsletter.
The Penn State Start Farming Website (for beginning farmers)
The Website had 719 “unique page views” in the past year, or about 60 per month.
-Hay and Forage Grower
http://hayandforage.com/grazing/mob-grazing-tool-not-master-plan
-Lancaster Farming
This article picked up by Morning Ag Clips (Keystone edition), June 25, 2013 edition.
http://www.lancasterfarming.com/results/Standing-Tall--Spring-Creek-Farms-Finds-Grazing-Niche-
Department of Animal Science, Penn State summarized the research in an article in the “Livestock and Environment” column.
http://www.lancasterfarming.com/results/Field-Trial-Looks-at-Mob-Grazing-for-Dairy-Herds-
-Country Folks
http://countryfolks.com/grazing-a-mob/
-Graze Magazine-March 2014 edition
http://onpasture.com/2014/04/07/how-mob-grazing-works-for-dairies-in-the-northeast/
-Northeast Pasture Consortium (includes download to the PDF), “Case Study: Dairies Using Ultra-high Stocking Density Grazing in New York and Pennsylvania”
http://grazingguide.net/2014/03/740/
-Pennsylvania Association for Sustainable Agriculture Web Site- has handout from the field day and photo gallery
Project Outcomes
-Case Study: Farmers were interviewed and asked about their perception of farm profitability. There were variable responses to this question with some farmers offering benchmark data and some farmers having no data but feeling that they were happy with their current financial situation.
-Field Day Discussion of Economics-A Penn State Dairy Educator prepared a handout on the economics of grazing farms for participants using data from several sources. He prepared a handout, which is included in the attachments. Originally, the plan was to develop a partial budget based on the participants’ suggestions but the person originally on the project with that expertise was no longer on staff. In my interviews with farmers, one out of the four farmers had concrete suggestions as to how to organize a partial budget. This may be something to examine in the future if this becomes a practice with more dairy farmers.
Farmer Adoption
There is little documented adoption by dairy producers as of yet because it is such a new practice. The intent of this research is more to help dairy producers understand that there is not a very large difference between what these graziers are doing and intensively managed grazing farms. Popular press articles present conflicting information to what we observed.
Areas needing additional study
One of the goals of this work was to help researchers know what are the issues to be studied. For example, Dr. Hafla, USDA-ARS, was working to develop a protocol for controlling variability when studying per cent Brix. There is a need to correlate the residue building practices with soil health (i.e. organic matter, permeability, etc.) as that was beyond the scope of this study. Controlled studies on farms could be conducted with beef and sheep operations because the forage quality requirements are more variable than dairy.