Optimizing Use of Grass on Dairy Farms for Environmental/Economic Sustainability
This three-year project helped farmers expand the use of perennial grasses by developing and validating best management practices for perennial grasses on Northeast dairy farms. Project activities contributed to increased awareness of grass as a high quality dairy feed and as a nutrient management tool. Based on information gained through the project, participants made changes to their recommendations to farmers regarding grass species selection, dry cow and lactating cow feed management, and nutrient management. The project resulted in an increase in intensive grass management and some shift from alfalfa and corn acreage to perennial grass. These changes protect soil from erosion, reduce chemical use and increase income per acre. The project’s full report, available through the SARE office, provides additional details of activities and findings by objective, an economic analysis and site information for the participating farmers.
1. Identify the optimum forage quality of perennial grasses for dairy cows to maximize profitability and to verify results through animal feeding trials.
2. Determine the appropriate harvest management to obtain optimum quality of perennial grasses, while maintaining stand persistence.
3. Develop an economic budget to demonstrate the advantages of proper grass and manure management on dairy farms and encourage increased use of perennial grasses.
4. Carry out a case farm study to demonstrate new BMP's for optimum grass management, including harvest management as well as nutrient/manure management.
Initial studies identified optimum forage quality of perennial grasses for dairy cows in a range of balanced rations using information from the Cornell Net Carbohydrate and Protein System model. It is clear from model results that many dairy farmers overfeed nutrients, particularly protein. Model results indicate that optimum grass fiber content is approximately 50-55 percent neutral detergent fiber, and optimum protein is 18-19 percent crude protein. Model results were verified with animal feeding trials to convince dairy farmers that grass can produce as much milk as alfalfa in a balanced ration. Feeding trials also indicated that the quality of forage fiber is important in determining dry matter intake and resulting milk production.
Agronomic grass management was studied in three field sites of timothy and reed canarygrass. Timothy stands persisted well over the course of the study at all three field sites, however, reed canarygrass forage averaged over two percentage units higher crude protein than timothy. As a result, timothy use is now being discouraged in New York state. A perennial grass harvest taken in 1998 to evaluate the residual effects of N fertilizer treatments showed that soil potassium was depleted over years in plots receiving more than 120 lbs N fertilizer per acre annually. For reed canarygrass, there appeared to be nitrogen carryover into the following year only in plots receiving the highest rate of N fertilization. Manure applications to grass at two of the sites resulted in significantly lower forage yields than manure plus nitrogen fertilizer. The study was not continued long enough, however, to evaluate the cumulative effects of manure.
A spreadsheet program used to compare economics of grass grown under different cutting management approaches and fertilizer applications clearly showed that harvest of grass hay with no application of manure or commercial fertilizer is a losing proposition. Farms that currently practice intensive grass management for dairy cattle were sampled to demonstrate that high forage quality was possible on commercial farms. Whole farm nutrient management planning on two of these farms demonstrated that manure nitrogen can be effectively utilized with intensive grass management. It also showed that farms practicing intensive management may have significant P and/or K nutrient balance problems, with excess P and K.
While it is very difficult to document an increase in more efficient grass management for dairy cattle, the interest in efficient grass management has been steadily increasing in New York. This project has certainly contributed to the increase in awareness of grass as a high quality dairy feed and as a nutrient management tool. Grower/producer/consultant attendance at extension meetings in NYS where grass management was featured from 1995 to 1998 are as follows: 1995: 355; 1996: 758; 1997: 676; 1998: 1164.
Based on project results we are suggesting the following recommendations to farmers:
Species selection: Consider reed canarygrass or orchardgrass over timothy (timothy is currently about 70% of the total grass seed sold in New York state) because of the higher level of protein in the forage across all levels of management. Management that allows for four cuttings per season produces high quality forage, provides greater flexibility in balancing rations, and optimizes milk production of cows fed grass forage.
Dry cow management: Results from this study have demonstrated that grass fields managed to produce forage for lactating dairy cows are not appropriate for production of dry cow forage. Set aside grass fields low in available soil potassium and manage them separately for dry cow forage. Harvest grass for dry cows at or after flowering, and use regrowth forage (lowest in K) for cows near calving, when the level of potassium is most critical for animal health. Timothy is consistently lower in potassium than other grasses, while orchardgrass is consistently higher. Fertilize grass fields for dry cow forage adequately with nitrogen, in order to deplete soil reserves of K, and produce economically acceptable yields.
Nutrient management: Farmers are encouraged to practice intensive grass management to aid in overall nutrient management. Nutrients in manure, particularly nitrogen, can be more effectively utilized under intensive grass management.
This project has directly resulted in an increase in intensive grass management in NYS and some shift of alfalfa and corn acreage to perennial grass. These shifts protect soil from erosion, reduce chemical use and increase income per acre. Extension specialists in most NYS counties have reported farmers shifting from alfalfa/corn to perennial grass acreage in the past three years. None have reported farmers shifting from grass to alfalfa/corn. Alfalfa/corn acreage statewide has not declined, however, presumably because large farm operations that bring idle land back into production will typically plant alfalfa/corn.
With intensive management and recommended manure and fertilizer applications using our spreadsheet program, returns over all production costs from 1994 to 1997 (Mt. Pleasant location) averaged $217 per acre more than the typical extensive grass management practiced in NYS.
Grass management methods were compared using a spreadsheet program developed by Darwin Snyder of Agrecord Management Services. Yield and quality data from each year of the study at the Mt. Pleasant, NY location for timothy and reed canarygrass were included in the analysis, and separate results were generated for hay and silage use, as well as with and without manure credits. Value of hay and silage crops was estimated using the latest version of the FORVAL program with current crop prices, developed by Gary Fick, Cornell University. Hay crop value was based on nutrient content and on current market prices for hay, grain and protein sources. Nutrient content of the forage is based on a weighted average of each forage quality parameter across all harvests. Establishment, maintenance and harvest costs are used for each harvest management/N fertilizer management combination to generate net return per acre for each method. Returns also were estimated with manure included as a fertilizer source.
As with any economic analysis, results can be dramatically affected by the assumptions made. Assumptions regarding variable and fixed costs are based in part on information taken from the annual New York Economic Handbook. The assumption of greatest concern, however, is the estimated feed value per ton, based on FORVAL. Detailed budgets were included in past annual reports.
Three years of results indicate that grass managed without some form of nitrogen fertilization will not be profitable. This project demonstrated that managed grass is profitable, and is more profitable the higher that grain prices rise. When grain prices were low, as in 1998, three-harvest management with its higher yields appeared to be more economically feasible than four-harvest management.
Optimum management, including crediting manure nutrients, resulted in positive returns per acre, except in years where drought reduces crop yield below that of the current state average for hay crops, such as 1995. In 1995, optimum fertility management resulted in returns over all production costs of -$85 per acre for four-harvest management and -$64 per acre for three-harvest management. Lack of N fertility management with perennial grass always resulted in large negative returns per acre. Yield variation from year to year resulted in returns over all production costs from 1994 to 1997 also varying from -$64 per acre in 1995 to $189 per acre in 1996. Results clearly indicate that only intensive management will be profitable, and only in years without severe drought.
The primary risk involved in shifting forage production to intensively managed grasses is the risk of drought. Grasses are not as productive as legumes under drought conditions. Nitrogen fertilization will be unprofitable if moisture stress severely limits yields. A full analysis of this risk is a project by itself, and is included as a suggested new area for study in Section 7 below.
Areas Needing Additional Study
1. Economic risk assessment dealing with the variability of grass yields related to weather extremes from season to season.
2. Investigation of legume species to be sown in mixture with perennial grasses, particularly for pasture. There is great need for a productive, persistent pasture legume for the Northeast.
3. Soil-specific forage species recommendations (grasses and legumes) to produce forage for specific uses, including pasture. Data accumulated here, along with other sources of data, can be used for this purpose, and we have developed a prototype program for NYS.
4. Whole farm nutrient management analysis in this study has indicated that dairy farms may have some very significant problems related to utilization of manure nutrients. The foundation of nutrient management planning software should include soil-specific forage species recommendations. This issue is not currently being effectively addressed in any of the many nutrient management packages under development.
Due to this successful study with grass for dairy cattle, we have obtained additional funding from Cornell University to conduct feeding trials in late 1999 to compare tall fescue, orchardgrass and alfalfa. Tall fescue has been agronomically superior to other grass species in recent trials, but feeding quality is not clear. Following these feeding trials, we are planning on summarizing all the field data and feeding trial data from this study and other studies in NYS, and also including relevant grass data from other NE states, to produce a NE publication on “Grass for Lactating Dairy Cows” in 2000. Preliminary discussions regarding the publication are underway, and the publication also will include SARE data from studies undertaken by Miner Institute, Chazy, NY.
Reported August 1999.