Jerry H. Cherney

Department of Crop and Soil Sciences

Debbie J.R. Cherney

Department of Animal Science

Cornell University

Properly managed perennial grass can produce high quality grass for lactating dairy cows, as well as improve the manure/nutrient management situation on most dairy farms. We currently have perennial grass experiments at Willsboro, Valatie, Canton, Chazy, Mt. Pleasant, Ithaca, and Aurora, NY. Grass species, varieties, cutting managements, manure management, and commercial fertilizer treatments are among the factors being evaluated relating to grass production for lactating dairy cows. Timothy and orchardgrass varieties also have been sown on 8 farms across NYS in the fall of 1996 to evaluate heading date (and possibly quality) of over 30 varieties. Grass samples also were taken from three feeding trials have been completed comparing low fiber grass, high fiber grass and alfalfa. This is a summary of our results to-date, mostly referring to grass that will be harvested and stored, as opposed to grazed grass. A more extensive summary, including economic analysis of alternative managements, is currently in progress.

For New York state, a world wide web program will be available shortly to provide site-specific forage species recommendations based on soil type and intended forage use (http://www.forage.org). The two primary factors to consider when selecting perennial forages species and varieties are 1) persistence, and 2) heading date. Of course, anti-quality factors must be taken into account. Choose only low-alkaloid reed canarygrass varieties (Palaton, Venture, Rival), and low-endophyte tall fescue varieties (many available).

Persistence. Grass species vary in their tolerance of pH and moisture extremes. Species ranking in adaptation to poorly drained soil conditions is:

Species ranking in adaptation to excessively drained soil conditions is:

Species ranking in ability to tolerate low soil pH is:

The general order of grass species to consider for intensive management where overwintering of grass is of concern is:

2) Heading date. Maturity is the single most important factor controlling forage quality in grasses (assuming no anti-quality components). Several varieties and/or species should be considered to spread out the spring heading date and the spring harvest window. In the past the general order of grass species heading date from earliest to latest has been:

New releases of orchardgrass are generally all later maturing, while new releases of timothy tend to be earlier maturing, to better match up with alfalfa. As a result, some new timothy varieties have headed as early as the latest new orchardgrass varieties. We determine heading date as the date that six heads were visible emerging from the boot. In 1997, grass varieties at eight sites across New York state headed relatively late in the spring, and varied considerably across sites and varieties as follows:

Species mixtures. Rarely is it advantageous to consider two perennial grass species in mixture. Sites with great soil variability may be candidates for grass mixtures, but heading dates of varieties in a mixture should be matched up as closely as possible. Otherwise, quality will be optimal in one part of the mix, but not the other(s). Relatively few soil types in Eastern Canada or the Northeastern U.S.A. are perfectly adapted to seeding pure alfalfa. Also, widespread mid-winter thaws in the region usually result in significant ice sheeting, placing pure alfalfa stands at great risk. Where alfalfa can be grown, alfalfa-grass mixtures generally are recommended. Reed canarygrass or timothy in mixture with alfalfa will result in a relatively small grass component in the mixture. Orchardgrass or tall fescue mixed with alfalfa, on the other hand, will result in considerably more grass in the mixture. Smooth bromegrass has large, fluffy seed that can be difficult to sow in mixture with other species. Smooth bromegrass also will likely not persist in a mixture with alfalfa, if intensive harvest management is practiced. Harvest of smooth bromegrass in the spring during stem elongation, prior to flowering, greatly stresses plants. Perennial ryegrass is very competitive with alfalfa, and varieties have not yet been identified that will consistently overwinter in our region.

All perennial grasses will produce reasonable yields if present in good stands and fertilized adequately. On good alfalfa soils, alfalfa will typically yield about 0.5 tons/acre more dry matter than grass with recommended N fertilization. However, if the soil resource is not well adapted to growing alfalfa, grass will outyield alfalfa. Grass yields will range from less than 1 and 2 tons/acre without any N fertilization, with the variation related to native soil fertility. Table 1 contains hay yields for 5 grass species, sown in 1993, managed under commercial N fertilization at recommended rates (Willsboro, Essex county, NY). Varieties were selected to have similar heading dates across species. Tall fescue consistently outyielded other species. Yields were considerably reduced in a dry growing season (1995). Timothy produced unexpectedly high yields, but was more affected than other species by dry conditions (1995). Application up to 30 tons/acre of semi-solid manure (data not shown) resulted in yields about 1/3 lower than recommended commercial N fertilizer in 1994-1996, with equal yields for commercial N applications vs. manure applications for orchardgrass and tall fescue in 1997. The site did not have a history of manure application prior to 1993.

Timothy and orchardgrass varieties (six of each) were established at two sites differing in soil drainage in 1993 at Canton, St. Lawrence county, NY. Grass was fertilized with commercial N according to recommendations and harvested 4 times in 1994 and 3 times in 1995-97. Grass yields (Table 2) shows that timothy maintained its yield on the more poorly-drained sited, while orchardgrass yield was reduced. Across years, Richmond and Tiller timothy outyielded other timothy varieties, while orchardgrass varieties were more variable, with OKAY tending to be consistently lower yielding than other orchardgrass varieties. Yields vary by soil type and season. A two-fold difference in yields from a given field can be expected in wet vs. dry years. Grass yields over the past 4 years at recommended N fertilizer rates have ranged from 3 to over 7 tons hay (12% moisture) per acre across northern NY.

Timothy varieties: Chazy, Climax, Mariposa, Mohawk, Richmond and Tiller.

Orchardgrass varieties: Benchmark, Dawn, Haymate, OKAY, Pennlate and Axiom.

Neither grass species nor varieties vary much in total fiber (NDF) when compared at similar maturity stages. Strive to harvest grass between 50 and 60% NDF, which means 3-4 harvests per year. Optimum forage quality (55% NDF) occurs in very early to early boot stage, and is likely to occur the last week of May (earlier for early to medium maturity orchardgrass). This compares to 40% NDF in alfalfa (ideal) which may occur from late May to June 10 or so. As soon as there is sufficient regrowth to justify a harvest, the NDF content will likely be between 50 and 60%. With recommended applications of nitrogen, crude protein (CP) content should range between 16 and 20%. Recommended N applications will rarely result in nitrate accumulations dangerous to livestock. Nitrogen applications exceeding recommended levels will greatly increase the risk of unacceptable nitrate levels in forage. Timothy tends to be 1-2 percentage units lower in CP than other perennial grass species, when compared at similar maturity stages. While tall fescue has very good yield potential, the palatability of new varieties for high producing dairy cows has yet to be evaluated sufficiently.

Grass management begins as soon as the grass begins growth, with application of 75 lbs of actual N/acre or an equivalent amount of manure, if possible (depends on form of the manure). Nitrogen fertilizer or manure should be applied as soon after subsequent harvests as possible (50 lbs actual N/acre or equivalent). Manure should be applied such that no manure ends up in the harvested forage. High forage potassium content is not a problem for lactating dairy cows, as it is for dry cows. Regrowth should be harvested as soon as there is sufficient regrowth to justify a harvest. This may occur 25 to 35 days after spring harvest, depending on available moisture. An early first harvest may result in an equal amount of dry matter yield in the second harvest as was obtained in the first harvest. Depending on temperature and moisture conditions, three to four harvests are possible in northern NY. After each harvest (except the last harvest of the season) 50 lbs of actual N/acre should be applied. There will be little carryover of N from the previous application to permit regrowth (that is, N applied after lst cut will benefit 2nd cut regrowth, but will not benefit 3rd cut regrowth).

Grass forage can be used in balanced rations to yield similar milk production to high quality alfalfa. Several feeding trials in Ohio and New York state have supported this. A New York study involved feeding alfalfa and orchardgrass hay at two maturities to mid-lactation dairy cows (Table 3). Milk yield was actually higher with the mature orchardgrass ration compared to the alfalfa ration, due to higher dry matter intake and higher concentrate intake. Rations were balanced for fiber, protein and energy, such that similar milk yield was expected from all rations.

Another feeding trial involved 60 Holstein cows in mid-lactation fed diets containing alfalfa-corn silage, immature orchardgrass-corn silage, or mature orchardgrass-corn silage as the forage source. All forages had been ensiled. Approximately 20% of forage dry matter fed was corn silage. Forages comprised 53, 47 and 44% of the total diet dry matter for alfalfa, immature and mature orchardgrass, respectively, with resulting milk production of 35, 39, and 33 kg milk/day. A third feeding trial involved 50 early-lactation Holstein cows fed immature or mature orchardgrass silage in balanced rations. The immature orchardgrass silage ration produced 35 kg milk/day compared to 31 kg milk/day for the mature orchardgrass silage ration. Quality of orchardgrass silage affected DM intake, which subsequently affected milk production.

Economics of grass. When production costs of alfalfa are compared to intensively managed early cut grass at 55% NDF (including proper manure management and fertilizer credits for manure), dollar return per acre was found to be similar for grass and high quality alfalfa, on good alfalfa land. Grass permits a higher level of forage NDF to achieve a similar milk production level, compared to alfalfa. Grass also is a slightly higher quality source of protein than alfalfa protein, resulting in less total protein required in the diet with grass compared to alfalfa. That is, alfalfa at 20% CP has the protein equivalent of grass at 19% CP.

If perennial grass is managed for production of high quality forage, milk production similar to that found using alfalfa forage can be achieved. Good grass haylage however, tends to be more difficult to make than good alfalfa haylage. High quality grass, in general, requires a higher level of management than does alfalfa. Intensive, aggressive perennial grass management and feeding is essential for economic survival on diary farms with soils not suited to alfalfa production.