Cropping/Forages: From A to Z (and from seed to feedbunk)

Whether you grow it or buy it, feed represents the largest cost item for a dairy. From seed to the feedbunk, each step requires management – from A to Z.

By Dave Natzke

Alfalfa. About 75 members of Congress  urged USDA to allow limited planting of Roundup Ready® alfalfa. The bipartisan group supports action  to allow farmers to plant seed that’s being held in inventory while USDA completes an Environmental Impact Statement (EIS) related to the product. The letter came on the heels of a Supreme Court ruling that found a lower court was in error when it placed a nationwide ban on the planting of genetically engineered alfalfa seeds.

Baleage. Dairy producers large and small are expressing more interest in baleage, said Mike Hutjens, University of Illinois Extension dairy specialist. Producing baleage does provide challenges, however. Harvest moisture level is critical, with 40%-50% dry matter “a magic spot.”  Wetter silage can lead to moisture in the bale’s base and development of butyric acid. But going too dry can also lead to problems – less fermentation and compaction, increasing mold risk and resulting in less stable silage. He recommends using an effective inoculant.

Costs. Having access to a quick and easy method of evaluating dairy feed cost can help dairy producers make decisions, according to Ken Bolton, University of Wisconsin-Extension dairy agent. A five-sheet Excel program, “Estimating Dairy Cow Feed Consumption and Cost” strives to address these issues. The spreadsheet titled “Feed$Cow” allows a quick look at daily feed cost/cwt. of milk produced based on the mature cow herd (lactating and dry) for both default and user inputted feed values.  A similar approach is utilized on the “Feed$Heifer” spreadsheet to produce feed cost values for the raised replacement enterprise. These spreadsheets are combined on the spreadsheet “Feed$Herd.” The “Feed$Budgets” spreadsheet guides users towards realistic feed usage levels for the lactating cow, replacement heifer and combined whole herd enterprises.

The free spreadsheet is available from the UW-Extension, Center for Dairy Profitability, “Decision Making Tools” website at cdp.wisc.edu/Decision Making Tools.htm and from the UW-Extension, “Dairy Cattle Nutrition” website at www.uwex.edu/ces/dairynutrition/.

Distiller’s dried grains with solubles. A Purdue University researcher found a way to predict the nutrient content in DDGS, which often have varying fiber, protein, sugar and amino acid levels, making many livestock nutritionists and producers wary of purchasing them. Klein Ileleji found the solution lies in the balance of the liquid and solids used to create the finished DDGS product. For instance, increasing the syrup leads to a decrease in fiber and protein, but an increase in residual sugars. Ileleji is creating a model to allow ethanol producers to blend DDGS to give specific nutrient profiles.

Equipment (see New Products)

Fall assessment. Fall is the best time to assess whether want to keep an alfalfa crop for the following year, noted Leo Brown, livestock information manager for Pioneer.

Look at the health of the stand and how it’s doing in the fall, and you’ll have a good idea of what will happen the following spring (although winterkill and icing could change things).

Look at how many plants and, even more important, how many stems are in a per-acre area.

If you’re going to keep their alfalfa crop for another year, what type of nutrients should be applied during the fall. Look at university and supplier recommendations for potash and potassium, based on your yield goals.

If it’s time to rotate that crop out, killing it with herbicides will also take care of all the other weeds, making it easier to work the field up next spring.

Determine the soil pH. There are soluble limes you can spray across the top that will trickle down and get into the upper layers of the soil, but that’s a lot more expensive than doing it right when you first establish the alfalfa stand.

Grass. It may come as a surprise, but grass is the most common crop ensiled in the world, followed by corn and alfalfa, according to Jerry and Debbie Cherney, with Cornell University.

In some cases, cropland soils may be better suited for perennial grasses. Grasses also have advantages when it comes to nutrient management, with a greater response to manure applied multiple times during the season. Grasses use large quantities of nutrients, minimizing the risk of nutrient leaching or runoff. They can remove over twice the nitrogen per acre compared to corn.

Improved management for high quality, advances in equipment, and innovations related to bale silage and other storage options, have made grass silage an attractive option. Wide swathing gives the potential to mow and chop haylage in a day.

While species and variety selection and  fertilization are important, harvest management will determine the success or failure of grass silage as a high-producing dairy cow forage.

Grass species and variety evaluation should be focused on maximum yield at optimum silage quality. Any grass stand can be specifically managed to produce low potassium forage for non-lactating cows.

New tall fescue varieties should be seriously considered for dairy systems in the northern USA, particularly those that combine grazing with silage options. Alfalfa/perennial grasses mixtures should lead to a better balance of ration ingredients to maximize total intake. A proper balance of grass and non-fibrous carbohydrates in the diet should increase intake and maximize milk production.

Hay sources. If you can’t grow it, you might have to buy it. There are a number of Internet-based hay lists – private and public – so check with your state Extension service or hay association. One of the more extensive private lists is www.hayexchange.com/index.php. It has hay sales listings for all 50 states, including the type of hay, quantity available, bale type, delivery availability, asking price and the seller’s area code, with registration required contact information. It also allows those seeking hay to post their needs and contact information.

Inoculants. There are a variety of inoculants used on forage crops, depending on your needs and the potential benefits of each inoculant. Silage inoculants are used for two primary reasons:

1) as fermentation aids, to stimulate or ensure a rapid fermentation. They generally contain efficient (homofermentative) lactic-acid-producing bacteria (LAB), and are mainly used on low dry matter forage crops with low concentrations of fermentable carbohydrates and high buffering capacity.

2) as  spoilage inhibitors, to reduce aerobic spoilage. They include propionic acid, specific LAB, and propionic-acid-producing bacteria, and are designed for use on materials more prone to aerobic spoilage, such as drier haylages (> 35% DM), corn and cereal silages, high moisture corn and cereal grains, baleage and dry/baled hay. For more information, visit www.qualitysilage.com/inoculants/.

Judge and jury. When it comes to crop  and feed quality, it’s the cows.

Kura clover. Craig Sheaffer, University of Minnesota forage agronomist, and Philippe Seguin, McGill, University, Quebec, Canada studied drought response of Kura clover, alfalfa, red clover and birdsfoot trefoil. They found Kura clover was the most persistent legume under drought and non-moisture limiting conditions, with the highest forage quality in both environments. However, it was also among the lowest yielding legumes, with mid-summer drought reducing Kura clover’s yield more than for the other legumes. Thus, Kura clover has great potential as a persistent pasture legume, but it will not provide significant amounts of forage during summer drought.

Land values and rental rates in major dairy states. (See October 2010 issue of Eastern DairyBusiness.)

Molds & mycotoxins. Whether you are  a producer, nutritionist or veterinarian, being aware and understanding the threat posed by molds and mycotoxins will ultimately have an impact on your herd’s health and your bottom line. A website (www.knowmycotoxins.com) can help increase your knowledge on mycotoxins, how they are produced, their impact on dairy cows and heifers, issues with feed sampling, and possible strategies to maintain your herd’s health and performance.

NDF digestibility. University of Wisconsin-Madison dairy nutritionists addressed neutral detergent fiber (NDF) in a Focus on Forage article, discussing how crop maturity affects NDF digestibility, and how forage NDF digestibility can best be managed.

One of the factors influencing NDF digestibility is the maturity stage at which grasses, legumes, corn silage and small grain forages are harvested. The rate of NDF digestibility decline is different between forage types, with the decline in grasses and small grain silages particularly dramatic.

With advancing maturity, the combined effect of physiological changes results in plant cell walls which are more difficult for rumen bacteria to attach to and to digest. As forages mature, they accumulate more NDF, decreasing forage energy content.

There’s really nothing new as to how to manage forages to optimize NDF digestibility.  Forages should still be harvested at their traditional stages of maturity (grasses = boot, legumes = bud, corn silage = ½ milk line) to maximize both yield and quality.  Understanding the decline in NDF digestibility places a double emphasis on harvesting forages at their proper maturity.

Organic. In a recent University of Vermont study, organic dairy producers in that state spent nearly $1,200 per cow per year on purchased feed (Parsons et al., 2009). Ninety-two percent of those purchases were for grain concentrates to increase the nutrient density of rations and improve milk production. Whether it is pasture during the grazing season or stored forages for winter months, forage quality determines what other feeds must be fed. Quality forages provide a nutritional base that maintains digestive function, improves animal health and provides nutrients to the cow in a cost-effective manner. For a list of articles related to organic dairying and forage production, visit www.extension.org/article/18624.

Porosity. Silage compaction guidelines have focused on silage dry matter (DM) density.  However, DM density does not account for porosity – the voids between solid particles of a material. These voids can be filled fluids or gases, and sets the rate at which air moves into the silage. This subsequently impacts the amount of spoilage and/or aerobic stability in ensiled feeds.

Brian Holmes, University of Wisconsin-Madison dairy engineer, modified equations available from composting research and related them to silage porosity in terms of both DM and silage bulk density (as fed density). Bulk density is affected by the same management practices as DM density, such as tractor weight, packing time per ton, layer thickness and height of the storage structure.  However, while DM density may increase with advancing DM of the feed, bulk density decreases. In other words, as forage becomes drier, the porosity increases across similar DM densities.

Porosity is difficult to measure in the laboratory and probably impossible to measure in the field. However, because porosity is relatively constant for a given bulk density, and because bulk density is more readily measured than porosity, it may be better to recommend a minimum bulk density.

The UW researchers recommend silage producers strive for <40% porosity.  A minimum bulk density of 44 lbs. AF/ft3 keeps porosity below 40% within the recommended range of DM content.

Forage at 30% DM can be packed to 15 lbs. DM/ft3 to give the desired bulk density. Dryer material (40% DM) must be packed to 20 lbs. DM/ft3 – a much more difficult task. In both cases, the porosity is close to 30%.

Resources for estimating silage densities based on your conditions and packing practices are the Bunker Silo Density Calculator and the Silage Pile Density Calculator. These are Excel spreadsheets available from the UW Team Forage Harvesting and Storage website: www.uwex.edu/ces/crops/uwforage/ storage.htm. For a link to Holmes’ work, visit www.uwex.edu/ces/crops/uwforage/Density-Porosity3.pdf.

Quality tests for forages. Forage

quality information is important for formulating nutritionally balanced rations, developing and allocating forage inventories, evaluating forage management practices  and marketing and pricing forages. The University of Minnesota recommends tests for determining dry matter (DM), crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), calcium (Ca), and phosphorus (P). Energy values (TDN or net energy) and relative feed values (RFV) can be calculated from these core analyses. Additional macro and micro mineral analyses are suggested.

Rumen acidosis. Today’s rations are

designed to maximize energy for milk production. While effective, they can also have an adverse effect on the rumen and induce acidosis. Typical acidosis causes include diets too high in fermentable carbohydrates, low fiber content, diets composed of very wet and highly fermented feeds or too finely chopped forage.

Acidosis symptoms may include low milk fat test; < 3.0%-3.3% or 1% below the herd average, sore hooves or laminitis, low rumen pH (< 5.8) in 30%-50% of animals tested and limited cud chewing.

To reduce risk of rumen acidosis, ensure sufficient long fiber in the diet to promote adequate cudding and saliva production to buffer rumen pH; ensure good cow comfort; avoid feeding excess amounts of rapidly fermentable carbohydrates; and offer a well managed TMR to minimize sorting of feed components. You may need to feed a probiotic to stimulate microbe production in the rumen.

Sieves. The Miner Institute presented a

paper titled  “Modification of the Penn State Particle Separator (PSPS) with 3.18- or 4.76-mm perforated steel sieves to measure physically effective fiber (pef) at the recent American Dairy Science Association meeting. They replaced the original 1.18 mm wire mesh screen with either 3.18 mm or 4.76 mm perforated steel sieve used in the Z-Box pef system. They shook a number of samples with both 3.18 and 4.76 sieves. The PSPS pef values were compared to pef value obtained with the standard dry sieve vertical shake RoTap method.

Overall, the results are promising, according to Kurt Cotanch (cotanch@whminer.com). The 3.18 screen tends to over-predict pef, while the 4.76 screen tends to under-predict pef. Individually, corn silage and TMR samples worked well; however, the HCS was less predictable. Results of the research will be presented at October’s Cornell Nutrition Conference.

Taking manure samples. It’s a dirty job, but somebody has to do it, and according to the University of Wisconsin’s Discovery Farms program, there are specific techniques to ensure accurate results. Find information on liquid manure sampling systems at:

Recommended Methods for Manure Analysis: http://uwlab.soils.wisc.edu/pubs/A3769.pdf

Recommended Methods for Manure Analysis: www.soils.wisc.edu/extension/
materials/Manure_Analysis_Methods.pdf

How to Sample Manure for Nutrient Analysis: www.extension.iastate.edu/publications/pm1558.pdf

U.S. Dairy Forage Research

Center. The center is a cooperative effort between USDA, the University of Wisconsin-Madison and other land grant universities. It focuses on problems that are national in scope and that limit effective and efficient use of forage for milk production. It coordinates multidisciplinary research involving engineers, microbiologists, chemists and plant and animal scientists in five states. The research is directed toward increasing yields and quality of forage grown and harvested, reducing losses associated with harvesting, storage and feeding, and maximizing use of forage nutrients by the dairy cow for milk production. Visit www.ars.wisc.edu/dairyforage/.

Variety trials. (See list below.)

Weeds. Penn State’s Department of Crop and Soil Sciences posts annual field crop herbicide evaluation trials on corn, soybeans, forages and small grains at http://weeds.cas.psu.edu/research.html.

eXtension. Looking for crop-related information and resources from public institutions? eXtension is an interactive learning environment delivering research from land-grant university minds across America. Visit www.extension.org/.

Yields. USDA’s September 2010 Crop Production report estimated the 2010 U.S. corn crop to yield an average of 162.5 bushels/acre 81.0 million acres, for a record harvest of 13.2 billion bushels. Soybean yields were projected a record 44.7 bushels/acre on 78.0 million acres, for a record-high U.S. harvest of 3.48 billion bushels.

Z index. The Moisture Stress Index for corn and soybean crops is a measure of the effects of drought and catastrophic wetness on national crop yield. It is calculated through the use of a drought index (the Palmer Z Index) and annual average crop productivity values within each U.S. climate division. It’s monitored by the National Oceanic and Atmospheric Administration. Really.

Variety Trials

Crop variety selection is about much more than just yield, notes Jim Rouse, Department of Agronomy at Iowa State University. Growers need to evaluate the various combinations of maturities, defensive traits and herbicide traits. Among those that meet your desired criteria, how do you choose those with the greatest yield potential? Predictive information for yield potential should come from multi-environment trial averages. If your favorite data report does not include district or regional yield averages, you should not use it to make selection decisions. A number of state universities collect crop variety field trials. Check these websites for specific results.

Alabama: www.ag.auburn.edu/agrn/alabamavarietytesting/

Arkansas: www.arkansasvarietytesting.com/

Florida: http://animal.ifas.ufl.edu/extension/CSFD/CSFD/

Georgia: www.caes.uga.edu/commodities/swvt/

Illinois: http://vt.cropsci.illinois.edu/

Indiana: www.ag.purdue.edu/agry/PCPP/Pages/default.aspx

Iowa: www.croptesting.iastate.edu/

Kansas: www.agronomy.ksu.edu/extension/

Kentucky: www.uky.edu/Ag/GrainCrops/varietytesting.htm

Louisiana: www.lsuagcenter.com/en/crops_livestock/crops/

Maryland: www.mdcrops.umd.edu/

Michigan: www.css.msu.edu/varietytrials/

Minnesota: www.maes.umn.edu/maespubs/vartrial/vt-cntnt.asp

Mississippi: http://msucares.com/crops/variety/index.html

Missouri: http://agebb.missouri.edu/cropperf/

Nebraska: http://cropwatch.unl.edu/web/varietytest/

New York: www.forages.org/forage.asp

North Carolina: www.ncovt.com/

North Dakota: www.ag.ndsu.edu/varietytrials

Ohio: http://agcrops.osu.edu/

Pennsylvania: http://cropsoil.psu.edu/extension

South Carolina: www.clemson.edu/extension/rowcrops/corn/guide/variety_trial.html

South Dakota: www.sdstate.edu/ps/pubs/index.cfm

Tennessee: http://varietytrials.tennessee.edu/

Vermont: http://pss.uvm.edu/vtcrops/

Virginia: www.grains.cses.vt.edu/

Wisconsin: http://agronomy.wisc.edu/

Midwest: www.agry.purdue.edu/pcpp/UCTA/index.html

U.S. corn: www.agry.purdue.edu/ext/corn/experts/cornspec.html

U.S. soybeans: www.agry.purdue.edu/ext/corn/experts/soyspec.html

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