Potentials for Plant and Other Toxicities in Cattle

While Johnsongrass is a good quality forage, it can be challenging to control in pastures where the perennial, warm-season grass is not desired. Prussic acid production under stress can pose a risk to livestock when grazing Johnsongrass, especially during prolonged droughts or after a frost.
( Dirk Philipp, University of Arkansas )

Fortunately, there has been plenty of rain this year. However, heading into late summer and fall are times of the year to watch out for plant toxicity in cattle.  In some cases, plants can become more toxic during drought and heat stress.  In addition, there is the increased potential for cattle to ingest toxic plants due to lack of other feedstuffs.  There may also be more access to toxic plants.  With droughts come increased weed infestation of pastures, hay and crop fields.   Penned cattle may also be in corrals or drawn to low lying areas that are still green, both of which are where toxic plants are likely to grow.  Differentiating “good” vs. “bad” plants is a learned behavior, so toxicity is more likely in young animals and animals moved to a new location.  A grazing management and supplemental feeding plan is essential to minimize problems.  Veterinarians and producers should be familiar with which plants can cause problems in their area, and try to avoid them.  The following discussion covers some of the plants and situations to watch for during drought situations.  There may be plants that grow some regions that are not covered.

Stressed plants more readily accumulate nitrates and prussic acid (cyanide).  Drought stress can cause both pasture forages and weeds to accumulate toxic amounts of nitrates.  Recently fertilized pastures are also at higher risk.  Plants that have accumulated nitrates remain toxic after baling or ensiling.  Test forages for nitrates to prevent poisoning.  Prussic acid accumulates most often in sorghums, sudans and Johnsongrasses, but these plants can accumulate nitrates also.  There is no test for prussic acid, but it dissipates when plants are baled or ensiled, so harvested forages are safe.  Cattle poisoned by nitrates or prussic acid are usually found dead, so prevention of these toxicities is critical.   Cattle with nitrate toxicity have methemoglobinemia (brown blood) and cattle with prussic acid toxicity have cyanohemoglobinemia (bright, cherry red blood).  Nitrate and prussic acid both interfere with oxygen carrying capacity in the blood, so pregnant cattle surviving these poisonings often abort.

Two of the most toxic plants found in croplands and pastures are coffeeweed and sickle pod.  Cattle will generally not graze the green plant unless other forages are scarce.  However, they will readily eat the seedpods that are dry after a frost.  The plant remains toxic when harvested in hay/balage/silage.   Coffeeweed and sicklepod are toxic to muscles and cause weakness, diarrhea, dark urine, and inability to rise.  There is no specific treatment or antidote, and once animals are down, they rarely recover.

Pigweed or carelessweed is very common in areas where cattle congregate.  Cattle will readily eat the young plants, but avoid the older plants unless forced to eat them.  A common pigweed poisoning is when cattle are penned where pigweed is the predominant plant and no alternative hay or feed is provided.  Red root pigweed is more toxic than spiny root pigweed, but is less common.  Pigweed can accumulate nitrates, so sudden death is the most common outcome.  It also contains oxalates, so renal failure can also occur.

Black nightshade is common in croplands, and like pigweed, in often in high traffic areas.   The green fruit is most toxic, so cattle should not have access to nightshade during this stage, and nightshade remains toxic in harvested forages.  Nightshade is toxic to the nervous and gastrointestinal systems, and causes weakness, depression, diarrhea, and muscle trembling among other signs.  Bullnettle and horsenettle are in the same plant family as nightshade.  They are also toxic, although less so, and are usually avoided by livestock unless other forages are not available.

Blue-green algae blooms in ponds can also occur in hot weather.  They are most common in ponds with high organic matter, such as ponds where cattle are allowed to wade, or where fertilizer runoff occurs.  The blue-green algae accumulates along pond edges, especially in windy conditions, and exposes cattle when they drink.  Both the live and dead algae are toxic.  The toxins can affect the neurologic system causing convulsions and death, sometimes right next to the source.  They can also affect the liver, causing a delayed syndrome of weight loss, and photosensitization (skin peeling in sparsely haired or white haired areas).

Perilla mint causes acute bovine pulmonary edema and emphysema (ABPE), usually in late summer.  It grows in most of the central and eastern United States and is common in partial shade in sparsely wooded areas, and around barns and corrals.   There is no treatment, so prevention is critical.

Cattle with access to wooded areas may eat bracken fern.  Cattle must eat roughly their body weight over time before toxicity occurs, but may do this in situations where other forage is not available. Braken fern toxicosis causes aplastic anemia.  Fever, anemia, hematuria, and secondary infections are some of the most common signs.

As summer moves into fall, the potential for acorn toxicosis increases.  Cattle have to eat large amounts usually to become sick, but those that are in poor body condition and hungry are more likely to do so.  Clinical signs include constipation or dark, foul-smelling diarrhea, dark nasal discharge, depression, weakness and weight loss.

The lack of summer forages and the need for supplemental feeding during a drought can increase the likelihood of feeding “accidents” and toxicities.  Producers may be tempted to feed cattle pruning’s of ornamental plants, many of which are highly toxic.  Grain overload is also a potential problem if access to concentrate feeds are not controlled.  Salt toxicity can occur if hungry cattle are allowed free access to high salt containing “hotmixes”.  Even though these are meant to limit intake, initial intake can be high enough to cause toxicity in starved or salt deprived cattle.  Feeding byproduct feeds, candy, bread, screenings, etc. may also be more common, all of which have the potential to cause problems.  Producers may also be tempted to feed moldy hay or feed, which can lead to toxicity problems.

With careful planning, plant toxicities can be avoided. If you have questions on toxic plants and how to identify/avoid them, please contact your local veterinarian or Extension agent. If you have further questions please feel free to contact me at, lstrick5@utk.edu, or 865-974-3538.

First Cutting in Alfalfa: Why Cutting Management is Important?

First cutting is the most important and critical of the alfalfa growing season. A late start of this growing season will determine multiple things during this year’s production. It is important to know that the success of the entire production will be based in determining a proper date to cut for highest yield and quality. As rule of thumb, forage quality varies with the environment and cutting management. If you are forced to delay the first cutting due to environmental conditions (rain or even drought), keep in mind that this could have negative consequences with a slower regrowth and perhaps a reduction in future yield production.

First cutting tends to have low quality if it is cut late during the growing season. Generally, during pre-bloom or bud stage the stems are highly digestible with high quality forage. Second and third cuttings still very important for production, however if there is a need to wait to harvest beyond the bud stage then the more the quality would suffer because of lower proportion of leaf and stem ratio. Below are some guidelines in plant height and harvest maturity in alfalfa. Producers should take this into consideration for future management and cutting strategies.

Table 1. Plant height and harvest maturity in alfalfa.

Cutting Schedule Plant Height (inches) Maturity Stage
First Cutting 32 Late vegetative to early bud
Second Cutting 23 Late bud to early flower
Third Cutting 19 Early to late flower
Fourth Cutting 16 Late flower

Source: Professor Marisol Berti; North Dakota State University for Midwest Forage Association (Forage Focus; May 2018).

Summary

Each growing season brings new challenges. It is important to plan ahead and be ready to make the best decisions. Oftentimes, compromising forage quality to avoid plant stress is one way to harvest a little later than expected. It all varies depending on climate and other factors such as: stand health, age of the stand, history of winter injury and winter kill, previous cutting management, soil tests, insect and disease problems.

Hay Moisture Levels

With the limited opportunities and short windows many have had to make hay so far this year, some hay may have been made at higher moisture levels than we would like. Moisture levels have a direct effect on hay quality. What we have found to be a consistent number in the literature is 20% moisture maximum. To be more specific:

    1. Small squares to be 20% or less,
    2. Large round, 18% or less and
    3. Large squares, 16%

Hay baled at 20% moisture or higher has a high probability of developing mold, which will decrease the quality of hay by decreasing both protein and total nonstructural carbohydrates (TNC) AKA energy! The mold will also make the hay less palatable to livestock and could potentially be toxic, especially for horses. Even hay baled between 15%-20% moisture will experience what is known as “sweating.” Sweating, in regard to hay bales, refers to microbial respiration, which will create heat and result in dry matter (DM) loss. A good rule of thumb is that you should expect a 1% DM loss per 1% decrease of moisture after baling. As an example, hay baled at 20% moisture that is stored and dried down to 12%; will result in 8% DM loss.

What happens if we bale hay and the moisture content is too high? Bad things. If lucky, maybe the hay will only mold, but if it is too moist and starts heating, it could catch fire. If the hay heats to 100-120 degrees F, it will be fine; if it goes above that, monitor daily. Once it gets to 140 degrees F, consider tearing down the stack. At 150-160 degrees F, call the fire department, and once it gets to 160 degrees F, there will be smoldering pockets and hot spots, and gases will ignite hay when exposed to air (source: Washington State University Extension, Steve Fransen and Ned Zaugg).

It can be a double edged sword in regards to losing quality by not baling, or losing quality by baling with moisture levels that are too high. Therefore, our recommendation to ensure adequate livestock nutrition this winter is to have a forage analysis done on the hay baled this year. Once you have those results, develop a corresponding supplemental feed program, if necessary, based on the nutritional requirements of your livestock.

The two short videos below by Clif Little and Rory Lewandowski will answer questions regarding forage testing, and subsequently interpreting the results of the test(s).

To bloom or not to bloom?

By Kassidy Buse

A common recommendation of agronomists is to let one alfalfa cutting reach bloom each year.

Ev Thomas, retired agronomist from the Miner Research Institute in Chazy, N.Y., says otherwise in The William H Miner Agricultural Research Institute Farm Report.

“For many years, I’ve said that in managing alfalfa for dairy cows, you should never see an alfalfa blossom, from seeding to plowdown,” says Thomas.

Thomas also notes there’s room for difference of opinion due to no research supporting either opinion.

But, if one cutting is to bloom, which cutting should it be?

The first cut of alfalfa-grass typically contains the most grass. Grass, even the late-maturing species, is close to heading when alfalfa is in the late bud stage.

The second cut is exposed to long, hot June days that result in highly lignified, fine stems. A Miner Institute trial found that the stem quality of bud-stage second-cut alfalfa was no better than full-bloom first-cut alfalfa.

The third cut can be influenced by prior harvest management. If it was a late second cutting, the third cut was growing during midsummer heat. This cut would also have highly lignified stems.

The fourth cut often takes a long time to bloom, if it makes it there. A killing frost might arrive first.

For any cutting, the more grass in the stand, the lower the forage quality if alfalfa is left to bloom.

“The objective of letting alfalfa bloom is to improve root reserves, and therefore extend stand life,” says Thomas. “We need to balance the impact of delayed harvest on plant health with the economics of feeding alfalfa of lower quality that is needed by today’s high-producing dairy cows,” Thomas adds.

How alfalfa and alfalfa-grass is managed depends on if the goal in mind is long stand life or high milk production potential.

Avoid Barn Fires, Let Hay Dry All The Way

Not only can wet hay catch fire, but it can mold. Hartschuh says bale temperatures of 120° to 130° F often results in mold growth and makes the protein less available to animals. ( Farm Journal )

Farmers across the country have either finished putting up their first cutting of hay, or they are in the process of doing just that. While it can be easy to get in a rush, avoid barn fires by ensuring your hay is dry enough before you bale it.

“When [hay] is baled at moistures over 20% mesophilic bacteria release heat causing temperatures to rise between 130°F and 140°F. If bacteria die and bales cool, you are in the clear, but if thermophilic bacteria take over temperatures can raise to over 175°F,” according to Jason Hartschuh a guest contributor to Ohio State University Extension’s Ag Safety Program.

Most wet bales catch fire within six weeks of baling, Hartschuh says. Here are some things to consider when determining if your hay is at risk of fire. Did the field dry evenly? Were moisture levels kept at or below 20%? If moisture was higher than that, was a hay preservative used?

If you are concerned that your hay is a fire risk, monitor it twice a day for the first six weeks or until low temperatures stabilize, he says. Temperatures should be taken from the center of the stack or “down about 8 feet in large stacks.”

Not only can wet hay catch fire, but it can mold. Hartschuh says bale temperatures of 120° to 130° F often results in mold growth and makes the protein less available to animals.

“While those temperatures are not high enough to cause hay fires, the concern is if the mold growth continues and pushes temperatures upward into the danger zone,” he says.

According to research from OSU, if the temperature in the hay continues to rise, reaching temperatures of 160° to 170° F, then there is cause for alarm.

“At those elevated temperatures, other chemical reactions begin to occur that elevate the temperature much higher, resulting in spontaneous combustion of the hay in a relatively short period of time,” Hartschuh says. “If the hay temperature is 175° F or higher, call the fire department immediately, because fire is imminent or present in the stack.”

 

Critical Temperatures and Actions to Take

The team from OSU extension recommends monitoring the following temperatures and taking appropriate action.

125° – No Action Needed

150° – Hay is entering the danger zone. Check twice daily. Disassemble stacked hay bales to promote air circulation to cool the hay outside.

160° – Hay has reached the danger zone. Check hay temperature every couple of hours.  Disassemble stacked hay to promote air circulation to cool hay have fire department present while unstacking from here on.

175° – Hot pockets are likely. Alert fire service to possible hay fire incident. Close barns tightly to eliminate oxygen.

190° – With the assistance of the fire service, remove hot hay. Be aware the bales may burst into flames.

200°+ – With the assistance of the fire service, remove hot hay. Most likely, a fire will occur. Keep tractors wet and fire hose lines charged in the barn and along the route of where bales are to be stacked.

 

Cutting Height in Hay Fields: How Low Can You Go?

The second consequence for mowing too close to the ground is increased ash content of the forage. All forage has a natural ash content of approximately 6%. However, mowing too closely with disk mowers can add soil to the crop, and increase the ash content by as much as 10-12% (18% ash content in total analysis). If we all had table-top smooth fields, it would also be much easier to make a closer cut across all fields. However, things such as groundhog holes and the unevenness of fields can add to increased ash content of our harvested forage.

So, the million dollar question is how low can you go? The best answer is…it depends! The first question I always ask is – is it a solid stand or a mixed stand? If you have grasses involved, you must keep cutting height higher than a pure stand of legume, if you want to keep the grass in the stand. Keep in mind these are minimum recommendations; it’s okay to mow higher than the numbers below. Here are my minimum cutting height recommendations:

Alfalfa or Clover

  • 2” minimum. Some literature shows a cutting height of 1” will not reduce stand longevity, but remember the increased ash content issue. Also, keep in mind that frequent cutting at early maturity will continue to deplete carbohydrate reserves. One cutting of alfalfa should be allowed to reach the bloom stage each year.

Cool Season Grasses (Orchardgrass, Timothy)

  • 4”during the establishment year
  • 3” minimum during production years. This is where we see most of our stand longevity issues. Frequent cutting of cool season grasses at a low height will continue to deplete energy reserves.

Mixed stands

  • You must manage for the predominant species. Do you have a grass stand with some alfalfa, or an alfalfa stand with some grass?
  • Alfalfa with some grass: 2.5” minimum
  • Grass with some alfalfa: 3” minimum (if you want to keep the grass sta

Hay Cost Calculator

Hay season is around the corner and many producers are likely greasing the wheels, sharpening blades, checking belt tension, and settling in for a long hay season. However, it may be wise to do some calculating and revisit some management decisions to determine hay needs and to see if there is a way to reduce hay needs. This could be important considering the tremendous cost of feeding cattle 365 days per year and knowing hay tends to be one of the most expensive feeds available.

In order to achieve the task of determining how much hay is needed and what the potential cost will be, Mr. Kevin Ferguson, Ms. Rebekah Norman, and Ms. Tammy McKinley developed an Excel based “Hay Calculator” to help with the calculations. That file can be found at https://ag.tennessee.edu/arec/Pages/decisionaidtools.aspx. The tool takes into account storage losses, feeding losses, bale size and weight, cattle weight, consumption, number of days fed, and hay price to determine hay needs and total cost. The calculator can also assist with hay quality analysis.

Based on several pieces of research, the method of storing and feeding hay significantly increase costs. Average storage losses for hay stored six months or longer range from 5 percent for hay in a barn to 30 percent for hay stored outside and uncovered. Hay stacked and covered with a tarp on a rock pad or pallets results in 12 and 14 percent loss respectively. Additional storage methods include a plastic sleeve and net wrap which result in average losses of 19 and 23 percent respectively.

Similar to storage, the method of feeding hay can influence hay loss. Feeding losses from feeding hay in a cone ring range from 2 to 5 percent while feeding hay in a conventional ring results in 4 to 7 percent hay loss. The use of a hay trailer generally results in 10 to 13 percent hay feeding losses while the use of a cradle will result in 15 to 20 percent losses. Unrolling hay on the ground has the most variability with losses ranging from 5 percent to 45 percent. Hay feeding losses are likely more a function of how much hay is fed at a time as opposed to the method. For instance, feeding a week’s worth of hay in a cone ring will result in more feeding loss than feeding one day of hay in a cone ring.

For illustration purposes, consider a producer with 30 cows averaging 1,200 pounds and feeding 2.5 percent of the cows body weight for 150 days. This would result in each cow needing 30 pounds of hay each day on a dry matter basis. Assuming 11 percent moisture would result in the herd needing 76 tons of hay or 152, 1,000 pound bales. If the bales cost $35 per bale then the total cost to the herd would be $5,320. However, storage and feeding loss have not been considered.

Now consider two management options with this herd: storing hay in a barn and feeding in a cone ring or storing net wrapped hay outside and feeding in a conventional ring. The first system of storing hay in a barn and feeding in a cone ring results in a total loss of 6.4 tons of hay or 13 bales of hay for an additional hay cost of $451 for the herd. The second system of storing net wrapped hay outside and feeding in a conventional hay ring results in a total loss of 21.6 tons of hay resulting in the need of 43 additional bales of hay and adding $1,513 to herd hay cost.

This basic illustration demonstrates changes in feed costs from differing hay storage and feeding management. Producers should consider methods of reducing hay storage and feeding losses to reduce total costs. Producers should also consider grazing management practices that reduce hay needs which have a potential of reducing feed costs.

Planning for the Alfalfa Growing Season

Planning for the growing season this year has been a little different than in previous years. The winter season seemed to be longer than usual and has producers wondering when they would be able to access their fields. Here is a bit of information for those producers that are considering planting alfalfa this year.

Field Selection

Establishment of alfalfa seed require a well-drained soil for optimum production. A germination soil temperature of 45oF is adequate for alfalfa establishment. Achieving a profitable stand of alfalfa is the result of proper field selection utilizing proven production practices to ensure germination and establishment. Poor soil drainage can cause problems with soil crusting which may cause poor soil aeration, micronutrient toxicity, and ice damage during winter.

Soil Fertility

It is important to remember to ALWAYS take soil samples before planting to determine pH and nutrient status of the field. Overall, there are 18 nutrients (macronutrients and micronutrients) essential for alfalfa growth. Some of these nutrients include:

  • Phosphorus: Helps root growth and increase seeding success. Low fertility soils can be improved with an application of 30-50 lbs per acre of P2O5, depending on soil test results.
  • Potassium: Research suggests that potassium has little effect or influence on improving stand establishment, however, adequate potassium should be added to meet the needs of alfalfa and even a companion crop.

Planting Alfalfa

Failure to successfully establish alfalfa can be expensive and may lead to issues related to production soil erosion. Some considerations for planting alfalfa include: (1) seedbed preparation; (2) seeding dates; (3) seeding depth and rate; (4) whether or not to seed with a companion crop; (5) 100% alfalfa seedings vs. alfalfa-grass mixtures.

  1. Seedbed preparation 
    Having a firm seedbed is a critical step to ensure good germination of alfalfa seed. Firm seedbeds will reduce the possibility of planting too deep and will help hold moisture closer to the surface. Packing the soil will help to insure a firm seedbed and good soil moisture retention.
  2. Seeding dates
    Determining when to plant alfalfa depends on several factors such as soil moisture and cropping practices. For best results in South Dakota alfalfa should be seeded between mid-April to mid-May. This all depends on weather conditions as well. This year might be safe to say that seeding alfalfa in mid-May might be the best option for producers.
  3. Seeding depth and rate 
    Seed should be covered with enough soil to provide moist conditions for germination. Seed placement of ¼ to ½ inch deep is appropriate on most soils at rates from 10 to 25 lb seed/acre.
  4. Seeding with or without a companion crop 
    Seeding alfalfa with a companion crop such as annual ryegrass, oats, spring barley, or spring triticale can help to minimize weed competition during establishment. However, planting alfalfa without a companion crop allows producers to harvest more alfalfa with higher quality in the seeding year.
  5. 100% alfalfa seedings vs. alfalfa-grass mixtures 
    Pure stands of alfalfa will produce the highest quality forage and for that reason has the highest demand from the dairy industry. Other producers whose animals’ nutrient requirements are lower may be interested in using alfalfa/grass blends to take advantage of improved persistency while still meeting the nutrient requirements of their livestock. Alfalfa-grass mixtures also offers some advantages such as reduced weed pressure and soil erosion.

The Bottom Line

It is always handy to remember that the first harvest seeding year is when alfalfa is seeded in the spring and considerations of taking one or two cuttings in the same year need to be made by then. The first harvest should be done after the flowers begin to appear, allowing greater energy reserves in the roots. Generally, alfalfa will reach this stage of development 60 to 70 days after emergence. Harvesting delays during this stage will cause large reductions in quality and a decline in total yield over the season because fewer harvests are possible.

I hope this growing season is another successful one. We might be a little slow this year; but that does not mean we won’t be able to achieve the goals for production.

Time to Check for Winterkill Injury

Winterkill Injury

There is a wide range of winterhardiness among alfalfa varieties. Some varieties may have suffered winterkill injury this winter, especially where the crop had no snow cover. Like in wheat, winterkill in alfalfa occurs when the crown is frozen. When this occurs, the taproot will turn soft and mushy. In the early spring, check for bud and new shoot vigor. Healthy crowns are large, symmetrical and have many shoots. Examine them for delayed green-up, lopsided crowns and uneven shoot growth. If any of these characteristics are present, check the taproots for firmness. Some plants may even begin to green-up and then die. Plants putting out second leaves are likely unaffected.

Interseeding alfalfa to thicken an alfalfa stand will generally not work. If the stand is one year old or less, plants will generally come up and then be outcompeted by the survivors from last year. Large dead spots should be disked first and then seeded. If the stand is two or more years old, interseeding alfalfa will not work because of autotoxicity.

Heaving Effect

As the soil freezes and thaws, alfalfa stands can be damaged by the heaving effect. This will be more likely to occur where soils are not under continuous snow or ice cover and where temperatures have been in the single digits at night. This winter has been cold enough to freeze the soil where it is not under snow cover. Soils with high levels of clay are especially prone to winter heaving.

If heaving has occurred, dig up some plants to determine if the taproot is broken. Plants with broken taproots may green-up, but they perform poorly and eventually die. Slightly heaved plants can survive, but their longevity and productivity will be reduced. Crowns that heaved 1″ or less are not as likely to have a broken taproot. With time, these plants can reposition themselves. Raised crowns are susceptible to weather and mechanical damage. Raise cutterbars to avoid damaging exposed crowns.

Evaluating Plants and Stands

Producers should start to evaluate the health of their alfalfa stands as soon as the soil thaws.

  • Look at the crowns and roots.
  • Buds should be firm, and white or pink in color if they have survived with good vigor.
  • The bark of roots should not peel away easily when scratched with a thumbnail.
  • When cut, the interior of healthy roots will be white or cream in color.

When alfalfa growth reaches 4 to 6″, producers can use stems per square foot to assess density measure. A density of 55 stems per sq. ft. has good yield potential. There will probably be some yield loss with stem counts between 40 and 50 per sq. ft. Consider replacing the stand if there are less than 40 stems per sq. ft., and the crown and root health are poor.

If an established stand was injured by winterkill or heaving, and large patches are dead, producers may want to buy some time before replacing the stand by temporarily thickening the bare areas with red clover. Red clover is not as susceptible as alfalfa to the plant toxins released by alfalfa (allelopathy) and helps provide good quality forage.

 

Test Hay, Don’t Guess

November 25, 2017 01:19 PM

Fall is here and the weather reminds us of the changing of the seasons. This is the time of year when many producers are hauling hay home for the winter as well as pricing and purchasing hay. There is a tremendous range in hay quality depending upon level of maturity, fertilization, growing conditions, harvest circumstances and storage methods. Accurately sampling and testing hay is the only way to get a real understanding of the nutritive value of feed. Using values from previous years or a “book value” can be costly since a producer may incorrectly develop a ration using values that aren’t representative.

Guidelines for sampling

When sampling hay, getting a representative sample is a critical first step. Samples must accurately represent the entire lot of hay. When obtaining a sample for analysis, it should be kept separate from other lots of hay. The UNL NebGuide “Sampling Feeds for Analyses” (PDF version, 655KB) states that a “lot” of hay should be harvested from the same field consisting of similar types of plants, cutting dates, maturity, variety, weed contamination, type of harvest equipment, curing methods and storage conditions. When these conditions differ, feed should be designated and sampled as a separate “lot”.

Hay samples should be taken using a hay probe or a core sampler. The hay probe should penetrate at least 12-18 inches into the bale and have an internal diameter of at least 3/8 of an inch. Using your hand to grab a sample will not consistently provide reliable results. Tips of hay probes should be kept sharp to cut through hay and prevent selective sampling. Avoid getting hay probes hot when using a drill to drive the probe into the bale, since friction from high speeds can heat the probe to a point where it damages the hay sample.

To get a representative hay sample from a “lot” of hay, select 15-20 bales in the lot. Knowing the total number of bales that are present can help identify a random method that should be used (such as sample every fourth bale) to obtain an accurate sample. Once all of the samples for a “lot” have been collected, the samples may need to be sub-sampled to get the feed down to a sample size that can be sent in for analysis. The UNL NebGuide “Sampling Feeds for Analyses” walks through a step-by-step process to do this. Being careful to ensure the sub-sample submitted is representative is important.

Once hay samples have been taken store in a plastic sealed bag in cool dry place until the sample is ready to be submitted. Samples that contain over 15% moisture should be frozen. Make sure to label the bag with your name, address, lot identification and feed type. Most commercial labs provide an information submittal form that allows producers to select a standard feed test for forages. Whenever possible, send samples into the lab early in the week to avoid having the samples sit over a weekend.

Analyze for moisture, protein and energy

Cattle feeds should be analyzed for moisture, protein and energy. Producers may also want to have forages tested for key minerals. Feed sample results are usually reported on an as-is and dry-matter basis.

When developing a ration for cattle or comparing feeds to one another, always utilize the nutrient analysis on a dry-matter basis. After formulating a ration on a dry-matter basis, the values can then be converted to an as-is basis using the moisture content of the feed to determine the actual amount of feed that should be fed to the cattle on an as-is basis.

Analyze forages for nitrates

In addition to moisture, protein and energy, annual forages harvested for hay such as foxtail millet, oats, sudan grass and sorghum-sudan hybrids should be analyzed for nitrates. These annual forages can accumulate high levels of nitrates under various growing conditions that can potentially reach toxic levels. The only way to know if high levels of nitrate accumulation have occurred is to test for it. See the UNL NebGuide “Nitrates in Livestock Feeding” (PDF version, 319KB) for additional information. For additional information on understanding the results from a hay analyses, please see the “Understanding a Feed Analysis” Learning Module on the UNL Beef website.

Conclusion

Accurately testing hay takes time and money. However, the value of this information is critical in accurately and cost-effectively formulating rations. Don’t let the small investment of time and money discourage you, it may be some of the best time and money you can invest in your operation.