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Purchasing Hay for Livestock

Purchasing Hay for Livestock


            How much hay does one store for a horse when you feed a flake of hay at a time?  Livestock consume 1.5-2% of their body weight a day.  An average 1,000# animal requires 15-20# of hay a day, less if feeding a high grain diet.  We do not recommend feeding over 5# of grain a day per adult horse, or even cow, goat, sheep or other livestock on a maintenance diet.  Pregnancy and growth will add a little to the dietary requirements, but for this discussion we will limit it to a mature animal being fed mostly 90+% of their diet as hay.  We recommend only grass hay for male goats, sheep and camelids; if you are feeding alfalfa hay to these animals please contact us regarding testing for urolithiasis.

            A bale of hay weighs anywhere from 40-80#, depending if it is a grass hay, alfalfa hay or another type of hay.  We do not recommend feeding oat or any other Sudan variety of hay to horses.  If livestock are on a good winter pasture they may need only a little supplementation, such as 5# of alfalfa hay a day for an adult cow.  When one considers that you need to feed 10-20% more hay, when the weather is below zero, you can understand that there are many variables in the total amount needed for winter feeding.  For convenience you should consider that livestock will consume 1/3 of a bale of hay a day, per 1,000# body weight; this is approximately 20# a day.  When purchasing hay in bulk we recommend that you pay for it by the ton, not the bale.  The lighter weight 40# bales will have 50 bales per ton of hay, while there will be 25 bales in the very heavy 80# bales.  A bale of grass hay usually weighs less than alfalfa.  The hay bailing machine can be set for different weight bales and packing density.

            Your storage facilities will usually determine the amount of hay you bring in at a time.  If you store hay on the ground and/or out in the open you can expect up to a 20% loss from mold.  We strongly recommend you keep your hay in a barn and/or under a shed.  To prevent hay fires do not store baled, wet indoors (or even purchase it if knowingly wet.  Spreading salt between the bales of hay does not prevent fires).  Feed this hay out first, ASAP, even if the animals are on pasture.  There are 20” long hay thermometers available to ensure the hay does not get over 110 degrees.  The minimum temperature to watch for a hay fire combustion is 140 degrees F.    We have a handout on testing hay for moisture if you are baling it yourself, and another handout on preventing hay fires.  Hay properly baled will not usually ferment into a hay fire if rain and moisture falls on the hay stack.  It will pay for itself to buy a hay tarp and wood pallets for beneath the hay if you store it outside.  Do not feed moldy hay to livestock or toxic problems can develop.  It should be noted that if you have large bales of hay (i.e. the round bales), and they get wet and/or are on the bottom of the row where moisture can cause an anaerobic growth, it is possible that these bales can cause botulism in horses.  We have a vaccine for botulism if you feed the large bales to your horse.   

            If you are buying more than 75 bales at a time, we recommend you ask about having the hay delivered by the load, especially after the bale wagon has picked up the load from a field.  The smaller wagons carry around 100 bales.  When you buy in bulk, and the handling is reduced by the hay producer, you usually save money buy purchasing the hay this way and/or buy the ton delivered by the truck load (approx .40,000# or 20 tons).  Get into the habit of asking all hay sellers for the results of the analysis for that hay stack or field/cutting; expect many will not have such data but those who do will indicate that they are a quality hay seller.   

            The larger the bale the less dense the baler can pack it.  The large round bales will have an expected 15-20% loss due to this inherent problem.  Large bales take less labor to bale and to feed out, but you need to consider this loss when purchasing hay.  Your average small bale has 5% or less loss if stored in a barn.  The type of hay and bale size becomes a factor when purchasing hay.   If purchasing Sudan/oat, ryegrass, stressed hay or a forage of questionable quality we recommend hay testing.  Total net energy is a term used to describe the amount of calories in food, whether it be from carbohydrates, protein or fat (there is no fat in hay).  The average net energy of alfalfa hay is 50-60 MCal/cwt, while grass hay is 40-50.  The protein can also be a variable factor, such as alfalfa can range from 13 to 20% crude protein, depending if it is poor or good quality.  Grass hay can have a protein range of 8 to 12%.  If purchasing large amounts of hay we recommend you not only buy it by the ton but also by the quality.  On the average grass hay should be 10% crude protein or higher, an ADF of 30-35% (45+ is poor hay), and a NDF of 40-50% (65+ is not very palatable).  The lower the ADF and NDF test results the higher the relative value (RF) of the hay.  A relative feed value for premium hay is above 180.  Some Cushing-like horses are prone to a grass-type founder, and a structural carbohydrate test needs to be performed.  Contact us if you need to have your forage tested for structural carbohydrates, which usually costs less than $50 (2010). If you raise your hay, we also recommend periodic soil sampling to balance the soil so it can be the most productive.  Soil sampling also saves fertilizer costs.  Our local CSU Extension office at the Boulder County Fairgrounds has available soil core drill as well as hay drills for a very reasonable fee; they do not send samples, yet see below.

            If you should have your hay tested at a forage lab, please have them fax the results also to use at the below fax number.


The Staff at the Nelson Road Veterinary Clinic

Fax = 303-678-7221


Industrial Laboratories, 4046 Youngfield St, Wheat Ridge, Co. 80333, 303-287-9691


Warren Analytical Lab, POB G, Greeley, Colo. 80632, 970-351-6344

            also does chemical testing for forages.


Weld Laboratories, Inc., 1527 1st Avenue, Greeley, Colo., 970-353-8118, does soil & forage


Colorado Department of Agriculture has other laboratories listed

      ( and search for “feed testing labs: in CSU in Fort Collins for soil testing only


Purchasing Hay By The Bale


            When one buys a stack of hay (125+ bales) for the first time, it may be cost effective toy pay $25 to test the 3+ tons of hay.  Larger purchases are usually sold by weight, and not by the bale.  Buying in small lots is more difficult to determine the quality received.  When hay sells for $120 a ton, there can be an equivalent range of $2.40 a bale for a 40# bale, to $3.60 for a 60# bale, to $4.80 for an 80# bale.  Each baler can be set to a different level of compaction.  Each variety of hay will also weigh differently for the same baler.  On the average a bale of “native” grass hay will weigh less than half of what alfalfa will weigh.  For the first time you buy hay from a different source, we recommend you weigh 2-4x bales of hay.  This knowledge of the weight will not alter the price the seller is selling the hay for per ton (2,000#), but it will educate you about what you are paying for. An adult horse or cow will eat approximately 1/3 of a small bale of hay a day. 

            The variety of hay will determine the nutritional equivalency.  This is where laboratory hay testing comes into place, and for the $25 or so it costs this may be advantageous when you are looking for a new source of hay.  The dependability of the source is also very important.  Some brokers will bring in hay from many different sources, and you may never have a similar quality or expect repeatability of the same purchase next month if you are using a hay testing laboratory.  Good alfalfa hay can have 20+% protein and an energy maintenance value of 0.71 Mcal/#.   Timothy hay can be 8% protein and 0.58 Mcal/#, while prairie hay can be 8% protein and 0.49 Mcal/#.  There is a difference in the hay testing value for maintenance versus net energy for gain (i.e. prairie hay for maintenance is 0.49, while for gain it is 0.13).   The protein and the energy are only two of the values to look at, and probably the most important for adult horses.  In growing horses and for cattle the levels of calcium, phosphorus and other minerals are very important for comparing hay quality.  For non-breeding, adult goats, llamas, rabbits and sheep we recommend only grass hay be fed, which will reduce the incidence of bladder stones.

            The names of the various hay types can be confusing.  It is alfalfa, or alfalfa-mixed with grass, or just grass hay?  And which type of grass hay is important.  Is it mountain hay, irrigated hay, or native hay?  Non-irrigated native grass hay can also be called prairie hay. Western wheatgrass, timothy, brome, Bermuda and other species of grasses have different nutritional values.  If the hay has clover, or another similar legume, this also determines the value of the hay. 

            For immature livestock alfalfa is the preferred hay.  Adult goats, sheep, rabbits, camelids, inactive pet cattle and pocket herbivores” such as guinea pigs should instead be on a grass hay.  The males in these species can be prone to urolithiasis and bladder stones; females do not block up with such a “water belly” situation.  Adult ewes and does can be fed alfalfa, yet long term the male sheep and male goats should be on grass hay, especially if they are neutered.  We recommend feeding grass hay if you have pet goats, sheep, etc.  (A blocked tom cat is a similar emergency where a stone has caused the urine tube to be blocked up).

            The cutting of the hay may make a difference, which will vary from each region and each type of hay.  Some areas of our state can have 6x cuttings of alfalfa, while 3-4x is the average in this area.  The first cutting may have more of the earlier sprouting of weeds than the 2nd cutting.  If the 3rd cutting is the last it may be affected by other weeds and/or frost.  The quality of the hay is more determined by the % of bloom the alfalfa had when it was hayed (cut), versus the sequential number of its cutting.  A cutting of 10% bloom has far less stems than a 75%+ bloom cut.  To confuse you even more, the amount of leaves in the hay can be determined by the time of the hay being baled.  Very dry alfalfa hay has a higher loss of leaves if baled in the mid day heat. Grass hay usually has 2x cuttings in our area, and rarely is the cutting number indicated (or needed).  Oat hay is also called Sudan hay, hay grazer, etc, and we do not recommend this hay for the average horse.

            If the hay was rained on after cutting and/or the moisture in the hay when it is baled also determines the quality of hay.  If the hay was rained on, it will have a color loss and bleached throughout the bale.  If there was too much water in the hay it will be moldy, especially in the center.  Hay baled too wet can lead to spontaneous combustion and hay stack fires.  We recommend the use of hay thermometers to monitor the temperature of stacked hay you feel is maybe too wet.  (As FYI, if concerned about moisture; cut the hay into 2” or less pieces, weigh on a gram scale, microwave the hay for 6 minutes, then reweigh.  It should be 17% or less in moisture.  Then microwave again on high for 2 more minutes to see if there has been any change).  If the hay is wet inside, pouring salt between the bales will not dry out the hay; it is an old wives tale.  Wet hay will only cause hay fires and moldy hay with toxins.  It is best to just feed out this hay baled too early ASAP and discard it when mold starts to develop.   Spread the hay out and do not store in a barn.  This is why it is very important to visually open a bale and look at its contents; you cannot always tell from the outside.  If you are only buying a pick load of hay, and you break open a bale for inspection, you should buy that bale if there are no problems.  Mold, weeds, the amount of green, stems and other factors are to be considered.  If the alfalfa hay was of the last cutting, and cut after a frost, you should have it tested for nitrate/nitrite toxicity.

            How the hay was stored is also very important.  Grass hay and quality alfalfa hay are usually stored inside.  Storing hay outside with a tarp can also provide quality hay, yet the outer bales still will have a nutritional loss.  Water and sunlight will destroy some of the nutritional contents, yet if the hay is a little brown on the outside and green inside, the hay usually has adequate vitamin A content.  When storing hay on the ground one should expect the bottom bales to maybe be degraded and lost to mold and moisture.

            Even the size of the bale of hay will determine the quality.   The larger the bale the more loss you should expect in nutritional value.  Larger bales cannot be compacted as tight in the center, thus one should expect about 15%+ difference in the same hay tested in a small bale versus the larger bales of 500# + .  When feeding out hay to cattle, the larger bales require less labor. The use of a tapered-cone hay feeder will reduce waste by about 10%, compared to spreading on the ground.  With the average cow not staying in the herd longer than 8-10 years, the concerns for long-term lung problems in cattle from the large size bales is different than those of a horse owner. 

            As a summary for small load purchases if calling for the first time, ask the seller how much the bales typically weigh.  Then weigh 2-3 bales of hay you are purchasing and break open at least 1-2 bales to look for anything that does not look right.  Pick a bale from a different part of the stack, as the hay in one area of a field may vary from the hay in another part.  Foxtails and cheat grass seeds in the hay will be a problem, and hay with these should especially be avoided.  If possible always ask the hay seller for the analysis of the testing for that hay stock, field or cutting.

            If you should have your hay tested at a forage laboratory please have them also fax us the results at the below fax number.  Our local CSU Extension office at the Boulder County Fairgrounds has some hay core drills available for you to collect samples; they also have soil core drills but they do not send off the samples.  If you are testing the hay for a equine metabolic syndrome (EMS), insulin resistance (IR) and/or for an equine Cushing’s like disease (ECD, PPID), the structural carbohydrate tests needs fresh green hay; we have more information and the testing laboratory(s) if needed.


The Staff at the Nelson Road Veterinary Clinic








            Quality hay starts in the field.   Whether it is alfalfa or grass hay, the timing of the cutting is one of the most critical decisions.  With advancing rain sometimes it is not convenient to cut at 10% alfalfa bloom, etc.  Sometimes the hay will be rained on, and bailing will be determined by the moisture content.  Hay should be baled at 17% moisture or less.  (Propionic acid can be sprayed onto the hay when baling if you live in a humid area where they have to bale at 17-25%.  As FYI silage and ensilage should be processed at > 65% moisture or abnormal fermentation problems will develop; these silages need a fermentation process to be properly stored).


To determine the hay moisture by microwave:

            Use a gram scale, or rent one of ours, to weigh your hay.  Use a paper plate and determine its weight (tare weight).

1.         Measure out 2-4 oz of hay (50-125 grams).

2.         Cut the hay into 1-2” pieces and spread evenly across the plate.

3.         Reweigh the plate to ensure you have no loss from the cutting step.

4.         Microwave the mixture on high.  Do not cover; instead leave the plate or container open.

                        Microwave for 6 minutes.  Remove and weigh the plate of hay.  Periodic stirring

                         of the hay is recommended.

                        Continue to remicrowave the mixture for 2-minute periods until the weight

                        is stable.  Allow the hay to cool down between heating periods.  Constantly

                        monitor the microwaving and stop the procedure if there is smoke or fire. 

                        Stop the procedure with any smoke, etc.

5.         The net green hay weight, less the net final weight, is the amount of moisture lost.  The tare weight must be subtracted from both weights.  Reweigh the plate or container to ensure it has not lost weight.


                        Net green weight

                       ——————–      (x)   Net green weight    =    % moisture

                        Net dry weight


6.         Repeat the procedure using hay from a different part of the field.  Using 4-5 samples is adequate for fields from 5 to 40 acres in size.  To use the hay weight in nutritional calculations, such as for immediate feeding, reveres the above ratio to find the dry matter (DM) weight (or 100 less moisture is the DM weight).


            After hay has been baled one may need to monitor hay for hot spots.  We recommend you check the hay stack’s temperature 4-5 days after baling.  Normal hay curing can have a temperature get as high as 120 degrees, when baled at 15-20% moisture.  Temperatures higher than this can degrade the hay.  If you know you baled hay at > 20% moisture the spreading of salt between the hay bale layers will not prevent a hay fire or even help the hay cure properly.  Molds grow at 110-150 degrees.  Fungal growth and respiration can cause a loss of some protein and fiber.  If the temperature is above 140-150 degrees check the hay daily, and call your fire department before you plan to move it; a spontaneous combustion can occur.  If above 160 degrees check it 3-4x a day.  At 175 degrees F you will want to notify the fire department of the temperature, yet not move the hay at all or you definitely can cause a fire.  Check the hay every few hours and once it is at 195 degrees you will need to call the fire department again to hose down the day unless it is in the open; spontaneous combustion is very possible and if the hay was in a barn you probably waited too long.  We have a similar handout for hay producers.


            To collect hay for lab testing we recommend that you obtain a sample from a truckload (approx. 20 tons) or from a maximum of 200 tons of hay per testing lot.  The lot should be from one single field, one variety, and same maturity of cutting and a baling date(s) of no more than 48 hours apart.  At least 12-15 samples are needed per lot of hay, taken from various bales.  For accurate results DO NOT test until 2 weeks after baling; testing before this time will have artificially high results.  Use the hay probe and collect from the ends of the bales, not from the sides to top.  The corer cuts easier when the hay is perpendicular to the tube.  Randomly select the samples from various areas and heights.  Up to 40 samples can be taken if the hay does not appear uniform.  Place the cores in a gallon Zip-lock type of bag, at least 1/2 full, with the air squeezed out.  Weigh the bag to see if approximately 1/2# of hay is to be tested.  The hay samples need to be sent or taken to the lab within 48 hours.  Store the hay sample out of sunlight and excess heat.  These commercially available corers we have available from the clinic, or you can buy one.  We recommend you use a corer with 3/8 -5/8” inch by 18” in length.  The sharp cutting edge is the best, as the corkscrew and auger type probes collect more leaves and fewer stems.

            Hay testing laboratories can be found by going to our state’s department of agriculture in an internet search, and do into the feed testing laboratory menu.  The site also has links to hay selling entities.  National Forage Testing Association is yet another good site.  The CSU Extension office at the Boulder County Fairgrounds does not send off forage samples, but they do have a drill to rent to collect samples for a very reasonable fee.    

            They hay testing lab should be qualified by the National Forage Testing Association (NFTA).  They will test for moisture, dry matter (DM), crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), total digestible nutrients (TDN), net energy (NE) and relative feed value (RFV).  The minerals tested for will be calcium (Ca), magnesium (Mg), phosphorus (PO4) and potassium (K).  Some laboratories will provide cattle values for Net Energy gain (NEg), maintenance (NEm) and/or lactation (NEl).  There are wet chemical tests procedures and Near Infrared Reflectance Spectroscopy (NIR) testing available; both type are adequate if the lab is accredited.  Routinely it is the alfalfa hay we recommend to be tested, as protein is the most expensive component of an animal’s feed.  Grass hay sources from the same area usually are similar in testing results, although one should test the pasture hay to the prairie hay if comparing sources and hay prices.   If the hay was stressed, of the oat hay or sorghum variety we strongly recommend you have nitrate test and a prussic acid test performed.  Ryegrass hay should be tested for ergot toxicity.  If they hay is going to be fed to high value pregnant animals the last two tests should be routinely performed on all hay.  If you have the hay tested please ask the forage testing laboratory to fax the results to our clinic fax number below.  If the horse is HYPP ensure the below laboratories will test for potassium.  If you are testing the hay for a horse with equine metabolic syndrome (EMS), insulin resistance (IR), equine Cushing’s like disease (ECD, PPID) and/or another species of animals with a high blood glucose and similar problems, there is a different laboratory to use which will need a fresh, green sample from the hay you plan to buy (in the summer); we have more information where you can have these tests performed, if the hay seller does not plan to do a structural carbohydrate test on the green forage for horses. 


The Staff at the Nelson Road Veterinary Clinic


We have a listing of forage laboratories that will test for specific toxins and/or nutritional requirements that are not normally found in your average forage test.


Hay fires

Hay Stack Fires and Preventing Them


            If one bales hay with the moisture content over 16-18% in a large bale, or 18-22% in a small bale, you have a potential set up for a hay fire.  It is the large bales of hay which create the environment for a potential hay fire.  Usually the first cutting of hay has more producers baling hay at this higher moisture level; we strongly recommend installing the hay testing equipment on a baler which will then estimate the moisture in the hay; and to daily check the level versus the manual microwave oven method found in our Hay Testing handout.  If you put up your own hay please check into these devices which will test and estimate the moisture of the hay you are bailing. 

            Wet hay, or hay that is over 18%, is a concern.  We recommend placing a few heat temperature monitors and alarms a few feet into the haystack, or approximately one sensor per 100′ of a linear stack.  If you take a core sample to test your hay for moisture and nutrient content, consider using a 20-36″ long compost thermometer at minimum to place into the core hole of this large bale until the moisture contents of this bale is back.   

            If there is a core temperature of 150 degrees in a hay stack you have a potential for a hay fire; at 175 degrees a fire probably will occur.  Moving hay when it is over 175 degrees may create the potential to start a spontaneous hay fire.  Hay should be watered if you are attempting to move it out of the hay barn; always remove the equipment and other valuable items first from the barn.  To pump nitrogen or carbon dioxide gases into the hay stack to reduce the oxygen content and potential for fire is not usually very successful unless the hay is in an air proof type of barn or silo.  It is best to call the local fire department if you have a reading over 175 degrees Fahrenheit, before you do anything.

            If you use a curing agent such as ethoxyquin or butylated hydroxytoluene (BHT) these compounds can form a deadly cyanide gas if there is a hay fire; you need to mention this to the fireman when you call them about the potential for a hay fire at your place. 


            To prevent fires in an animal barn do not store hay inside at all, especially if it is not properly cured and/or baled within a month.  You can determine if there is a potential for a hay fire using a moisture test and especially a thermometer probe for the bale’s inside temperature(s).  You can store hay inside in a barn properly to help keep up the quality of the hay, just have a separate barn for hay and transfer over smaller bales of hay if/when needed to the animal barn.  If constructing a barn, doing remodeling and/or adding onto a structure where there are animals or hay, we recommend using electrical conduit and not just Romex wire.  Rodents can chew through the insulation in an electrical line and cause a fire.  When remodeling or building a barn use ground fault interrupter (GFI) outlets.  You may need a different outlet for the outside water tank heaters than a GFI outlet, if you have a problem with the heaters on a GFI circuit and the heater is operating safely.  Having your barn as a non-smoking site, which will help prevent an accidental fire; if you post “No Smoking” signs then enforce this rule.  If you allow the parking of vehicles and small tractors inside ensure they are parked where there is no hay, grain or dust; a hot engine or a backfire spark can start a fire.  A fire extinguisher should be at every entrance of the barn.  We have a separate handout preventing fires in chicken coops and other animal enclosures if you are using heaters; this other handout also give the rules for extension cord sizes, distance and amperage.   


The Staff at the Nelson Road Veterinary Clinic





  FEED                        NE maintenance           NE gain                      CRUDE PROTEIN %


Alfalfa hay -good       0.71 Mcal/#                 0.27 Mcal/#                 20.6%

Alfalfa -poor               0.47                             0.09                             13.7

Corn stover                 0.56                             0.26                             6.5

Oat hay                       0.52                             0.18                             9.9

Prairie hay                   0.49                             0.13                             8.1

Timothy hay,full bloom 0.58                          0.25                             8.0     

Corn silage                  0.73                             0.43                             8.0

Beet pulp                     0.73                             0.47                             9.6

Fat, animal                  2.08                             1.27                               –

Soybean meal sol        0.87                             0.59                             48.9

Barley,44-46#/bu        0.80 Mcal/#                 0.53                             13.3

Corn, Dent #2             1.02                             0.67                             10.0

Oats,32#/bu                 0.74                             0.47                             13.8

Wheat                          1.00                             0.65                             14.3



And the full content is found, updated in livestock feed comparison FEEDCOMParison (the below is from FEEDINGCOWs):



  FEED                         NE maintenance         NE gain                       CRUDE PROTEIN %

Alfalfa hay -good                   0.71 Mcal/#     0.27 Mcal/#                             20.6%

Alfalfa -poor                           0.47                 0.09                                         13.7

Barley straw                            0.46                 0.07                                         4.1

Bermuda hay                           0.48                 0.13                                         7.9

Corn stover                             0.56                 0.26                                         6.5

Milo stover                              0.41                 0.13                                         3.6

Oat hay                                   0.52                 0.18                                         9.9

Prairie hay                               0.49                 0.13                                         8.1

Timothy hay,full bloom          0.58                 0.25                                         8.0     

Wheat straw                            0.16                 0.07                                         4.3

Corn silage                              0.73                 0.43                                         8.0

Alfalfa Dehy – 17%                0.60                 0.31                                         19.2

Beet pulp                                 0.73                 0.47                                         9.6

Cottonseed whole                   0.91                 0.54                                         25.6

Soybean meal sol.                   0.87                 0.59                                         48.9

Soybeans whole                      1.08                 0.70                                         42.1

Wheat middlings                     0.87                 0.49                                         17.2

Barley,44-46#/bu                    0.80 Mcal/#     0.53                                         13.3

Corn, Dent #2                         1.02                 0.67                                         10.0

Milo, semi process                   0.90                 0.60                                         10.0

Oats,32#/bu                             0.74                 0.47                                         13.8

Wheat                                      1.00                 0.65                                         14.3

Ammonium chloride               –                       –                                               163

Urea                                        –                       –                                               281


The above are only averages for dry matter analysis, energy and protein balances need to be considered, esp. NPN sources.  Processing methods change the analysis