What information can you give me on multispecies grazing with horses?

J. S.CaliforniaAnswer: Horses can be grazed successfully with other livestock species. There are really no behavioral reasons why they should not, but the main consideration when grazing animals of different species on the same pasture is uniform utilization of the pasture. Having two or more livestock species grazing a pasture makes management a bit more difficult but with knowledge of grazing principles and animal behavior, multispecies grazing with horses can be very successful. My rationale for this letter is to offer some models of successful multispecies horse grazing operations and introduce the concepts of forage requirements for livestock and forage yield on pasture, and try to bring them together to help estimate how many animals and how much land is needed to sustainably graze livestock. The examples I use should be adjusted for your own situation. I will also provide some online resources I have found helpful for managing pasture and developing a grazing system.I understand you are particularly interested in models and working ranches that utilize horses in a multispecies grazing scenario. I have contacted Kathy Voth of Livestock for Landscapes who is doing some project work on multispecies grazing throughout the country. Kathy responded to me that she will place this question in her next newsletter so practitioners that graze horses with other species can contact me with relevant information. I mentioned that I will also offer the concepts of forage management for successful multispecies grazing with horses. I think, and this is the reason I go into such detail on grazing, that this is fundamental to being successful in this kind of grazing operation. Pasture Implications of Multispecies Grazing with HorsesMultispecies grazing can be accomplished by maintaining animal diversity on pasture in time or space. For example, horses can be grazed in the same pasture with goats or cattle, or can follow other species in a pasture rotation. Managing grazing with different species of livestock requires knowledge of (1) daily forage demand of the livestock in question, (2) forage yield expected from the pasture, (3) and the differences in forage selection of the various livestock species involved. Forage DemandForage demand is relatively easy to estimate. A good way to estimate daily demand is to calculate intake based on the animal’s weight and a utilization value. Daily utilization rates are expressed as a percentage of body weight. The utilization rate may take into consideration actual forage intake, loss of forage through trampling or plant death, and wildlife use. The formula used to calculate daily forage intake or demand is:(# of animals) x (average animal weight) x (daily utilization rate) = daily forage requirementThe chart below can help determine the utilization factor to use for calculating forage intake on a daily basis. Some practitioners add an extra 0.5% to account for loss of forage through trampling or plant death, and wildlife use.

Animal group % body weight
(forage demand = % x animal body weight)
Beef cattle, lactating 2.0 ? 2.5
Beef cattle, growing and finishing slaughter stock 2.25 ? 3.35
Goats, weaned, slaughter or replacement stock 2.25
Goats, brood or lactating 4.0
Horses, mature 1.5 – 2.0
Horses, lactating 2.0 – 3.0
Horses, working 1.5-3.0
Horses, young 2.0 – .0
Sheep, weaned, slaughter or replacement stock 3.3
Sheep, brood or lactating stock 3.65

Note: horses that are lactating or growing have higher nutrient requirements than mature, idle horses.The daily forage requirement for horses is (# of animals) x (average weight) x (daily utilization rate) = daily forage requirement:→ Example: 1 horse x 817 lb average weight x 0.035 = 28.6 pounds per dayThe daily forage requirement for goats is (# of animals) x (average weight) x (daily utilization rate) = daily forage requirement:→ Example: 1 goat at 45 lb average weight x 0.055 = 2.5 pounds per dayForage Yield(1) Clip and Weigh Forage Yield Measurement. This method is rather time consuming but provides the most accurate assessment of forage productivity. To determine forage yield, clip all the forage from a 1.92 square foot quadrat and weighs the sample in grams. The quadrat is constructed from PVC pipe and measures 11.5 inches by 22 inches. The quadrat is thrown randomly on the ground and all the forage inside the quadrat is harvested with shears or scissors. This sampling procedure is repeated at least ten times to get a representative sample of the area.The weights of the samples in grams are summed and multiplied by the percent dry matter of the forage that was harvested. Fresh, succulent vegetative forage in most improved pastures has a moisture content of 75 to 85%. Below is a table that shows the % dry matter for various forages at different stages of maturity. Generally, the more mature a forage is, the less the moisture content. The dry matter forage weight is then multiplied by a conversion factor ? in this case the conversion factor is 50 for a 1.92 sq ft quadrat. Multiplying the dry weights of the forage in grams by 50 results in lb/ac yield, which is the forage dry matter yield for the site sampled. Percent Dry Matter for Various Forages

Plants Before heading Headed out Seed ripe Leaves dry Dormant
Cool season grasses 35 45 60 85 95
Warm season grasses Tall grasses
Mid grasses
Short grasses



Calculating annual forage yield (lb/ac)

  Forage Samples, grams        
Forage 1 2 3 4 5 6 7 8 9 10 Sum Conv.
%DM lb/ac
Grama 2 1 0 0 2 2 1 0 3 2 13 50 55% 357
Bluestem 10 12 12 10 14 15 13 13 11 15 125 50 45% 2812
  Total                           3169

(2) Estimating forage yield per acre-inch. This method works well especially for dense, vegetative, productive pastures. The tables below can be used to estimate the amount of forage in your pastures. This method is easy to use, and involves measuring forage height with a ruler and multiplying the height in inches by the appropriate yield per acre-inch from one of the tables. For instance, if your forage height is 7 inches, and the percent cover (density of the stand as a percent of plants covering the soil surface) is between 75 and 90%, the pounds per acre yield would be around 1400 to 2100 pounds per acre. Also included below is a table that depicts average and ranges of yields per acre inch for various forage grasses.

<75% forage cover 75 to 90% forage cover > 90% forage cover

100-200 lb/ac/in

0 lb/ac/in

300-400 lb/ac/in

Forage species Dry matter pounds/acre/inch
Average Range
Alfalfa and grass mixes 225 75-400
Arrowleaf clover 200 100-300
Bermudagrass 260 150-500
Caucasian bluestem 180 75-350
Crimson clover 200 100-300
Kentucky bluegrass 160 100-175
Native warm season grasses 100 50-250
Orchardgrass 180 75-300
Orchardgrass + clover 200 100-300
Red clover 220 100-300
Annual ryegrass 250 75-400
Oats, wheat, rye 150 75-250
Tall fescue 210 100-350
Tall fescue + clover 190 80-325

Estimating Carrying CapacityTo more accurately divide grazing resources among different species of livestock, the concept of animal unit equivalence is used. An animal unit (AU) is roughly equated to the amount of forage consumed by a 1000 pound cow. All other species are relative to 1 AU. Typical animal unit equivalence values (AUEs) for different livestock species and classes are: Cow and calf = 1 AUWeaned calf = 0.75 AUBull = 1.5 to 2 AUSheep and goats = 0.20 AUHorses = 1.5 AUThis concept will come in handy below when we estimate carrying capacity of a pasture.Calculating Carrying Capacity with Animal Days per Acre (ADA)Animal days per acre (ADA) is a subjective measure of how long a pasture or paddock will supply forage to a given number of animals. It is an estimate of how many days an acre will support one animal or, how many days a given number of acres will support a herd of a given size. The ADA method is useful if a producer has a good idea of how much land area an animal unit (AU) will need for grazing for one day. In fact, it can be a very good method once the producer, through observation and monitoring, becomes more accurate at estimating the amount of area needed for one animal unit (AU) for one day. The ADA method can be used to estimate carrying capacity for pastures during the growing season or for grazing winter stockpiled forage. The ADA method is useful in planning grazing but, as was stated above, is only as good as the initial estimate of animal daily forage needs. The examples above on estimating daily forage demand and forage yield can be helpful here in determining the area needed for one animal unit (AU).Producers need to also take into consideration (1) yield estimates for the forage and (2) forage stubble height after grazing when determining the area needed for one animal for one day. The ADA method is especially useful for estimating the number of days grazing for stockpiled forage or for strip-grazed systems where the animals graze along a front and do not return to previously grazed pasture until plants have recovered fully.To calculate animal days per acre, an area is first paced off that represents the amount of land an animal needs for one day. For example, suppose a producer knows that an animal unit (AU) needs an area of 12.25 yards by 12.25 yards (150 square yards) of forage to provide enough dry matter intake for one day. 12.25 yards X 12.25 yards = 150 square yards. Next, divide 4840 (number of square yards in an acre) by 150 square yards to get 32 stock days per acre (SDA). This means that one acre will support one animal unit for 32 days. SDA is multiplied by the total number of acres in the pasture to arrive at the number of stock days in the pasture (SD). To continue the example, 32 SDA X 200 acres = 6400 stock days for the pasture. To get an estimate of the number of days a herd can graze the pasture, divide SD by the number of animal units in the herd. In the example, assuming 50 AUs, 6400 SD ÷ 50 AUs = 128. So, in this example a producer could graze 50 animal units (AUs) on 200 acres for 128 days.In the preceding example, 50 animal units are assumed on 200 acres. These 50 animal units can be split up between horses, goats, cattle, etc. If you had 30 horses to graze, you would multiply 30 by 1.5 AU to arrive at the number of AUs representing the horses. 30 x 1.5 = 45 AU for the horses. 50 ? 45 = 5 AUs left for other livestock species or classes. If grazing sheep, these 5 AUs represent 25 sheep (one sheep is 0.20 AU, so 5 ÷ 0.20 = 25).Forage SelectionGrazing livestock consume varying amounts of the different forages that are available in a pasture, which makes pasture plant species diversity and grazing management very important in multispecies grazing. Horses are primarily grass eaters, but will consume some amount of forbs (broadleaf plants) and browse (brush or tree species). Their mouthparts and grazing behavior allow for very close cropping of forage plants, so particular attention should be given to ensure horses do not overgraze a pasture. Goats are more nimble in their mouthparts and primarily consume browse, but will also eat forbs and some grasses. Sheep consume forbs and grasses, and cattle prefer grasses and legumes (clover, alfalfa) but will also consume many other forbs and even some browse when the plants are succulent. If different species are grazed the same pasture at the same time, careful attention to utilization should be considered. Pay close attention to which plants each are eating and move them when the plants have been grazed to a pre-determined height. Having two or more livestock species in a pasture at the same time makes it a little more difficult to achieve uniform grazing unless animal density is high. There are also fencing considerations. Fencing is no problem if a sheep fence is used, but if using a barbed wire or single electric polywire, you might have a hard time keeping sheep and goats contained. Grazing ManagementA grazing system rations out forage according to animal requirements, allowing full plant recovery while minimizing forage waste. A sustainable grazing-management system has a number of elements:? Proper timing of grazing to correspond to plant physiological stages? Proper intensity of grazing (duration on the pasture)? Residue or plant height after grazing? Plant recovery time after grazing? Adaptive management of grazing time depending on pasture recovery rates (For example, grazing time on a pasture may increase during less productive times of the year to allow for more plant-recovery time after grazing.) An example of a good grazing system is one that employs a rotation in which animals are placed on a paddock (pasture subdivision) at a high density and moved to another paddock at the appropriate time. High animal density is necessary for uniform grazing. Most rotational grazing systems utilize 10 or more paddocks to best achieve the benefits of the system. This type of rotational grazing has been called planned grazing, cell grazing, controlled grazing, management-intensive grazing, high-density grazing, and intensive rotational grazing. Whatever the name, the main point of this system is that it allows for more effective forage use through increased forage quality and through decreased grazing selectivity due to highly dense numbers of animals.Intensive rotational grazing is a management system designed to maintain forages in their growing stage throughout the grazing season. Forage grasses are grazed prior to the reproductive (seed) stage of development and allowed adequate rest for regrowth prior to being grazed again. This is done to maintain the competitive nature of grasses in a forage system by preventing them from getting too mature. Grazing grasses before they go to seed also encourages tillering. Tillering occurs when new grass shoots grow from the base of the plant, resulting in more leaf area and a more dense forage sward. So a strategy of grazing grasses before their reproductive stage and leaving adequate leaf area for regrowth is an important way to manage pastures for quality, quantity, and weed resistance.A word on overgrazing?Many times we are tempted to assume that overgrazing occurs when too many animals are on the pasture. However, overgrazing is the result of how much time animals are on pasture, not the number of animals. In other words, overgrazing is caused by allowing animals, whether many or few, to remain on a pasture for too long. Livestock select the most nutritious plants in a pasture while they are grazing. Once a grass plant is grazed, it begins to regrow from growing points close to the base of the plant. If animals are left on a pasture for more than a few days, livestock are likely to graze off the new growth, causing stress to the plant. As plants are grazed successively in this manner, the grass’s root system will begin to decline, and the plant will eventually die. Grazing management is a matter of keeping an animal from grazing new regrowth until it has had a chance to grow several inches and renew the root system’s energy stores.A grazing system allows adequate time for forage leaf and root regrowth. If not, an overgrazed pasture is the result. There are a great many well-prepared resources available to assist producers in designing and implementing a controlled grazing system. ATTRA offers the following publications: ? Paddock Design, Fencing, and Water Systems for Controlled Grazing? Rotational Grazing? Nutrient Cycling in Pastures? Assessing the Pasture Soil Resource? Pastures: Sustainable Management? Managed Grazing in Riparian Areas? Pasture, Rangeland, and Grazing ManagementResourcesSmith, Ray and Mike Panciera. 2007. Using a Grazing Stick for Pasture Management. Kentucky Cooperative Extension.http://www.ca.uky.edu/agc/pubs/agr/agr191/agr191.pdfHorse Forage and Forage Management, The Samuel Roberts Noble Foundationhttp://www.noble.org/Ag/Forage/HorseForage/index.htmlOSU Extension. Getting Started Grazing. Henry M. Bartholomew, editor. Ohio State University. http://ohioline.osu.edu/gsg/index.htmlPasture & Range Information, The Samuel Roberts Noble Foundationhttp://www.noble.org/Ag/Research/Forages.htmUSDA. 2008. Pasture Management Guide for Horse Owners. Missouri NRCS.http://www.mo.nrcs.usda.gov/news/pubs_download/out/Pasture%20Management%20for%20Horse%20Owners.pdfRangeland Health and Planned Grazing Field Guidehttp://quiviracoalition.org/Detailed/QC_Publications/Field_Guides/Rangeland_Health_and…_83.htmlAn introduction to planned grazing on arid and semi-arid rangelands.NRCS National Range and Pasture Handbookhttp://www.glti.nrcs.usda.gov/technical/publications/nrph.htmlHow to Measure Forage Production For the Astute Producer, Texas NRCS http://www.texasglci.org/docs/forage.pdf