Forage Considerations for Goats
Forages are the backbone of any ruminant livestock operation. The ruminant digestive system is designed to utilize cellulose for a majority of the energy needs of the grazing animal. Goats have earned an undeserved reputation for eating low-quality forages, or possibly eating nearly anything. This view has developed from the fact that goats are capable of selecting a high-quality diet from a forage base that is not generally very high quality.
How to establish goat specific forages?
Soil fertility and its importance to small ruminants?
What to look for in forage quality?
How to plan a forage program?
The physiology of forage characteristics?
Useful forage species for small ruminants?
What is the importance of biodiversity?
General considerations in goat grazing management?
How to control parasites in goats?
What is mixed species grazing?
Goats are what is referred to as browsers. This means that goats select the leaves and the tender growing tips of many plants. These plant parts are much more digestible and higher in protein and mineral content than the woody (lignified) stems of the plant. The long narrow mouth of goats facilitates browsing and allows goats to survive and thrive on generally low-quality pastures and range that would not suffice for cattle or sheep. Other grazing livestock species prefer primarily grass or forbs in their diet due to mouth shape, grazing behavior and preference (Table 1).
Table 1. Tolerance of forage species to soil pH.
With this said, although goats may be able to do quite well on low-quality pasture, if we pay strict attention to the forage that is made available to goats, we can improve their productivity and general health. To better accomplish this goal, goat producers need a basic understanding of forage growth and management. This chapter will focus on some of the basics of forage management, including establishment of new pasture plantings, fertilization, principles of forage quality and the growth characteristics of various forage species.
The proper establishment of forage species is essential to the success of new pasture plantings. If there is a desire to develop improved pastures, then several key principles must be followed to obtain a successful stand. There are two major methods of establishing forage species from seed. No-till establishment maintains vegetative cover on the soil surface, which reduces the potential for erosion during the establishment period. No-till also provides a firmer base for animals in the winter. Conventional tillage destroys existing vegetation and prepares a bare soil surface in preparation for seeding. Whether using reduced tillage or conventional tillage, good soil-seed contact is necessary to insure proper germination. If the seedbed is too cloddy, seed will not be able to get enough moisture to support germination and a spotty stand will result. A fine, firm seedbed is ideal for seedling establishment in a prepared seedbed situation. Typically, tilled seedbeds establish quicker, but can have more weed problems and are prone to pugging (compacting mud with hoof action) if grazed in wet conditions.
No-till establishment necessitates careful attention to weed control and may require the use of special equipment. Although no-till establishment can be performed without the use of a no-till drill, use of a drill generally results in better seedling establishment because the seed are placed in better contact with the soil surface. Effective control of competition from the plants already present in a pasture is essential for no-till establishment to be successful. Use of a burndown herbicide such as glyphosate or paraquat at planting will assist in seedling establishment. Glyphosate can be applied at 1-8 pints of a 4 lbs/gallon formulation to suppress existing vegetation. Glyphosate will take 10-14 days to control existing vegetation, depending on environmental conditions. The effects of paraquat are evident within 24-48 hours. A rate of 0.3 – 0.5 lbs/acre is sufficient to give desired control of existing vegetation to reduce competition. Glyphosate at higher rates will kill existing vegetation, while a single application of paraquat will typically suppress perennial vegetation but will allow regrowth over a period of several months.
There are a number of establishment alternatives that require less inputs and rely on the natural interactions of animals with the environment. It is possible to broadcast seed in the late winter or early spring into existing vegetation and rely on goat hoof action and freezing/thawing of the soil surface to incorporate the seed. Judicious grazing management with goats can be used to control weeds that are competing with the desired forage seedlings. Care must be taken when using goats for vegetation control to insure they do not graze too close to the ground surface and pull out the developing forage seedlings. As a general rule goats should not be allowed to graze below 6 inches above the soil surface.
When establishing pastures, care must be taken to insure that seeds are planted at the proper time and depth. If seeds are planted too early or too late in the season, seedlings may succumb to adverse environmental conditions. For example, planting too late in the fall may result in seedlings freezing out during the winter. The same problem may result from seeding too early in the spring. Even if seedlings survive freezing temperatures, they may be pulled from the ground by cycles of freezing and thawing and succumb to frost heaving. Seeding too late in the spring can result in stand loss due to heat and drought. Obviously great care must be taken to insure that seed are planted at the ideal time for the species in question.
If seeds are planted too deep, then seedlings may not reach the soil surface before the stored food in the seed is exhausted. If seeds are planted too shallow, the roots of the seedling may not be sufficiently deep to attain the moisture necessary to support growth. A general rule of thumb is to plant seed at a depth 8 times the diameter of the seed. For most small-seeded species a seeding depth of ¼ to ½ inch is ideal.
Using the proper seeding rate will insure that a sufficient number of seedlings develop to provide for an adequate stand. Rates are determined by the number of seed per pound of each forage species. Rates are increased to overcome seedling loss due to natural causes such as drought, heat stress and pests. Generally, 50-60 percent of the seed sown succumbs to competition, disease, insects, winter injury, drought or other causes within the first year after seeding. Therefore, suggested seeding rates are increased to take these factors into consideration. Careful attention to proper planting date, seedling rate and seeding depth is essential to insure successful pasture establishment.
Soil fertility at establishment may make the difference between success and failure. It is critical to perform a soil test prior to seeding to determine soil pH, phosphorus, and potassium levels. Soil samples should be collected for every part of the pasture that can and will be managed separately. A minimum of 15 random soil cores or slices from the surface six inches of the soil should be collected for each area that will be fertilized differently, with the area represented not amounting to more than ten acres. These cores should be thoroughly mixed together and then sent to the state soil testing laboratory.
Low soil pH can be a major contributing factor to stand failure. Many forage seedlings are very susceptible to the adverse effects of acid soils. This is particularly true of legumes. The relative tolerance of forage species to soil pH is given in Table 2. Ideally, soils should be limed to pH 6.0-6.5 prior to planting, especially when establishing legumes. In addition to liming, care must be taken that adequate levels of P and K are present in the soil. A soil test should be taken prior to seedbed preparation or no-till seeding and suggested levels of P and K applied to support seedling growth. If legumes are included in the seed mixture the proper inoculum for the species being planted should be applied to the seed. This will insure that the legumes are nodulated with the proper bacteria for nitrogen fixation.
Table 2. Tolerance of forage species to soil pH.
To summarize, the key to successful pasture establishment requires strict adherence to the following steps:
- Select the proper seeding rate
- Plant within the proper seeding date window
- Insure good soil-seed contact and plant at proper depth
- Control competition from weeds and existing vegetation
- Make sure soil pH and fertility are adequate by soil testing
- Inoculate legumes
The guidelines in Table 3 give some ideas regarding potential hazards associated with successful establishment.
Table 3. Potential reasons for stand loss of forages during establishment.
The availability of mineral nutrients is critical to optimum forage growth, regardless of whether the pasture is a new seeding or an established unit. In fact, proper fertilization can be a key to improving forage yield and quality of established pastures. The single most important soil fertility factor governing mineral nutrient availability and forage growth is soil pH. Most forage are best adapted to a soil pH of 6.0-6.5. Figure 1 shows that this corresponds to the point of major availability of most of the important mineral nutrients derived from the soil.
Figure 1. Relative availability of mineral nutrients in relation to soil pH.
From Troeh and Thompson, 2005
The major mineral nutrients important to forage and browse management for goats are nitrogen (N), phosphorus (P) and potassium (K). These are typically called the fertilizer or macro-nutrients and represent the three nutrients listed in a fertilizer analysis, such as 12-24-10 (12 % N, 24% P2O5 , 10% K2O). By convention, N is always listed as a percentage of the element, while P and K are listed as their percentage composition of the phosphate and potash oxides, respectively. There is no adequate soil test for nitrogen, but typically a recommendation is made for the rate and timing of application of nitrogen based on desired plant growth.
Phosphorus is derived from deposits of rock phosphate commonly found in Florida, the Carolinas and Tennessee. This rock mineral is mined and reacted with acid to form phosphate fertilizers such as diammonium phosphate (DAP 18-46-0), monoammonium phosphate (MAP 11-52-0), or triple superphosphate (TSP 0-46-0). Phosphorus is primarily involved in energy storage and transfer and is very important to root growth in young plants.
Potassium is also a mined mineral. Large deposits of potassium minerals are located in Canada and New Mexico. These minerals are mined and conditioned to make granular KCl that is applied directly to fields as dry fertilizer. Potassium is important to plant water relations, winter hardiness and disease resistance. Therefore, potassium fertilizer applications are often made in the fall to insure good K fertility as pasture plants prepare for the winter. Much of the K in plants is contained in the stems, so if excess forage is harvested for hay, K levels are often reduced.
Generally, micronutrients such as iron (Fe), sulfur (S), boron (B), chlorine (Cl), copper (Cu), managanese (Mn), molybdenum (Mo), and zinc (Zn) are present in the soil in sufficient amounts to provide for plant needs. Liming can enhance the availability of these nutrients for plant uptake. Sometimes one or more of these nutrients may not be present in forage in sufficient quantities to provide for animal needs. The best way to overcome this problem is to provide mineral supplements on pasture to insure adequate mineral nutrition for the grazing livestock.
The best way to manage soil fertility on pastures is to develop a regular program of soil testing. Soil samples should be collected from each pasture unit that will be managed separately. You should also collect separate samples from areas that differ in soil type or past management. Often, steep slopes are managed differently from other land types, so steeper slopes should be considered separately from the rest of the field in sampling plans. In other words, if you are able and plan to apply different rates of fertilizer to different units, then these units should be sampled separately to monitor changes in fertility. This not only applies to separate pastures, but also to separate paddocks within a pasture.
The number of acres that each sample represents will be determined to some degree by the amount of variability in the pasture and the number of subdivisions you have. Each sample should consist of 15 or more randomly collected soil cores or slices from the surface 6 inches of the soil. These samples should then be mixed together in a clean, dry plastic bucket and a sample of dry soil place in a soil sample bag.
The results from the state soil testing lab will give recommendations based on the plant species you are growing for establishment and maintenance applications of P and K fertilizer. Establishment applications should be made when planting a new stand or renovating an existing stand. Maintenance applications should be made annually after the establishment year. Soil samples should be collected every other year to monitor changes in soil fertility. Excess application of potash can cause an imbalance of calcium and magnesium, which can result in grass tetany during periods of rapid forage growth and high animal demand for Mg.
Although the amount of forage produced on a pasture is an important consideration, the quality of the forage that is available for browsing livestock is an even more important consideration. When we refer to forage quality we are referring to both the palatability and composition of the browse. Palatability relates to factors that influence the acceptability of the forage or browse to the grazing animal. This includes such factors as texture of the forage, hairiness of the leaves, the presence of thorns or spines on the plants, the amount of moisture in the forage and the leafiness of the plants. Other factors that may affect the desirability of pasture plants to grazing livestock include aroma, sugar content and mineral content.
There are several laboratory methods of evaluating forage quality. The two most commonly used are the Proximate Analysis System and the Detergent Fiber System. The Promimate Analysis System analyzes the digestibility of various forage components to come up with the proportion of the forage that is capable of being digested by the animal. This portion of the forage is termed the total digestible nutrients or TDN, and is made up of the digestible fiber, protein, soluble carbohydrates, and fats in the forage that are capable of being broken down.
The Detergent Fiber System uses a series of laboratory solvents to remove the various forage components. The first solvent is a neutral detergent solution that removes soluble sugars, starches, and proteins contained inside the plant cells. These materials are the portion of the forage that is readily digested by the animal. The residue that remains after this extraction is termed the neutral detergent fiber (NDF). The NDF residue is highly correlated with intake and is used to determine how much of a forage animals can consume. The next solvent used is a solution of sulfuric acid and detergent that dissolves the hemicellulose and some of the cellulose contained in the cell walls of forage plants. The residue that remains after this extraction is termed the acid detergent fiber (ADF). The ADF is highly correlated with forage digestibility and is used to estimate the percentage of forage dry matter that is digestible.
Either the proximate analysis system (which measures TDN or total digestible nutrients) or the detergent fiber system (which measures NDF and ADF) can be used to compare the relative digestibility of forage samples. Goats typically select the youngest, most tender portions of forage crops when they are browsing. To insure top quality it is best to maintain pastures in a young, vegetative state of growth (Figure 2). Not only does this result in the best forage quality, it also keeps the forage plants in their most rapid growth phase, resulting in increased forage yield. Allowing forage to become mature reduces the growth rate of the pasture and, if allowed to accumulate to the senescence stage beyond Phase 3, forage will actually be lost due to plant death and decay.
Figure 2. The standard growth curve of forage crops.
If the pasture has a heavy component of browse and forbs, goats should be allowed to graze these plants first, followed by cattle, to maintain a vegetative stand. If grazing a nearly pure grass stand, goats will prefer more mature grasses and graze from the top down, starting with seedheads.
To successfully implement a forage program for the goat herd, it is necessary to understand some basics with regard to forage plants. Knowing how forage plants grow, when they are productive and how they respond to various environmental conditions will assist in making the most effective use of the plants at your disposal.
Typically, forage plants for goats can be classified into four main groups: grasses and grass-like plants, forbs, legumes, and browse. Grasses differ quite markedly from other forage crops in a number of characteristics. Grasses generally have long, linear leaves with parallel veins and exhibit a fibrous root system. Early in the life cycle of grasses, most of the topgrowth is composed of leaves that originate from an underground crown. The crown is made up of a number of nodes that are tightly packed together so the leaves originate in somewhat of a clump (Figure 3). The internodes between the nodes do not elongate until flowering occurs, at which time the stem or culm of the grass emerges to expose and elevate the seedhead.
Figure 3. The crown of the grass plant. a) senescing leaf; b) mature leaf; c) newest fully expanded leaf; d) emerging leaf; and e) immature leaf enclosed in older leaves. From A. J. Turgeon. 1999. Turfgrass Management, 5th Edition. Prentice Hall
Forb is the term used to describe any non-woody plant other than grasses and grass-like plants or legumes. Forbs include things like chicory, docks, brassicas and other non-leguminous broadleaf plants. Dicotyledonous, or broadleaf plants tend to have their veins arranged in a net-like pattern in their leaves and have tap root systems.
Legumes are unique in that they typically fix atmospheric nitrogen and thereby naturally provide additional nitrogen to pasture systems. Legume plants form symbiotic nodules on their roots with bacteria that are capable of converting atmospheric N to ammonia that is then usable by the plant. This ammonia is then converted into plant proteins that either benefit grazing livestock or are provided to associated grasses as legumes die and decay. Goats, because of their tendency to select the leaves of broadleaf plants, can obtain a particularly high-protein diet on pastures with a high legume content, especially on pastures where very little N fertilizer is applied, since the leaves contain the highest protein concentration. The preference of goats for various legumes varies, in that they often prefer more high-tannin forages, such as lespedezas, to other legumes such as white and red clover.
Browse refers to the leaves and stem tips of woody plants. Goats tend to consume large amounts of browse if it is available. Since most of the available protein in plants is stored in the leaves, and the leaves and young stem tips are the most digestible portions of these woody plants, goats are able to obtain a fairly high-quality diet from this type of plant material.
Because grasses keep their growing point at or below the soil surface for much of their life, they are very tolerant of grazing and other defoliation. Legumes and other forbs are more susceptible to damage from grazing since the growing point is typically elevated (Figure 4). Therefore, if grazing livestock are allowed to graze these plants too close to the ground, their productivity will be reduced. If the main growing point is removed, these plants must regrow from buds at the base of the plant or in the axils of stem branches. There is some variation in this general rule with regard to the growth habit of various forbs. Plants that reproduce vegetatively through stolons (aboveground horizontal stems), such as white clover, are much more tolerant of grazing since their nodes are maintained at the ground surface. If goats are forced to browse too heavily, they will begin to remove bark from around the stems/trunks of these plants, which can often result in plant death. In fact, this is the basis for using goats to control undesirable woody vegetation. Goats should also not be forced to graze lower than a six-inch stubble to reduce their likelihood of ingesting parasites.
Figure 4. Comparison of the growing point of grasses and forbs or woody species. From Griffin, T., W. Schacht, W. Fick, and P. Hain. 2005. Library of Crop Technology Lesson Modules.
Forage crops can be classified into several groups based on their growth characteristics. Management practices need to be implemented with these characteristics in mind. One major classification of forage crops relates to their season of growth. The classification of plants as either cool-season or warm-season refers primarily to when they complete the majority of their life cycle. Grasses such as tall fescue and orchardgrass are cool-season plants because they produce the majority of their growth when temperatures are 60-80°F. Warm-season grasses, on the other hand, produce the majority of their growth when temperatures are 85-95°F. Although optimum temperatures for growth of legumes differ among individual species, typically most grow optimally at temperatures similar to that for cool-season grasses, but generally fall in a narrower range of 65-75°F.
Cool-season plants will typically produce the majority of their vegetative growth in late winter and early spring and flower in late spring to early summer, while warm-season plants will initiate vegetative growth in late spring and flower in mid to late summer. Planting cool-season plants too late in the spring will risk death of young plants due to high temperature and drought stress. Conversely, planting warm-season plants too late in the summer or fall will run the risk of loss due to winter kill, since the plants will not have time to develop adequate belowground biomass to survive the winter.
The final classification of importance to forage plants relates to their life cycle or the length of time a plant requires for development from seed to the point where it flowers and sets new seed. Annuals are plants that complete their life cycle in one year, developing from seed into a mature plant that produces seed in one year. New plants must develop each year from seed. Perennials, on the other hand, come back each year from vegetative organs such as stolons, rhizomes or roots and will generally set seed each year. The primary difference between annuals and perennials is that perennials come back each year from the original plant, while annuals must set seed to develop new plants each year. Therefore, if you are managing pastures that are based on annual forage species, you must either allow the forage crop to set seed or be prepared to replant your pasture each year. Some care must be taken with perennials so that they are not overgrazed. This allows for storage of carbohydrates in stolons, rhizomes and roots to support regrowth the next year.
Table 4 lists a number of species that may be useful in forage systems for goats in Tennessee and classifies them according to the plant types and physiological characteristics described above. Following is a short description of the use of each of these groups of forages and special management considerations for each group. For further and more in-depth discussion of specific management requirements for the individual species listed in Table 3, you should refer to “Southern Forages – Third Edition” by Drs. Don Ball, Garry Lacefield, and Carl Hoveland. (2002, Potash and Phosphate Institute, Norcross GA).
Table 4. Classification of some useful forages for goat pasture systems in Tennessee.
Browse refers to the twigs, stem tips and leaves of woody shrubs and trees that goats utilize by selecting these nutritious portions. The long, narrow mouth of goats ideally suits them to utilize these species. Due to their preference for browse, goats may also be used to control woody species in pastures where these plants are not desired.
Goats also graze forbs, which are herbaceous plant species that are neither grass nor legumes. Included in this group are a number of nutritious weeds that are very acceptable to goats, and when grazed at a young stage of growth, are very palatable. These plants can be used very beneficially to fill production gaps of the major forage species. There are also forb species of limited nutritional value that are often avoided by goats, as well as species that at times have toxic properties. Both perennial and annual species exist and complete their life cycles in both the warm- and cool-season periods. We have grouped the forbs that are useful as forage together due to the limited number we are considering.
Cool-Season Perennial Grasses
Grasses in this group make up the primary pasture base of Tennessee pastures. Their long growing season and high quality make them desirable forage crops. Their adaptation to cooler temperatures and greater soil moisture conditions may limit their productivity and survival in periods of prolonged summer drought. Goats will make use of these grasses, but prefer them when they are more mature, allowing the goats to utilize the seedheads and eat the stems from the top down.
Warm-Season Annual Grasses
These grasses typically need to be seeded each year and will provide grazing only during a two- to three-month period during the summer. Because these grasses must be established each year, they tend to be more expensive than perennials, so their profitable use in goat production systems is limited. Goats will use these species as they get more mature, eating seedheads and leaves from the top of the stem down, similar to their normal grazing pattern with cool-season grasses. This is particularly true of the sorghums and millets.
Cool-Season Annual Grasses
These grasses can be overseeded on warm-season perennial grass pastures or established on fallow cropland to provide grazing in late fall and winter. They typically provide high-quality grazing, but due to the need to establish them each year, they are an expensive forage option. These forages have limited use in goat production systems.
Warm-Season Perennial Legumes
These plants can provide a highly digestible, high-protein diet to goats. The ability of these plants to fix atmospheric nitrogen makes them an inexpensive protein source. They are especially desirable to goats, since goats are able to select primarily the leaves of these persistent species. Warm-season legumes initiate growth in late spring after soil temperatures reach 65°F. Many of these species contain high levels of tannins, which can help reduce parasite loads.
Cool-Season Perennial Legumes
Although these species are termed cool-season, many continue to be productive throughout the summer. Periods of drought will reduce growth. These species also provide good, high-protein goat pasture. Birdsfoot trefoil is a species that contains elevated tannin levels that improve by-pass protein concentration and also help reduce parasite loads. It is slow to establish and may easily die out in pastures in Middle and West Tennessee due to drought and heat stress.
Warm-Season Annual Legumes
These species will often naturally reseed themselves and can be an important, high-quality component of summer pastures. The lespedezas are high in tannin and may help reduce parasite loads. Partridge pea is a native species that is often planted for wildlife and goats relish its vetch-like leaves. The same is true of the common weed hemp sesbania.
Cool-Season Annual Legumes
These species may be seeded in the fall to provide a higher quality late winter/spring pasture. Crimson clover and vetch will naturally re-seed themselves, so they can become an important part of pastures for a number of years if initially planted and allowed to adequately establish.
Biodiversity refers the assortment of forage species, varieties, growth forms and plant types that are present in a pasture. Although it may be simpler to manage a monoculture of grass because of its uniform response to fertilization and uniform flowering date, the productivity and quality of the forage produced from a more diverse mixture of plants can be much greater. This is especially true for goats, since they graze a wider variety of plant types and plant parts due to their browsing behaviors. Mixtures of grasses and legumes take advantage of the ability of legumes to add N to the pasture system through N fixation. The combination of the broadleaf canopy of the legume, combined with the more narrow erect leaf canopy of grasses, generally results in better capture of the available sunlight.
The goal in grazing management is to maintain grasses in the vegetative growth stage as long as possible so that the more digestible leaf tissue is the primary forage is available. The grazing preference of goats depends greatly on what forages are available. Goats differ somewhat in their preferences in that they will often selectively graze seedheads of grasses to obtain the high-energy carbohydrates stored in the developing seed. Goats will also preferentially select the leaves and young twigs of browse plants to obtain a high-protein, digestible diet. Typically, goats will select broadleaf plants including legumes over grasses, but this does not mean that goats will not eat grass leaves. When given a choice, goats will consume a diet composed of 40-60 percent browse, 10-30 percent forbs and legumes including broadleaf weeds, and 20-30 percent grass, including seedheads. These diet preferences affect how goats must be managed with regard to grazing.
If you are attempting to establish new tree plantings in a pasture or agroforestry situation, it may be necessary to fence out the young trees to protect them from the goats, since goats can preferentially browse on the young trees, resulting in tree damage or death. This is the same reason that goats can be used to eliminate undesirable woody species from pastures. It is also possible to use intense grazing management, manipulating stocking rates and timing of grazing pressure in agroforestry situations, allowing goats to control undesirable weeds while not damaging tree saplings.
It is best not to use set continuous stocking with goats due to the potential problems this can create with parasites. It is possible to obtain improvements in pasture utilization and productivity with rotational stocking. Rotational stocking concentrates the goat herd on a small fraction of the total pasture (paddock) for short periods of time, resulting in more complete consumption of the available forage. The animals are then moved to another small section of that pasture and the process is repeated until the first paddock has produced enough re-growth to support the herd again. Paddock size and number of paddocks are determined by the growth rate of the pasture species that are present and the amount of forage required by the goat herd.
Most forage species exhibit a 28-35 day growth cycle. For this reason, the rest period between grazing periods needs to be approximately 21 days to maintain the forage plants in the active vegetative growth phase as mentioned above (Figure 2). It is best to base pasture management and rotation schemes on pasture growth and not on calendar days. Goats should be turned into new pasture when it reaches a height of 8-10 incehs and allowed to graze the forage to a six-inch stubble. Grazing below six inches can increase parasite problems. During periods of rapid pasture growth, re-growth may make it necessary to return to the first paddock before the herd has reached the last paddocks in the rotation. These paddocks can then be either harvested for hay or mowed to allow them to re-grow to a desirable vegetative stage before the next grazing period.
This system of rotating livestock through a series of pasture subdivisions provides the goat herd with a high-quality diet and results in better pasture growth by allowing the forage plants adequate rest to re-grow and store nutrients in their crowns and roots. In addition, there may be health benefits obtained by the herd from rotational stocking.
Parasites are a major constraint to goat production. If goats are continually grazed on the same pasture, the potential for goats to ingest viable parasite eggs is increased. The closer to the ground surface goats are forced to graze, the more likely they are to ingest parasites. Although parasite eggs can survive up to 60 days, the number of viable eggs that remain after a 28-day rest period is greatly reduced. Also, the available forage canopy will be higher above the ground, which further reduces parasite intake. The use of taller-growing forages such as sericea lespedeza, pearl millet and kudzu will assist with reducing parasite intake, since the animals will graze higher above the ground. There is also good support for using forages containing high levels of tannin, such as lespedeza, to reduce parasite loads in goats. All of these forage management practices will assist in reducing parasite problems in the goat herd, but parasites should continue to be monitored using fecal sampling and/or FAMACHA.
We have already discussed the preference of goats for the tender portions of woody species, grass seedheads and leaves of broadleaf plants. This differs a great deal from the preferences of other livestock species. Cattle typically prefer grasses, but depending on pasture composition, forbs and legumes may make up as much as half of their diet. Cattle consume forage by wrapping their tongue around a mass of forage and pulling the bite into their mouth, detaching the leaves from the plant by pulling their head back. Because of this grazing habit, cattle perform better on pastures that exhibit a high forage availability. If the pasture is too short, cattle will have to travel farther to get a full meal. Sheep, due to their cleft upper lip and tendency to nip off forage with their incisors, prefer pastures that are shorter, allowing them to be more selective in diet selection.
Given these differences in grazing behavior, it is possible to gain better pasture utilization by grazing multiple species together. The success of this practice will depend on the pasture composition and how well grazing is managed. If a pasture contains a significant proportion of woody species, goats can be effectively used in combination with cattle to make use of this browse, which may also increase grass growth by reducing shading and competition from the woody species. Typically, if cattle and goats are grazing the same land, a stocking rate of one goat per cow is the recommended stocking rate. This stocking rate will not impact cattle grazing and will provide the best forage environment for both goats and cattle. If pasture growth rates are high, sheep may benefit from cattle reducing the forage canopy height prior to their grazing. There are numerous benefits to the producer of utilizing mixed grazing. The primary benefit is to make more efficient use of the available pasture. Another benefit is that income will be diversified by having animals of different types for sale at different times of the year. This can result in more even cash flow than relying on income from the sale of one animal species.
Although it has been mentioned above, the use of goats for weed control deserves further discussion. Goats are an excellent resource for opening new land and gaining control of invasive woody species. Goats will browse new growth of woody species, reducing their vigor and allowing more desirable forage species a competitive advantage. Goats may also consume bark of some woody species, resulting in death of the plant due to girdling. Goats can also provide control of other broadleaf weeds such as ragweed and kudzu due to their preference for the leaves of these species. Further consideration of the use of goats for brush control is given in the chapter entitled “Utilization of Goats in the Restoration / Enhancement of Land.”
Ball, D.M., C.S. Hoveland, and G.D. Lacefield. 2002. Southern Forages, Third Edition. Potash and Phosphate Institute.
Bates, G.E. 2000. Grazing Manual, Foraging Ahead for a Greener Tomorrow. Univ. of
Tennessee Agricultural Experiment Station, University of Tennessee Agricultural
Extension Service, and USDA Natural Resources Conservation Service.
Goats and Nutrition. 2005. The Facts and the Myths – Goats and Nutrition. [Online] Available at http://www.goatworld.com/nutrition/ (Verified 22 August 2005)
Troeh, F.R., and L.M. Thompson. 2005. Soils and Soil Fertility. 6th Edition. 489 p.
Blackwell Publishing, Ames IA.
USDA-NRCS. 1997. National Range and Pasture Handbook. Publication 190-vi-NRPH.
Vallentine, J.F. 2001. Grazing Management, 2nd Edition. Academic Press.
FORAGE CONSIDERATIONS FOR THE GOAT HERD
Richard E. Joost, Professor, Crop Science, Univ. of Tennessee at Martin
Gary E. Bates, Professor, Plant Sciences, UT Extension
Gregory L. Brann, Grassland Specialist, USCA-NRCS