FORAGES AND PASTURES | Annual Forage and Pasture Crops – Species and Varieties

FORAGES AND PASTURES

Contents Annual Forage and Pasture Crops – Species and Varieties Annual Forage and Pasture Crops – Establishment and Management Perennial Forage and Pasture Crops – Species and Varieties Perennial Forage and Pasture Crops – Establishment and Maintenance Grazing Management

Annual Forage and Pasture Crops – Species and Varieties E J Havilah, Formerly New South Wales Agriculture, Berry, NSW, Australia ª 2011 Elsevier Ltd. All rights reserved.

Introduction Annual forages are important components of feed supply for dairy cows worldwide. They include crops with very high forage yield potential such as maize. Many annual forages can be grazed but with conservation as hay or silage they are also important in spreading feed supply across the seasons. Annual forages are available with summer–autumn production or winter–spring production. There are legumes and grasses that produce in either period. Brassicas also make a useful addition to summer–autumn and winter feed supply. The annual forages are discussed in five groups: (1) warm season grasses, (2) warm season legumes, (3) cool season grasses, (4) cool season legumes, and (5) Brassicas. Within each group, there is a range of suitable species and within these species a much larger number of varieties are available worldwide. Suitable species within each of the annual forage groups have been presented elsewhere but here the varieties within each species are listed. Many varieties have been evaluated in different regions and the most suitable varieties for the local environment are well understood. Suitable varieties have been bred for local conditions or have been imported, tested, and shown to be effective. The best varieties are usually tolerant of local diseases and insects, and are adapted to the local climate and management systems. They are also bred or selected for feed quality, including digestibility, energy and protein content, and also the time taken to reach maturity. High yields of annual forages should be sought to cover the high costs of production. Management must

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be effective at all stages of crop development to produce high yields. Land preparation, sowing, growing, grazing, or conserving the crop should all be managed to maximize yield. High dry matter (DM) yields may be obtained but feed quality, particularly energy and protein content, declines rapidly as maturity approaches, particularly in annual forage grasses. Care should be taken to harvest hay and silage crops from annual forages at a stage of development where the feed quality level will be effective in the milk production system. There is a wide range of water use efficiencies (WUEs), that is, DM produced relative to water from irrigation or rainfall inputs. With the annual forages useful for milk production, WUE should be an important criterion when selecting the best forage, for example, maize growing in the summer–autumn has a very high WUE.

Annual Forages and Pastures Annual forages and fodder crops are used worldwide as key feed sources for dairy systems. They produce all their feed in 1 year or season and usually are reestablished from fresh seed in the following year. Annual forages include annuals, which set seed and die within 1 year, • true self-regenerating which reestablish from seed • set and returned toannuals, the soil in previous years, and and weak perennials, which are replaced with • biennials fresh seed in the second year because of reduced plant populations and hence low production potential.

Forages and Pastures | Annual Forage and Pasture Crops – Species and Varieties

Grasses, legumes, and brassicas either sown alone or in mixtures are used as annual forages. Annual forage crops are fed fresh by grazing or greenchopping or conserved as hay, silage, or grain. Specialist annual forage crops are grown for conservation of feed reserves. Maize silage is an important component of dairy cattle feeding worldwide. Feed costs from annual forage include land preparation, sowing, fertilizing, and harvesting, and these have to be recovered in a single year, whereas perennial pasture costs are spread over several years. High yield of utilized feed is essential in realizing maximum profit from annual forages. Adequate feed quality to sustain milk production should be sought but lower quality feed can be used for dry and young stock. Cost-effectiveness should be analyzed when choosing between forages. Some annual forages can be more cost-effective than perennials. The most profitable forage crop can also differ between farms. Strategies for use of annual forages include 1. high-intensity production systems in which highyielding forages are grown in combination to produce DM yields in excess of 40 tonnes ha1 (e.g., maize followed by brassica and annual clover), 2. filling seasonal feed gaps in perennial pasture systems, 3. developing productive rotations, 4. building fodder reserves, to use in seasons when feed supply is restricted, or establishing drought reserves, 5. specifically augmenting protein or energy available to the dairy herd, 6. oversowing perennial pasture to increase production across seasons or to extend production for a further year, 7. supplying feed when establishing and replacing perennial pastures, 8. emergency feed supply after drought, flood, or winterkill, and 9. cover crops to restrict erosion when establishing perennials.

The high yield potential of maize is valuable in the area of farm required for conservation, • reducing allowing stored silage to meet forage • shortages insufficient a dry year, manure and effluent to reduce fertilizer imports • using to the farm, and • taking advantage of the high WUE of the maize crop. Variety selection

Maize breeding emphasizes on increasing grain yield and quality, and not on total forage production. Varieties bred for grain production can be used for forage. The forage potential of the local grain varieties is not always clear. Varietal characteristics that count in maize forage production are as follows: for high total DM yield: The highest forage • Potential yielding varieties should be identified from the grain

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The useful annual forages are discussed below.

Warm Season Grasses Maize

Maize has the potential to yield more feed energy per hectare than other forages. Maize forage is high in energy but low in protein content. Attempts to improve the protein content of maize include breeding or intersowing with a high-protein legume crop that can be ensiled with the maize. The usual effect is to reduce total yield. Maize should be regarded as a specialist energy source with additional protein supplied from a protein-rich feed.

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varieties used locally. High grain yield: Grain is highly digestible (80% of DM) and high grain yield per hectare in the forage enhances its energy content. High grain to stover ratio: The grain content of maize forage is in the range of 30–50%. Stover, the nongrain component of the plant, has a high fiber content and is less digestible than grain; thus, a high proportion of grain increases digestibility and available energy in the feed. High stover digestibility: Increased stover quality is linked to decreases in lignin or fiber. Brown midrib (BMR bm3 gene) maize varieties have lower lignin and increased stover digestibility but they yield less forage than current hybrids because of lower yields and lodging. Acidosis can be induced by the low fiber in diets containing more than 50% BMR maize. Breeding continues to improve the yield potential of BMR varieties. Improvement in feed quality has to be balanced with higher seed costs and potential yield loss. Appropriate maturity: Maize silage maturity is controlled by the accumulation of heat units measured as growing degree-days (GDD). Varieties require different GDD to stimulate flowering: varying from 85 to 150 days. The days to maturity guides the choice of sowing and harvest times. Harvest date should avoid frosts. If sowing is delayed, the maturity of the sown variety can be changed. Harvest window: Varieties that stay green until harvest provide an extended harvest window at the correct moisture content for ensiling; however, they can be too moist for ensiling at the best grain development stage. When the maize is harvested at less than 28% DM, feed quality is reduced and high levels of effluent produced during the ensiling process. When the staygreen crop is dry, the grain may have matured and forage digestibility will be reduced. A balance is required.

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resistance: Locally bred grain varieties usually • Disease have acceptable resistance to major corn leaf diseases,

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and stalk and ear rots. Lodging resistance with changing population: Lodging can cause yield losses through restricted growth and harvesting difficulties. Standability is influenced by stalk rot resistance, stalk strength, lignin content, plant height, and ear placement. High plant populations can produce smaller stalks and increase lodging risk. Nutrition profile: The nutritional profile of maize has been changed by breeding varieties with high sugar, high oil, high lysine, more amylopectin, high amylose, less fiber, increased nutritional density, and greater leafiness. Often, the nutritional composition is improved but yield potential is lost. The benefits from breeding specialist forage varieties have yet to be realized. Effective grain varieties with high forage yield potential and a high grain to stover ratio remain useful forage varieties.

Sorghum

Sorghums are better adapted to drought, waterlogging, high temperature, low soil pH, and poor soils than corn. Sorghums are drought resistant and become dormant in extended dry periods. They have moderate tolerance to salinity and are less expensive to establish. Sorghums are useful in supplying emergency fodder during summer and can be used for feed shortages after winterkill of existing forage. Sorghums can be conserved as chopped pit silage or wrapped bale silage, utilized fresh as green chop, or grazed. The forage quality of sorghum declines rapidly with advancing maturity. Sorghums can be divided into two groups: cut: Grain sorghums and sweet sorghums (forage • Single sorghum) are usually harvested for silage in a single

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cut. They provide sufficient quality for milking cows when harvested early. Multicut: Sudan grass and hybrid forage sorghum (sorghum  Sudan grass hybrids) can be cut 2–3 times per season at about 1 m. Later cuts produce higher yields but lower quality feed.

Single cut: Grain sorghum. Under favorable conditions, sorghum will yield less than maize but under less favorable conditions it could produce higher yields than maize. Sorghum silage is harvested between the milk and dough grain stage. The grain content of the forage is near 50%, which is higher than maize. Special silage varieties have been developed that are taller than the dwarf grain varieties. They can yield close to 20 tonnes DM ha1 and are nearly equal in quality to corn silage.

Factors influencing feed quality are content: Varieties with low levels of tannin in • Tannin both grain and plant may be more digestible. apparent digestibility of grain: Nearly 20% of • Low whole sorghum grain can pass into the dung

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undigested. Rolling the silage so that 95% of the grain is cracked improves grain digestion. Specialist forage varieties with high grain digestibility are required. Protein digestibility: The crude protein content of sorghum forage is usually higher than that of maize but the protein is less digestible and as with maize protein supplementation is required. Other improvements: Grain sorghum forage could be improved by increasing some or all of stem digestibility, stem sugar content, DM yield, stay-green attributes, and drought resistance.

Forage sorghum (sweet sorghum) (Sorghum vulgare). Sweet sorghum or sorgo has tall sweet juicy stems with small grain heads and is used mostly for silage. Quality and yield are stable near harvest with a balance between stem sugar content and grain yield. DM yields can be as high as those of maize but the yield of total digestible nutrients is much lower. Protein content is similar to that of maize but energy content is usually less than that of maize. BMR varieties have been developed with similar digestibility to maize but they will lodge. Multiple cut: Sudan grass (Sorghum bicolor L. Moench var. sudanense). Sudan grass tillers extensively and regrows rapidly. Stems and tillers are finer and more suitable for grazing, and dry down for haymaking more readily than other sorghum types. Flowering is day length sensitive, which restricts running to head early in the season. Sudan grass has lower yield than sorghum  Sudan hybrids but can be managed to produce higher quality feed. Sudan grass hybrids have been developed from crosses of Sudan grass strains. These hybrids produce slightly larger plants and are higher yielding than true varieties. Sorghum  Sudan grass hybrids. Hybrid forage sorghums are usually developed from a forage sorghum female and a Sudan grass male plant. Hybrids have more propensity to run to head than Sudan grass and generally produce higher yields of lower quality feed. More than 50% of the yield is in the stems. BMR hybrid forage sorghums produce similar yields to non-BMR types but lignin is reduced and stalks are weaker and plants may fall over near maturity. BMR varieties should be harvested early. BMR hybrid forages offer real improvements so that production and quality are similar to that of maize when managed efficiently.

Forages and Pastures | Annual Forage and Pasture Crops – Species and Varieties

Important antinutritional factors of sorghum include poisoning, • HCN sulfur deficiency, • low sodium, and • nitrate poisoning. •

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(German, Italian, Siberian, or Hungarian) millet • foxtail (Setaria italica L. Beauv), millet (Echinochloa colonum var. frumentacea • Siberian Ridley), (white French) millet (Panicum miliaceum L.), and • proso browntop millet (Panicum ramosum L.). •

Millets

Sugarcane

Millets are useful forages for emergency sowings to fill feed gaps both early and late in the summer–autumn period. Pearl millet managed efficiently is a useful high-yielding and high-quality summer–autumn forage. Short-season millets can be sown much later than other summer forages and still give reasonable DM yields. One benefit is that they can use nutrients from a failed crop. Millets tend to be lower yielding than other summer crops and forages, particularly in wet and cool years; however, they can withstand dry and relatively low-fertility conditions. Some millets can be grazed effectively when plants are 15–30 cm tall, as with more mature plants the nutritive value declines and regrowth is restricted. Hay can be made at the boot stage but thick culms make drying difficult. Millets ensile readily.

Sugarcane is used in Brazil and other tropical and subtropical areas as a high-energy roughage. Mineral content is low, and phosphorus, sulfur, zinc, and manganese supplements could be required. Protein levels are low and urea is mixed with the forage as a nonprotein nitrogen source and added sulfur may also assist in rumen protein synthesis. Cane varieties with high sugar content should be used. The forage should be chopped just before feeding and the additives mixed in carefully. The harvested material should not be stored for more than 2 days. Sugarcane can fill feed gaps. Preparing and feeding sugarcane is labor intensive.

Pennisetum millets

The Pennisetum millets have various names worldwide including pearl, bulrush, candle, or cattail millet. Synonyms for the species name include Pennisetum glaucum (L.) R. Br., Pennisetum typhoides (Burm.) Stapf & Hubb., and Pennisetum americanum (L.) Leeke. Pearl millet has the highest yield potential of all millets. It tillers profusely and has a high leaf to stem ratio and strong regrowth potential. Flowering is induced with increasing day length and late-maturing varieties give leafy feed late in the season. Pearl millets mainly grow in the summer and early autumn, producing forage with about 15% protein at 1.5 m, which is higher than other millets, sorghums, and maize. Pearl millet is useful for hay, silage, and grazing. Pearl millet crops are more susceptible to establishment failure than other summer annual forage grasses if they are not sown carefully. Japanese millet (Echinochloa crus-galli)

Japanese millet has superior cold tolerance to all summer forages and will establish when soil temperature reaches 14  C. It is the most useful forage to fill early summer feed gaps. Grazing is available 4–6 weeks after planting and grain ripens 45 days from seeding. DM yield is lower than other summer forages. Japanese millet is adapted to wet soils and tolerant to low pH and salinity. There are four millets that can be used as late-sown rescue crops or sown under more extreme conditions than other summer forages:

Cool Season Grasses Annual ryegrass

Annual ryegrass produces high-quality feed and is used worldwide for grazing and hay and silage production. It prefers mild to warm climates with production suppressed by low temperatures in winter and by high temperatures in summer. Annual ryegrasses grow further into the summer than many other cool season grasses, with peak growth in the temperature range of 20–25  C. Rapid establishment and a long growing season mean that the first grazing of annual ryegrass is 2–3 weeks earlier than for perennial ryegrass and lasts 2–3 months longer than for oats. Effective systems incorporating annual ryegrass include the following: into existing summer grass pastures • Overseeding (e.g., kikuyu, couch, paspalum) to extend the growing

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season. Oversowing in autumn at a high seed rate will provide autumn, winter, and spring feed. Annual legumes, red clover, or white clover can also be combined in mixtures for oversowing to enhance feed quality. Oversowing of small-grain and annual ryegrass mixtures to provide a good spread of production. Small grains (oats, barley) produce their highest production from autumn to midwinter and then ryegrass takes over in late winter and spring. Oversowing into perennial ryegrass pastures to increase late autumn, winter, and early spring production; however, the perennial ryegrass may be weakened. Oversowing into brassicas (e.g., turnips) to extend summer–autumn production into winter–spring, or

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autumn–winter production into spring (kale, rape, or pasja). Cover crop for perennials (fescue, cocksfoot).

The following annual ryegrass types are useful for annual forage production: Italian ryegrass (Lolium multiflorum Lam.)

Italian ryegrasses are biennials to short-term perennials, which can grow in the second year but produce much less forage than from a fresh sowing. Best results are obtained by resowing each year. Doubling the chromosomes in normal diploid varieties breeds tetraploid varieties. Tetraploids have higher sugars, higher digestibility, larger leaf and seed size, and fewer but larger tillers than diploid varieties. The tillers are more open and less competitive with legumes. They are also grazed preferentially. Nevertheless, diploids often grow better, are more grazing tolerant, and regrow more rapidly, providing more grazings. Westerwolds ryegrass (Lolium multiflorum var. westerwoldicum)

Westerwolds ryegrass is a true annual, which will mature, set seed, and die in the year of sowing. It has less heat tolerance than other annual ryegrasses. Short-rotation ryegrass (Lolium hybridum Hausskn (Lolium perenne  Lolium multiflorum))

Short-rotation ryegrasses or hybrid ryegrasses are variable; some are like Italian ryegrass, some closer to perennial, and some intermediate. They usually grow more aggressively than perennial ryegrass and often have the flowering characteristics of Italian ryegrass. Many cultivars have been developed within each of the three types. The main differences are in maturity and resistance to disease, particularly leaf, crown, and stem rusts. Annual ryegrass can usually flower when day length is greater than 10 h. There are varietal differences in day length requirement. Stress speeds up flowering and favorable conditions hold it back. Snow cover will assist winter survival in cold climates. Annual ryegrass has a deep root system, prefers fertile soils, responds significantly to N fertilizer, and competes successfully with weeds and other crops. Self-regenerating annual ryegrass

Annual ryegrasses are available that will regenerate from seed set in the previous year. These ryegrasses are valuable in Mediterranean climates characterized by cool and wet winters and springs, and hot and dry summers. Wimmera ryegrass (Lolium rigidum Guad): Wimmera is early maturing, and has heavy seed set, which will not germinate during hot and dry summers. It is not useful in high-rainfall environments.

Subterranean clover (sub-clover) is often sown in combination with Wimmera ryegrass. Wimmera ryegrass has a high weed potential in cropping areas. Small-grain cereals

The small-grain cereals, wheat, oats, barley, triticale, and rye, are useful as annual forages. Potential uses of smallgrain cereals as forage for dairy production include the following: 1. Whole-crop silage or hay harvested at the optimum time for accumulation of digestible nutrients per hectare. Legumes can also be sown with cereals to increase protein. 2. Double-cropping with maize to produce high perhectare production. 3. Grazing followed by growing out for hay, silage, or grain production. 4. Grazing only. ^ Specialist crop planted for grazing may be mixed with legumes and sown on clean seedbed or direct drilled. ^ Oversown into existing pastures either alone or in mixtures with annual ryegrass or legumes to extend the season of growth of the pasture into the autumn and winter. 5. Emergency forage when stands or new sowings of perennial forage fail. Winter and spring cereals

The flowering stimulus in different cereal varieties can be managed to produce forage from cereal in most seasons. Winter cereals need a period of low temperature before they are vernalized and will proceed to flowering. Spring cereals have no cold requirement and will flower in response to increasing day length. Some winter cereals, once vernalized, also require increasing day length to flower. In cold climates, winter hardiness is important in the seasonal distribution of cereal forage. Cereals with adequate cold tolerance are effective in very cold climates. Rye has the best winter hardiness potential (25 to 33  C) followed by wheat, triticale, barley, and oats (15  C); however, there can be large differences between cultivars in winter hardiness. Acclimatization is needed to harden off plants. Planting early allows tolerance to increase from(?) 3  C at the beginning of autumn to 19  C by early winter. Crowns should be well developed before freezing conditions commence (2–3 leaves sufficient for survival). Cold hardiness is maintained if crown temperatures remain below freezing, but hardiness declines rapidly with warm winter temperatures. Snow cover helps crowns survive when temperatures fall below minimal survival temperatures. Varying combinations of variety, vernalization requirement, day length response for flowering, and

Forages and Pastures | Annual Forage and Pasture Crops – Species and Varieties

sowing date provide a range of opportunities for forage production from cereals. sowings of winter cereals provide forage through • Spring late spring, summer, and autumn as the cereal will not

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flower until vernalized. Spring cereals sown at the same time will flower and set grain as day length increases. Intercropping of spring-sown spring and winter wheat provides earlier forage production from the spring wheat and later production from the winter wheat. Silage and grazing can be obtained by spring sowing mixtures of winter and spring cereals. Silage is made from the spring cereal, and the winter cereal is grazed after the silage is removed. Sowing winter wheat in autumn allows grazing in late autumn and early spring, but care must be taken not to graze when stems start to ascend. Rye is the best cereal to do this at high latitudes. Sow early to get grazing and also to increase winter hardiness.

Specialist forage varieties of cereals are available but grain varieties predominate as forage varieties mainly for their high level of disease resistance. Specialist forage varieties also need high levels of disease resistance to leaf rusts, stem rusts, and viruses. Tall varieties usually produce more forage than dwarf varieties, and late-maturing varieties also increase forage yield potential. Forage quality in cereals can fall rapidly with advancing maturity. Stage of harvest for hay and silage is critical in ensuring forage of sufficient feed quality is obtained. At the preboot stage, cereals usually contain about 20% protein and have an IVDM digestibility of about 80%. By the milk stage, protein falls to about 12% and In vitro dry matter (IVDM) digestibility to about 62%. The stage of harvest for different cereal types to produce forage of sufficient quality for milking cows is as follows: Should be harvested no later than the boot stage. • Rye: Preboot is best as chemicals in the head reduce feed

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intake through unpalatability, and feed quality also falls rapidly. Triticale: Should be harvested in the boot stage with less than 25% of heads with visible seed heads; any later, feed becomes unpalatable and intake is reduced. Oats, wheat, and barley: Should be harvested in the boot to milk stage.

Insect pest attack should be avoided with appropriate sowing dates or controlled if infestations occur (e.g., Hessian fly in North America). The most suitable cereal will vary between environments and farmers should use the cereal that best meets local climatic conditions. Choices are between the following cereals: Wheat: Wheat varieties are separated into winter- and spring-flowering stimulus, soft or hard grain, and red or

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white grain. Red grain varieties resist sprouting in the head, and hard and soft grain varieties are suitable for forage. Many of the grain varieties are dwarfs, which restricts forage yields. Oats: Oats is the best cereal for oversowing into existing pasture, alone and in association with annual ryegrass, to fill feed gaps. Careful grazing management, controlling the interval and height of defoliation, is required to ensure that the growing points are not removed. Oats grown as a pure stand can give three grazing plus a hay crop. Oats tolerates acid and poorly drained soils but requires more moisture than other cereals, and is prone to heat damage and lodging. Days to maturity vary among oat varieties. Barley: Barley matures earliest of all the small grains. There are 2- and 6-row varieties. Some have rough awns and should not be used for hay, but ensiling adequately softens the awns. Barley uses moisture efficiently, is tolerant to salinity but is sensitive to acid soils, and is responsive to soil fertility and good management. Winter barley is less winter hardy than winter wheat. Rye: Rye will grow at cooler temperatures and provide later autumn and earlier spring pasture than other winter grains. It is the earliest of winter cereals. Early plantings in North America avoid Hessian fly damage and it is the best cereal for autumn and spring pasture. Rye is the most winter hardy of all grains and is resistant to winterkill. Quality is maintained when rye is used as pasture. Rye matures rapidly with declining feed quality and can be lower in quality than other small grains when taken for hay or silage. It is highly unpalatable if matured past the boot stage. Lighter and poorer soils that are not suitable for other cereals can be used for rye production. Triticale: Triticale varieties are developed from wheat  rye or durum wheat  rye hybrids. Spring and winter varieties are available that have potential for high forage yield. Spring types need a long growing season and will produce more silage than oats or barley. The forage yield of winter triticale is usually higher than that of wheat. It takes longer to develop winter hardiness than wheat, so it must be sown earlier than wheat. Once developed, the hardiness of triticale is similar to that of wheat. Tall varieties are susceptible to lodging but shorter varieties are available. Triticale is drought tolerant and produces adequate forage in areas with restricted water supply. In some countries, triticale grain is not harvested as there are no markets, but in Australia the grain is used in the dairy industry as a stock food. Annual Legumes Warm Season Legumes

Summer annual legumes produce high-quality feed in late summer and autumn in tropical and subtropical environments at a time when quality is declining in

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summer grasses and forages. Frequently, half their forage is leaf and half is stem. Leaf digestibility is 60–75% and stem digestibility is 50–55%. Leaf crude protein is about 20% and that of stem about 10%. Grazing stock should be removed when the leaves are eaten to allow regrowth. Severe cutting will restrict regrowth. Bloat can occur but the risk is low. At the first grazing stock will avoid the legume and eat grasses first. These legumes can be used in mixtures with millets and sorghums. They fix nitrogen and supply protein to summer diets. Important summer legumes include the following: Cowpeas (Vigna unguiculata): DM yield potential is 2–3000 kg DM ha1 from dryland and 8000 kg DM ha1 from irrigation. Regrowth is obtained if grazing is delayed to flowering and 2–3 grazings are possible. Silage taken at midflowering provides the best quality. Cowpeas can also produce grain. Soybeans (Glycine max): Yield potential in irrigated crops is up to 10 000 kg DM ha1. Grazing is available only once when green pods are present. Stock reject stems when fed as hay but will eat more as silage. Late-maturing varieties will maximize yield potential. Lablab (Lablab purpureus): Dryland yields are variable (500–5000 kg DM ha1) and irrigated yields up to 14 000 kg DM ha1 can be obtained. Lablab can be grazed up to 3 times. Lablab flowers later than other summer legumes (12–14 weeks compared to 10–12 weeks) with a higher growth rate in autumn. Trampling tolerance is better than cowpeas. Silage can be cut after 12 weeks growth. To widen the range of potentially useful summer legumes, the following can be useful in specific situations: Phasey bean and Aeschynomene (Aeschynomene americana) can be useful in wet areas prone to flooding. Alyce clover (Alysicarpus vaginalis (L.) DC.) can be useful for late sowing for hay production. Quality is retained through a 4- to 6-week harvest window. Annual lespedezas (common Kummerowia striata and Korean Kummerowia stipulacea) tolerate soil acidity and low soil phosphorus. They are adapted to infertile sites and produce high nutritive value feed from low-input systems. There is a huge potential for further worldwide development of legumes as many legume genera have not been effectively exploited. Domestication of wild legumes for specific purposes could enhance dairy productivity, particularly in tropical and subtropical environments.

Strategies for use of these legumes include 1. as pure stands to be grazed or made into hay or silage, 2. planting with other legumes and grasses such as annual ryegrass or cereals for grazing and conservation, and 3. as break crop in dryland cropping rotations. Different legumes have seasonal differences in growth. Legume seed is more expensive than that of grasses and although seeding rates are lower than for grasses cost can influence sowing of some legumes. The erect habit of some varieties is valuable in competing with grass species. Deep-rooted species like arrowleaf and crimson clover extend green feed supply. Legume protein is highly degradable in the rumen. Degradability is reduced with increasing tannin content and advancing maturity. When crude protein in the diet exceeds 25%, energy is required to excrete the excess and essential amino acids may be used inefficiently. Annual legumes can be divided into two groups: 1. legumes resown annually and 2. legumes self-regenerating from hard seed. Resown annuals

Egyptian or berseem clover (Trifolium alexandrinum): Berseem clover falls into two groups: 1. Single cut (var. alexandrinum Boiss.): Unbranched or slightly branched Fahl group of cultivars, which have later maturity. 2. Multicut (var. serotinum Zoh and Lern): Branches from the base. This includes the Mescawi group of varieties such as Bigbee and Multicut. Berseem is adapted to neutral to alkaline soils and has tolerance to salinity. Winter growth rate is better than that of other annual legumes, and berseem lasts longer into the spring, but it will not tolerate severe winters and requires irrigation. High yields of up to 22 tonnes ha1 are possible. When making hay, conditioning helps to dry forage cut with a high moisture content. Several cuts are possible after autumn sowing. High growing points restrict grazing potential. A quick grazing rotation is required with resting periods for regrowth, rather than set stocking or prolonged grazing.

Cool Season Legumes

Trifoliums Trifoliums make up the largest group of cool season annuals. Varieties with the best resistance to local diseases and insects should be used.

Annual cool season legumes are important in supplementing protein and providing a highly digestible feed source. They fix nitrogen, which stimulates grass growth and builds nitrogen fertility, but can cause bloat.

Crimson (Trifolium incarnatum) Crimson clover can be grazed in winter and cut for silage or hay in the spring. The Caprera variety of crimson clover is characterized by high levels of soft seed, which restricts regeneration

Forages and Pastures | Annual Forage and Pasture Crops – Species and Varieties

potential. It is quick to establish, and grows erectly with some autumn and early winter growth, but its highest production is in early spring. Deep rooting extends the spring growing period. Sow early with wheat or oats for grazing. Seed production is cheaper than for sub-clover. Persian (shaftal) (Trifolium resupinatum) Persian clover has rapid regrowth after grazing, high tolerance to waterlogging, and moderate tolerance to salinity. It is sometimes called shaftal or giant shaftal, but shaftal is really T. clusii (annual strawberry clover). There are two subspecies of Persian clover: 1. Trifolium resupinatum var. majus has an erect habit, thick hollow stems, large leaflets, low hard seededness (1–2%), and late flowering and maturity. Varieties include Maral, Leeton, Laser, and Lightning. 2. Trifolium resupinatum var. resupinatum has a more prostrate habit, thinner stems, and smaller leaflets. It flowers earlier than majus with more hard seededness and higher seed yields. Varieties include Kyambro and Nitro Prolific. Persian clover is palatable and nutritious providing up to five grazings and a hay cut, yielding up to 16 tonnes DM per year. Regrowth is rapid after grazing. The plant’s erect habit allows it to grow and compete effectively with annual ryegrass and small-grain cereals. Mixtures with sub-clover can extend the growing season after sub-clover seed is set. Arrowleaf clover (Trifolium vesiculosum) Arrowleaf originated in the Mediterranean region and is characterized by rapid spring growth and is one of the latest maturing of the annual clovers. Establishment is slow due to delicate and drought-susceptible seedlings and grazing must be delayed to allow establishment. Arrowleaf will regenerate from seed, but is best used as a one-season annual. Arrowleaf responds well to rotational grazing (every 2–3 weeks), but when not grazed efficiently, it will become rank and be rejected by stock and associated grasses will be shaded. High level of hard seed affects regeneration and seed should be scarified before sowing new stands. Rose clover (Trifolium hirtum) Rose clover is useful when a balance between cold tolerance and winter production is required. It will reseed naturally but does not tolerate poor drainage and is sensitive to heavy grazing. Rose clover is used in mixtures with medics and sub-clover.

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regeneration by autumn rains. Sub-clover stands out as a regenerating annual. Subterranean clover Sub-clover is useful in Mediterranean climates with hot and dry summers, cool and wet winters, and rainfall in the range of 350–1200 mm. There are three subspecies: 1. The subspecies subterraneum is the most common and requires well-drained, slightly acid soils. 2. The subspecies brachycalycinum is adapted to neutral to slightly acid soils. On alkaline soils, varieties require self-mulching cracking soils to enable seed burial. 3. The subspecies yanninicum tolerates poorly drained soils. Plants are not hairy and the seed color is cream to light brown. Plants are not suited to sandy soils but will produce well in acid soils of pH 5–6 (CaCl2) and are tolerant to soil aluminum (<15% of cation exchange capacity (CEC)). Sub-clover can be sown in mixtures with annual and perennial grasses. The main annual is Wimmera ryegrass, and perennials include fescue, cocksfoot, and phalaris. Sub-clover is useful in areas marginal for dairy production and is productive for seasonal dairying in Mediterranean climates. Maturity in sub-clover varieties ranges from 77 to 150 days. High levels of seed reserves are required in the soil for persistence of sub-clover. An adequate proportion of the seed should be hard to resist early germination. Seed set is increased by not grazing close to flowering. Seed reserves are depleted by false seasonal breaks, which reduce the viable seed in the soil. Sub-clover can be highly persistent as a regenerating annual if managed correctly. Leaves of sub-clover plants are less digestible than the rest of the plant. Lenient grazing increases the proportion of leaves and reduces quality. Balansa clover (Trifolium michelianum Savi) Balansa has low estrogen and is resistant to clover scorch (Kabatiella spp.). It is also suitable for waterlogged or salty soils and as a companion species to salt-tolerant grasses in salty areas. Balansa can regenerate from seed if managed for heavy seed set by restricting grazing close to flowering. Up to 80% of seed is hard seed and 30–40% of the seed eaten passes through stock, which compares to 5% passing with sub-clover. Varieties are available with a range in maturity. Small seed size leads to slow establishment. Hay production leads to low seed set and no regeneration.

Self-regenerating annuals

Medics (Medicago spp.)

Self-regenerating annuals perform best if the seed is buried and the appropriate level of hard seed is available for

Medics can produce high-quality feed that will remain green longer than sub-clover. Some varieties are more

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drought tolerant than sub-clover. Medics may not tolerate extended waterlogging. They can produce high levels of hard seed, which may restrict regeneration in the second year. Medics can be used effectively as break crops for disease control in cereal rotations and at the same time be a high-yielding forage crop that can be conserved or grazed Other annual legumes

There is a wide range of cool season legume species that are used in limited situations. Many of these have not been effectively exploited for intensive dairy production. Examples of such annual legume species include serradella (Ornithopus spp.), Biserrula spp., sweet clover (Melilotus spp.), and gland clover (Trifolium glanduliferum). The twining legumes, vetch (Vicia spp.) and peas (Pisum spp.), can be usefully sown in combination with small-grain cereals to increase the protein content of harvested hay or silage, and to widen the harvest window. Pea seed can be expensive and seeding rates may need to be restricted to contain sowing costs. Brassicas Plants from the family Cruciferae are useful as annual forages, with the genus Brassica the largest source. Brassicas supply highly digestible and high-quality feed with a high moisture content. They are usually grazed but can be green chopped, and ensiling techniques have been developed for kale. Brassicas are useful in extending summer feed supply (e.g., turnips sown in the spring) or for sowing in late summer to produce autumn and winter feed. Some brassicas are biennials but are usually managed as annuals. They are relatively drought tolerant. Brassicas usually supply adequate protein, with leafy types such as kale or rape having 20–25% protein in their tops but only about 10% in the stems. Root types such as turnips have about 15% protein in tops and 8% in the roots. They are all highly digestible with a DM digestibility of about 90%. Moisture content is also high, with DM content down to 7–8%. The fiber content of brassicas is low (15%) and adequate roughage must be supplied to assist digestion. The amount of brassicas in the diet should not be more than two-thirds of the total diet on a DM basis. Care must be taken in introducing cows to brassicas because rumen flora need 2–3 days to adjust. Brassicas can be grown alone or in mixtures with grasses. allow ensiling with kale. • Mixtures with annual ryegrass will extend growth • Oversowing period into spring in mild climates. Early autumn growth of brassicas is not always better than from the existing pasture if it is adequately fertilized and

watered. The potential production from existing pasture should be evaluated before replacing it with a brassica crop. Brassica species and varieties have major differences in root to leaf and stem proportion, yield potential, cold tolerance, and capacity to regenerate after grazing. Some brassicas are suitable for only one grazing, while others will regenerate for 2–3 grazings. DM yields are in the range of 5–15 tonnes ha1. Brassica species suitable for annual forage for dairy cattle include the following: Turnip (Brassica rapa var. rapa Barkant)

Turnips have rapid growth, reaching maximum yield within 80–90 days. A range of maturity is available between varieties. The varietal tops to root ratio ranges from 90/10 to 15/85. Top growth predominates in early growth (first 45 days), then there is a change to root development. The protein content of roots is about half that of the tops and thus the root to top ratio influences protein content. Turnips can be green chopped or grazed more than once if grazing is commenced at or near 30 cm of growth and grazed down so that more than 12.5 cm of residue remains. With adequate residue, growing points are not damaged and regrowth potential is preserved. One or more grazings are for top growth followed by once for root growth. DM yields are not as high as for rape or kale. Swede (Rutabagas) (Brassica napus L. var. napobrassica)

Swedes have a large edible root (swollen stem) and are slow to mature (150–180 days). They are grazed once and do not regrow after harvest. Cold-tolerant varieties of swedes can be the best brassica in terms of DM yield and protein content. Stems will elongate at the expense of root development when sown with tall crops. Swedes are susceptible to waterlogging. Rape (Brassica napus var. napus Bonar)

There are two rape types: giant and dwarf. The giant type is more suitable for cattle as it is more palatable and provides higher yields. Stems vary in thickness and length between varieties. The most suitable grazing interval varies depending on the variety. Rangi is best grazed at 90-day intervals, while the variety Winfred is best when allowed to accumulate yield for a single 180-day period. Some rape hybrids can be first grazed after 60 days, regrazed 30 days later, and then the regrowth utilized after a further 30 days. Kale (Chou Moellier) (Brassica oleracea Kestral)

Leafy kale can be divided into two groups based on stem development: stemless and marrow-stemmed. Stemless kale establishes rapidly and reaches maturity in 90 days at 60 cm height. In contrast, marrow-stemmed kale is

Forages and Pastures | Annual Forage and Pasture Crops – Species and Varieties

slower to establish and matures in 150–180 days at 150 cm height. Generally, kale can be grazed only once, but there is one stemless kale that will regrow if not grazed too heavily. There is the opportunity to plant a second crop of stemless kale in the same season. Kale is the most coldtolerant brassica and can survive severe cold. Feed quality is intermediate between turnip and rape. Other crucifers used as forage for dairy cattle include 1. Hybrids Hybrids between Chinese cabbage and other brassicas give useful cultivars: (a) Chinese cabbage  rape Brassica campestris sensulato  B. napus: varieties Pasja and Perko. (b) Chinese cabbage  turnip B. campestris sensulato  B. rapa L.: variety Tyfon. (c) Chinese cabbage  swede B. campestris sensulato  B. napus L. var. napobrassica: variety Wairangi. 2. Fodder radish (Rhaphanus sativus) 3. Mustard (Sinapis alba) 4. Fodder beet and sugar beet (Beta vulgaris) are fed to dairy cows in Europe as a high-energy supplement and as a concentrate substitute. Fodder beet tubers are stored and fed back, and sugar beet pulp and sugar beet mash silage are also used.

Genetically Modified Annual Forages Genetically modified (GM) plants are being developed in many counties with a range of aims. The major aims are 1. herbicide resistance (e.g., glyphosate tolerance), 2. disease resistance, particularly for virus diseases, and 3. insect pest resistance; reducing requirement for insecticides (e.g., Bt (Bacillus thuringiensis) toxin incorporated through genetic engineering). GM crops include maize, sugar beet, canola, and soybean. These modified crops could be used for annual forage production for dairy cows. There are concerns, however, that genetic modification could be harmful through the generation of harmful toxins in the food chain or may have severe ecological consequences due to GM varieties outcrossing with other varieties and native or naturalized plants. GM crop plants have been widely adopted in many countries particularly in North and South America. In other countries, a more conservative approach has been adopted and in many countries the sowing of GM crop plants has been controlled. In Europe, Bt maize was cultivated on 21 000 ha under regulatory approval in 2007. GM rapeseed was sown for the first time in Australia in 2008. Studies have been conducted for evaluating the impact of GM plants on dairy animals. Up to 2008,

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no harmful effects had been detected. The impact of GM plants on the food chain does however remain an open question.

See also: Forages and Pastures: Annual Forage and Pasture Crops – Establishment and Management; Grazing Management; Perennial Forage and Pasture Crops – Establishment and Maintenance; Perennial Forage and Pasture Crops – Species and Varieties.

Further Reading Adamson AH and Reeve A (1992) Nutritional evaluation of whole-crop wheat. In: Stark BA and Wilkinson JM (eds.) Whole-Crop Cereals, pp. 85–96. Aberystwyth, UK: Chalcombe Publications. Aumaitre A (2004) Safety assessment and feeding value for pigs, poultry and ruminants of pest protected (Bt) plants and herbicide tolerant (glyphosate, glufosinate) plants: Interpretation of experimental results observed worldwide on GM plants. Italian Journal of Animal Science 3(2): 107–121. Aumaitre A, Aulrich K, Chesson A, Flachowsky G, and Piva G (2002) New feeds from genetically modified plants: Substantial equivalence, nutritional equivalence, digestibility, and safety for animals and the food chain. Livestock Production Science 74(3): 223–238. Bal MA, Shaver RD, Al-Jobeile H, Coors JG, and Lauer JG (2000) Corn silage hybrid effects on intake, digestion and milk production of dairy cows. Journal of Dairy Science 83: 1264–1373. Bogdan AV (1977) Tropical Pasture and Fodder Plants. In: Rhind D (ed.) Tropical Agriculture Series, xiii þ 474pp, 1st edn. London, UK: Longman Group Limited. Callow MN, Michell P, Baker JE, and Hough GM (2000) The effect of defoliation practice in western Australia on tiller development of annual ryegrass (Lolium rigidum) and Italian ryegrass (Lolium multiflorum) and its association with forage quality. Grass and Forage Science 55(3): 232–241. Cherney JH and Cherney DJR (1993) Advances in corn breeding for improved animal performance. Proceedings of the 1993 Cornell Nutrition Conference for Feed Manufacturers, pp. 55–62. Rochester, NY, USA, 19–21 October. Cherney JH, Cherney DJR, Akin DE, and Axtell JD (1991) Potential of brown-midrib, low-lignin mutants for improving forage quality. Advances in Agronomy 46: 157–198. Cohen DC (2001) Degradability of crude protein from clover herbages used in irrigated dairy production systems in Northern Victoria. Australian Journal of Agricultural Research 52(3): 4156–4425. Davidson JL, Christian KR, Jones DB, and Bremner PM (1985) Responses of wheat to vernalisation and photoperiod. Australian Journal of Agricultural Research 36: 349–359. Densley RJ, Austin GM, Williams ID, Tsimba R, and Edmeades GO (2006) Maize silage and winter crop options to maximise drymatter and energy for NZ dairy systems. Proceedings of the New Zealand Grassland Association 68: 193–197. Duncan RR (1996) Breeding and improvement of forage sorghums for the tropics. Advances in Agronomy. American Society of Agronomy 57: 161–185. Easton S, Baird D, Baxter G, et al. (1998) Annual and hybrid ryegrass cultivars in New Zealand. Proceedings of the New Zealand Grassland Association 59: 239–244. Eckard RJ, Salardini AA, Hannah M, and Franks DR (2001) The yield, quality and irrigation response of summer forage crops suitable for a dairy pasture renovation program in north-western Tasmania. Australian Journal of Experimental Agriculture 41(1): 37–44. Faust M, Smith B, Rice D, et al. (2007) Performance of lactating dairy cows fed silage and grain from a maize hybrid with the cry1F trait versus its nonbiotech counterpart. Journal of Dairy Science 90(12): 5706–5713.

562 Forages and Pastures | Annual Forage and Pasture Crops – Species and Varieties Frame J, Charlton JFL, and Laidlaw AS (1998) Temperate Forage Legumes. Wallingford, UK: CAB International. Garcia SC, Fulkerson WJ, and Brookes SU (2008) Dry matter production, nutritive value and efficiency of nutrient utilization of a complementary forage rotation compared to a grass pasture system. Grass and Forage Science 63(3): 284–300. Gomez-Campo C (1999). Biology of Brassica coenospecies (Developments in Plant Breeding and Genetics), Vol. 4 Amsterdam, The Netherlands: Elsevier Science Publishers. ix þ 489pp. Helsel ZR and Thomas JW (1987) Small grain for forage. Journal of Dairy Science 70: 2330. Hopkins W, Davies DA, and Doyle C (l994) Clovers and other grazed legumes in UK pasture land. IGER Technical Review No. l, 61pp, Institute of Grassland and Environmental Research, Aberystwyth, UK. Humphreys LR and Partridge IJ (1995) A Guide to Better Pastures to the Tropics and Subtropics, revised 5th edn. Paterson, NSW: NSW Agriculture. Jacobs JL, Ward GN, and Kearney G (2004) Effects of irrigation strategies and nitrogen fertiliser on turnip dry matter yield, water use efficiency, nutritive characteristics and mineral content in western Victoria. Australian Journal of Experimental Agriculture 44(1): 13–26. Jacobs JL, Ward GN, McKenzie FR, and Kearney G (2006) Irrigation and nitrogen fertiliser effects on dry matter yield, water use efficiency and nutritive characteristics of summer forage crops in south-west Victoria. Australian Journal of Experimental Agriculture 46(9): 1139–1149. Jung GA, van Wijk AJP, Hunt WF, and Watson CE (1996) Ryegrasses. In: Moser LE, Buxton DR, and Casler MD (eds.) CoolSeason Forage Grasses, ASA Monograph 34, pp. 605–641. Madison, WI: ASA. Khorasani GR, Jedel PE, Helm JH, and Kennelly JJ (1997) Influence of stage of maturity on yield, yield components, and chemical composition of cereal grain silages. Canadian Journal of Animal Science 77: 259–267. Kung L, Jr., Moulder BM, Mulrooney CM, Teller RS, and Schmidt RJ (2008) The effect of silage cutting height on the nutritive value of a normal corn silage hybrid compared with

brown midrib corn silage fed to lactating cows. Journal of Dairy Science 91(4): 1451–1457. Milne JA (1990) Brassica leaf and root crops: A review of research findings in relation to animal production. In: Pollott GE (ed.) Milk and Meat from Forage Crops, Occasional Symposium 24, pp. 191–201. Reading, UK: British Grassland Society. Neal J, Fulkerson W, and Lawrie R (2008). Level of water stress substantially affects productivity and water use efficiency of 30 forages used by the Australia dairy industry. Multifunctional grasslands in a changing world. Proceedings of the XXI International Grassland Congress and VIII International Rangeland Congress, Vol. 1, pp. 838. Hohhot, China, 29 June–5 July. Phipps RH (1994) Complementary forages for milk production. In: Garnsworthy PC and Cole DJA (eds.) Recent Advances in Animal Nutrition 1994, pp. 215–230. Loughborough, UK: Nottingham University Press. Skerman PJ, Cameron DG, Riveros F, et al. (1988) Tropical Forage Legumes., 2nd edn. Rome, Italy: FAO. 692pp. FAO Plant Production and Protection Series No. 23, 832pp. Stockdale CR (1992) The nutritive value of subterranean clover herbage grown under irrigation in Northern Victoria. Australian Journal of Agricultural Research 43: 1265–1280. Taylor NL (ed.) (1985) Clover Science and Technology. 616pp. Agronomy Monograph Number 25. Madison WI: American Society of Agronomy, Crop Science Society of Agronomy, Soil Science Society of America. Thom ER and Prestidge RA (1996) Use of Italian ryegrass on seasonal dairy farms in northern New Zealand. 1. Feed production and persistence. New Zealand Journal of Agricultural Research 39(2): 223–236. Thomson NA, Exton PR, McLean NR, and Dawson JE (1997) The impact of turnips on dairy production as evaluated by component trials, simulation modelling and farm systems research. Proceedings of the New Zealand Society of Animal Production 57: 165–168. Ward GN, Jacobs JL, and McKenzie FR (2006) Using limited irrigation water – Crops or pasture? Proceedings of the New Zealand Grassland Association 68: 173–176.