Bilag til Grovfoderseminar 2004 Arrangeret af Dansk Landbrugsrådgivning Aktuelt nyt om græs de nye græsblandinger og de nye arter Af Karsten A. Nielsen, Dansk Landbrugsrådgivning, Landscentret, Planteavl - 1 -
Aktuelt nyt om græs - De nye græsblandinger og de nye arter Forfatter: Karsten A. Nielsen, Dansk Landbrugsrådgivning, Landscentret, Planteavl Rajsvingel Gennem de seneste år er der afprøvet nye sorter af Rajsvingel. grunden til de ikke er med i de anbefalede Frøblandinger til Græsmarker er, at der på nuværende tidspunkt ikke har været tilstrækkelige mængder til at anvende i faste blandinger. Men de kan bestilles på frøbestillingsskemane eller direkte hos de, der formidler frø. Det gælder for rajsvingel sorterne: Sorter af Rajsvingel Sort Type Forhandler Felopa Alm. rajgræs Hunsballe Perun Alm. rajgræs DLF - Trifolium Hykor Strandsvingel DLF - Trifolium Anvendelse og egenskaber: Sorter som ligner alm. rajgræs (Felopa og Perun) kan anvendes til afgræsning og til slæt i blanding med kløver og i renbestand. Sorter, der ligner strandsvingel (Hykor) kan anvendes til slæt i blanding med kløver. I renbestand vil disse typer normal producere et højt udbytte med afgrøden har let ved at blive tung fordøjelig. Ellers skal der gennemføres 5 til 6 slæt årlig for at få en høj fordøjelighed.. Afprøvningen af de nye sorter har vist i forhold til alm. middeltidlig rajgræs: større resistens mod kronrust (især Hykor) større udbytte i første slæt større udbytter generelt, især under forhold, hvor vand og kvælstof er de begrænsende faktorer vi må forvente at persistensen er større såvel under tørre som våde forhold. Indtil der kommer tilstrækkelige mængder rajvingl frø på markedet og der bliver lavet blandinger, der indeholder rajsvingel kan man evt. supplere følgende blandinger: Bl. nr 22: Suppleres med 4 til 6 kg Felopa eller Perun, dvs. ca.20 kg bl. 22 + 4 til 5 kg rajsvingel pr ha.. Denne supplering er især interresant, hvor der satses på at øge slætandelen i forhold til afgræsning. Bl. nr. 42. Suppleres med 5 til 7 kg rajsvingel til slæt. Denne supplering er især interessant, hvor der er tørre forhold eller begrænsede vandingsmuligheder. Sorter Felopa og Perun anvendes, hvor foderværdien sættes højt og sorten Hykor, hvor udbyttet sættes over foderværdien eller der er mulighed for at 1. slæt gennemføres meget tidlig. - 2 -
Arter Rajsvingel Hybridrajgræs Nye græsarter Krydsninger mellem Strandsvingel og ital. rajgræs Engsvingel og ital. rajgræs Alm. rajgræs og ital. rajgræs Hykor og Lofa Sorter Felopa, Perun, Paulita og Forum Citeliac og AberExcel De nye græsarter - kvaliteter Afgræsningsforsøg, hvidkløver 1. 2. Slætforsøg, rent græs Arter Brugsår 1. 2. Alm. rajgræs Rajsvingel Sorter Middeltidl. målebl. Felopa Perun Hykor Citeliac AberExcel 1,17 1,18 1,21 1,21 1,18 1,21 Kg tørstof pr. FE 1,13 1,14 1,14 1,19 1,16 1,14 1,16 1,20 1,22 1,22 1,19 1,22 1,17 1,20 1,20 1,28 1,19 1,22 Oversigten, s. 278 Oversigten, s. 277 Arter Alm. rajgræs Rajsvingel Hybridrajgræs De nye græsarter - udbytter Sorter Brugsår Middeltidl. målebl. Felopa Perun Hykor Citeliac AberExcel Hybridrajgræs Afgræsningsforsøg, hvidkløver 1. 10.910 103 102 97 102 98 Udbytter eller fht. FE pr. ha 2. 10.910 103 103 110 97 93 Slætforsøg, rent græs 1. 11.690 104 104 103 100 103 2. Kar. for overvintring* 9.150 Rajsvingel Felopa -2,0 7 8 Perun -0,9 9 7 116 Hykor 2,5 3 9 113 Hybridrajgræs Citeliac -0,8 13 7 131 AberExcel -1,6 9 6 93 * = Kar. 0-10, 10 = god overvintring Oversigten s. 278/283 82 De nye græsarter - Afgræsningsegenskaber Vraggræs Udb. og merudb., hkg ts. pr. ha Kronrust pct. dækning Arter Brugsår 1.+2. 1. 2. Alm. rajgræs Sorter Middeltidl. Målebl. 6,4 14 7-3 -
Nye typer af græs De nye græsarter - konklusion Sorter Slæt Afgræsning Alm. rajgræs Hybrid rajgræs AberExcel Rajsvingel, Hykor Arter Alm. rajgræs Rajsvingel I renbestand Hybridrajgræs Brugsår Middeltidl. målebl. Felopa Perun Hykor Citeliac AberExcel Med kløver () I renbestand Med kløver () Arter Alm. rajgræs Rajsvingel Hybridrajgræs De nye græsarter udbytte og kvalitet, 1. slæt, hvidkløvergræs Sorter Middelt. målebl. Felopa Perun Hykor Citeliac AberExcel 60 80 100 120 140 D D D D FK in vitro = D Fht. for a.e. pr. ha og FK in vitro Nye typer af græs Fht. udbytte og pct. Fordøjelighed, 4 slæt 13.550 FE 220 kg N pr. ha 310 kg N pr. ha 120 3.020 kg 100 80 60 40 Bl. 42* Rødkløver Hybridrajgræs Rødkløver Rajsvingel Hybridrajgrærajgræsvingel Hybrid- Raj- Alm. rajgræs Fht. for FE Fht. for hkg råprotein FK NDF FK org. stof * = Rød-og hvidkløver, alm.- og hybridrajgræs Oversigten s. 279-4 -
Rødkløver kontra hvidkløver ensilering og fodring Dyrkning af rødkløver udgik næsten af dyrkningen, da der først i 90-erne blev satses på afgræsning på afgræsning i reguleret storfold, hvortil rødkløver ikke egner sig pga. af den oprette vækstform. Derfor har der kun været få aktiviteter med hensyn til rødkløver, dvs. næsten ingen nye sorter i afprøvningen og i dyrknings- eller fodringsforsøg. International har der heldigvis været en betydelig forskningsaktivitet med rødkløver. Et stort EU - projekt om bælgplanterensilage og animalsk produktion (LEGSIL) er gennemført i mellem England, Sverige, Finland og Tyskland. En populær rapport http://www.royagcol.ac.uk/flg/pdf/legsil.pdf. (vedlagt). Fra Sverige er der netop publiceret resultater fra to års ensileringsforsøg og fodringsforsøg med højtydende malkekøer ( J Bertilson and Myphy). Grass and Forage Seince, Volume 58, no 3. Effects of feeding clover silages on feed indtake, milk production and digestion in dairy cows. side 309. Materiale og metoder. Græsmarksplanterne: Hvidkløver: Sonja Rødkløver: Vivi Alm. rajgræs: Helmer, tetraploid. Det 1. forsøgsår er der anvendt ensilagen fra 2. slæt, hvor alm. rajgræs er høstet 8. august, rødkløver den 10. august. Og hvidkløver d. 24. august. Det 2. forsøgsår er der anvendt ensilage fra 1. slæt, hvor alm. rajgræs er høstet d. 8 juni, rødkløver og hvid kløver den 16. juni. 2. slæt i hvidkløver er høstet den 20. august. Blandingerne med 50 pct. alm. rajgræs og hvid- eller rødkløver er blandet i en mixervogn. Besætningen: Rød Svensk og Hvid Breed (SRB) Tilskudsfoder: 8 kg pr. ko daglig af en blanding bestående af sukkerroer pulp, tørret mask, varmebehandlet rapsfrø, havre, byg, sojabønne mel og hvedklid. Den kemiske sammensætning var følgende: Pct. Tørstof 88,6 Aske 5,3 Råprotein 20,7 Eff, protein nedbrydelighed 63,5 NDF 30,9 Eff. fiber nedbrydelighed 48,2 Lignin 4,0 Stivelse 15,5 Beregnet energi MJ/kg ts. 12,7-5 -
Afgrødekvalitet Tabel 1. Kemisk indhold i alm. rajgræs, rød- og hvidkløver, 1. år I afgrøden Alm. rajgræs Rød kløver Hvid kløver Pct. Råprotein 13,8 19,9 27,3 Pct. NDF 51,5 35,4 29,8 Pct. Sukker 11,3 8,6 5,3 Ppm Nitrat - N 1,25 0,34 1,11 Buffer kapacitet* 7,1 7,6 7,7 *) g Hla pr. 10 g ts. ½ rødkløver: ½ alm. rajgræs ½ hvidkløver: ½ alm. rajgræs Tabel 2. Kemisk indhold i alm. rajgræs, rød- og hvidkløver, 2. år I afgrøden Alm. rajgræs Rød kløver Hvid kløver Pct. Råprotein 15,4 20,4 24 Pct. NDF 44,1 29,9 25,5 Pct. Sukker 19,8 10,9 7,4 Ppm Nitrat - N 0,4 0,4 0,4 Buffer kapacitet* 5,4 6,6 6,4 *) g Hla pr. 10 g ts. ½ rødkløver: ½ alm. rajgræs ½ hvidkløver: ½ alm. rajgræs Bemærkninger: Man skal være opmærksom på, at der ikke er samme slættidspunkt i alle afgrøder. - 6 -
Ensilagekvalitet Tabel 3. Kemisk indhold i alm. rajgræs, rød- og hvidkløver, 1. år I ensilagen ½ rødkløver: ½ alm. rajgræs ½ hvidkløver: ½ alm. rajgræs Alm. rajgræs Rød kløver Hvid kløver Pct. Tørstof 34,1 26,3 20,2 30,7 25 Pct. Råaske 11,3 11,4 11 10,8 10,9 MJ pr. kg ts. 10 9,6 9,4 10 10,3 Energi Pct. Råprot. 14,5 20,5 27,2 17,7 20,1 Pct. NDF 49,5 35,3 29,2 39,7 31,2 Poten. ndb. NDF 68,1 58,4 57,5 g/kg NDF Pct. Mælkesyre 4,5 6,8 9 5,7 7,2 Pct. Eddikesyre 1,5 2,7 3,8 2 2,6 Pct. Smørsyre 0,3 0,1 0,1 0,1 0,1 Pct. Etanol 0,8 0,7 0,1 0,6 0,5 Tabel 4. Kemisk indhold i alm. rajgræs, rød- og hvidkløver, 2. år I ensilagen ½ rødkløver: ½ alm. rajgræs Alm. rajgræs Rød kløver Hvid kløver Pct. Tørstof 34,1 30,6 40,8 33,5 42,3 Pct. Råaske 8,9 10,1 10,6 9,6 9,2 MJ pr. kg ts. Rødkløver ( 2. Slæt ) 11,3 10,8 10,9 10,7 9,8 Energi Pct. Råprot. 16,6 19,6 22,9 17,7 16,7 Pct. NDF 43,7 32,9 24,8 38,8 34,6 Poten. ndb. NDF 85,7 68,3 77,9 55,6 g/kg NDF Pct. Mælkesyre 3,5 7,9 5,3 4,9 0,6 Pct. Eddikesyre 0,5 1,7 1 0,9 0,2 Pct. Smørsyre 0,04 0,01 0,01 0,02 0 Pct. Etanol 0,7 0,2 0,2 0,6 0,1 Bemærkninger: I det 1. forsøgsår har tørstof indholdet været for lavt i bælgblanterne. Det har der været rettet op på i det 2. forsøgsår. Råaske indholdet har næsten været den samme i hvidkløver og i rødkløver og den er selvfølgelig højre end i alm. rajgræs pga. af et større mineral indhold i kløverarterne. Proteinindholdet er lavest i alm. rajgræs og højest i hvidkløvergræs. Indholdet af NDF er væsentlig lavere i rød- og hvidkløver end det er i alm. rajgræs. Den potentielle ned brydelighed af NDF er væsentlig lavere i kløverarterne end i alm. rajgræs. ( Bemærk at det ikke er det samme som FK NDF men det ligner. Ensilerbarheden har været særdeles tilfredsstillende i begge kløvervarter. Der er produceret mere mælkesyre og eddikesyre end i alm. rajgræs og mindre smørsyre. - 7 -
Foderoptagelse og Mælkeydelse Tabel 5. Foderoptagelse og produktion pga. af alm. rajgræs, rød- og hvidkløver, 1. år Alm. rajgræs Rød kløver Hvid kløver ½ rødkløver: ½ alm. rajgræs ½ hvidkløver: ½ alm. rajgræs LSD Foder optagelse Ensilage (kg ts. ) 13,2 14,1 12,7 15,1 14,7 1,5 Total (kg ts) 20,3 21,2 19,7 22,1 21,7 1,5 Mælkeproduktion (daglig) Kg EKM 27,6 29,2 28,8 28,2 29,9 1,5 Kg Fedt 1,17 1,22 1,19 1,16 1,27 0,09 Kg protein 0,82 0,88 0,87 0,86 0,89 0,04 Lactose 1,26 1,26 1,38 1,35 1,37 0,7 Urea mmol pr. L 5,9 7,4 9,6 7,5 7,8 1 Vægtændring (kg pr. dag) 0,12 0,44 0,13 0,6 0,4 0,7 Tabel 6. Foderoptagelse og produktion pga. af alm. rajgræs, rød- og hvidkløver, 2. år ½ rødkløver: Alm. rajgræs Rød kløver Hvid kløver ½ alm. rajgræs Rødkløver ( 2. Slæt ) LSD Foder optagelse Ensilage (kg ts. ) 15,2 13 14,5 16 16,3 1,4 Total (kg ts) 22,3 20,1 21,6 23 23,4 1,6 Mælkeproduktion (daglig) Kg EKM 31,3 29,3 29,9 31,9 29,7 2,8 Kg Fedt 1,34 1,23 1,15 1,35 1,27 0,17 Kg protein 0,94 0,87 0,97 0,95 0,88 0,07 Lactose 1,39 1,38 1,51 1,46 1,36 0,14 Urea mmol pr. L 6 7,3 8,1 6,6 5,9 0,7 Vægtændring (kg pr. dag) 0,57 0,12 0,09 0,8 0,3 0,44 Bemærkninger: Foderoptagelsen: I1. forsøgsår har foderoptagelsen været ensartet og høj i begge 50 pct. blandingerne med hvid- og rødkløver. Foder optagelsen har været større i rødkløver end i hvidkløver men det skyldes evt. en højre tørstofprocent. Den totale foderoptagelse har været ensartet og høj uanset om køerne har fået ensilage af kløverarterne i renbestand eller i 50 pct. blandinger. I 2. forsøgsår har foderoptagelsen været størst i hvidkløver og 2. slæt rødkløver, det kan være betinget af en højre tørstofprocent. Den totale foderoptagelse har været ensartet og høj uanset om køerne har fået ensilage af kløverarterne i renbestand, i 50 pct. blanding eller af rødkløver fra 2. slæt. I 1. forsøgsår har ydelsen i EKM har været størst med fodring af en blanding med 50 pct. hvidkløver og 50 pct. alm. rajgræs og større end tilsvarende blanding med rødkløver, der har givet mælk med et lidt lavere fedt ind hold. I 2. forsøgsår har fodring med rød- og hvidkløver ensilage givet samme ydelse i EKM, uanset om rødkløveren er fra 2. slæt. Der tendens til, at en blanding med 50 pct. rødkløver og 50 pct. alm. rajgræs har givet en lidt større ydelse i EKM. - 8 -
Konklusion: Rødkløver kontra hvidkløver Rødkløver og rødkløvergræs har haft en mere hensigtsmæssig indhold af råprotein end ren græs, der ofte er for lav eller hvidkløvergræs der ofte er for højt. Rødkløver og hvidkløver giver ca. samme foderoptagelse, når de har næsten samme energi indhold, men foderoptagelsen er afhængig af tørstofindholdet. Rødkløver og hvidkløver er med hensyn til ensilerbarhed ens og der produceres større mængder af mælkesyre og eddikesyre og mindre smørsyre og alkohol end i alm. rajgræs ensilage. Produktionen af EKM er på samme niveau ved fodring af rødkløver og hvidkløver ensilage med ens kvalitet. I et forsøg med en blanding af 50 pct. hvidkløver og 50 pct. alm. rajgræs var ydelsen lidt højre end i tilsvarende blanding med rødkløver - 9 -
Legume Silages for Animal Production Increasing Profits with Forage Legumes
Legume Silages for Animal Production Edited by R.J. Wilkins The production of this booklet has been funded by the European Union Grant QLK5-2000-30052 Legumes for silage in low input systems of animal production; appraisal of results and technologies. This booklet is focussed on the UK with other booklets in the series dealing with other parts of northern Europe and being published in Finnish, German and Swedish.The booklets are based on research carried out in the project LEGSIL out from 1997 to 2001 with funding from the EU (FAIR CT 96-1832) and national governments. Individual sections were drafted by Jan Bertilsson and Magnus Halling (SLU, Sweden), Guenter Pahlow (FAL, Germany), Chris Doyle (SAC) and Roger Wilkins (IGER). The research in the UK was carried out by IGER and SAC and contact points are: General and ensiling Roger Wilkins, IGER, North Wyke, Okehampton, EX20 2SB (tel. 01392 851337; email roger.wilkins@bbsrc.ac.uk) Agronomy Alan Hopkins, IGER, North Wyke, Okehampton, EX 20 2SB (tel. 01837 883536; email alan.hopkins@bbsrc.ac.uk) Animal production Richard Dewhurst, IGER, Plas Gogerddan, Aberystwyth, SY23 3 EB (tel. 01970 823072; email richard.dewhurst@bbsrc.ac.uk) Environmental impact David Scholefield, IGER, North Wyke, Okehampton, EX20 2SB (tel. 01837 883552; email david.scholefield@bbsrc.ac.uk) Economics Chris Doyle and Kairsty Topp, SAC, Auchincruive, Ayr, KA6 5HW (tel. 01292 525053; email c.doyle@au.sac.ac.uk) Further copies of this booklet are available from Melanie Leonard, IGER, North Wyke, Okehampton, EX20 2SB (tel. 01837 883500; email melanie.leonard@bbsrc.ac.uk) More detailed results of LEGSIL were presented at a Workshop in Braunschweig in July 2001. The proceedings will be published as FAL Agricultural Research Special Issue available free of charge from Christian Paul, Institute of Crop and Grassland Science, FAL, Bundesallee 50, D-38116 Braunschweig, Germany. This booklet is printed by Hedgerow Print, 16 Marsh Lane, Lords Meadow, Crediton, EX17 1ES (tel. 01363 777595; email sales@hedgerowprint.free-online.co.uk). December, 2001
Why forage legumes? Forage legumes can contribute to efficient production systems through: Nitrogen fixation by bacteria in root nodules reducing or eliminating the need for fertiliser nitrogen. Production of feeds of high nutritive quality reducing the need for concentrate feeds. Legumes are essential for organic production, but can also play a key role in adapting conventional systems to the requirements of the 21st Century, through reductions in inputs, saving in costs and reducing the risks of pollution. Reliable methods are now available for the production, conservation and use of legumes for milk production. This will: Reduce costs of milk production. Increase farm profitability. This booklet highlights key factors for the efficient use of legumes using conclusions and recommendations from research in the project LEGSIL carried out from 1997-2001 with EU and national funding. The research was undertaken by six partners: Institute of Grassland and Environmental Research, UK. University of Helsinki, Finland. Swedish University of Agricultural Sciences, Uppsala, Sweden. Institute of Crop and Grassland Science, FAL, Braunschweig, Germany. Scottish Agricultural College, Ayr, UK. Valio Ltd, Helsinki, Finland.
Herbage production from forage legumes Experiments were carried out to determine the herbage production from legumes, cut at the silage stage, in comparison with grass. Five legume species were sown pure or in mixture with grass at the IGER sites at North Wyke (Devon), Bronydd Mawr (Powys) and Trawsgoed (Ceredigion). The legumes and mixtures received no N fertiliser. They were cut three times annually for two years. Yield of legumes in pure stand (average of three sites for two years) Yield of legume-grass mixtures (average of three sites for two years)
General conclusions from trials For red clover and lucerne yields were comparable to grass receiving 200kg N/ha; there was little difference according to whether these legumes were sown alone or with grass. Yields for white clover and lotus were lower, but were increased when grown in mixture with grass, which would be the normal recommendation. Establishment of the legumes can be critical. Galega did not establish satisfactorily at any of the UK sites, although giving promising results in the other countries. This failure may have occurred because of competition with unsown grasses and white clover. Persistency can be a problem for legumes. Yields and average legume contents declined in the second year, particularly for lotus and red clover. At the upland site at Bronydd Mawr, only a few plants of lucerne survived into the second year, whilst red clover persisted well for three harvest years. The legume species Red clover had a high yield with relatively little variation between sites, but yield was lower in the second year except at Bronydd Mawr. Mixtures with grass had a high content of red clover. Lucerne had the highest yield potential but yields varied a lot between sites. Establishment was a problem at sites with low ph and high competition from unsown species, White clover, in mixture with grass, was consistent across sites and yield tended to improve with time. Lotus was not outstanding at any site, with a low yield and low persistence. The three harvest system may have penalised lotus, because better performance has been found in Sweden when only two cuts are taken. Galega was rather variable in yield but showed very good persistence, especially in the third year in Sweden and Finland. Establishment can be a problem and galega failed in the UK.
General points for successful legume production Establishment is generally better on a well-structured soil; use lime if ph is below 5.5. Inoculate with appropriate rhizobia if species that have not been commonly grown are used. Ensure adequate P and K, but avoid N. If a cover crop is used, spring barley can be a good choice, but reduce seed and N fertiliser rate. Control perennial weeds before sowing. Annual weeds can be controlled with a cover crop or by taking several cuts during establishment leaving a high stubble. Mixtures with grass often give the best performance. Choose a companion grass with similar development and competitiveness. Growth characteristics for the silage legumes Characteristic Red clover White Lucerne Lotus Galega clover Soil type All types Not too Well All types Prefer heavy drained lighter Ideal ph 6.0-7.5 6.0-7.0 6.0-8.5 5.0-7.5 6.0-7.5 Establishment rate Fast Medium Medium Slow Slow Inoculation needed No No Yes Yes Yes Drought tolerance High Medium Very high High High Persistence Low High Medium Medium High Regrowth rate High High High Medium Medium Red clover with grass White clover with grass
Agronomic characteristics of the silage legumes Characteristic Red White Lucerne Lotus Galega clover clover Production High Medium Very high Medium Uncertain potential Stability in yield Medium High Low Medium Uncertain Varieties See NIAB See NIAB See NIAB Norcen, Gale list list list Georgia 1, Leo Companion grass T, Mf, Pr, Mf, Pr, Mf T, Mf, Pr T, Mf Hr, It Hr Competition High Medium High Low Low in mixture Number of cuts* 3-4 3-5 3-4 2-3 2-3 Seed rate (kg/ha) Pure 12-16 18-22 20-30 With grass 6-10 4-5 14-18 4-5 12-18 Rate of grass** 15-20 15-20 8-12 8-12 8-12 T = timothy, Mf = meadow fescue It = Italian ryegrass * Including possibility of grazing red and white clover and lotus Pr = perennial ryegrass Hr = hybrid ryegrass ** Reduce to about one third this rate for timothy Lucerne with grass Lotus with grass Galega with grass
Making silage from legumes Robust and reliable techniques are needed for the conservation of legumes. However, forage legumes give some difficulties with ensiling because of: Low contents of water-soluble carbohydrates (WSC), which are required for fermentation to the preserving lactic acid. High contents of buffering substances, which counteract the desired quick acidification. Water-soluble carbohydrates in legumes and ryegrass Rubber rollers in Krone mower-conditioner give effective conditioning of legumes
Technology must be adapted to allow for these features of legume composition. Preservation was consistently good provided that: Fermentability coefficient (FC) is increased by wilting to above 30% dry matter (DM). Fermentability coefficient integrates the effects of WSC, buffering capacity and DM content. A value of at least 45 is required for successful preservation without additives. The cut crop is wilted rapidly. The use of a mower-conditioner with rubber rollers has been particularly effective as it crimps the stems and increases drying without increasing field losses. Effective additives are used. Fermentability coefficient in legumes and ryegrass Direct cut 25% DM 40% DM Galega 29 35 47 Lucerne 27 35 48 Lotus 24 34 47 Red clover 27 38 50 Ryegrass 41 48 63 Note that the fermentability coefficient for ryegrass at 25% DM is similar to that of the legumes at 40% DM, indicating the need for extra measures with legumes to achieve successful preservation.
Slight wilting of legumes to 25% DM alone was not sufficient, generally, to avoid poor fermentation, which resulted in butyric acid production and ammonia formation from protein decomposition. The table shows the effect of either a single strain inoculant (Ecosyl) (10 6 cfu Lactobacillus plantarum per gram of the crop) or formic acid (6 l per t at 25% DM and 3.5 l per t for heavily wilted crops) compared to the control: While both products were equally successful in reducing butyric acid content to an acceptable low level, formic acid was more efficient in preventing the protein breakdown as indicated by the ammonia fraction expressed as percent of the total nitrogen (TN). It was particularly important to achieve a high DM content or use a high rate of acid additive with lucerne and galega. Effect of additives on quality of silage fermentation Additive Butyric acid Lactic acid NH 3 N Treatment % DM % DM % TN Control 0.46 6.6 12 Inoculant 0.09 8.8 8 Formic acid 0.06 2.2 5 Legume silages have good stability on exposure to air: None of 264 legume silages showed any heating or fungal spoilage when exposed to air for 4 days and 90% of the silages were stable for 7 days. Mixtures of legumes and grass (50:50) also produced silages with high aerobic stability. 90% of pure grass silages deteriorate within 4 days. These results in relation to preservation and aerobic stability were confirmed in experiments at a field scale using both big bales and bunker silos. Suitable technology is available for the successful ensiling of all the forage legumes.
Nutritional characteristics of legumes There are major differences between legumes and grass silages that relate to differences in physical and chemical composition. Especially the contents of crude protein (CP), neutral detergent fibre (NDF) and water-soluble carbohydrates (WSC) differ between species. WSC content is lower while mineral contents are higher for legumes than for grasses. All silages used in the animal experiments were of good hygienic quality. Silages used for dairy cow experiments Species CP NDF Ammonia-N (%) (%) (% total N) Grass 15 53 7 Red clover 19 38 8 White clover 25 29 8 Galega 22 50 8 White clover is highest in protein and lowest in NDF. Galega and lucerne are high in fibre and fibre digestibility is much decreased by late cutting. Red clover and lotus are intermediate between the extremes above. Silages from baled legumes are of good hygienic quality. No negative health aspects were observed even when 100% legumes were fed. No signs of bloat were observed in any of the trials. Wrapping of bales Disintegration of bales
High intake potential when feeding legume silages Feed intake studies were carried out for dairy cows and sheep. For both categories of animals feed intake was higher for legumes and legume-grass mixtures compared to grass. Forage dry matter intake vs. organic matter digestibility by sheep Silage intake by dairy cows fed 8 kg concentrate Means over countries and years, kg DM/cow/day (G=grass, RC=red clover, WC=white clover, Gal=Galega, combinations of legends indicate mixtures, 50/50 on DM basis)
Production from dairy cows fed legume silages Cows produced more milk and lambs grew faster when legume and legume-grass silages were fed compared to grass silages. Milk production from dairy cows Means over contries and years, kg/cow/day (legends as in figure on silage intake) Highest milk yield with white clover but lowest milk fat content and nitrogen efficiency. Similar milk production on pure red clover and red clover-grass mixes. Results from feeding galega showed that harvest stage is crucial. Lucerne was fed in only one experiment. Intake was very high, but milk production was lower than with white or red clover.
Increased concentrate levels decreased the intake of silage by 0.3-0.4 kg DM and increased milk production by around 1 kg per kg concentrate. This was the same for grass and legume. Nitrogen efficiency in the cow is negatively correlated to N content in feeds. Typical nitrogen efficiencies for dairy cows fed silage-dominated diets, as in the LEGSIL trials, are 20-30%. More forage and higher legume proportions lead to higher contents of unsaturated fatty acids in the products. This may be positive for human health, but increases the risk of oxidation of fat in milk and meat. There was little effect of legume silages on rumen ph, VFA and digestion. Rumen microbial protein production was increased with legume silages, but this arose from higher intake of nitrogen, rather than enhanced microbial efficiency with legume silages. Rapid digestion and particle breakdown in the rumen are probably the major drivers for increased intake and production with legume silages. In other UK studies lambs grew faster on legumes and the highest growth rate was obtained when feeding lotus silage.
Economics of forage legumes Production costs and crop values From the LEGSIL trials conducted in the UK, estimates have been obtained of the costs of producing silage from forage legumes and the economic value of the feeds. The costs and feed values are shown in per t dry matter for pure and mixed crops of grass, white clover (WC), red clover (RC), lucerne (Luc) and lotus (Lot) in the figures below. In the case of pure grass silage, production costs are presented for swards receiving both 200 (G200) and 400 (G400) kg of fertiliser N per hectare. In all other cases, no fertiliser N is applied. Production costs Economic food value General conclusions Silage from red clover and lucerne costs about 10 per cent less than grass silage to produce. Grass-legume silages have similar or slightly lower production costs per t DM. Pure legume silages have the highest economic value as a feed. Grass silage is the least valuable feed.
Comparative profitability The attraction of growing forage crops is not determined by either costs of production or the economic value of the feed, but rather by the profitability per hectare. The comparative profitability of growing and ensiling forage legumes is shown in the figures below. In every case, the profits for the different forage legumes have been expressed as the increase in profits expected to be realised from growing a particular forage legume relative to ensiling a grass crop receiving 200 kg of N per hectare. Increase in profits General observations Red clover and grass-red clover mixtures appear to be the most profitable forage legumes to grow for silage. White clover and lucerne, either as pure crops or mixtures with grass, also appear to be economically more attractive than even grass silage produced on swards receiving 400 kg of N per hectare. It would appear that pure legume silages are more profitable to grow than grass-legume mixtures. However, the LEGSIL trials elsewhere in Europe showed that grass-legume mixtures performed better than pure legume silages.
Profitability of organic legume systems As legume-based systems potentially do not require inorganic fertiliser, they are very attractive for organic livestock systems. Using the results of feeding trials, the comparative profitability of organic dairy systems based on legume silages are shown in the figures below. In each case these show the increase in profits per hectare from growing and feeding organic legume silages relative to conventional grass-based conservation systems. The gains in profits have been calculated at organic milk price premiums of 20 and 40 per cent. Increase in profits organic milk price premium of 20% Increase in profits organic milk price premium of 40% General observations Using forage legumes, organic systems should achieve profits in excess of those for conventional grass-based systems, even with a milk price premium of around 20%. Red and white clover, whether grown as sole crops or as mixtures, seem especially promising forages for organic silage systems. Overall forage yields for organic conservation systems would need to be 15% to 20% less than those obtained from conventional grass silage systems to wipe out the economic advantage.
Potential problems with forage legumes Some possible problems with legumes for silage are discussed below: Nitrogen losses to the environment Although inputs of fertiliser N are low, levels of N leaching from fields with pure legumes may be slightly higher than from grass with 200 kg N/ha. Action: Losses reduced with grasslegume mixtures. Avoid pure legumes in nitrate vulnerable zones. The high crude protein (CP) content in legumes may increase the quantity of nitrogen lost in excreta, particularly urine. Action: Reduce CP in concentrate feeds. Use grass-legume mixtures or feed with low CP forages, such as maize or whole-crop cereals. Animal health Fresh legumes may cause bloat, but this is rarely a problem with silages. Bloat does not occur with lotus. Some varieties of red clover have high contents of oestrogens, which can reduce fertility, particularly in sheep. Milk quality Differences in taste were detected in LEGSIL between milk from cows fed legume and grass silages. This is not thought to be a major problem.
Conclusions Forage legumes can increase profitability in milk production systems. The most suitable species as special silage crops are red clover and, in the right conditions, lucerne, giving yields at least as high as grass with 200 kg N/ha. Where legumes are to be grazed as well as ensiled, grass-white clover mixtures are the most suitable. Legumes can be successfully ensiled in bunkers and big bales when wilted to 25% DM with acid additives and when wilted to 35% DM with either acid or an effective inoculum. Legume silages give higher milk production than grass silages, associated with high levels of silage intake. Legumes should generally be fed with concentrates or forages of low crude protein content in order to reduce losses of nitrogen in faeces and urine.