Paper presented at the 58th New Zealand Grassland Association Conference, 21-24 October 1996, Oamaru.Increasing concerns about food quality and animal
fat in the human diet have promoted research into
the effects of different forage species on carcass
quality and fat content. This trial investigated the
effect on carcass composition and the intensity of
sheep meat flavour and odour of five different pure
pasture species: Grasslands Lancelot plantain
(Plantago lanceolata), Grasslands Puna chicory
(Cichorium intybus), Grasslands Huia white clover
(Trifolium repens), Grasslands Nui high-endophyte
perennial ryegrass (Lolium perenne) and Grasslands
Goldie lotus (Lotus corniculatus). Although pasture
species did affect meat quality and fat content,
there appeared to be an inverse relationship with
carcass weight: larger lambs had more fat, which
was related to difference in body size and relative
maturity rather that pasture species. Pasture species
also influenced muscle ultimate pH, sheep meat
odour, foreign odours, and flavours, but did not
affect sheep meat flavour.The authors would like to thank the Meat Research
Development Council and the Foundation for Research Science and Technology for funding

Fraser, TJ

Rowarth, JS

Scott, SM

Lincoln University Research Archive

63Proceedings of  the New Zealand Grassland Association 58: 63–66 (1996)Pasture species effects on carcass and meat qualityT.J. FRASER1, S.M. SCOTT2 and J.S. ROWARTH1,31AgResearch, PO Box 60, Lincoln, Canterbury2Meat Industry Research Institute of New Zealand (Inc.), PO Box 617, Hamilton3Plant Science Department, PO Box 84, Lincoln University, CanterburyAbstractIncreasing concerns about food quality and animalfat in the human diet have promoted research intothe effects of different forage species on carcassquality and fat content. This trial investigated theeffect on carcass composition and the intensity ofsheep meat flavour and odour of five different purepasture species: Grasslands Lancelot plantain(Plantago lanceolata), Grasslands Puna chicory(Cichorium intybus), Grasslands Huia white clover(Trifolium repens), Grasslands Nui high-endophyteperennial ryegrass (Lolium perenne) and GrasslandsGoldie lotus (Lotus corniculatus). Although pasturespecies did affect meat quality and fat content,there appeared to be an inverse relationship withcarcass weight: larger lambs had more fat, whichwas related to difference in body size and relativematurity rather that pasture species. Pasture speciesalso influenced muscle ultimate pH, sheep meatodour, foreign odours, and flavours, but did notaffect sheep meat flavour.Keywords: Cichorium intybus, meat flavour, Loliumperenne, Lotus corniculatus, meat odour, Plantagolanceolata, Trifolium repensIntroductionIncreasing concerns about food quality and animal fat inthe human diet have promoted investigations into theeffects of different forage species on carcass quality andfat content. Lambs grazing Lotus pedunculatus, whichcontains tannins, are reported to have lower levels offatness at the same carcass weight than their counterpartsgrazing white clover (Purchas & Keogh 1984). Tanninsin sulla (Hedysarum coronarium) have also been shownto reduce carcass fatness (Terrill et al. 1992a). Chicory(Cichorium intybus L.; Terrill et al. 1992b) and plantain(Plantago lanceolata L.; Dorfler & Roselt 1989) arereported to contain tannins, thus they, too, might affectcarcass composition.Flavour is also of concern in meat quality. Over thepast 30 years many studies have been conducted todetermine if diet influences the flavour of sheep meat.Several studies have shown that meat from lambs grazedon white clover pastures has a more intense flavour thanthat from lambs grazed on ryegrass (Cramer et al. 1967;Czochanska et al. 1970; Shorland et al. 1970). In contrast,a large study by Purchas et al. (1986) found that pasturetype did not significantly affect the flavour of the lamb,although there was a trend for lambs fed on lotus orwhite clover to have a stronger flavour than those grazedon lucerne or perennial ryegrass.The present study examined the effect of pasturespecies on animal productivity (see Fraser & Rowarth1996), carcass quality, and sheep meat odour and flavour.Materials and methodsPure stands of Grasslands Lancelot plantain (Plantagolanceolata L.), Grasslands Puna chicory (Cichoriumintybus L.), Grasslands Huia white clover (Trifoliumrepens L.), Grasslands Nui high-endophyte perennialryegrass (Lolium perenne L.) and Grasslands Goldielotus (Lotus corniculatus L.) were established in spring1992 at AgResearch Lincoln. Grazing periods were 83days in year 1 and 120 days in years 2 and 3. Full detailsof trial protocol were given by Fraser & Rowarth (1996).Carcass weight, dressing-out %, ultrasound GR,actual GR (measured over the 12th rib, 11 cm from themidline of the spine, with a sharpened stainless steelruler), muscle ultimate pH., and, for year 1 of trial,carcass composition including muscle:bone ratio andfat:bone ratio were measured on half carcasses from 20lambs per treatment.In year 3, one leg was removed from each carcassafter development of rigour, frozen at -35oC, andprepared for ultimate pH determination and sensoryevaluation. Ultimate pH was determined from shavingsfrom the semi-membranous muscle of the frozen legs,placed into 10 ml distilled water and homogenised. AnOrion Ross spear electrode (8130), attached to an OrionSA250 meter, was used to measure the pH of thehomogenate. Two lamb legs in the pH range of 5.56–5.63 (mean pH 5.6; low pH samples) and two lamblegs in the pH range of 5.74–6.19 (mean pH 5.9; highpH samples) were selected from each pasture type toeliminate the influence of meat pH on sensory traits(Young et al. 1993)Meat was separated into fat and lean, and thenrecombined in the ratio 3:17 before being minced twice64through a Bauknecht mincer with a 3 mm plate. Sampleswere frozen at -35oC and thawed before sensoryevaluation. Thirty minutes before tasting, each samplewas placed into a separate stainless steel pot, coveredwith a lid to prevent odour transfer, and cooked in aboiling water bath until just brown. At this stage 2% (w/w) caseinate and 1% (w/w) starch were stirred into eachmince sample to bind the fat and water, respectively.The sample was then cooked for another 5 minutes toallow the mince to thicken slightly (Cummings 1989).Each sample was served into 30 ml polycarbonate portioncups which were placed in a Bain-marie and held untilserved to panellists (within 30 minutes).For formal evaluation, trained panellists wererandomly served five samples per session. Over thecourse of two sessions held on the same day, eachpanellist tasted one high and one low pH sample fromeach pasture type. Samples were scored for sheep meatodour and flavour and foreign odour and flavour. Eachattribute was scored on a 10-point category scale where0 = absent and 9 = intense.Data were analysed using Genstat.Results and discussionUltrasound GR (Table 1) and actual GR (Table 2)measurements were higher for white clover, lotus andchicory than for plantain and ryegrass. This wasassociated with greater carcass weight for white clover,lotus and chicory than for plantain and ryegrass (Fraser& Rowarth 1996). Dressing-out percentage varied withyear but was always lowest for ryegrass. Carcass analysis(Table 3) showed that white clover-fed lambs had thegreatest muscle:bone, but also had the greatest fat:bone.Ryegrass-fed lambs had the smallest fat:bone, but alsohad the smallest muscle:bone. The relationship betweenthe two ratios was positive, indicating that increasedmuscle is associated with increased fat. This wassupported by the results from all three years of the trialcomparing GR and carcass weights (R2=0.80).Pasture species affected liver and kidney weights(Table 3). Adjustment for carcass weight removed somedifferences, but adjusted liver weights in white cloverwere significantly (P<0.05) higher than for other species.This is consistent with results from Koong et al. (1983),who showed that fast-growing animals tend to havelarger organs than slow-growing animals. Adjustedkidney weights were greatest in plantain, followed bywhite clover, chicory and ryegrass; all species weresignificantly different from each other (P<0.05). Theheavy kidney weight in plantain-grazed lambs may havebeen due to the presence of active diuretics in the plantain(Deaker et al. 1994).Lambs grazing white clover or lotus had significantlylower mean pH than those fed on plantain or ryegrass(Table 4); the pH of lambs grazing chicory wasintermediate between those of these two groups. Lambsfed on white clover had a significantly stronger sheepmeat odour than lambs fed on ryegrass or plantain, butpasture type did not influence the intensity of the sheepmeat flavour (Table 5). Lambs fed on white clover orlotus also had a significantly higher foreign odour andforeign flavours than lambs fed on ryegrass, plantain orchicory. As the possible effect of pH on odour andflavour had been taken into account in the tasting trialdesign, it can be concluded that although pasture typesignificantly affected the ultimate pH of lambs, pasturetype had no significant effect on sheep meat flavourintensity. This result supports work by Purchas et al.(1986) and Suzuki (1985).ConclusionsAlthough pasture species affected meat quality and fatcontent, there appeared to be an inverse relationshipwith carcass weight: larger lambs had more fat, whichwas related to differences in body size and relativematurity rather than pasture species (Deaker et al. 1994).Table 2 Effect of pasture species on hot carcass weight (kg) and GR (mm).Year Chicory Plantain White clover Lotus RyegrassHCW1 GR HCW GR HCW GR HCW GR HCW GROne 18.3 9.8 ± 0.62 16.8 8.4 ± 0.4 20.1 10.8 ± 2.6 n/a3 n/a 15.6 7.2 ± 0.4Two 20.8 12.4 ± 1.0 14.1 5.6 ± 0.6 23.4 16.4 ± 0.6 19.3 12.0 ± 0.7 14.6 4.7 ± 0.5Three 26.0 17.8 ± 1.1 17.1 8.3 ± 0.9 25.1 17.5 ± 0.8 25.9 17.7 ± 1.2 18.4 9.9 ± 0.41 Hot carcass weight2 Standard error3 Not availableTable 1 Effect of pasture species on ultrasonically assessed GR(mm).Year C h i c o r y P lan ta i n White clover L o t u s R y e g r a s sO n e 12.2 ± 0.41 10.6 ± 0.4 12.5 ± 0.4 n / a 9.6 ± 0.4T w o 12.6 ± 0.7 8.0 ± 0.5 15.7 ± 0.5 12.1 ± 0.4 7.1 ± 0.3Three 18.6 ± 0.6 12.3 ± 0.5 20.4 ± 0.9 19.8 ± 0.5 14.1 ± 0.61 Standard error65Table 3 Effect of pasture species on carcass weights, dressing out%, muscle:bone and fat:bone ratios, kidney and liverweights in year one. All values adjusted to constantcarcass weight by covariance.Chicory Plantain White RyegrasscloverCarcass weight (kg) 18.3 16.8 20.1 15.6Dressing out % 47.9 47.9 48.3 45.2Muscle:bone 3.49 3.47 3.51 3.43Fat:bone 0.94 0.87 1.06 0.81Liver (g) 648.9b 579.8a 749.6c 545.4aKidney (g) 121.0b 142.5c 135.1c 101.5aAdjusted liver(g/kg HCW) 35.6a 33.9a 38.4b 34.5aAdjusted kidney(g/kg HCW) 6.74b 8.17d 7.32c 6.16aMeans within a row that do not share the same letter aresignificantly different at the 5% level.Table 4 Effect of pasture species on mean, maximum and minimumultimate pH values of meat in year 3.Chicory Plantain White Lotus Ryegrassclovern 15 14 13 16 17mean 5.75ab 5.89bc 5.66a 5.72a 5.97cmax 6.14 6.4 5.83 6.19 6.52min 5.40 5.60 5.50 5.50 5.61Means within a row that do not share the same letter aresignificantly different at the 5% level.Table 5 Effect of pasture species on sheep meat odour, sheep meatflavour, foreign odour and foreign flavour. Higher valuesindicate a greater intensity; tests were done on 2 high-pHand 2 low-pH legs for each treatment.Chicory Plantain White Lotus RyegrasscloverSheep meat odour 3.9abc 3.5c 4.7a 4.4ab 3.7bcSheep meat flavour 5.1a 5.2a 5.3a 5.4a 5.7aForeign odour 0.9b 1.1b 2.2a 2.2a 0.8bForeign flavour 1.7b 1.7b 2.8a 2.6a 0.8bMeans within a row that do not share the same letter aresignificantly different at the 5% level.Science and Technology for funding, Mr Trevor Knightand Mrs J. Deaker for assistance, and Dr A. Bray forcomments on the manuscript.REFERENCESCramer, D.A.; Barton, R.A.; Shorland, F.B.; Czochanska,Z. 1967. A comparison of the effects of white clover(Trifolium repens) and of perennial ryegrass (Loliumperenne) on fat composition and flavour of lamb.Journal of agricultural science, Cambridge 69: 367–373.Cummings, T.L. 1989. New cooking methods for meatminces prepared for analytical taste panels. MeatIndutry Research Institute of New Zealand RM189.Czochanska, Z.; Shorland, F.B.; Barton, R.A.; Rae, A.L.1970. A note on the effect of the length of the restingperiod before slaughter on the intensity of flavourand odour of lamb. New Zealand Journal ofAgricultural Research 13: 662–663.Deaker, J.M.; Young, M.; Fraser, T.J.; Rowarth, J.S.1994. Carcass composition of lambs grazing plantain(Plantago lanceolata), chicory (Cichorium intybus),white clover (Trifolium repens) or ryegrass (Loliumperenne). Proceedings of the New Zealand Society ofAnimal Production 54: 197–200Dorfler, H.; Roselt, G. 1989. The dictionary of healingplants. London, New York and Sydney, BlandfordPress, 328pp.Fraser, T.J.; Rowarth, J.S. 1996. Legumes, herbs orgrass for animal performance? Proceedings of theNew Zealand Grassland Association 58: this issue.Koong, L.J.; Neinaber, A.J.; Mersmann, H.J. 1983.Effects of plane of nutrition and organ size andfasting heat production in geetically obese and leanpigs. Journal of nutrition 113: 1626–1631.Purchas, R.W.; Keogh, R.G. 1984. Fatness of lambsgrazed on ‘Grasslands Maku’ lotus and ‘GrasslandsHuia’ white clover. Proceedings of the New ZealandSociety of Animal Production 44: 219–222.Purchas, R.W.; Johnson, C.B.; Birch, E.J.; Winger, R.J.;Hagyard, C.J.; Keogh, R.G. 1986. Flavour studieswith beef and lamb. Massey University, unpubl.Shorland, F.B.; Czochanska, Z.; Moy, M.; Barton, R.A.;Rae, A.L. 1970. Influence of pasture species on theflavour, odour and keeping quality of lamb andmutton. Journal of the science of food and agriculture21: 1–4Suzuki, J. 1985. Influence of finishing diets on objectiveand subjective flavour of lamb. Unpubl. PhD thesis,University of Missouri, Columbia.Terrill, T.H; Douglas, G.B.; Foote, A.G.; Purchas, R.W.;Wilson, G.F.; Barry, T.N. 1992a. Effect of condensedPasture species also influenced ultimate pH., sheepmeat odour, foreign odours and flavours, but did notaffect sheep meat flavour as assessed by a scientificpanel.ACKNOWLEDGEMENTSThe authors would like to thank the Meat ResearchDevelopment Council and the Foundation for Research,66tannins upon body growth, wool growth and rumenmetabolism in sheep grazing sulla (Hedysarumcoronarium) and perennial pasture. Journal ofagricultural science, Cambridge 119: 265–273.Terrill, T.H.; Rowan, A.M.; Douglas, G.B.; Barry, T.N.1992b. Determination of extractable and boundcondensed tannin concentrations in forage plants,protein concentrate meals and cereal grains. Journalof the science of food and agriculture 58: 321–329.Young, O.A.; Reid, D.H.; Scales, G.H. 1993. Effect ofbreed and ultimate pH on odour and flavour ofsheep meat. New Zealand journal of agriculturalresearch 36: 363–370.!

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