Influence of slaughter age and carcass suspension on meat quality in Angus heifers

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1 Animl, pge 1 of 9 & The Animl Consortium 2012 doi: /s niml Influence of slughter ge nd crcss suspension on met qulity in Angus heifers M. Lundesjö Ahnström 1, A. Hessle 2, L. Johnsson 1, M. C. Hunt 3 nd K. Lundström 1-1 Deprtment of Food Science, Swedish University of Agriculturl Sciences, PO Box 7051, SE Uppsl, Sweden; 2 Deprtment of Animl Environment nd Helth, Swedish University of Agriculturl Sciences, PO Box 234, SE Skr, Sweden; 3 Deprtment of Animl Sciences nd Industry, Knss Stte University, Mnhttn, KS 66506, USA (Received 12 Septemer 2011; Accepted 15 Decemer 2011) This study investigted the effects of pelvic suspension nd slughter ge on longissimus thorcis et lumorum (LTL) from 40 heifers with t lest 75% Angus reeding. A totl of 20 heifers were slughtered directly from psture t 18 months of ge, nd crcss sides were hung either y the Achilles tendon or the pelvic one. The other 20 heifers were ssigned to n dditionl winter housing period nd slughtered t 22 months of ge; crcss sides were hung only y Achilles suspension. All crcsses were electriclly stimulted nd ssessed ccording to the EUROP crcss clssifiction system. In ddition, the LTL muscles were ged for 7 or 14 dys efore met qulity ws evluted for intrmusculr ft (IMF), drip loss, colour, sher force, compression nd sensory nlysis. The 22-month-old heifers were hevier, ftter nd hd more IMF thn 18-month-old heifers. Conformtion scores (muscling) did not differ etween the two slughter groups. Pelvic suspension reduced oth etween- nd within-niml vrition for pek force, totl energy nd compression pek force. For the 18-month-old heifers, pelvic suspension lso decresed pek force, totl energy nd compression vriles for the LTL muscles from oth geing periods, wheres Achilles-suspended smples hd lower sher force vlues only t dy 14. Sensory nlysis showed tht pelvic-suspended sides hd greter tenderness, lower ite resistnce, less thrediness, higher juiciness nd met flvour nd less visile mrling thn met from Achilles-suspended sides. Pelvic-suspended sides t 18 months of ge were similr in pek force nd totl energy vlues to the 22-month-old heifers. The importnce of geing the Achilles-suspended sides ws more ovious for smples from 18-month-old heifers thn from the 22-month-old nimls. The correltions etween the different instrumentl mesurements nd sensory tenderness were considerly higher for crcsses suspended y the Achilles tendon (r to 0.20) thn for those hung y the pelvic one (r to 0.19). More correltions etween sensory-evluted tenderness nd sher vriles were significnt fter 7 dys (n 5 6) of geing thn fter 14 dys (n 5 4) of geing. This study clerly shows the enefits of pelvic suspension, which reduces the need for dditionl feeding fter psture. Keywords: eef, pelvic suspension, tenderness, sher force, compression Impliction Met from less intensive ut more economiclly sustinle production regimens is often lower in qulity thn met from more intensive systems. Thus, dditionl vlue-dded processing is necessry for met to e equivlent to the met from intensive systems. This study clerly shows tht use of pelvic suspension for crcsses from cttle on lessintensive feeding regimen will yield met tht is s pltle s tht from more intensive production processing system. Furthermore, if met-pcking plnts use Achilles suspension, Present ddress: Lövst Kött AB, Funo-Lövst 129, SE Uppsl, Sweden. - E-mil: kerstin.lundstrom@slu.se it is oligtory to invest longer, more extensive feeding system to crete met with equl sensory properties s pelvic-suspended met. Introduction In mny countries, cttle production is sed more on feeding forge thn on grin. Economic constrints on the production segment often involve shorter feeding times with less-intensive dietry regimens, wheres the met production segment optimizes cost y incresing crcss weight per niml. These forces often conflict. Longissimus muscle properties re ffected y nutritionl ckground (Bowling et l., 1977; Schroeder et l., 1982; 1

2 Lundesjö Ahnström, Hessle, Johnsson, Hunt nd Lundström Mitchell et l., 1991), crcss suspension method (Hostetler et l., 1975; Troy, 1999) nd geing (Mitchell et l., 1991; Brewer nd Novkofski, 2008). Ahnström et l. (2009) reported tht pelvic suspension ws useful tenderness intervention for met from forge-fed Chrolis heifers, lte-mturing reed. Correltions etween sensory evlution nd ojective mesures of met tenderness vry widely in the literture (Szczesnik, 1968; Pechey et l., 2002). The strength of these correltions seems to vry depending on gender (Pechey et l., 2002) nd the mount of vrition in the dt set (Szczesnik, 1968). In erlier studies, we hve shown tht pelvic suspension significntly reduced oth etween- nd within-niml vrition in Wrner Brtzler pek force mesurements (Ahnström et l., 2006 nd 2009), ut no further investigtions on different instrumentl mesurements of tenderness were crried out in those studies. However, differences etween suspension methods re clerer when nlysed sensorilly insted of with Wrner Brtzler sher evlutions (Ahnström et l., 2009). Becuse compression vriles nd sensory tenderness hve higher correltions thn Wrner Brtzler evlutions nd sensory tenderness (Bouton et l., 1975), compression my e one wy to improve our understnding out tenderness differences relted to pelvic suspension. The min purpose of the study ws to exmine the effects of pelvic suspension on met qulity prmeters ssessed in longissimus thorcis et lumorum (LTL) muscle from forgefed Angus heifers. This study lso compred the comined effects of more extensive nutritionl regimen nd Achilles suspension with psture feeding system nd Achilles or pelvic suspension. Finlly, the study lso investigted the reltionships etween different instrumentl mesurements (Wrner Brtzler sher force nd compression forces) nd sensory tenderness in met from nimls differing in etween- nd within-niml vrition. Mteril nd methods Cttle ckground, feeding regimen nd slughter ge A totl of 40 Angus heifers wened t 8 months of ge were fed forge-sed diet consisting of grss clover silge during 5-month initil indoor period; they were then grzed on seminturl grsslnd for 5 months. Hlf of the heifers (n 5 20) were slughtered directly from psture t n ge of 18 months. The other hlf (n 5 20) were housed during the winter for 4 months, while eing fed forgesed diet consisting of grss clover silge, nd were slughtered t 22 months of ge. Averge live weight gin of the heifers ws 0.69 kg/dy efore wening, 0.63 kg/dy during the initil indoor period nd 0.68 kg/dy during the grzing period. Weight gin during the second indoor period ws 0.44 kg/dy for the 22-month-old heifers. Detils of this feeding regimen re descried y Hessle et l. (2007). Slughter, chilling nd crcss suspension The nimls were slughtered t commercil plnt. Whole crcsses were electriclly stimulted (80 V for 30 s) 30 min fter exsnguintion. Conformtion nd ftness were grded ccordingtotheeuropschemesmodifiedtotheswedish system, in which 15 clsses re used (Swedish Bord of Agriculture, 1998; Commission of the Europen Communities, 2005). The EUROP clsses were trnsformed to numericl figures for conformtion score (1 5 P2,poorestnd155 E1, est) nd ftness (1 5 12, lenestnd155 51, fttest). Cold crcss weight ( hot crcss weight) ws recorded. For the heifers slughtered t 18 months of ge, the left side from ech crcss ws hung y the oturtor formen of the pelvic one, wheres the right side ws suspended y its Achilles tendon. Pelvic suspension ws performed using rope to re-hng the crcsses, just efore the crcsses entered the cooler,,1 h fter stunning. Only Achilles suspension ws used for nimls slughtered t 22 months of ge.crcsses were chilled t 28 to 48C until the next dy nd then cut commercilly t commercil plnt fter seprting the forequrters nd hindqurters etween ris 10 nd 11. Qulity nlyses A 50-cm section of LTL (ri 11 to the lst lumr vertere; Figure 1) ws removed from ll crcsses 24 h fter slughter. Muscles were vcuum pckged nd ged t 48C for 7 dys post mortem. The ph ws mesured fter geing t the nterior end using proe electrode (Knick SE104, Knick Elektronische Messgeräte GmH & Co. KG Berlin, Germny) ttched to ph meter (WTW ph 340, WTW GmH, Weilheim, Germny). A 1.5-cm-thick slice of LTL ws removed (see Figure 1) for colour mesurements nd chemicl intrmusculr ft (IMF) nlysis. Two 10-cm-thick smples for sher force mesurements were removed from the LTL nd vcuum pckged. One smple ws frozen (2208C) directly (7 dys post mortem) nd the other ws ged until 14 dys post mortem efore freezing t 2208C. A 20-cm smple for sensory nlyses ws removed, vcuum pckged nd ged until 14 dys, nd then frozen t 208C. Instrumentl tenderness Instrumentl tenderness ws (Tle 1) mesured on LTL smples using Wrner Brtzler sher force nd compression force methods descried y Honikel (1998) with modifictions s indicted elow. Pek force (N), totl energy (Nmm), hrdness (N), compression re 1 nd 2 (Nmm), Figure 1 Smple loctions of the longissimus thorcis et lumorum for technologicl nd sensory evlution of met from Angus heifers. 2

3 Met qulity in Angus heifers Tle 1 Vriles for sher, compression nd sensory nlysis Sher vriles Pek force (N) Totl energy (Nmm) Sher firmness (N/mm) Doule Compression vriles Hrdness (N) Compression re 1 nd 2 (Nmm) Springiness (mm) Cohesiveness Gumminess Sensory vriles Tenderness Bite resistnce Thrediness Juiciness Mrling Ftty tste Acidity Met flvour Mximum pek force The re under the curve The slope of line drwn from the origin of the curve to its pek Pek of first compression curve The re under the first nd second compression curves Width of the second curve The rtio of the re under the second curve to the re under the first curve Hrdness 3 cohesiveness Overll tenderness judged fter chewing eight times Force needed to ite through slice of met A perceived senstion of thredlike net on the tongue fter chewing eight times Juiciness perceived fter chewing four to five times Judged visully s mount of mrling using pictures s reference Ftty tste nd degree of ft film in the mouth fter chewing eight times Acidulous tste fter chewing five times Overll met tste fter chewing eight times springiness (mm), cohesiveness nd gumminess were recorded ccording to Honikel (1998), nd sher firmness (N/mm) ws mesured (Tle 1) s descried y Lrmond nd Petrsovits (1972). Smples were thwed overnight t 48C while remining in their vcuum pckges nd then plced in wter th (208C) for 1 h to stndrdize the smple temperture efore evluting the juice loss. The smples were gin vcuum pckged nd cooked in the g in wter th for 2 h t 708C. The weight of the met smples ws recorded efore freezing, fter thwing nd fter cooking to clculte the freezing (including thw loss) nd cooking losses. The smples ged for 14 dys were frozen without re-pckging; thus, freezing losses fter 14 dys of geing is the comined loss of oth geing nd thwing. The cooked met smples were stored t 48C overnight. From ech smple, 40-mm-long strips with 100-mm 2 ( ) cross-sectionl re were removed with the fire direction prllel to the longitudinl dimension of the smple. The Wrner Brtzler nd compression ssessments were mde 15 mm from ech end, which mde it possile to use oth methods on every strip. The sher force mesurements were conducted perpendiculr to the fire xis using Stle Micro System Texture Anlyser HD 100 (Godlming, Surrey, UK) equipped with Wrner Brtzler sher force lde with rectngulr hole of 11 mm 3 15 mm. The lde ws 1 mm thick nd hd speed of 0.83 mm/s when cutting through the smples. On verge, 11.8 strips (s.d. 0.58) from ech smple were tested nd the men clculted. Compression mesurements were recorded perpendiculr to the fire direction with squred flt-ended plunger ( mm) driven t 0.83 mm/s twice verticlly 80% of the wy through the strip. The strips were plced in metl cell fitted with two lterl wlls long the long dimension of the strips (10 mm wide 3 20 mm high 3 50 mm long); thus, there ws lterl strin on oth sides nd movement possile only in the longitudinl direction long the fire xis. On verge, 11.7 strips (s.d. 0.66) from ech smple were tested nd the men clculted. Sensory nlysis Smples from the LTL were thwed overnight t 48C, then wrpped in luminium foil nd cooked in conventionl oven t 1258C to n internl end point temperture of 708C. Seven pnelists, experienced t ssessing eef nd trined in ccordnce with ISO (1993), conducted descriptive test profile (ISO, 1985). The cooked smples were tempered to room temperture (,208C) nd served in coded Petri dishes in replictes s rectngulr, 3.8-mm-thick slices. The crust nd outer lyer of connective tissue were removed efore pnel evlution. The sensory ttriutes of cidity, ftty tste, met tste, juiciness, tenderness, ite resistnce, thrediness nd visile mrling (Tle 1) were judged on n unstructured intensity line scle from 0 to 100. The ssessments were performed in duplicte in room with seprte ooths for ech pnelist nd norml white light ccording to ISO 8589 (1988). The PSA progrm (PSA system/ ) ws used for dt collection. Unslted wfers nd wter were ville for use etween smples. Chemiclly determined IMF Smples frozen on dy 7 were prtly thwed, chopped into smll pieces nd mixed. Duplicte susmples were nlysed for IMF y the SBR method (Nordic Committee on Food Anlysis (NMKL), 1989) fter hydrolysis with HCl diethyl ether nd petroleum ether for extrction. Vlues for the duplictes were verged. Colour mesurements Freshly cut smples were loomed on dy 7 for 1 h nd evluted using Minolt Chrom Meter CR300 (Minolt, Osk, Jpn) with n 8-mm perture nd 08 viewing ngle with the 3

4 Lundesjö Ahnström, Hessle, Johnsson, Hunt nd Lundström speculr component included. A white tile (L* , * nd * ) ws used for stndrdiztion ccording to the mnufcturer s recommendtions. CIE (Commission Interntionle de l Eclirge) L* (lightness), * (redness) nd * (yellowness) vlues (Illuminnt D-65) were otined from three scns of ech stek nd verged. Sttisticl nlysis Sttisticl evlution ws crried out using the Procedure Mixed in SAS (Version 9.1, SAS Institute Inc., Cry, NC, USA). For the crcss nd ft trits, slughter ge (18 nd 22 months) ws included in the model s fixed effect. For the met qulity trits, suspension method nd slughter ge were the fixed effects with niml s rndom effect. For cooking loss, IMF ws dditionlly included in the model s covrite. As only Achilles suspension ws used in nimls slughtered t 22 months of ge, no interction effect etween suspension method nd slughter ge could e included. For the sensory evlution, the rndom effect of pnel memer ws lso included. Differences etween lestsqures mens were evluted with the estimte option. Differences due to geing (7 v. 14 dys) were evluted within suspension method/slughter ge sugroup with geing time s fixed nd niml s the rndom effect. Results Crcss trits Crcsses from heifers slughtered t 22 months of ge (Tle 2) were hevier (P ) nd ftter (P ) nd hd more IMF (P ) thn heifers slughtered t 18 months of ge. No differences in musculrity sed on conformtion score (P ) were due to slughter ge. Technologicl met qulity ph, colour nd wter loss. The LTL muscle from the 18-month-old group hd slightly lower ph in the pelvicsuspended sides thn muscle from the Achilles-suspended sides (5.49 v. 5.50, P ). At 22 months of ge, muscle ph from the Achilles-suspended sides did not differ (P. 0.05) from either of the 18-month-old groups. In heifers slughtered t 18 months of ge, LTL muscles hung y the pelvic one were slightly lighter (higher L* vlues, P ) nd more yellow (higher * vlues, P ) thn LTL from the Achilles-suspended side (Tle 3). Slughter ge influenced oth * nd * vlues, where heifers slughtered t 22 months of ge hd more red (P ) nd yellow (P ) colour ttriutes thn those slughtered t 18 months of ge. Sturtion index Tle 2 Crcss qulity trits in Angus heifers slughtered t 18 nd 22 months of ge, lest-squres mens nd s.e. Qulity trit 18 months (n 5 20) 22 months (n 5 20) s.e. P-vlue Crcss weight (kg) Conformtion Ft clss IMF (%) s.e. 5 stndrd error; IMF 5 intrmusculr ft. 1 Conformtion; clssifiction ccording to the EUROP grding system: 6 5 O1; 75 R2, where higher numer mens higher muscling. 2 Ft clss; clssifiction ccording to the EUROP grding system: ; , where higher numer mens thicker ft cover. 3 Chemiclly determined intrmusculr ft percentge in longissimus. Tle 3 Colour, ph nd loss vlues for longissimus thorcis et lumorum from Angus heifers slughtered t 18 nd 22 months of ge, lest-squres mens nd s.e. Slughter ge 18 months Slughter ge 22 months P-vlue 1 Qulity trit Achilles suspension Pelvic suspenison Achilles suspension s.e. Slughter ge Suspension method Numer of oservtions ph L* * * c Sturtion index Freezing loss 7 dys (%) 6.6 x 5.5 x Freezing loss 14 dys (%) 4.6 y 3.8 y 6.6 c Cooking loss 7 dys (%) 22.9 x 22.3 x 20.7 x Cooking loss 14 dys (%) 18.1 y 18.0 y 16.9 y s.e. 5 stndrd error. 1 P-vlue for the effects of slughter ge nd suspension method; significnt vlues re formtted old (P, 0.05).,,c Mens within row with the sme or no superscript letter re not different (P. 0.05). x,y Mens within column nd vrile with no x or y superscript letter re not significntly different etween 7 nd 14 dys of geing (P. 0.05). 4

5 Met qulity in Angus heifers Tle 4 Sher nd compression vrile trits for longissimus thorcis et lumorum from Angus heifers slughtered t 18 (n 5 20) nd 22 (n 5 20) months of ge nd suspended y the Achilles tendon or the pelvic one, lest-squres mens nd s.e. Slughter ge 18 months Slughter ge 22 months P-vlue Vrile Achilles suspension Pelvic suspension Achilles suspension s.e. Slughter ge Suspension method 7 dys of geing Pek force (N) 48.8 x Totl energy (Nmm) x x Sher firmness (N/mm) 6.7 x 5.0 x 4.6 x Compression pek (N) x 93.2 x 97.0 x Compression re 1 (Nmm) x x x Compression re 2 (Nmm) 44.3 cx 34.9 x 39.4 x Springiness 1.6 x 1.4 x 1.7 x Cohesiveness 10.1 x x Gumminess x dys of geing Pek force (N) 36.1 y Totl energy (Nmm) y y Sher firmness (N/mm) 4.7 y 4.4 y 3.9 y Compression pek (N) 93.7 y 84.4 y 80.3 y Compression re 1 (Nmm) y y y Compression re 2 (Nmm) 34.3 y 27.9 y 30.0 y Springiness 1.3 y 1.2 y 1.5 cy Cohesiveness 11.0 y y Gumminess y s.e. 5 stndrd error.,,c Mens within row with the sme superscript letter re not different (P. 0.05). x,y Mens within column nd vrile with no x or y superscript letter re not significntly different etween 7 nd 14 dys of geing (P. 0.05). vlues were lso higher t 22 months of ge indicting more sturted, vivid red colour. Freezing nd cooking losses for the LTL were prtly ffected y suspension method nd slughter ge (Tle 3). Muscles from 18-month-old heifers ged for oth 7 (P ) nd 14 dys (P ) hd lower freezing losses for pelvicsuspended sides thn for Achilles-suspended sides. The smples ged for 14 dys from 22-month-old heifers whose sides were suspended y the Achilles tendons hd higher freezing losses thn smples from 18-month-old heifers. Cooking loss ws lower for the Achilles-suspended sides ged for 7 dys from heifers slughtered t 22 months of ge (P ) compred with the 18-month-old groups, where no differences could e found. Including IMF s covrite in the sttisticl model removed the differences in cooking loss etween ge groups. For smples ged for 14 dys, cooking losses did not differ etween the different tretments. When evluting the effects of 7 v. 14 dys of geing, freezing losses were reduced fter geing in smples from heifers slughtered t 18 months of ge, wheres cooking losses were reduced in muscle from oth the ge groups. Wrner Brtzler sher force nd compression mesurements. The LTL smples ged for oth 7 nd 14 dys from the 18-month-old group hung y the pelvic one hd lower pek force nd required less totl energy to sher smples thn the Achilles-suspended group, with lrger difference etween suspension methods for the smples ged for 7 dys (Tle 4). The compression prmeters responded similrly. For sher firmness, the difference etween suspension methods ws significnt only for smples ged for 7 dys. Smples from heifers slughtered t 22 months of ge hd sher nd totl energy vlues similr to smples from the pelvic group with the 18-month slughter ge. The pelvic-suspended sides from 18-month-old heifers were similr to Achilles-suspended sides from 22-month-old heifers, except for springiness nd cohesiveness fter oth 7 nd 14 dys of geing, for compression re 2 fter 7 dys of geing nd gumminess fter 14 dys of geing, indicting more tender met for pelvic-suspended sides for these vriles (Tle 4). Vrition in Wrner Brtzler sher force clerly decresed in pelvic-suspended smples compred with Achillessuspended smples. Between-niml vrition nd withinniml vrition, clculted s the coefficient of vrition, decresed in smples ged for oth 7 nd 14 dys. Betweenniml vrition decresed from 36.9% to 11.9% for smples ged for 7 dys nd from 31.0% to 16.7% for smples ged for 14 dys. The corresponding vlues for within-niml vrition were decresed from 28.0% to 14.5% (P ) for smples ged for 7 dys nd from 21.2% to 13.2% (P ) for smples ged for 14 dys. For the compression pek, the decrese in within-niml vrition ws evident, with decreses from 23.6% to 14.8% (P ) fter 7 dys of geing ut from 13.4% to 11.6% (P ) fter 14 dys of geing. For the etween-niml vrition, the decreses 5

6 Lundesjö Ahnström, Hessle, Johnsson, Hunt nd Lundström Tenderness Bite Resistnce Thrediness Tle 5 P-vlues for sensory chrcteristics of longissimus thorcis et lumorum smples from Angus heifers for the effect of slughter ge nd suspension method (Figure 2) Slughter ge Suspension method Juiciness Mrling Ftty Tste Acidity Met Flvour c Tenderness Bite resistnce Thrediness Juiciness Mrling Ftty tste Acidity Met tste Sensory score 18 months chilles suspension 22 months chilles suspension 18 months pelvic suspension Figure 2 Lest-squres mens for sensory chrcteristics of longissimus thorcis et lumorum smples ged for 14 dys from Angus heifers with slughter ge of 18 nd 22 months nd Achilles nd pelvic suspension. Sensory scores within n ttriute with the sme letter re not different (P. 0.05). P-vlues for ech trit cn e found in Tle 5 (s.e ). were from 15.2% to 7.5% for smples ged for 7 dys nd from 13.4% to 11.6% for smples ged for 14 dys. When evluting the effects of 7 v. 14 dys of geing for the LTL (Tle 4), smples from Achilles-suspended sides ged for 14 dys were more tender with reduced pek force nd totl energy thn those ged for 7 dys. Moreover, sher firmness nd the compression prmeters except gumminess were lower fter 14 dys of geing. Pek force nd totl energy from the pelvic-suspended sides ged for 7 dys did not differ from those ged for 14 dys, ut sher firmness nd ll compression prmeters except cohesiveness were reduced fter geing. The importnce of geing Achillessuspended sides ws more ovious for smples from the 18-month-old heifers thn from the 22-month-old nimls, where pek force ws similr fter 7 nd 14 dys of geing (P ). However, totl energy nd ll compression prmeters except gumminess showed the effect of geing in the 22-month-old smples s well. Sensory. Sensory nlysis performed on LTL smples ged for 14 dys clerly showed tht suspension method strongly (P ) ffected ll sensory trits except ftty tste (P ) nd cidity (P ; Figure 2 nd Tle 5). Muscles from pelvic-suspended sides hd higher tenderness, lower ite resistnce, less thrediness, higher juiciness nd met flvour nd less visile mrling thn met from Achilles-suspended sides t 18 months of ge. The sensory prmeters lso greed with the compression texture trits tht met from pelvic-suspended sides hd different profile thn Achilles-suspended sides t the sme ge. Prolonging the cttle rering period from 18 to 22 months of ge incresed tenderness nd decresed ite resistnce nd thrediness in the Achilles-suspended sides to vlues similr to pelvic-suspended sides. Visile mrling nd ftty tste were higher for heifers slughtered t 22 months of ge (P for oth; Figure 2 nd Tle 5). Reltionships etween instrumentl nd sensory dt. The reltionships etween the different instrumentl mesurements nd sensory tenderness for the LTL muscle re presented in Tle 6. Correltions were considerly higher for crcsses suspended y the Achilles tendon thn those hung y the pelvic one, where instrumentl texture dt did not correlte significntly with sensory-evluted tenderness. For the smples from heifers slughtered t 18 months of ge nd suspended y the Achilles tendon, sensory-evluted tenderness nd sher vriles were more significntly correltedfter7dysofgeingthnfter14dysofgeing, wheres this difference etween geing times ws sent in the 22-month-old heifers. Discussion The results from this study showed tht slughtering heifers directly fter the grzing period nd using the conventionl suspension method from the Achilles tendon did not lwys produce eef with optiml tenderness. Pelvic suspension nd finishing period improved tenderness nd other sensory trits nd lso reduced vrition etween nimls. In ddition, clerly, met from crcsses hung y the pelvic one hd more positive pltility nd texturl profile thn met from Achilles-suspended crcsses unless n extended feeding period is used. Moreover, pelvic suspension cn clerly reduce or replce geing n dditionl 7 dys. Sensory prmeters positively influenced y pelvic suspension in this study were tenderness, ite resistnce, thrediness nd juiciness. These results re supported y other studies on pelvic-suspended met where sensory prmeters mesuring tenderness hve een improved (Bouton et l., 1973; Clus et l., 1997). The sher vlues declined significntly ecuse of pelvic suspension, which confirms other findings on heifers y Mooney et l. (1999) nd Ahnström et l. (2009) nd severl studies on other gender ctegories (Hostetler et l., 1970; 6

7 Met qulity in Angus heifers Tle 6 Correltions etween sensory tenderness (ssessed t 14 dys of ging) nd sher vrile trits (mesured t 7 nd 14 dys of geing) in longissimus thorcis et lumorum from Angus heifers slughtered t 18 nd 22 months of ge nd suspended y the Achilles tendon or the pelvic one (only 18 months) Slughter ge, 18 months Slughter ge, 18 months Slughter ge, 22 months Achilles suspension Pelvic suspension Achilles suspension Vrile 7 dys 14 dys 7 dys 14 dys 7 dys 14 dys Pek force (N) Totl energy (Nmm) Sher firmness (N/mm) Compression pek (N) Compression re 1 (Nmm) Compression re 2 (Nmm) Springiness Cohesiveness Gumminess Significnt vlues re formtted old (P, 0.05). Bouton et l., 1973; Whlgren et l., 2002; Deryshire et l., 2007). However, other studies report no differences in sher force for pelvic-suspended heifers, lthough ulls did show differences (Ahnström et l., 2011). Sher nd compression vriles clerly decresed with incresed geing time for Achilles-suspended smples, especilly for heifers slughtered t 18 months of ge. Pelvic suspension reduced the need for geing y producing tender met lredy fter 7 dys of geing. This my e of mjor importnce for the met industry to chieve fster throughput of met while t the sme time mintining good tenderness level. Similr results hve een reported in Ahnström et l. (2009), Bouton et l. (1973) nd Bouton nd Hrris (1972). For plnts tht cnnot prctice pelvic suspension, our dt indicte tht incresed time on feed from 18 to 22 months of ge will improve met colour nd mny mesures of tenderness, increse crcss weight nd increse IMF while using the more trditionl Achilles-suspension system. Smples from the 22-month feeding regimen needed less geing thn the 18-month-old product. However, using the comintion of pelvic suspension nd the shorter feeding time (18 months) ws the most efficient nd required the lest feed nd lour per kg produced met. The finl ph mesured fter 7 dys of geing ws slightly lower in pelvic-suspended sides thn in Achilles-suspended sides from heifers slughtered t 18 months of ge. This hs een shown in erlier studies on Chrolis heifers y Ahnström et l. (2009) nd for heifers of the diry reed Swedish Red in Ahnström et l. (2011). No such decrese in ph ws, however, oserved for the ulls nd cows in the ltter study. In ddition to lower ph, the pelvic-suspended sides lso hd lower freezing losses thn Achilles-suspended sides, ut no difference ws found in cooking loss. Although the lower ph vlues for met from pelvic-suspended sides could increse moisture losses, the opposite occurred likely ecuse of the effects of incresed srcomere lengths tht ccompny pelvic suspension (Ahnström et l., 2011). In ddition, Brnier nd Smulders (1994) reported decresed losses for pelvic-suspended sides. When compring losses from the two slughter ges, the cooking losses fter 7 dys of geing were lower for 22-month-old smples, which could prtly e explined y the higher IMF content t 22 months of ge. Similr results were lso found y Jeremih et l. (2003). Post-rigour muscle ph increses s geing time increses (Bokye nd Mittl, 1993), which tends to improve wter-holding cpcity. This my explin our results with lower freezing nd cooking losses fter 14 dys of geing thn fter 7 dys of geing. As the purge ws not mesured seprtely ut included in the 14-dy freezing loss in this study, we hve no record of when the fluid ws lost from the met. However, ecuse the freezing loss fter 14 dys of geing ws lower thn fter 7 dys of geing, purge seems to e lrger during the first period of geing. The lower mount of visile mrling in met from pelvicsuspended heifers found in Ahnström et l. (2009) ws confirmed in this study. This my e ecuse of stretching of muscle fires in the dipose tissue, leding to less ovious visile mrling. As some consumers prefer to uy met with low mrling even though the tste of met with higher mrling is preferred (Grunert, 1997; Ngpo nd Drnsfield, 2006), use of pelvic suspension could lso provide n dvntge in juiciness nd flvour in ddition to its greter tenderness. In this study, we included oth 7 nd 14 dys of geing efore performing the instrumentl sher force nd compression evlution, compring tht to sensory eting qulity fter 14 dys of geing. Interestingly, the instrumentl sher force nd compression mesurements performed fter the sme geing time s the sensory testing did not show higher correltions thn the 7-dy smples. This cn e prtly due to vrition in tenderness long the LTL muscle, ecuse the 14-dy instrumentl smple ws tken t ri 11, site tht hs een reported to hve higher tenderness thn more 7

8 Lundesjö Ahnström, Hessle, Johnsson, Hunt nd Lundström posterior smples (Griepy et l., 1990). The 14-dy smples were lso somewht lower in etween-niml vrition nd could therefore show weker correltions, s discussed y Szczesnik (1968). Generlly, correltions for the compression trits were of the sme mgnitude or lower thn the sher force trits. The compression vriles springiness, cohesiveness nd gumminess were not significntly correlted with the sensory-evluted tenderness. The only exception ws for springiness fter 14 dys of geing (r ; P ) in the Achilles-suspended sides nd ws ecuse of very tender smple with vlues in line with pelvic-suspended sides. Correltions etween sensory-evluted tenderness nd instrumentl tenderness mesurements in the pelvicsuspended sides were quite low nd likely ecuse of the higher level of tenderness nd less vrition etween smples. Our conclusion tht the strength of the reltionship etween sensory nd instrumentl tenderness vries depending on vrition in the ctul mteril grees with Brdy nd Hunecke (1985), who showed poor correltions etween compression trits nd sensory tenderness. Our results were not in line with those of Toscs et l. (1999) who climed compression ws the est predictor of tenderness. Insted, we conclude tht, for this mteril, pek force nd totl energy were good predictors of sensory tenderness. Conclusions Our dt clerly show dvntges of pelvic suspension in the industry to improve tenderness, decrese vrition in tenderness nd reduce the need for extended geing of ovine LTL muscle. Pelvic suspension is lso effective in producing met tht is sufficiently tender from cttle directly from psture where conventionlly hung crcsses my show suoptiml tenderness. This will increse flexiility in oth production nd processing segments. Acknowledgements The uthors re grteful for the help provided y Dr Ingemr Hnsson nd Ms Gertrud Andersson during smpling nd nlysis nd for help with the sensory nlysis y Ms Ktrin Virhmmr. All stff t the Götl reserch sttion re thnked for cre of the nimls nd smpling t the slughterhouse. References Ahnström ML, Enfält A-C, Hnsson I nd Lundström K Pelvic suspension improves qulity chrcteristics in M. semimemrnosus from Swedish dul purpose young ulls. Met Science 72, Ahnström ML, Hessle A, Johnsson L, Hunt MC nd Lundstrom K Influence of crcss suspension on met qulity of Chrolis heifers from two sustinle feeding regimes. Animl 3, Ahnström ML, Hunt MC nd Lundström K Effects of pelvic suspension of eef crcsses on qulity nd physicl trits of five muscles from four genderge groups. Met Science 90, Brnier VMH nd Smulders FJM The effect of pelvic suspension on sher force vlues in vrious eef muscles. In 40th Interntionl Congress of Met Science nd Technology, the Hgue, the Netherlnds, S-IVB,05. 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9 Met qulity in Angus heifers Pechey BM, Purchs RW nd Duizer LM Reltionships etween sensory nd ojective mesures of met tenderness of eef M. longissimus thorcis from ulls nd steers. Met Science 60, Schroeder JW, Crmer DA nd Bowling RA Postmortem muscle ltertions in eef crcss temperture, ph nd pltility from electricl stimultion. Journl of Animl Science 54, Swedish Bord of Agriculture Directions of clssifictions of crcsses from the Swedish Bord of Agriculture. Proceedings of the SJVFS 127. Swedish Bord of Agriculture, Jönköping (in Swedish). Szczesnik AS Correltions etween ojective nd sensory texture mesurements. Food Technology 22, Toscs PJ, Shw FD nd Beilken SL Prtil lest squres (PLS) regression for the nlysis of instrument mesurements nd sensory met qulity dt. Met Science 52, Troy DJ Enhncing the tenderness of eef, Reserch report, The Ntionl Food Centre, Dulin, Irelnd, No. 11, 28pp. Retrieved Jnury 19, 2012, from pdf Whlgren NM, Görnsson M, Linden H nd Willhmmr O Reducing the influence of niml vrition nd geing on eef tenderness. Proceedings of the 48th Interntionl Congress of Met Science nd Technology, Rome, Itly, pp