VARIATION IN PORCINE MUSCLE QUALITY OF DUROC AND HAMPSHIRE BARROWS 1

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Hugo Barnard Ellis
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1 VARIATIO I PORCIE MUSCLE QUALITY OF DUROC AD HAMPSHIRE BARROWS 1 H. B. HEDRICK, R. K. LEAVITT AD M. A. ALEXADER University f Missuri, Clumbia OSIDERABLE research has been re- C prted cncerning physical and chemical factrs that characterize and affect prcine muscle quality. Particular attentin has been given t the cnditin f pale, sft, exudative (PSE) musculature in the scientific literature during the last decade. The incidence f PSE musculature has been bserved t be greater in sme breeds than in thers (Judge et al., 15; Sayre et al., 163; Briskey, 164; Pease and Smith, 165; Allen et al., 166), and influenced by seasn f prductin and slaughter (Wismer-Pedersen, 15; Osinska and Kielanwski, 160; Frrest et al., 163; Jnnsn, 163). The present paper reprts experiments designed t: (1) present additinal data shwing the variatin in muscle quality between Durc and barrws f knwn breeding which were reared and slaughtered under similar cnditins; (2) investigate prductin characteristics assciated with muscle quality; and (3) investigate quantitative carcass characteristics assciated with muscle quality. Materials and Methds Data were btained frm 123 Durc and 155 barrws frm the Missuri Swine Testing Center. The pigs were the prgeny f 50 Durc and 77 bars and 107 Durc and 13 dams. The pigs were delivered t the testing center when 8 t 10 wks. f age and fed with littermate bars. The ratin was cmpsed principally f crn and sybean meal and cntained 16% prtein t apprximately 57 kg. liveweight and 14% prtein t slaughter weight. When the pigs reached 0 t 5 kg. liveweight, feed was withheld and the pigs placed in a pen fr apprximately 24 hr. with ther pigs t be slaughtered. During this perid the pigs had free access t water, were well-bedded during cld weather and kept cl during ht weather by frequent wetting f sawdust in the pen. Sme fighting was h- 1 Cntributin frm Missuri Agricultural Experiment Statin, Jurnal Series Apprved by the Directr. served ccasinally amng the pigs during the hlding perid. The pigs were trucked apprximately six miles t the University f Missuri abattir and slaughtered. Slaughter perids represented were January-March, 164 (Trial I); June-August, 164 (Trial 2); January-March, 165 (Trial 3); and June-August, 165 (Trial 4). After slaughter the carcasses were chilled 24 hr. and prcessed int whlesale cuts. Marbling scres (l=devid t 10=abundant) f the lngissimus drsi at the 10th rib; subjective firmness scres f the l. drsi and ham (l=sft, 2=mderately sft, 3= mderately firm and 4=firm); subjective clr scres f the ham (l=very pale and tw-tned, 2=pale grayish pink and twtned, 3=unifrm grayish-pink and 4=dark tw-tned t unifrm dark); and subjective clr scres f the I. drsi at the 10th rib (1--very pale, 2=pale grayish-pink, 3=nrmal grayish-pink and 4=dark) were recrded. Immediately after the lin and ham were cut, ph determinatins were made f the I. drsi muscle at the 10th rib and gluteus medius and gluteus accessrius muscles. A Beckman Mdel G ph Meter was used t measure the ph by placing the electrdes directly n the freshly cut crss-sectinal surface. A 3.8-cm. chp was remved frm the 10th rib area f the lin and cked in deep fat at 14 ~ C. t an internal temperature f 68 ~ C. Tenderness measurements were made n 1.27-cm. cres using the Warner-Bratzler shear device. Ttal cking lss was determined n each chp. Simple crrelatin analysis and analysis f variance were used t ascertain the relatinships and differences between breeds fr the varius prductin and carcass characteristics studied. Results and Discussin The means fr prductin and carcass characteristics fr the tw breeds by slaughter perids and the significance f differences between breed means are presented in table 1. 48

2 PORCIE MUSCLE QUALITY 4 0 ~ 0 ~ 0 0 ~ ~ ~ ~ ~ ~2. 0 v Oe~l.4 V/ r.) ') ~ 0 ~ 0 0 ~ 0 ~ ~ W 6 W W W W W ~ " '3 r~. e~ ~0 V r.) r...) M

50 HEDRICK, LEAVITT AD ALEXADER With the exceptin f trial 2, the daily rate f gain was higher (P~.01) and feed cnsumed was less (P~.01) fr the Durcs than fr the s.

3 50 HEDRICK, LEAVITT AD ALEXADER With the exceptin f trial 2, the daily rate f gain was higher (P~.01) and feed cnsumed was less (P~.01) fr the Durcs than fr the s. The yield f fur lean cuts was higher (P~.01) and back fat thinner (P~.01) fr the s than fr the Durcs in all trials. The s had larger (P(.01) I. drsi muscles in all trials except trial 4. in all trials the lins and hams frm the Durcs were firmer and darker in clr (P(.01) and the lins cntained mre marbling (P(.01) than thse frm s. Likewise, in all trials the l. drsi, gluteus medius and gluteus accessrius muscles f the Durcs had higher (P(.01) average ph values. There were n significant differences in tenderness f cked lin chps as determined by the Warner-Bratzler shear between the tw breeds. Hwever, less cking lss (P(.01) was bserved fr chps frm the Durcs. As shwn in figure 1 a higher percentage f the hams and lins frm the barrws were scred pale in clr and sft than were hams and lins frm the Durc barrws. These results are in agreement with the reprt f Briskey (164), wh bserved that the frequency f pale, sft muscle was greater in barrws than in Durc barrws at the 162 atinal Barrw Shw. Crrelatin cefficients between subjective firmness and clr scres and prductin and carcass characteristics are given in table 2. These data indicate that firmness and clr scres f the lins were nt significantly related t rate f gain fr either breed. Hwever, fr bth breeds a slight psitive relatinship existed between bth firmness and clr scres f hams and rate f gain. The crrelatins between feed efficiency and bth firmness and clr scres indicated that the Durcs that gained mre efficiently had firmer and darker lins (P~.01). A lw but ppsite relatinship was bserved fr the s. The crrelatins between feed efficiency and bth firmness and clr scres f the hams were nt significant but the trend f the relatinships were similar t thse fr the lin scres. Back fat thickness and 1. drsi area were nt related cnsistently t clr and firmness f ham and lin. Hwever, in mst instances there was an indicatin in bth breeds fr firmer lins and hams t be assciated with carcasses having a lwer yield f fur lean cuts. Durc carcasses with the lwer yield f fur lean cuts had darker and firmer hams (P(.01). When data f bth breeds were cmbined, higher negative relatinships (P~.01) existed between yield f lean cuts and firmness and clr scres f hams and lins. These results supprt the bservatins cited by Briskey (164) f Clausen and Thmsen, and Ludvigsen, that mre muscular 80' 70 6O 5O I~,q. 30 2O 10 /g d ~ 0 Ham Lin Ham L n Ham L~n Ham Lin Ham k~n Ham Lin Ham Lln Hrn Lin Clr Firmness Clr Firmness Clr F rmness Clr Firmnes~ Scre ] Scre 2 Scre 3 Scre 4 Figure 1. Distributin f subjective clr and firmness scres fr hams and lins frm Durc and barrws.

TABLE 2. CORRELATIO COEFFICIETS BE- TWEE SUBJECTIVE HAM AD LOI SCORES AD PRODUCTIO AD CARCASS CHARAC- TERISTICS OF DUROC AD HAMPSHIRE BARROWS and Cmparisn Durc * b DurcC Firmness scre, l.in vs.

4 TABLE 2. CORRELATIO COEFFICIETS BE- TWEE SUBJECTIVE HAM AD LOI SCORES AD PRODUCTIO AD CARCASS CHARAC- TERISTICS OF DUROC AD HAMPSHIRE BARROWS and Cmparisn Durc * b DurcC Firmness scre, l.in vs.: Rate f gain Feed efficiency Fur lean cuts, % Backfat thickness L. drsiarea Marbling scre Clr scre lin L. drsi ph O Clr scre, ham Firmness scre, ham O Gluteus medius ph Gluteus accessrius ph Shear value Cking lss, % Clr scre, lin vs.: Rate f gain O Feed efficiency Fur lean cuts, % Backfat thickness L. drsi area Marbling scre O Clr scre, ham O. 44 O L. drsi area Firmness scre, ham Gluteus medius ph Gluteus accessrius ph Shear value Cking lss, % Firmness scre, ham vs.: Rate f gain Feed efficiency Fur lean cuts, % Backfat thickness L. drsiarea Marbling scre Clr scre, ham L. drsi ph Gluteus medium H Gluteus accessrius ph Shear value Cking lss, % Clr scre, ham vs.: Rate f gain Feed efficiency Fur lean cuts, % Backfat thickness L. drsiarea Marbling scre O L. drsih Gluteus medius r~h Gluteus accessrius ph Shear value Cking lss, % O. O a Crrelatin f 0.18, P=0.05; 0.23, P=0.01. b Crrelatin f 0.16, P=0.05: P--O.01. c Crrelatin.f 0.12, P=0.05; 0.15, P=0.01. barrw carcasses have sfter and lighter clr musculature than less muscular carcasses. Hwever, within breed cmparisns did nt reveal cnsistently that mre muscular carcasses had sfter and lighter clr musculature. The hams and lins f bth breeds were firmer (P.01) frm carcasses that were scred t have mre marbling in the l. drsi muscle. Hams and lins were als darker in clr frm Durc (P.05) and (P.01) carcasses with mre marbling. These findings are nt in accrdance with a reprt by Henry and Bratzler (160) in which little PORCIE MUSCLE QUALITY 51 relatinship existed between fat cntent f prk muscle and its clr. Hwever, in the present study the cmparisn was made between marbling scre and subjective clr scre. In the study by Henry and Bratzler the cmparisn was made between percent fat and quantity f myglbin. In all instances higher muscle ph values f the l. drsi, gluteus medius and gluteus accessrius muscles were psitively assciated with firmer and darker clr lins and hams. The firmer and darker clr lin chps frm the barrws had the higher shear values, while the sfter and lighter clr chps frm the Durcs had the higher shear values. Firmer chps frm bth breeds had lwer cking lsses. Crrelatin cefficients between muscle ph and prductin and carcass characteristics are presented in table 3. In the case f the Durcs there was a slight tendency fr barrws that gained mre efficiently t have higher muscle ph values. definite trend existed fr the s. In bth breeds there was a slight tendency fr higher rates f gain t be assciated with higher muscle ph values. There was a slight tendency fr carcasses f bth breeds with lwer yields f lean cuts t have higher muscle ph values. When car- TABLE 3. CORRELATIO COEFFICIETS BE- TWEE MUSCLE ph AD PRODUCTIO AD CARCASS CHARACTERISTICS OF DUROC AD HAMPSHIRE BARROWS and Cmparisn Durca b Durc e L. drsi ph vs. Rate f gain Feed efficiency Fur lean cuts, % Backfat thickness L. drsiarea ~.26 Marbling scre Gluteus medius ph Gluteus accessrius ph Shear value Cking lss, % Gluteus medius ph vs,: Rate f gain Feed efficiency Fur lean cuts, % Backfat thickness L. drsiarea Gluteus accessrius ph O. 73 Shear value Cking lss, % Gluteus accessrius ph vs.; Rate f gain Feed efficiency Fur lean cuts, % II --.2 Backfat thickness L. drsi area Shear value I Cking lss, % a Crrelatin f 0.18, F=0.05; Crrelatin f 0.16, P=0.05; e Crrelatin f 0.12~ r~o.o,~i 0.23, P= , P=0.01. O,15, P=O.O1.

52 HEDRICK, LEAVITT AD ALEXADER casses frm bth breeds were cmbined these relatinships were significant (P.01). Significant psitive relatinships (P.01) existed between muscle ph values f the I.

5 52 HEDRICK, LEAVITT AD ALEXADER casses frm bth breeds were cmbined these relatinships were significant (P.01). Significant psitive relatinships (P.01) existed between muscle ph values f the I. drsi, gluteus medius, and gluteus accessrius muscles. cnsistent relatinships existed between muscle ph values and shear values r cking lsses. Summary Varius carcass and prductin characteristics f 123 Durc and 155 barrws f knwn breeding were cmpared. Lins and hams f Durc barrws were significantly firmer and darker in clr (P.01) and the lins cntained mre marbling (P.01) than lins and hams frm the barrws. The I. drsi, gluteus medius and gluteus accessrius muscles f the Durcs had higher (P.01) average ph values than the s. There was sme indicatin within each breed that firmer lins and hams and higher muscle ph values were assciated with carcasses that had lwer yields f the fur lean cuts. Hams and lins f bth breeds were firmer (P.01) and darker in clr frm carcasses that cntained mre marbling in the l. drsi muscle. Firmness and clr f lins were nt related t rate f gain fr either breed. Feed efficiency was psitively (P.01) assciated with firmer and darker lins f the Durcs, but a lw negative relatinship was bserved between these same factrs fr the s. Firmer and darker clr lin chps frm the s were less tender, while the sfter and lighter clr chps frm the Durcs were less tender. Literature Cited Allen, E., J. C. Frrest, A. B. Chapman,. First, R. W. Bray and E. J. Briskey Phentypic and genetic assciatins between prcine muscle prperties. J. Animal Sci. 25:62. Briskey, Ernest J Etilgical status and assciated studies f pale, sft, exudative prcine muscultature. Adv. Fd Res. 13:8. Frrest, J. C., R. F. Gundlach and E. J. Briskey A preliminary survey f the variatins in certain prk ham muscle characteristics. Prc. Am. Meat Inst. Fundatin Res. Cnf. 15:81. Henry, W. E. and L. J. Bratzler Effect 2 mineral supplementatin n prk muscle clr as measured by spectrphtmetry and disk clrimetry. J. Animal Sci. 1:115. Jnnsn, J Danish pig prgeny testing results.. Tierz. acht. Bil. 78:205. Judge, M. D., V. R. CahiU, L. E. Kunkle and W. H. Bruner. 15. Prk quality. I. Influences f sme factrs n prk muscle characteristics. J. Animal Sci. 18:448. Osinska, fia and J. Kielanwski Relatinship between meat clur and feed efficiency in pigs. An. Prd. 2:20. Pease, A. H. R. and C. Smith A nte n the heritability f muscle clur in pigs. An. Prd. 7:273. Sayre, R.., E. J. Briskey and W. G. Hekstra Cmparisn f muscle characteristics and pst-mrtem glyclysis in three breeds f swine. J. Animal Sci. 22 : Wismer-Pedersen, J. 15. Quality f prk in relatin t rate f ph change pst-mrtem. Fd Res. 24:711.

A STUDY OF CROSSBREEDING SHEEP K. P. MILLER AND D. L. DAILEY

A STUDY OF CROSSBREEDING SHEEP K. P. MILLER AND D. L. DAILEY University ] Minnesta 1 OST crssbreeding experiments reprted have used rams f M varius breeds in matings t Rambuillet ewes. One f the earliest