Effects of growth path and post-slaughter chilling regime on carcass composition and meat quality of ewe lambs

1992 ◽  
Vol 43 (4) ◽  
pp. 819 ◽  
Author(s):  
LP Thatcher ◽  
GM Gaunt

Sixty-five Poll Dorset x (Border Leicester/Merino) ewe lambs. were grown at pasture on one of four growth paths commencing at mean age of 24 weeks and a mean liveweight of 37-5 kg. These were, continuous growth between 24 and 34 weeks (HH), maximum possible growth for 6 weeks followed by weight loss for 4 weeks (HL), no gain for 6 weeks followed by rapid gain for 4 weeks (LH) and weight maintenance (LL). Lambs were slaughtered as soon as possible after LH and HL lambs were the same full weight. There were significant differences between treatments in average growth rate, liveweight, hot carcass weight (HCW) and dressing percentage. After adjustment for HCW, LH had significantly (P < 0.05) less omental and kidney fat than HH, and there was a strong tendency for less subcutaneous fat, intermuscular fat and a lower tissue depth over the twelfth rib (at the GR site). Eye muscle area was significantly larger in LH than HH, but this did not translate to a significant difference in dissectible 'soft tissue' measurement. The Warner Bratzler shear value for LL in the M. longissimus dorsi was significantly higher than LH and HH. There were no differences between treatments for pH, Warner Bratzler shear values of the M. semimembranosus, cooking loss, or the colour measurements using a Minolta chromameter of L* (lightness) or b* (yellowness). The difference in a* (redness) between HL and LH was significant. Warner Bratzler shear values for M. longissimus dorsi and M.semimembranosus were significantly higher at 4�C than 10�C. The a* was significantly higher at 10�C, but there were no differences between L* and b*. There were no interactions between the post-slaughter chilling regime and the pre-slaughter nutritional management. It was concluded that the growth path had little effect on meat quality unless the lamb had been continuously on a restricted diet. Therefore there was some potential for the use of growth paths to manipulate carcass composition, and further research into management systems at pasture is recommended.


1992 ◽  
Vol 32 (4) ◽  
pp. 429 ◽  
Author(s):  
DL Hopkins ◽  
KD Gilbert ◽  
KL Pirlot ◽  
AHK Roberts

Growth and carcass parameters were studied for 62 second-cross lambs (Poll Dorset rams over Border Leicester x Merino ewes) and 55 purebred Elliottdale lambs. Second cross lambs grew faster (P<0.001) from weaning to the first slaughter time than Elliottdale lambs and consequently weighed more and had heavier carcasses. Elliottdale lambs produced significantly (P<0.001) more wool between birth and weaning. The slope of the relationship between GR (tissue depth over the 12th rib 110 mm from the midline) and carcass weight was 1.24 � 0.23 mm/kg for second cross lambs and 0.82 � 0.17 mm/kg for Elliottdale lambs, indicating the latter lambs were leaner at heavier weights. Measures of subcutaneous fat depth at the 5th/6th and 12th/13th ribs were similar when carcass weight differences were considered for a subsample of 21 second cross and 26 purebred Elliottdale lambs. Subjective assessment of fat distribution and carcass conformation by 2 assessors revealed a significant (P<0.001) difference between breeds; second cross lambs having a better conformation. Saleable meat yield, carcass composition, and muscle content of several cuts were determined for a subsample of lambs. At a common side weight of 8 kg there was no significant difference in saleable meat yield. At this weight, crossbred lambs had a significantly (P<0.05) higher muscle content (505 g/kg) than Elliottdale lambs (480 g/kg). Fat content was similar at 300 g/kg with crossbred lambs having significantly (P<0.05) less bone (190 g/kg) than Elliottdale lambs (2 10 g/kg). The legs of carcasses from crossbred lambs were shown to contain significantly more muscle than those of Elliottdales (206 v. 195 g/kg). Carcass weight explained some of the variation in weight of leg and forequarter muscle (r2 = 0.63 and 0.61). This was improved by including an assessment for conformation from 1 assessor (r2 = 0.69 and 0.64). Eye muscle area at the 12th rib did not add significantly to the prediction; it was not different between breeds, nor was its depth to width ratio different between breeds. The pH measurements of the M. longissimus thoracis et lumborum were similar between breeds.



1979 ◽  
Vol 30 (6) ◽  
pp. 1207 ◽  
Author(s):  
JM Thompson ◽  
KD Atkins ◽  
AR Gilmour

Half-carcasses of 108 wether and ewe lambs from six genotypes, slaughtered at 34, 44 and 54 kg liveweight, were dissected into subcutaneous fat, intermuscular fat, muscle, bone and connective tissue. The six genotypes were the progeny of Dorset Horn and Border Leicester rams mated to Merino, Corriedale and Border Leicester x Merino first-cross ewes. As carcass weight increased, the proportion of subcutaneous and intermuscular fat increased (b > 1 ; P < 0.05) and the proportion of muscle and bone decreased (b < 1; P < 0.05). Lambs sired by Border Leicester rams had more subcutaneous fat (12.7%), more intermuscular fat (7.6%) and more bone (5.7%) than lambs sired by Dorset Horn rams at the same carcass weight (P< 0.05). Similarly, lambs sired by Dorset Horn rams had more muscle (7.2%) than lambs sired by Border Leicester rams at the same carcass weight (P < 0.05). Breed of dam had no effect on carcass composition. Wether lambs had a greater proportion of bone (5.7%) than ewe lambs at the same carcass weight (P < 0.05). The breed of sire effect and the lack of a breed of dam effect on carcass composition, in conjunction with estimated mature weights for the breeds, suggest possible differences between sire and dam breeds in the partitioning of fat between the carcass and non-carcass depots. ____________________ *Part I, Aust. J. Agric. Res., 30: 1197 (1979).



2014 ◽  
Vol 43 (2) ◽  
pp. 147-153 ◽  
Author(s):  
MS Rana ◽  
MA Hashem ◽  
S Akhter ◽  
M Habibullah ◽  
MH Islam ◽  
...  

The research was conducted to study the effect of heat stress on carcass characteristics and meat quality in indigenous sheep. Nine sheep were divided into three groups which were almost similar in age, sex and weight. Three groups were divided as zero hour (T0), four hours (T4) and eight hours (T8) heat exposure to direct sunlight. During experimental period temperature–humidity index (THI) value was calculated as 27.09 which indicated T4 and T8 groups were subjected to heat stress condition for at least four hours and eight hours respectively every day. Slaughter weight, body length and heart girth had no significant difference among the treatment groups. Dry matter, ash and ether extract had no significant difference (p>0.05) among the treatment groups but crude protein were increased with the increase of heat stress from T0 to T8 group (p<0.05). Drip loss was increased (p<0.05) in non-exposure group than treated groups but there is no significant result (p>0.05) found in pH and cooking loss. Carcass weight and eye muscle area had no significant difference (p>0.05) among the treatment groups but dressing percentage was decreased with the increase of time in heat treated groups (p<0.01). Significant difference (p<0.05) were found in weight of heart, kidney, lung + trachea and pluck between control and heat treated groups. The significant difference (p>0.05) in empty gut was found in gut with content and gut fill in heat treated groups. It can be concluded that heat stress had significant changes on carcass characteristics and meat quality of indigenous sheep.DOI: http://dx.doi.org/10.3329/bjas.v43i2.20717 Bang. J. Anim. Sci. 2014. 43 (2): 147-153



1999 ◽  
Vol 69 (1) ◽  
pp. 81-92 ◽  
Author(s):  
A. F. Carson ◽  
B. W. Moss ◽  
R. W. J. Steen ◽  
D. J. Kilpatrick

AbstractThis study investigated the effects of the percentage of Texel or Rouge de l’Ouest (Rouge) genes in lambs (0, 50, 75 or 100%; the remainder being Greyface (Border Leicester × Scottish Blackface)) on lamb carcass characteristics and meat quality. Ewe lambs were slaughtered at 34, 40, 46 and 52 kg and ram lambs were slaughtered at 40, 46, 52 and 58 kg live weight. Dressing proportion increased (P < 0·001) by 0·53 and 0·27 g carcass weight per kg live weight for each 1% increase in Texel or Rouge genes respectively. Carcass conformation classification increased (P < 0·001) by 0·016 and 0·007 units (on a five-point scale) for each 1% increase in Texel or Rouge genes respectively. Carcass fat depth measures were reduced by Texel and Rouge genes such that at a constant fat depth end point, carcass weight could be increased by 0·029 and 0·023 kg for each 1% increase in Texel or Rouge genes. Carcass lean content increased (P < 0·001) by 0·99 and 0·27 g/kg for each 1% increase in Texel or Rouge genes. Subcutaneous fat content was reduced (P < 0·001) by 0·36 and 0·29 g/kg for each 1% increase in Texel or Rouge genes. Intermuscular fat content was reduced (P < 0·01) by 0·38 g/kg per 1% increase in Texel genes, whereas Rouge genes had no effect. Similarly, bone content was reduced (P < 0·01) by Texel genes only (0·31 g/kg per 1% increase in Texel genes). Warner-Bratzler shear force values showed a quadratic effect with increasing Texel and Rouge genes, with an initial decrease from 0 to 50% followed by an increase to 100%. Cooking loss increased (P = 0·05) as the percentage of Rouge genes in lambs increased. Increasing the percentage of Texel or Rouge genes significantly increased L* values (P < 0·01 and P < 0·05 respectively), b* values (P = 0·05 and P< 0·05 respectively) and H° values (P < 0·001).



1995 ◽  
Vol 35 (4) ◽  
pp. 461 ◽  
Author(s):  
DL Hopkins ◽  
PJ Holst ◽  
DG Hall

Objective and subjective tests for quality were performed on the meat from 40 cryptorchid second-cross lambs fed lucerne only (L; n = 8), lucerne plus an oat grain supplement ad libitum (LO; n = lo), lucerne plus wilted lucerne silage ad libitum (LS; n = 11), or an oat-lupin grain (3:1) supplement at 90% of ad libitum while grazing dry summer annual pasture (OL; n = 11). All carcasses complied with the Elite lamb specification of weight >22 kg and GR measurement 6-15 mm. There was no significant difference between groups for hot carcass weight, the mean (� s.e) values being 25.1 0.43, 25.2 � 0.36,25.2 � 0.38, and 25.3 � 0.36 kg for L, LS, LO, and OL groups, respectively. When the GR and fat depth over the eye muscle at the 12th rib were adjusted to a common carcass weight of 25.2 kg there was no significant difference between groups. There was no significant difference between groups for pH, or the colour values a*, b*, and L* of the M. longissimus thoracis et lumborum (a* is relative redness, b* relative yellowness, and L* relative lightness). The shear force values for the loin muscle were significantly (P<0.05) greater for lambs from group OL than for those from group LO. Cooking loss for the loin muscle was significantly (P<0.05) greater for OL lambs than all other groups. A comparison of the mean values for aroma and flavour showed the lambs from group OL produced meat that was considered significantly (P<0.05) less desirable for these characteristics, with other groups being similar. Meat from OL-fed lambs was considered oilier and less meaty than meat from lambs fed the other diets. There was a significant (P<0.05) difference in absolute scores between panellists, but their ranking was not affected and there was no panellist x sample interaction. Because many producers use grain supplements such as oats and lupins for finishing lambs on dry forages, further study is recommended that focuses on the interaction between supplement and the base forage.



1996 ◽  
Vol 1996 ◽  
pp. 166-166
Author(s):  
Jennifer M.L. Anderson ◽  
G.M. Webster

This trial sought to increase the knowledge of the changes in the endocrine status of male sheep as they mature, and to link this with sexual and agonistic behaviour when they are reared in the presence or absence of females from weaning.80 twin-reared Suffolk x Mule lambs were selected at birth. 32 of the male lambs were castrated (C) and 32 were left entire (E); there were 16 female lambs (F). The ewes were stocked at a rate of 20 ewes per hectare. The lambs were weaned at 12 weeks of age in late June, when they were separated into two groups. The first group (+F) comprised 16 entire males, 16 castrated males and 16 females that were run together until the end of July. Thereafter, raddled vasectomized rams were run with the ewe lambs to show when the first oestrous cycles occurred.



1982 ◽  
Vol 62 (2) ◽  
pp. 353-361 ◽  
Author(s):  
L. E. JEREMIAH ◽  
A. H. MARTIN

A total of 119 bovine carcasses were utilized in three separate but related experiments to evaluate histological and textural parameters of the longissimus dorsi muscle at 45 min postmortem (unchilled), at 90 min postmortem (45 min cooler chill) and after a 24-h chill in a cooler at 2 °C. Samples were also examined after prerigor (90 min postmortem) freezing at −18 °C and subsequent slow thawing (24 h at 2 °C). The composite results of these experiments provide no evidence that conventional chilling of carcasses, with a subcutaneous fat cover of 4.57–19.56 mm at the eleventh thoracic vertebra, produced detrimental effects (P < 0.05) upon certain histological or textural properties of bovine longissimus dorsi muscle. However, prerigor freezing and subsequent thawing produced substantial (P < 0.05) effects on the susceptibility of fibers to fragmentation and incidence of wavy fibers, but did not produce detrimental effects (P > 0.05) on tenderness under the conditions imposed in the present study. The results from the present study also demonstrated that the issues involved in the transition of muscle to meat are far from resolved, and that additional research will be required to document fully the relevance of carcass chilling and meat handling procedures to meat quality. Key words: Beef, histological properties, shear values, prerigor chilling, prerigor freezing, fat cover



Author(s):  
X. H. Zhang ◽  
H. .Liao ◽  
Y. X. Qi ◽  
Y. Q. Wang ◽  
Y. Z. Pang ◽  
...  

Extracellular matrix (ECM) is the major macromolecule in skeletal muscle, and collagen is main component of ECM surrounding muscle fiber and adipocyte, which affect meat quality greatly. The remodeling of ECM is regulated by matrix metalloproteinases, such as ADAMTS2, which is essential for the maturation of triple helical collagen fibrils in body. The expression patterns of COL1A1, COL2A1, COL3A1 and ADAMTS2 in longissimus dorsi muscle were explored by qRT-PCR and results indicated that the expression levels of COL1A1, COL3A1 and ADAMTS2 were significantly higher at 3 and 24 month, while significantly lower at 12 and 30 month. The expression of ADAMTS2 and COL1A1 had significant positive relationships with intramuscular fat content, while expression of COL3A1 had significant positive relationship with shearing force and water holding capacity in cattle. The expression levels of collagen and ADAMTS2 were significantly higher in mesenteric fat, mammary fat pad and subcutaneous fat than in longissimus dorsi muscle, biceps femoris and infraspinitus tissues. The expressions levels of COL1A1, COL3A1 and ADAMTS2 were significantly lower in marbling fat than in other fat tissues. This study indicated that the expression of collagen and ADAMTS2 had important effects on postnatal skeletal muscle development and meat quality.



Metabolites ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 804
Author(s):  
Felista W. Mwangi ◽  
David J. C. Blignaut ◽  
Edward Charmley ◽  
Christopher P. Gardiner ◽  
Bunmi S. Malau-Aduli ◽  
...  

Lipid metabolism, carcass characteristics and fatty acid (FA) composition of the Longissimus dorsi (loin eye) muscle were evaluated in tropical crossbred steers backgrounded on Desmanthus spp. (desmanthus) with or without feedlot finishing. It was hypothesized that steers backgrounded on isonitrogenous diets augmented with incremental proportions of desmanthus will produce carcasses with similar characteristics and FA composition. Forty-eight Brahman, Charbray and Droughtmaster crossbred beef steers were backgrounded for 140 days on Rhodes grass (Chloris gayana) hay augmented with 0, 15, 30 or 45 percent desmanthus on dry matter basis. Lucerne (Medicago sativa) hay was added to the 0, 15 and 30 percent desmanthus diets to ensure that they were isonitrogenous with the 45 percent desmanthus diet. After backgrounding, the two heaviest steers in each pen were slaughtered and the rest were finished in the feedlot for 95 days before slaughter. Muscle biopsy samples were taken at the beginning and end of the backgrounding phase. Carcasses were sampled at slaughter for intramuscular fat (IMF) content, fat melting point (FMP) and FA composition analyses. Increasing the proportion of desmanthus in the diet led to a linear increase in docosanoic acid (p = 0.04) and omega-6/omega-3 polyunsaturated FA ratio (n-6/n-3 PUFA; p = 0.01), while docosahexaenoic acid decreased linearly (p = 0.01). Feedlot finishing increased hot carcass weight, subcutaneous fat depth at the P8 site and dressing percentage (p ≤ 0.04). The n-6/n-3 PUFA ratio was within the recommended < 5 for human diets. IMF was within the consumer-preferred ≥3% level for palatability. The hypothesis that steers backgrounded on isonitrogenous diets augmented with incremental proportions of desmanthus will produce similar carcass characteristics and FA composition was accepted. These findings indicate that a combination of tropical beef cattle backgrounding on desmanthus augmented forage and short-term feedlot finishing produces healthy and highly palatable meat.



Animals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1884 ◽  
Author(s):  
Gertruida L. van Wyk ◽  
Louwrens C. Hoffman ◽  
Phillip E. Strydom ◽  
Lorinda Frylinck

Weaner male Boer Goats (BG; n = 36; 21 bucks and 15 wethers) and large frame Indigenous Veld Goats (IVG; n = 41; 21 bucks and 20 wethers) were raised on hay and natural grass ad libitum and the recommended amount of commercial pelleted diet to a live weight between 30 and 35 kg. Carcass quality characteristics (live weight, carcass weights, dressing %, chilling loss and eye muscle area) were measured. The right sides of the carcasses were divided into wholesale cuts and dissected into subcutaneous fat, meat and bone. Large frame Indigenous Veld Goat (IVG) wethers were slightly lighter than the IVG bucks with no significant difference observed between BG. Wethers compared to bucks had higher dressing %, subcutaneous fat % in all primal cuts, intramuscular fat %, kidney fat % and, overall, slightly less bone %. Some breed–wether interactions were noticed: IVG wethers were slightly lighter than the IVG bucks, but the IVG bucks tended to produce higher % meat compared to other test groups. Judged on the intramuscular fat % characteristics, it seems as if wethers should produce juicier and more flavorsome meat compared to bucks.



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