Influences on the loin and cellular characteristics of the m. longissimus lumborum of Australian Poll Dorset-sired lambs

2006 ◽  
Vol 57 (1) ◽  
pp. 1 ◽  
Author(s):  
P. L. Greenwood ◽  
J. J. Davis ◽  
G. M. Gaunt ◽  
G. R. Ferrier
Keyword(s):  
Muscle Hypertrophy ◽  
Carcass Weight ◽  
Longissimus Muscle ◽  
Eye Muscle ◽  
Nutritional Influences ◽  
Longissimus Lumborum ◽  
Ad Libitum ◽  
Estimated Breeding Values ◽  
Improved Pasture

Offspring of 4 Poll Dorset rams differing in eye muscle depth estimated breeding values (EBVs) were studied to determine sire, sex, and nutritional influences on cellular characteristics in the longissimus lumborum muscle. At 12 weeks of age, 62 lambs were individually fed a concentrate diet with or without protected nutrients ad libitum for 120 days while 39 lambs were grazed on improved pasture. Sire influenced the percentages of type 2A and 2B/2X myofibres, but not myofibre number or size. Progeny of the highest eye muscle depth EBV ram had less type 2A and more 2B/2X myofibres than the lowest ranking sire. At equivalent carcass weight, amount of RNA and protein in the longissimus muscle was influenced by sire, consistent with differences in eye muscle depth EBVs. Sex had little effect on muscle cellular characteristics, whereas lambs fed pasture had less type 1 myofibres than those fed concentrates and had less muscle RNA and a higher ratio of protein to RNA. The findings demonstrate differences in m. longissimus lumborum cellular characteristics in offspring of sires differing in muscle EBVs. The extent to which these differences relate to the Carwell muscle hypertrophy gene remains to be determined.

Myofibre characteristics of ovine longissimus and semitendinosus muscles are influenced by sire breed, gender, rearing type, age and carcass weight

2007 ◽  
Vol 47 (10) ◽  
pp. 1137 ◽  
Author(s):  
P. L. Greenwood ◽  
S. Harden ◽  
D. L. Hopkins
Keyword(s):  
Carcass Weight ◽  
Longissimus Muscle ◽  
Relative Area ◽  
Semitendinosus Muscle ◽  
Cross Sectional ◽  
Age Related ◽  
Longissimus Lumborum ◽  
Female Sheep ◽  
Sire Breed

The objective of this study was to determine the extent to which sire breed (Merino, primarily a wool-producing breed, and Poll Dorset, primarily a meat-producing breed), gender (castrate and ewe), rearing type (single- or multiple-reared), age (4, 8, 14 and 22 months) and carcass weight influence ovine (n = 204) myofibre characteristics. In Merino-sired sheep, the relative area (% of total myofibre area) of type 2X myofibres was lower and of type 2A myofibres higher in the longissimus lumborum (longissimus) muscle than in Poll Dorset-sired sheep. Female sheep had a higher relative area of type 2X and a lower relative area of type 2A myofibres than castrate sheep in the longissimus muscle. The percentage of type 2A myofibres increased and of type 2X myofibres decreased in the longissimus between 4 and 22 months of age. Type 1 myofibres in the semitendinosus muscle were more prevalent and type 2X myofibres less prevalent in Merino than in Poll Dorset-sired sheep. The percentage of type 1 myofibres was lower in female than in castrate sheep. Age-related effects on semitendinosus myofibre characteristics varied with gender, sire breed and rearing type. Influences of rearing type on myofibre characteristics were evident in the semitendinosus muscle at younger ages, but did not persist to 22 months of age. The greatest increases in myofibre cross-sectional areas occurred between 8 and 14 months of age in the longissimus muscle, and between 14 and 22 months of age in the semitendinosus muscle. Carcass weight significantly influenced cross-sectional area of type 2A, 2AX and 2X myofibres in longissimus and semitendinosus muscles. It is concluded that influences of sire breed, gender, rearing type, age and carcass weight on ovine myofibre percentages varies between longissimus and semitendinosus muscles. Furthermore, the pattern of postnatal myofibre growth differs between these muscles.

Effect of grain or silage supplementation on meat quality attributes of cryptorchid lambs grazing lucerne or annual grass-clover pastures

1995 ◽  
Vol 35 (4) ◽  
pp. 461 ◽  
Author(s):  
DL Hopkins ◽  
PJ Holst ◽  
DG Hall
Keyword(s):  
Meat Quality ◽  
Shear Force ◽  
The Other ◽  
Carcass Weight ◽  
Annual Grass ◽  
Eye Muscle ◽  
Mean Values ◽  
Significant Difference ◽  
The Mean ◽  
Ad Libitum

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.

Lamb myofibre characteristics are influenced by sire estimated breeding values and pastoral nutritional system

2006 ◽  
Vol 57 (6) ◽  
pp. 627 ◽  
Author(s):  
P. L. Greenwood ◽  
G. E. Gardner ◽  
R. S. Hegarty
Keyword(s):  
Cross Sectional Area ◽  
Eating Quality ◽  
Longissimus Muscle ◽  
Relative Area ◽  
Sectional Area ◽  
Semitendinosus Muscle ◽  
Cross Sectional ◽  
Eye Muscle ◽  
Breeding Values ◽  
Estimated Breeding Values

The objective of this study was to establish the extent to which lamb myofibre characteristics at ~8 months of age were influenced by sire (n = 9) estimated breeding values (EBVs) and pasture-based nutritional systems (low and high quality and availability, LOW and HIGH) from birth to slaughter (n = 56). Immunostaining of myosin heavy chain isoforms in longissimus muscle fibres revealed that as the post-weaning eye muscle depth EBV (PEMD) increased, the percentage of type 2B/X myofibres increased and the percentage of type 2A myofibres decreased. The percentage of type 2B/X myofibres also increased with increasing PEMD in the semimembranosus muscle, but not in the semitendinosus muscle. Post-weaning fat depth (PFAT) EBV was negatively related with the percentage of type 2B/X myofibres in longissimus and semitendinosus muscles and with the relative area of more glycolytic to more oxidative fibre types, although there was an interaction with nutritional system in the semitendinosus muscle, with this ratio increasing with the PFAT EBV among the LOW nutrition lambs. Overall, post-weaning weight (PWWT) EBV had less effect on myofibre characteristics than PEMD and PFAT EBVs. Average cross-sectional area of myofibres was more affected by the LOW than HIGH nutritional system in longissimus muscle (–25%) compared with semitendinosus (–21%) and semimembranosus (–15%) muscles. LOW nutrition resulted in a significantly smaller cross-sectional area of all myofibre types in longissimus muscle and of types 2A, 2AB/X, and 2B/X in semimembranosus and semitendinosus muscles. Overall, the relative area of glycolytic myofibres increased and/or more oxidative myofibre types decreased in LOW compared with HIGH nutritional system lambs in longissimus and semimembranosus, but not in semitendinosus muscle. The results demonstrate significant influences of sire EBVs on myofibre characteristics of lambs, the extent of which depends upon muscle type and nutritional regimen. More specifically, they suggest continued selection for increased muscling and reduced fatness in lambs are associated with shifts in the proportions of myofibre types, with potential for adverse effects on eating quality. They also show that the direction and magnitude of the effects of chronic, moderate postnatal nutritional restriction at pasture on myofibre characteristics vary between muscles with different contractile, metabolic, and/or functional characteristics.

Genotype and age effects on sheep meat production. 2. Carcass quality traits

2007 ◽  
Vol 47 (10) ◽  
pp. 1147 ◽  
Author(s):  
E. N. Ponnampalam ◽  
D. L. Hopkins ◽  
K. L. Butler ◽  
F. R. Dunshea ◽  
R. D. Warner
Keyword(s):  
Muscle Development ◽  
Carcass Weight ◽  
Meat Production ◽  
Carcass Quality ◽  
Quality Traits ◽  
Muscle Area ◽  
Muscle Weight ◽  
Eye Muscle ◽  
Younger Age ◽  
Estimated Breeding Values

The present study examines carcass quality traits in different genotypes of Australian sheep slaughtered at 4, 8, 14 and 22 months of age. Poll Dorsetgrowth × Border Leicester Merino (PDg × BLM), Poll Dorsetgrowth × Merino (PDg × M), Poll Dorsetmuscling × Merino (PDm × M), Merino × Merino (M × M) and Border Leicester × Merino (BL × M) genotypes were compared. Sires were selected on the basis of growth (PDg, M and BL) and muscle (PDm) using estimated breeding values (EBVs). Approximately 150 mixed sex animals were slaughtered at each age (595 in total for the four slaughters) and carcass quality traits, including hot carcass weight, loin and semitendinosus (ST) muscle weights, GR fat, fat C, rump fat depth and eye muscle area (EMA), were determined at 45 min to 3 days postslaughter. With age, all carcass quality traits increased in magnitude. Merinos produced the lightest and leanest carcasses (P < 0.01) with lowest values in nearly all the carcass quality traits. At 4 and 8 months of age carcass and loin weights, EMA and GR fat measures were greater (P < 0.01) in second-cross PDg × BLM sheep than all other genotypes. However, traits related to muscle content were similar between first- and second-cross Poll Dorset genotypes at 14 and 22 months of age. The BL × M genotype had lower values than the PD × M genotypes for these traits, at all ages. Traits related to carcass fatness showed that sheep with Border Leicester genetics tend to deposit more fat (P < 0.001) in the carcass than those with Merino or Poll Dorset genetics from 14 months of age onwards. Most carcass quality traits did not differ (P > 0.05) between first-cross Poll Dorset genotypes selected for growth or muscling (PDg × M v. PDm × M). Sires with high muscling EBVs are associated more with shorter carcass length than low muscling EBVs. From ~8 months of age, wethers had greater values (P < 0.05) than ewes of the same age for most carcass quality traits related to size and muscle development, but no effect was present for carcass quality traits that were related to fat deposition. It was clear that the carcass weight of M × M at 8 and 14 months were similar to that observed in PDg × BLM at 4 and 8 months, respectively. Loin weights of M × M and BL × M at 13 and 8 months were similar to that weights observed in PDg × BLM at 8 and 4 months of age, respectively. Animals slaughtered to a muscle weight specification will reach the target at a younger age when they have more Poll Dorset than Border Leicester background genetics. Alternatively animals slaughtered at a specified fat score (using fat C or rump fat depth) will reach the specification at a younger age when they have more Border Leicester than Poll Dorset genetics.

Accuracy and consistency of prediction of pig carcass lean concentration from P2 fat thickness and sample joint dissection

1991 ◽  
Vol 53 (3) ◽  
pp. 345-352 ◽  
Author(s):  
J. Planella ◽  
G. L. Cook
Keyword(s):  
Carcass Weight ◽  
Regression Equations ◽  
Muscle Area ◽  
Data Set ◽  
Eye Muscle ◽  
Regression Slope ◽  
Different Populations ◽  
Fat Thickness ◽  
Ad Libitum ◽  
Pig Carcasses

AbstractCommercial carcass grading measurements and sample joint dissection were evaluated as predictors of carcass lean concentration using a data set of 1320 pig carcasses from four breeding companies. Entire males, castrated males and gilts from White-type and Meat-type populations were reared on ad libitum or restricted feeding regimens and slaughtered to achieve a carcass weight of either 52·5 kg or 72·5 kg. A model was fitted which examined the accuracy and stability of regression equations for different populations, sexes and feeding regimens, and different values of P2 and carcass weight. The regression slope of lean concentration on P2 differed by sex and population. Lean concentration decreased faster with increases in P2 among gilts than among entire or castrated males. At the same level of P2 and carcass weight, pigs fed ad libitum contained 5 g/kg less lean in the carcass than pigs fed at a restricted level. Biases among populations, sexes and feeding regimens were also found when carcass lean concentration was predicted from additional measurements: muscle depth at P2, fat thickness and muscle depth at 3/4 last ribs, and eye-muscle area. The regression slope of lean concentration on sample joints showed little evidence of variation among populations (except for the hand joint), sexes or feeding regimens. There were important differences in the intercept for different populations. The ham was the most accurate (residual s.d. = 11 g/kg) and least biased joint.

scholarly journals Consumer Perceptions of Meat Redness Were Strongly Influenced by Storage and Display Times

Foods ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 540
Author(s):  
Maddison T. Corlett ◽  
David W. Pethick ◽  
Khama R. Kelman ◽  
Robin H. Jacob ◽  
Graham E. Gardner
Keyword(s):  
Correlation Coefficient ◽  
Storage Period ◽  
Intramuscular Fat ◽  
Consumer Perceptions ◽  
Display Time ◽  
Eye Muscle ◽  
Longissimus Lumborum ◽  
Retail Display ◽  
Lamb Growth ◽  
Long Storage

Lamb (n = 79) meat colour was scored by 879 untrained consumers using a scale of 0 (brown) to 100 (red). This consumer colour score (CCS) was obtained on m. longissimus lumborum (loin) and m. semimembranosus (topside), stored for short (5–7 days), medium (33–35 days), and long periods (110–112 days) and a retail display time of up to 4 days. Consumers perceived topside to be less red initially and changed from red to brown more rapidly when stored for the long-storage period (p < 0.01). Whereas, the initial CCS of loin samples were similar across the storage periods (p > 0.05). CCS and the instrument measure oxy/met (reflectance of light at wavelengths 630 nm and 580 nm) had a low correlation coefficient of 0.33 (p < 0.01). The propensity for lamb growth and leanness indicated by sire breeding values for lamb weight, eye muscle depth, eye muscle fat depth, and loin intramuscular fat had varied and inconsistent effects on CCS. Therefore, even the selection on CCS.

The area of eye muscle of beef cattle carcasses

1963 ◽  
Vol 3 (10) ◽  
pp. 249
Author(s):  
RM Seebeck
Keyword(s):  
Beef Cattle ◽  
Cross Sectional Area ◽  
Carcass Weight ◽  
Sectional Area ◽  
Muscle Area ◽  
Cross Sectional ◽  
Eye Muscle ◽  
Angus Cattle ◽  
The Cross

Variations in the cross-sectional area of eye muscle of carcasses cut between the tenth and eleventh ribs were investigated, using 105 Hereford and 51 Angus steers aged 20 months. These cattle consisted of three groups, born in successive years. At constant carcass weight, statistically significant differences in eye muscle area were found between breeds and between years. Breed and year differences were also found in eye muscle area with width and depth of eye muscle constant, so that there are limitations to the estimation of eye muscle area from width and depth measurements. A nomograph is given for estimating eye muscle area from width and depth for Hereford and Angus cattle, when all animals are reared in the same year and environment. The use of eye muscle area as an indicator of weight of carcass muscle is discussed.

scholarly journals Effect of forage to concentrate ratio and duration of feeding on growth and feed conversion efficiency of male lambs

2018 ◽  
Vol 2 (4) ◽  
pp. 419-427 ◽  
Author(s):  
Noel A Claffey ◽  
Alan G Fahey ◽  
Vasiliki Gkarane ◽  
Aidan P Moloney ◽  
Frank J Monahan ◽  
...  
Keyword(s):  
Conversion Efficiency ◽  
Carcass Weight ◽  
Feed Conversion ◽  
Fresh Weight ◽  
Viable Option ◽  
Financial Return ◽  
Feed Conversion Efficiency ◽  
Ad Libitum ◽  
The Cost ◽  
Concentrate Inclusion

Abstract Rations (DM basis) for spring-born male lambs consisting of concentrates ad libitum (CON), 50:50 (50% concentrate:50% forage), and forage ad libitum (FORG) were evaluated across feeding periods of three durations (36, 54, and 72 d). Lambs on CON diets were offered ad libitum access to concentrate along with 400 g of fresh weight silage (daily), while 50:50 diets were offered 0.9 and 3.0 kg of concentrate and silage, respectively. Lambs on FORG were offered ad libitum access to 25.5% DM silage. These rations were fed to 99 spring-born male Texel cross Scottish Blackface lambs which were assigned to a 3 × 3 factorial arrangement. Lambs were slaughtered following completion of their respective treatments. Lambs fed CON diets had greater ADG, FCE, and carcass weight (P &lt; 0.001) and carcasses with greater conformation score (P &lt; 0.001) than lambs fed 50:50 or FORG diets. Duration of feeding had no effect on production variables across all three concentrate inclusion levels. It was concluded that the inclusion of concentrates is needed to adequately finish lambs fed indoors. Feeding lamb’s 50:50 diets resulted in modest responses and may be a viable option for finishing lambs or to maintain growth in lambs when the cost of concentrate feed is high relative to the financial return on the lamb meat.

scholarly journals Characterizing Pork Quality of Carcasses with an Average Weight of 119 Kg

2019 ◽  
Vol 3 (2) ◽  
Author(s):  
H. Price ◽  
A. B. Lerner ◽  
E. A. Rice ◽  
J. E. Lowell ◽  
B. N. Harsh ◽  
...  
Keyword(s):  
Iodine Value ◽  
Total Population ◽  
Fiber Type ◽  
Carcass Weight ◽  
Average Weight ◽  
Pork Quality ◽  
Quality Traits ◽  
Quality Measurements

ObjectivesBetween 1995 and 2018, average hot carcass weight of U.S. pork carcasses increased from 82 kg to 96 kg, which is an increase of approximately 17%. At current rates, pork carcasses in the U.S. will weigh on average, 105 kg by the year 2030 and over 118 kg by 2050. Although this represents an increase in throughput efficiency due to increases in economy of scale, projecting continued increases in the future raises some concerns. Therefore, the objective was to characterize pork quality of carcasses ranging from 78 to 145 kg with a mean weight of 119 kg.Materials and MethodsCarcass composition, such as hot carcass weight (HCW), back fat depth and loin depth were measured on 666 carcasses. Additionally, loin quality measurements, such as pH, loin instrumental and visual color, and iodine value of clear plate fat were measured on approximately 90% of the total population. Ham quality, 14 d aged loin and chop quality measurements, and loin chop slice shear force (SSF) were evaluated on approximately 30% of the total population. Finally, myosin heavy chain fiber type determination was completed on approximately 50 carcasses selected from carcasses ranging from 97 to 133 kg. The slope of regression lines and coefficients of determination between hot carcass weights and quality traits were calculated using the REG procedure in SAS and considered significantly different from 0 at P ≤ 0.05.ResultsAs HCW increased loin depth (b1 = 0.2496, P < 0.0001), back fat depth (b1 = 0.1374, P < 0.0001), loin weight (b1 = 0.0345, P < 0.0001), chop weight (b1 = 1.6626, P < 0.0001), and ham weight (b1 = 0.1044, P < 0.0001) increased. There was a decrease in estimated lean (b1 = –0.0751, P < 0.0001) and iodine value (b1 = –0.0923, P < 0.0001) as carcass weight increased, however, HCW only accounted for ≤ 24% (R2 = 0.24) of the variation in estimated lean and iodine value. Additionally, there were no significant differences in gluteus medius pH (b1 = 0.0009, P = 0.30) or instrumental lightness (b1 = 0.0301, P = 0.15), redness (b1 = –0.0036, P = 0.73) or yellowness (b1 = 0.0058, P = 0.57) of the ham as carcass weight increased. As carcass weight increased, 1 d loin instrumental yellowness (b*) increased (b1 = 0.0092 P < 0.01), however HCW only explained 1% of the variation in b*. Heavier carcasses were more tender (decreased SSF of chops cooked to 71°C, (b1 = –0.0674, P < 0.0001), although HCW only explained 9% of the variation in SSF. Total cook loss of chops used for SSF determination decreased as HCW increased (b1 = –0.0512, P < 0.0001), and HCW explained 15% (R2 = 0.15) of the variation in total cook loss. There were no significant differences in fiber type percentage, type 1 (b1 = –0.0170, P = 0.81), 2a (b1 = –0.0786, P = 0.23), 2x (b1 = –0.0201, P = 0.80), or 2b (b1 = 0.1224, P = 0.37), or fiber type area, type 1 (b1 = –26.6331, P = 0.22), 2a (b1 = –40.7257, P = 0.07), 2x (b1 = –46.9459, P = 0.25), or 2b (b1 = –26.2537, P = 0.38) as HCW increased.ConclusionDue to the lack of variation explained by HCW (≤ 15%), pork quality traits are not expected to be compromised as HCW continues to increase. The results suggest that increasing HCW to 119 kg did not have detrimental effects on pork quality attributes.

THE INFLUENCE OF EXOGENOUS GROWTH HORMONE ON OVULATION RATE IN GILTS

1988 ◽  
Vol 68 (4) ◽  
pp. 1097-1103 ◽  
Author(s):  
R. N. KIRKWOOD ◽  
P. A. THACKER ◽  
A. D. GOONERATNE ◽  
B. L. GUEDO ◽  
B. LAARVELD
Keyword(s):  
Growth Hormone ◽  
Crude Protein ◽  
Ovulation Rate ◽  
Daily Injection ◽  
Corpora Lutea ◽  
Blood Samples ◽  
High Incidence ◽  
Exogenous Growth ◽  
Ad Libitum

A total of 32 prepubertal gilts of Yorkshire and Landrace breeding were selected at 138 d and fed ad libitum a 16.2% crude protein diet formulated to provide 13.1 MJ DE kg−1. From selection until the end of second estrus, the gilts were exposed to a boar for 30 min d−1 to facilitate the detection of pubertal and second estrous periods. From 14 d after puberty, the gilts received daily injections of either porcine growth hormone at 90 μg kg−1 body weight (GH; n = 20) or vehicle (CT; n = 12) until 24 h after the onset of second estrus and were then killed 9 d later to determine ovulation rate. Gilts not displaying a second estrus by 24 day after puberty were considered anestrus and the injection regime was halted. Anestrous gilts were killed 30–32 d after puberty and their ovaries examined for the presence of corpora albicantia and the absence of corpora lutea. Blood samples were obtained from all gilts at 14, 17, and 20 d after puberty. There was no treatment effect on the duration of the estrous cycle (20.8 vs. 21.3 d for GH and CT, respectively), but while all CT gilts cycled normally, only 55% of the GH gilts had a second estrus (P < 0.01). In those gilts having a second estrus, the daily injection of growth hormone increased ovulation rate (14.3 vs. 12.4 for GH and CT respectively; P < 0.03). Serum type 1 insulin-like growth factor (IGF-1) concentrations were higher (P < 0.001) in GH than in CT gilts, but there was no difference between cycling and anestrous GH gilts. We suggest that the effect of growth hormone on ovulation rate was mediated by increased secretion of IGF-1. The etiology of the high incidence of anestrus is, however, not known. Key words: Gilts, growth hormone, ovulation rate

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