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

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.


2020 ◽  
Vol 60 (5) ◽  
pp. 725
Author(s):  
R. J. Anaruma ◽  
L. G. Reis ◽  
P. E. de Felício ◽  
S. B. Pflanzer ◽  
S. Rossi ◽  
...  

Castration in beef cattle production has been proposed to reduce sexual and aggressive behaviour, increase carcass fat deposition, and improve meat quality traits, such as tenderness and juiciness. The aim of the present study was to evaluate the effects of the age of castration on performance, subprimal yield and meat quality of Nellore cattle raised on a pasture system. A total of 24 Nellore males were raised in a grass-fed system with Brachiaria brizantha since birth until slaughter (at 30 months old). Three treatments were assigned: castration at weaning (CW); castration at 20 months old (C20); and intact bulls (NoC). Males were weighed, and muscle and fat thickness were periodically evaluated by ultrasonography. The cold carcass weight, dressing and carcass pH (pH 24), and subprimal cut weights were recorded after 24 h of chilling. Samples of Longissimus lumborum (LL) were taken to measure meat quality traits. Animals that were castrated at weaning had lower bodyweight after 10 months of age with no changes in the supplement intakes, average daily gain, hot carcass weight and cold carcass weight compared with NoC. Intact males had greater cooking losses and carcass yield compared with others, with no differences for LL pH 24 according to the treatments. The castration did not change the LL muscle area, but decreased total forequarter, chunk, shoulder and eye of round weights, and increased the back fat over LL and rump fat. Animals castrated at weaning had higher marbling compared with others. In addition, regardless of age, castration improved tenderness, increased LL total lipids and decreased moisture compared with NoC. For sensory property, steers castrated at 20 months of age had lower juiciness, and NoC had a greater global sensory property compared with steers castrated at 20 months old. In conclusion, steers castrated at weaning had lower growth rate, final bodyweight and meat production compared with intact males. However, when castration was performed at 20 months, animals did not differ in most cases from castration at weaning and NoC. Tenderness was improved by castration, but sensory traits did not differ between groups.



2009 ◽  
Vol 49 (6) ◽  
pp. 525 ◽  
Author(s):  
W. A. McKiernan ◽  
J. F. Wilkins ◽  
J. Irwin ◽  
B. Orchard ◽  
S. A. Barwick

The steer progeny of sires genetically diverse for fatness and meat yield were grown at different rates from weaning to feedlot entry and effects on growth, carcass and meat-quality traits were examined. The present paper, the second of a series, reports the effects of genetic and growth treatments on carcass traits. A total of 43 sires, within three ‘carcass class’ categories, defined as high potential for meat yield, marbling or both traits, was used. Where available, estimated breeding values for the carcass traits of retail beef yield (RBY%) and intramuscular fat (IMF%) were used in selection of the sires, which were drawn from Angus, Charolais, Limousin, Black Wagyu and Red Wagyu breeds, to provide a range of carcass sire types across the three carcass classes. Steer progeny of Hereford dams were grown at either conventional (slow: ~0.5 kg/day) or accelerated (fast: ~0.7 kg/day) rates from weaning to feedlot entry weight, with group means of ~400 kg. Accelerated and conventionally grown groups from successive calvings were managed to enter the feedlot at similar mean feedlot entry weights at the same time for the 100-day finish under identical conditions. Faster-backgrounded groups had greater fat levels in the carcass than did slower-backgrounded groups. Dressing percentages and fat colour were unaffected by growth treatment, whereas differences in ossification score and meat colour were explained by age at slaughter. There were significant effects of sire type for virtually all carcass traits measured in the progeny. Differences in hot standard carcass weight showed a clear advantage to European types, with variable outcomes for the Angus and Wagyu progeny. Sire selection by estimated breeding values (within the Angus breed) for yield and/or fat traits resulted in expected differences in the progeny for those traits. There were large differences in both meat yield and fatness among the types of greatest divergence in genetic potential for those traits, with the Black Wagyu and the Angus IMF clearly superior for IMF%, and the European types for RBY%. The Angus IMF progeny performed as well as that of the Black Wagyu for all fatness traits. Differences in RBY% among types were generally reflected by similar differences in eye muscle area. Results here provide guidelines for selecting sire types to target carcass traits for specific markets. The absence of interactions between growth and genetic treatments ensures that consistent responses can be expected across varying management and production systems.



Author(s):  
Abdelkareem E. Ahtash ◽  
Abdulla S. Biala ◽  
Aiad F. Magid ◽  
Hamed M. Marhoun

This study was conducted to evaluate the carcass characteristics of Mahali (M), Damascus (D) and Morcia Granada (G) goats and their crosses. Live weight, carcass weight, dressing-out %, rib eye muscle area, non-carcass components and kidney fat were measured. The results showed significant superiority of Damascus goats in live weight (65.8 kg), carcass weight (34.3 kg), dressing-out %( 52.1%), rib eye muscle areas (22.7 cm²) over the Mahali and Morcia Granada goats. The crossbred group (1/2 M ҳ 1/2 D) was superior in live weight (50 kg), carcass weight (24.2kg), dressing-out %( 48.4%), and rib eye muscle area (21.2cm²) over other crossbreds. The crossbred group (3⁄4D ҳ 1⁄4M) was superior in live weight (61.7kg), carcass weight (31 kg) and rib eye muscle area (21.3cm²) over the other 3⁄4 crossbreds. This study indicated that crossing between Mahali ҳ Damascus breed was beneficial for increasing live weight, carcass weight and meat production. 



2009 ◽  
Vol 49 (11) ◽  
pp. 1052
Author(s):  
W. A. McKiernan ◽  
J. F. Wilkins ◽  
J. Irwin ◽  
B. Orchard ◽  
S. A. Barwick

The steer progeny of sires genetically diverse for fatness and meat yield were grown at different rates from weaning to feedlot entry and effects on growth, carcass and meat-quality traits were examined. The present paper, the second of a series, reports the effects of genetic and growth treatments on carcass traits. A total of 43 sires, within three 'carcass class' categories, defined as high potential for meat yield, marbling or both traits, was used. Where available, estimated breeding values for the carcass traits of retail beef yield (RBY%) and intramuscular fat (IMF%) were used in selection of the sires, which were drawn from Angus, Charolais, Limousin, Black Wagyu and Red Wagyu breeds, to provide a range of carcass sire types across the three carcass classes. Steer progeny of Hereford dams were grown at either conventional (slow: ~0.5 kg/day) or accelerated (fast: ~0.7 kg/day) rates from weaning to feedlot entry weight, with group means of ~400 kg. Accelerated and conventionally grown groups from successive calvings were managed to enter the feedlot at similar mean feedlot entry weights at the same time for the 100-day finish under identical conditions. Faster-backgrounded groups had greater fat levels in the carcass than did slower-backgrounded groups. Dressing percentages and fat colour were unaffected by growth treatment, whereas differences in ossification score and meat colour were explained by age at slaughter. There were significant effects of sire type for virtually all carcass traits measured in the progeny. Differences in hot standard carcass weight showed a clear advantage to European types, with variable outcomes for the Angus and Wagyu progeny. Sire selection by estimated breeding values (within the Angus breed) for yield and/or fat traits resulted in expected differences in the progeny for those traits. There were large differences in both meat yield and fatness among the types of greatest divergence in genetic potential for those traits, with the Black Wagyu and the Angus IMF clearly superior for IMF%, and the European types for RBY%. The Angus IMF progeny performed as well as that of the Black Wagyu for all fatness traits. Differences in RBY% among types were generally reflected by similar differences in eye muscle area. Results here provide guidelines for selecting sire types to target carcass traits for specific markets. The absence of interactions between growth and genetic treatments ensures that consistent responses can be expected across varying management and production systems.



1963 ◽  
Vol 3 (10) ◽  
pp. 249
Author(s):  
RM Seebeck

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.



2006 ◽  
Vol 57 (1) ◽  
pp. 1 ◽  
Author(s):  
P. L. Greenwood ◽  
J. J. Davis ◽  
G. M. Gaunt ◽  
G. R. Ferrier

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.



1993 ◽  
Vol 33 (7) ◽  
pp. 825 ◽  
Author(s):  
D Perry ◽  
AP Yeates ◽  
WA McKiernan

The association between visually assessed muscle scores on live steers and their carcasses, eye muscle area, and the yield of saleable and lean meat was determined on 156 steers of mixed breeds (mean carcass weight 282 kg, mean P8 fat depth 13 mm). The contribution of subcutaneous and intermuscular fat to differences in saleable meat yield was also investigated. There was a negative correlation between P8 fat depth and both live ( r = -0.21) and carcass muscle score (r. = -0.31); therefore, the assessors were not scoring fatter steers as having better shape. The correlation between live and carcass muscle scores was 0.79. The correlation between carcass muscle score and eye muscle area was 0.58. When live muscle score, carcass muscle score, or eye muscle area was included in regression models already containing weight and fat depth, there was a significant (P<0.001) increase in the amount of variation in saleable and lean meat yield explained by the models. At the same liveweight and fat depth, a change in live muscle score from C (moderately muscled) to B (well muscled) was accompanied by an increase of 1.7% in saleable meat and 2.2% in lean meat, when these were expressed as a percentage of carcass weight. The equivalent change in carcass muscle score in carcasses of the same weight and f a t depth was accompanied by an increase of 1.9% in saleable meat and 2.4% in lean meat. The increased weight of saleable meat was not due to an increase in the dissected fat content of the meat. Weight of subcutaneous fat decreased as muscle score increased (P<0.01). There was no significant association between the amount of intermuscular fat and either live or carcass muscle score (r. = -0.075 and -0.18, respectively).



1993 ◽  
Vol 33 (3) ◽  
pp. 275 ◽  
Author(s):  
D Perry ◽  
WA McKiernan ◽  
AP Yeates

Domestic trade weight steers (149) were assessed visually for subcutaneous fat and then given a live muscle score based on the thickness and convexity of their shape relative to frame size, having adjusted for subcutaneous fat. After slaughter, carcasses were given visually assessed carcass muscle scores based on the same critera. Fat depths at the P8 site and 12-13th eye muscle area were measured. Half of each carcass was boned-out into primal joints with subcutaneous fat trimmed to 6 mm. The weights of these joints plus meat trim (85% visual lean) were added to obtain the weight of saleable meat. The weight of fat trimmed from the carcass, primal joints, and meat trimmings during the bone-out process was added to obtain weight of fat trim. The assessors did not give steers with a greater subcutaneous fat depth better muscle scores when scoring for muscle and intermuscular fat. There was a negative correlation between live muscle score and P8 fat depth (-0.37), and no significant correlation between carcass muscle score and P8 fat depth. The associations between muscle score and yield of saleable meat were investigated using multiple regression techniques, with fat depth and muscle score sequentially added after weight in the model. The coefficient of determination and the residual standard deviation were compared at each stage. For saleable meat yield (kg), liveweight and carcass weight were the main contributors to the variation explained by the models fitted. For saleable meat yield as a percentage of carcass weight, most of the variation accounted for by the models fitted was explained by fat depth, muscle score, and eye muscle area. When added after weight and fat depth in regression models, muscle score significantly increased the coefficient of determination in all cases, with an associated decrease in the residual standard deviation. The effect was strongest for percentage of saleable meat. At the same weight and fat depth, animals or carcasses with better muscle scores produced more saleable meat.



1970 ◽  
Vol 48 (4) ◽  
pp. 770-776
Author(s):  
C.N. Ncobela ◽  
A.T. Kanengoni ◽  
M. Chimonyo

The response of Windsnyer pigs to diets containing varying levels of potato hash silage in nutritionally related blood biochemistry, carcass traits and primal pork was estimated. Thirty-six growing clinically healthy male Windsnyer pigs with an initial weight of 36 kg ± 4.89 (mean ± standard deviation (SD)) were randomly assigned to six experimental diets containing 0, 80, 160, 240, 320, and 400 potato hash silage g/kg dry matter (DM). Experimental diets were derived from mixing a summit diet containing no potato hash silage and a dilution diet containing 400 g potato hash silage/kg in various proportions. Pigs were allowed ad libitum access to diets and water. There was no relationship between inclusion levels of potato hash silage and albumin: globulin ratio, total protein, and uric acid. As inclusion levels of potato hash silage varied, there was a positive linear relationship between silage and albumin concentration. Globulin concentration had a positive quadratic relationship with the inclusion of potato hash silage. Inclusion levels of potato hash silage resulted in a positive quadratic relationship in alkaline phosphatase. There was a negative linear response in warm carcass weight and cold carcass weight to inclusion levels of silage. A negative linear response was observed in dressing percentage. Different inclusion levels of potato hash silage caused a positive quadratic relationship in cooler shrink. There were negative linear relationships between inclusion of potato hash silage with shoulder fat, carcass length and backfat thickness. There was a negative linear relationship between eye muscle area and inclusion level of ensiled potato hash. There was a positive quadratic relationship between hindquarter length (HQL) and inclusion levels of silage. The observed linear relationship between hindquarter circumference (HQC) and inclusion levels of potato hash silage was negative. There is a need to predict the optimum inclusion level of potato hash silage without compromising the healthiness and carcass yield of pigs.Keywords: Alkaline phosphatase, backfat thickness, cold carcass weight, cooler shrink, dorsal fat thickness, eye muscle area, hindquarter circumference, total protein



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