Path analysis and robust prediction of lamb carcass composition

1989 ◽  
Vol 48 (1) ◽  
pp. 139-148 ◽  
Author(s):  
G. L. Bennett

ABSTRACTPath analysis was applied to correlations among lamb carcass measurements. Correlations were obtained from lamb carcasses averaging 15·7 kg and 270 g fat per kg carcass weight. Correlations were adjusted to represent within breed, sex and management group relationships. The purpose of the analysis was to study the relationships of carcass weight with carcass measurements and to identify carcass measurements that are independent other than through their relationships with carcass chemical fat concentration and carcass weight. The direct effect of live weight on all carcass measurements was positive. Thus, heavier carcasses with the same fat concentration had larger fat and tissue depths, muscle measurements, leg measurements and kidney fat weights. The results of correlations among the residuals suggest that fat depths C and J, specific gravity, muscle width A and kidney fat weight are nearly independent estimates of carcass composition in the sense that they are only correlated through their relationships with carcass weight and carcass fat composition. Robust predictors of carcass composition were developed by first adjusting carcass measurements for the direct effects of carcass weight and then computing regressions on the adjusted measurements. These predictors appeared to be better predictors of environmental and genetic differences than least-squares multiple regression yet reduced the accuracy of within group prediction only slightly.

1972 ◽  
Vol 15 (3) ◽  
pp. 229-237
Author(s):  
C. E. Hinks ◽  
J. H. D. Prescott

SUMMARYTwo experiments concerning the effects, on the carcass and meat characteristics of 18-months-old Friesian steers, of variation in grazing intensity and the level of barley feeding with silage are reported.Groups of 12 steers were grazed at different intensities over 5-month grazing periods, such that live-weight differences of 38 kg and 16 kg were recorded at housing. No compensatory growth was recorded during the subsequent winter feeding period.Whilst the grazing treatments had little effect on carcass or meat quality, higher levels of barley feeding with silage over the winter period (710 v. 410 kg/steer) had significant effects on live-weight gain, and increased carcass weight by 21 kg at slaughter. The higher yield of carcass weight was reflected in significant differences in carcass composition, joint proportions and retail cut-out value. Sixty per cent of the carcass weight difference was removed as trim fat. Differences in carcass fatness were not associated with any differences in eating quality.


1984 ◽  
Vol 8 ◽  
pp. 103-103
Author(s):  
A. J. Brown ◽  
B. W. Butler-Hogg ◽  
J. D. Wood

Future improvements in British lamb sales depend on increasing the lean to fat ratio in cuts and joints offered for sale, since numerous surveys have shown an aversion to fat on the part of consumers. This ratio can be changed by manipulating breed and live weight at slaughter, since breeds of large mature size slaughtered at light weights are considerably leaner than those of small mature size slaughtered at heavy weights. However, there are other aspects of carcass value than overall lean and fat content. These include factors such as the proportions of individual joints and their composition. This study was carried out to examine carcass composition and carcass quality changes between 12 and 24 kg cold carcass weight (CCW) in 317 castrated males and 238 females from six pure breeds.


1967 ◽  
Vol 9 (1) ◽  
pp. 115-119 ◽  
Author(s):  
D. Levi ◽  
M. Soller ◽  
A. Shilo

Data were collected during 1961–2 on the live-weight, age and warm carcass weights of 83 lots of Israel-Friesian bull calves, 525 animals in all, the offspring of 26 sires. For varying numbers of these animals weight of various non-saleable fat components, including ruminal fat, kidney fat, inguinal fat and scapular fat were also obtained. Ruminal fat alone and ruminal fat plus kidney fat were found to be highly correlated with total non-saleable fat (r = 0·84 and 0·94, respectively). Heritability of dressing percentage was 0·20, of live-weight rate-of-gain 0·92, and of carcass rate-ofgain 0·49. The genetic correlation between live-weight and carcass weight was 0·7. Between-lot correlations indicated that increased rate-of-gain achieved through management will be accompanied by decreased dressing percentage and increased non-saleable fat content.


1996 ◽  
Vol 76 (1) ◽  
pp. 49-53 ◽  
Author(s):  
S. D. M. Jones ◽  
W. M. Robertson ◽  
M. A. Price ◽  
T. Coupland

A total of 281 lamb carcasses covering three weight groups (18–22.9, 23–25.9 and 26–30 kg) and fatness (< 3 mm, 3–5 mm and > 5 mm) were used to determine the usefulness of several carcass measurements for predicting saleable meat yield. Carcasses were measured for fat and muscle depth, 3–4 cm from the mid-line between the 10th and 11th ribs, 12th and 13th ribs and immediately adjacent to the 13th rib using a Hennessey Grading Probe. This technique also determined total tissue depth at 11 cm from the mid-line between the 10th and 11th and 12th and 13th ribs. The depth of tissues over the 12th rib 11 cm from the mid-line was measured with a ruler. Carcasses were also visually assessed for muscle development (conformation score) on a 5-point scale (1 = thinly fleshed; 5 = thickly fleshed). All carcasses were fabricated into primal cuts which were trimmed to 5 mm of fat and deboned to provide an estimate of saleable meat yield. Ewe lamb carcasses had a higher proportion of kidney fat than wethers in all weight and fat groups (which ranged from 2.6 to 17.9 g kg−1 carcass weight). Saleable meat yield decreased as carcasses became fatter, whereas weight group had little influence on saleable meat yield within a fat group. Ewe lamb carcasses had lower saleable meat yields than wether lamb carcasses, mainly because of their higher amounts of kidney fat. A ruler measurement of tissue depth over the 12th rib combined with carcass conformation score provided the most precise prediction (R2 = 0 61; RSD 17.1) of saleable meat yield. It was concluded that a simple manual system based on these two measurements provided an adequate prediction of saleable meat yield. The accuracy of the procedure would be increased by excluding kidney fat from carcass weight for the prediction of saleable meat yield. Key words: Lamb, carcass, composition, probe, fat, grade


1993 ◽  
Vol 57 (2) ◽  
pp. 253-261 ◽  
Author(s):  
J. E. Vipond ◽  
G. Swift ◽  
R. C. Noble ◽  
G. Horgan

AbstractThe effect of grazing clover on ewes and lambs was studied using nitrogen-fertilized grass (G) and grass/white clover pastures (GC) containing proportionately 0·18 clover. Carcasses of lambs grazed on GC were significantly heavier than carcasses of lambs grazed on G pastures. An interaction with weaning occurred. Carcasses from lambs grazed on GC for 53 days post weaning were 2·3 kg heavier (F < 0·01) but lambs slaughtered at weaning had similar carcass weights. Diet had no effect on relative joint components of carcasses. The effect of clover in the diet on carcass weight was attributed to higher levels of protein retention.Analysis of the fatty acid composition of intramuscular and subcutaneous and perirenal lipids indicated small but significant effects of diet. Lean tissue lipids of lambs grazing clover showed significant increases in C18:2 and reduced C20: 5 fatty acids. In tissue fats there were small increases in C14:0, C16:0 and C18:2 with reduced C18:1 content.Twin suckled lambs grazing GC for 94 days from turn-out in early April showed increased live-weight gain over lambs on G of 336 v. 287 g/day (s.e.d. 84; P < 0.001). Post weaning live-weight gain of lambs was 173 and 221 g/day on G and GC respectively. Sward height was maintained at 5.18 and 5.24 (s.e.d. 0.075) cm on G and GC paddocks by adjusting ewe numbers. GC pastures carried proportionately 0.82 of the stock on G pastures but output of lamb was similar at 1289 and 1247 kg/ha for G and GC respectively.Results showed that the production penalty of lower stocking rate associated with grass/clover v. grass fertilized with 190 kg nitrogen per ha was ameliorated by higher lamb live-weight gain and carcass weight without change in joint composition or nutritionally significant change in fatty acid composition of carcass tissues.


2015 ◽  
Vol 19 (1) ◽  
pp. 19-26
Author(s):  
Roxana Savescu ◽  
Georg Ploetz

Abstract Until the introduction of SEUROP system, price negotiation between pig producers and slaughterhouses was based on two subjective criteria: animal weight and visual inspection of the quality of pigs. To ensure producers a fair payment, European Union created the possibility of binding the price on two objective factors: carcass weight and carcass composition. This paper describes the pricing mechanism developed by Romania in order to respond to European Union requirements for ensuring a fair payment to pig producers. It raises the attention on the difficulties encountered by the producers in understanding the way the commercial value of a pig carcass is calculated in case the selling price is negotiated on a flat rate basis or on a lean content basis (per kg of carcass weight or per kg of live weight).


1962 ◽  
Vol 59 (2) ◽  
pp. 207-214 ◽  
Author(s):  
A. Cuthbertson ◽  
R. W. Pomeroy

1. The object of the experiment was to make a detailed investigation of the carcass composition of Large White hogs at 68, 91 and 118 kg. live weight (i.e. 50, 68 and 92 kg. carcass weight). Ten hogs were dissected at each stage.2. A dissection technique suitable for this investigation is described, involving the dissection of one side into individual bones and muscles, subcutaneous and intermuscular fat deposits, skin, tendon, glands and blood vessels. Some possible modifications of the method for future investigations are also discussed.3. The complete dissection of one side took approximately 110 man-hours and the average weight loss in dissection was 0·798%.


1990 ◽  
Vol 50 (2) ◽  
pp. 261-269 ◽  
Author(s):  
D. Zygoyiannis ◽  
K. Stamataris ◽  
S. Kouimtzis ◽  
J. M. Doney

ABSTRACTNine male and nine female lambs each from the Karagouniko (K), Chios (C) and East Friesland (F) breeds were weaned at a mean age of 50 days and were killed over a commercial range of live weight from 16 to 44 kg (carcass weights 6 to 22 kg).Carcass weight was linearly related to fasted live weight prior to slaughter (r = 0·994). There were significant but small differences between breeds in mean weight of lungs, pelt and internal fat. The carcass components of bone, muscle and fat tissues were related to carcass weight by linear or quadratic regression. Adjusted to mean carcass weight, the mean weight of bone did not differ between breeds (2·82 kg, s.e. = 0·056 at 12·8 kg carcass). The K and C lambs had significantly less muscle than the F lambs (6·77, 6·63 and 8·20 kg, respectively, s.e.d. = 0·094) and more fat (2·87, 2·95 and 1·29 kg, respectively, s.e.d. = 0·017) when compared at mean carcass weight. The breed differences were significant over the whole range whether compared at equal weight or at an equal proportion of estimated mature weight. At the same proportion of carcass fat, corresponding to the United Kingdom market average (250 g/kg) the calculated carcass weights were 16, 17 and 30 kg, respectively, for K, C and F lambs.It is concluded that the Friesland breed differs from many others in the proportions of muscle or fat at corresponding carcass weights but this difference is not a general characteristic of dairy sheep. Comparison of breeds at defined proportions of carcass components, as determined by market standards, can be effectively achieved by serial slaughter over a suitable weight range.


1988 ◽  
Vol 47 (3) ◽  
pp. 369-377 ◽  
Author(s):  
G. L. Bennett ◽  
H. H. Meyer ◽  
A. H. Kirton

ABSTRACTThe effects of average carcass fat concentration of a group of lambs on correlations among lamb carcass measurements within the group and of slaughter age on variances of carcass measurements were studied. Three-hundred and sixty-eight crossbred lambs from one experiment were slaughtered on 10 days over a 2-year period. Average carcass fat concentration of the 10 groups ranged from 179 to 326 g/kg carcass weight. Variances of carcass fat, water and protein concentrations and of muscle measurements did not increase at later slaughter ages but variances of kidney fat weight, fat depths and total tissue depths increased. Several correlations among carcass measurements had significant regressions on average carcass fat composition of the groups slaughtered. When measurements were adjusted for age but not weight, correlations of carcass weight, kidney fat weight, specific gravity, tibia and tarsus length and m. longissimus depth with carcass fat, water and protein concentrations weakened as carcass fat concentration of the group increased. Correlations of kidney fat, specific gravity and m. longissimus width with fat, water and protein concentrations adjusted for carcass weight weakened as average carcass fat concentration of the group increased. Multiple regression equations did not reveal any advantage in using combinations of muscle or leg dimensions to predict fat concentration.


1975 ◽  
Vol 47 (5) ◽  
pp. 385-444
Author(s):  
Hilkka Ruohomäki

In the present study the main objectives were to determine whether sufficiently accurate estimation of live weight, carcass weight and carcass composition with live measurements is possible, and whether an accurate estimation of carcass composition with any other procedure than total carcass dissection is possible. The material consisted of 205 1-year old steers and bulls and 174 bull calves. Within experiment each trait of each animal was corrected for age, breed and feeding with a correction factor obtained with the least squares method. In the stepwise regression analysis the results for both age groups were analysed separately. From live measurements the best estimators in both age groups were width of chest, heart girth and natural length. The most reliable predictor of meat quantity was carcass weight. Revalue was 96 % for both age groups. In estimation of meat percentage the Revalue obtained for the olds with cutting results of fore shanks was 56 %, the respective value for the 1-year olds was considerably lower. With 1-yearolds the carcass weight and some byproducts gave the highest estimations for the quantity and percentage of fat, R2 were 62 % and 50 % respectively, and for the 14-yearolds the kidney fats and the cutting results of flanks gave the highest estimations, R2 were 70 % and 59 % respectively. For the quantity and percentage of bone the R2 for the 1-yearolds obtained with cutting results of shanks were 68 % and 55 % respectively, and for the 14-year olds 82 % and 70 % respectively. When the cutting results of the fore and hind quarters were used as estimators the R2 obtained for all the traits were higher in both age groups than with any other estimator, R2 obtained with carcass quality scores remained lower.


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