An assessment of carcass probes for use in Great Britain for the EC pig Carcass Grading Scheme

1989 ◽  
Vol 48 (2) ◽  
pp. 427-434 ◽  
Author(s):  
G. L. Cook ◽  
J. P. Chadwick ◽  
A. J. Kempster

ABSTRACTTo gain approval for use in the revised European Community (EC) Pig Grading Scheme to be introduced in 1989, methods of estimating carcass lean proportion must be shown to do so with a coefficient of determination greater than 0·64 and a residual s.d. of less than 25 g/kg. A trial was carried out to assess a number of methods for use in the EC Scheme as applied in Great Britain. Subcutaneous fat and m. longissimus depths at the head of the last rib and at the third/fourth from last rib were measured using the optical probe (OP), the Fat-O-Meater (FOM), the Hennessy Grading Probe II (HGP) and the Destron PG-100 Probe (DST) on a broad sample of 162 commercial carcasses representative of the ranges in fatness and weight found nationally. The left side of each carcass was separated into component tissues. Although the instruments all achieved similar levels of accuracy in predicting carcass lean proportion, some differences were found. The DST just failed to reach the required statistical criteria for approval in the EC Scheme. The results for the other three instruments were submitted to Brussels as evidence of suitability and they have been approved.Using the regression relationships found between carcass composition and fat thickness together with results from earlier studies, it was estimated that the carcass separable fat proportion of British slaughter pigs has fallen at the annual rate of 7 g/kg since 1975.

1986 ◽  
Vol 106 (2) ◽  
pp. 223-237 ◽  
Author(s):  
A. J. Kempster ◽  
J. P. Chadwick ◽  
D. D. Charles

SUMMARYCarcass data for 1053 steers from the Meat and Livestock Commission's beef breed evaluation programme were used to examine the relative precision of alternative fatness assessments for predicting carcass lean percentage. The data were from four trials and comprised both dairy-bred and suckler-bred cattle by a wide range of sire breeds.A visual assessment of carcass subcutaneous fat content to the nearest percentage unit (SFe) was the single most precise predictor both overall (residual S.d. = 2·28) and within breed (residual S.d. = 2·05). Precision was improved by the addition in multiple regression of the percentage perinephric and retroperitoneal fat (KKCF) in carcass, a visual score of the degree of marbling in the m. longissimus and selected fat thickness measurements taken by calipers on cut surfaces (residual S.d. = 2·11 (overall) and 1·90 (within breed)).When the best overall equation was applied to the breed means, there was substantial bias (predicted – actual carcass lean percentage). Biases ranged from +2·5 (purebred Canadian Holstein and Luing) to – 1·3 (Limousin crosses).Breeds differed significantly in carcass lean content when compared at equal levels of fatness measurements. The differences depended both on the precision with which the measurements predicted carcass lean content and the observed differences in carcass composition that existed before adjustments to equal fatness were made.The robustness of prediction equations was examined by applying them to independent sets of data (a total of 334 carcasses) from four other trials involving steers, heifers, cows and young bulls. Equations were stable for cattle of the same breed, sex and similar levels of fatness but important bias was found between more extreme types of cattle.


1987 ◽  
Vol 45 (1) ◽  
pp. 97-102 ◽  
Author(s):  
S. M. Joyal ◽  
S. D. M. Jones ◽  
B. W. Kennedy

AbstractAn electronic meat-measuring equipment (EMME) determination (average of three consecutive readings) and backfat thickness (averaged over two sites) were taken on each of 107 live Yorkshire pigs weighing approximately 110 kg. After slaughter, 10 carcass traits: killing out, grade fat (fat thickness at maximum loin of split carcass), in. longissimus area, total and individual weights of the four untrimmed primal cuts (butt, picnic, loin and ham) and total weight of lean and subcutaneous fat in the four primal cuts, were measured and used to evaluate the EMME and ultrasound backfat probe, alone and in combination, in predicting carcass merit. Value of prediction was measured as significant improvement in correlation over a base model (A/?2). After adjustment for live weight and treatment (diet, sex and housing) differences, the EMME alone was significant in predicting grade fat (A/?2 = 007), weight of the four untrimmed primal cuts (A/?2 = 0·03) and weights of ham (A/?2 = 0·04), lean (A/?2 = 0·17) and subcutaneous fat (A/?2 = 0·08). Backfat thickness alone was significant in predicting grade fat (AR2 = 0·21) and the weights of loin (AR2 = 0·03), ham (AR2 = 0·02), lean (AR2 = 0·09) and subcutaneous fat (AR2 = 0·42). Their combined information was superior in predicting fat thickness (AR2 = 0·24), weight of lean (AR2 = 0·21) and weight of subcutaneous fat (AR2 = 0·44). Similar results were obtained when treatment effects were ignored. Correlations of the EMME number with fat thickness, weight of total lean and total subcutaneous fat were 0·31, 0·49 and -0·30, respectively. Correlations of backfat thickness with grade fat, weight of total lean and total subcutaneous fat were 0·53, -0·35 and 0·72, respectively.


1975 ◽  
Vol 20 (2) ◽  
pp. 257-265 ◽  
Author(s):  
J. F. O'Grady ◽  
F. W. H. Elsley ◽  
R. M. MacPherson ◽  
I. McDonald

SummaryThe live-weight changes of 48 sows were recorded over three reproductive cycles. All sows were given standard amounts of feed in gestation and one of four energy allowances during lactation. The daily intakes of digestible energy during lactation ranged from 12·2 to 182·2 Meal in the first, 122·9 to 192·6 Meal in the second and 132·2 to 202·2 Meal in the third lactation. Weight change in lactation responded to energy intake; sows on the lowest energy intake lost weight whilst those on the highest intake gained. At weaning of their third litters, sows on the highest energy allowance weighed 44 kg more than those on the lowest level and this was equivalent to a carcass difference of 372·3 kg at slaughter.All the sows were slaughtered after the third litters had been weaned and the carcasses were dissected into lean, subcutaneous fat+skin, and bone. Sows from all treatments had less subcutaneous fat+skin and more muscle and bone than non-pregnant gilts killed at a mean weight of 129 kg, a weight equivalent to that of the experimental animals at their first mating.The reduction in fat reserves was linearly correlated with dietary energy intake of the sows. Sows receiving the lowest energy intake in lactation possessed fat reserves which were estimated to be only 25% as great as in gilts comparable to those used to initiate the experiment. This reduction in body reserves has implications with regard to the long-term effects of feeding lactating sows low intakes of energy during 6-week lactations.


1983 ◽  
Vol 101 (1) ◽  
pp. 241-248 ◽  
Author(s):  
J. P. Chadwick ◽  
A. J. Kempster

SUMMARYFat thickness measurements, taken over the M. longissimus between the 6th and 13th ribs by the automatic-recording probes, SFK Meat-Fat probe (MF), Hennessy and Chong Fat Depth Indicator (FDI) and Ulster probe (UP), and a simple ruler probe (RP), were compared with one another and a visual fat score (VSC) in terms of the precision with which carcass lean and subcutaneous fat percentages were predicted. The comparisons were made in four separate trials with RP and VSC common to all of them. A total of 182 carcasses were involved; 130 of these were probed both hot and cold. Comparisons were made among carcasses of the same weight.VSC was the best single predictor in most circumstances. Fat thickness measurements taken on the cold carcass provided a more precise prediction than those taken on the hot carcass. There was an interaction between the relative precision of the MF and RP probes and the condition of the carcass: the former generally gave the more precise prediction on cold carcasses and the latter on hot carcasses. Measurements taken by FDI tended to be better predictors than those taken by RP on both hot and cold carcasses. The use of two fat thickness measurements gave an improvement in precision over the best individual fat thickness measurements. There was also an improvement in precision in most circumstances when a fat thickness measurement was used in addition to VSC.There was little indication that specific fat measurements were particularly precise predictors when taken by specific probes, and no fat measurement was consistently the best predictor. A measurement taken 7·5 cm from the dorsal mid line at the 6th rib occurred most commonly in pairs of measurements giving the most precise prediction.


1982 ◽  
Vol 62 (2) ◽  
pp. 371-379 ◽  
Author(s):  
S. D. M. JONES ◽  
J. S. WALTON ◽  
J. W. WILTON ◽  
J. E. SZKOTNICKI

Thirty-eight lambs (22 rams, 16 ewes), 25 Holstein cows and 30 steers were evaluated ultrasonically for subcutaneous fat thickness. Urea space was also estimated, using the dilution principle, by a single injection of a known amount of urea and taking a single blood sample 12 min later. All lambs and cattle were slaughtered within 2 days and the half-carcasses were separated into fat, lean and bone. Urea space (R2 = 0.10) and fat thickness (R2 = 0.18) in lambs were poorly related to the weight of half-carcass lean tissue. Neither urea space nor fat thickness improved the level of explained variation in half-carcass lean tissue weight over that explained by liveweight alone (R2 = 0.73). Urea space showed a larger association with half carcass lean weight in cows (R2 = 0.55) than in steers (R2 = 0.14), but again did not improve the relationship provided by liveweight alone (R2 = 0.60). Fat thickness provided nonsignificant regressions (P < 0.05) with half-carcass lean weight both in cows and in steers. Liveweight was the dominant independent variable (R2 = 0.33) for predicting total fat in lamb half-carcasses; urea space (R2 = 0.08) and fat thickness (R2 = 0.13) did not improve the prediction given by liveweight alone. Fat thickness was poorly related to total fatness both in steers (R2 = 0.12) and in cows (nonsignificant regression). A multiple regression equation combining fat thickness and liveweight provided the best prediction of half-carcass fat in cows, whereas a similar equation with the addition of urea space gave the best prediction of half-carcass fat in steers. The measurement of urea space and fat thickness to predict the weight of carcass tissues (lean, fat) in live lambs and cattle over the weight (41.9 + 9.7 kg(SD) lambs, 624 ± 62.8 kg cows and 466 ± 63.2 kg steers) and fatness (19.9 ± 3.27% (SD) lambs, 21.9 ± 2.18% cows and 20.9 ± 3.98% steers) ranges studied was of limited value. Key words: Urea dilution, ultrasound, live animal evaluation, carcass composition


1985 ◽  
Vol 41 (3) ◽  
pp. 383-391 ◽  
Author(s):  
A. Diestre ◽  
A. J. Kempster

AbstractData for 1002 pigs slaughtered between 1979 and 1982 from the Meat and Livestock Commission's Commercial Pig Evaluation scheme were used to examine the relative precision of different measurements for predicting carcass lean concentration. The sample covered the main market weights in Britain and comprised gilts and barrows. The overall means of carcass weight and lean concentration were 66·1 (s.d. 20·00) kg and 499 (s.d. 44·2) g/kg. Predictors were examined when used in addition to carcass weight.Of the measurements taken on the intact or centre-split carcass, fat thickness measured by optical probe 65 mm from the dorsal mid line over the m. longissimus at the last rib was the most precise predictor of lean concentration (residual s.d. = 24·6 g/kg). The precision was improved significantly when a mid-line loin fat thickness measurement was added (residual s.d. = 23·7). The stability of the selected regression equations was examined by applying them to data for three other sets of carcasses (totalling 489 carcasses) sampled from commercial abattoirs between 1975 and 1983. Biases (predicted minus actual lean concentrations) ranged from +13 to −25 g/kg.Among the measurements taken on the cut surface at the last rib, fat thickness 8 cm from the dorsal mid line was the most precise predictor (residual s.d. = 22·4 g/kg). The precision was improved significantly when m. longissimus depth was added (residual s.d. = 20·3 g/kg). Prediction bias with these measurements was similar to that recorded with the intact or split-carcass measurements. In both cases, bias tended to increase with the number of independent variables in the prediction equations.


1993 ◽  
Vol 57 (1) ◽  
pp. 65-72 ◽  
Author(s):  
R. Priyanto ◽  
E. R. Johnson ◽  
D. G. Taylor

AbstractThe effects of breed and feeding on the prediction of carcass fat and carcass muscle using rump ‘P8’ subcutaneous fat thickness were investigated in heavy-weight beef carcasses (277 to 512 kg). Hot side weight, eye muscle area and their combination added to fat thickness were evaluated as additional predictors. The predictions of carcass composition from grass-fed steers were validated on data from grain-fed steer carcasses. There were differences between breeds and feeding regimes in the level of tissue proportions at a given fat thickness, but no differences in regression slopes. Fat thickness alone was, therefore, not an accurate indicator of the proportions of side fat or side muscle in heavy-weight carcasses. In the grain-fed steers, the correlations between P8 and tissue proportions were relatively strong, and the addition of hot side weight and eye muscle area, alone or in combination, did not significantly improve the predictions. Conversely, in grass-fed steers where the relationships between carcass composition and fat thickness were weaker, the addition of hot side weight and eye muscle area made a significant contribution to prediction. In the predictions of tissue weights, hot side weight and eye muscle area when added to fat thickness, significantly contributed to the prediction of side muscle weight for both feeding systems. These three variables did not account for the observed differences between breeds or feeding regimes in the proportion or weight of fat, nor in the proportion of muscle; but they effectively eliminated these groups' differences in the estimation of muscle weight.


1993 ◽  
Vol 73 (4) ◽  
pp. 839-845 ◽  
Author(s):  
N. N. Aziz ◽  
W. A. Rae ◽  
R. O. Ball

Data from 204 sows were used to predict percentage carcass lean yield and lean weight. Backfat thickness (probe fat) and muscle depth (probe lean) were measured with an electronic probe. Fat thickness was also measured by ruler at the midline at maximum fat depth over the lumbar vertebrae (maximum fat), fat depth at the last rib (last-rib fat), and fat depth between the 3rd- and 4th-last ribs (fat depth 3–4). Fat depth over maximum loin-muscle depth (loin fat 1), maximum fat depth over loin muscle (loin fat 2), maximum loin depth (loin lean 1) and maximum loin width (loin lean 2) were measured on loin cross section. On the warm carcass, the prediction accuracy of percentage lean yield was highest for probe fat (R2 = 0.77), whereas probe lean had the lowest coefficient of determination (R2 = 0.01). Among the ruler measurements, maximum fat was associated with the most accurate prediction of percentage lean yield (R2 = 0.71). Among cross-section measurements, loin fat 2 was the most accurate predictor of percentage lean yield (R2 = 0.78). For predicting lean weight in the carcass, carcass weight gave the highest coefficient of determination (R2 = 0.82) of any single measurement, but addition of probe fat to the equation improved R2 by 11% and reduced the RSD from 3.16 to 2.00. A single measurement by probe (probe fat) or ruler (maximum fat) was concluded to be sufficient to accurately predict percentage lean yield in sow carcasses. Key words: Lean yield, sows, prediction, carcass composition, grading


Author(s):  
M. P. Grantley-Smith ◽  
J. R. Southgate ◽  
D. W. Jones ◽  
A. R. Peters ◽  
M. Dobson

Oestradiol 17β (Compudose-365 ) is widely used as a growth promoter in steers and the daily gain response is well known. However, for bull beef production the efficiency of the hormone implant is not so well researched, particularly in Great Britain, where there is not yet a product licence for use in bulls. Work in the U.S.A. has shown that Oestradiol 17β implants in bulls stimulate daily gain and improve carcass shape, but at the same time increasing subcutaneous fat levels (Johnson et al, 1984). The trial described here was designed to study the effect of Oestradiol 17β under a range of farm conditions in Great Britain.Sixteen groups of bulls on 14 farms, totalling 450 bulls, were selected. Fourteen of the groups were wholly British Friesian, the remainder Friesian/Holstein or Limousin cross. The bulls were weighed at 3-4 months of age and paired by weight. One of each pair was implanted subcutaneously in the ear with a silastic rubber implant containing 45 mg Oestradiol 17β (Compudose-365, Elanco Products Ltd.). The bulls were weighed after three and six months (mean 108 and 180 days respectively), and about half were weighed within four days of slaughter (mean 222 days).


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