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| Livestock Research for Rural Development 23 (1) 2011 | Notes to Authors | LRRD Newsletter | Citation of this paper |
The present work was performed to estimate the carcass weight of zebu cattle using carcass measurements. The carcass data were obtained from 297 hot carcasses of Baggara bulls. Their weight ranged between 113 to 384 kg. The results showed that carcass heart girth around the hump had the highest correlation coefficient (r = 0.79, P < 0.001) and a straight line relationship between hot carcass weight and carcass heart girth around the hump. A regression equation to predict carcass weight of zebu cattle was then calculated as: Y= 2.66x – 243.613 (± 0.09), R2= (0.62).
Grouping of carcass data according to carcass weight showed a highly positive correlation coefficients between hot carcass weight and hind leg circumference (r =0.86, P<0.001) in group A, for group B carcass heart girth around the hump (r = 0.62, P<0.001) and for group C carcass length (r = 0.54, P<0.001). This indicated a high accuracy in using the former measurements for estimation of carcass weight of zebu cattle. Regression equations were then calculated to predict hot carcass weight of cattle: Y = 1.47x + 24.629 for light weight zebu (l13 - 171) kg, Y= 1.5748x -52.215 for medium weight zebu (174 - 292) kg and Y = 1.7507x – 83.533, for heavy weight zebu (293 - 384) kg.
Keywords: Carcass measurements, heart girth, zebu cattle
Sudan is the largest country in Africa covering 2.5 million square kilometers. It has a large cattle population estimated as 41 million head, which represents 29.3% of the total livestock population (140 million head) in Sudan depending on the pasture as the main source of feeds. The total slaughter of cattle in the year 2008 was 5 million head with an extraction rate of 19.1 %. (Ministry of Animal Resources and Fisheries 2008). Eye ball judgedment is used There is a lack of weighing scales to determine the carcass weight of cattle. These instruments are costly to obtain and found only in research stations and modern slaughter houses. At present meat traders depend on cutting the carcasses into pieces using small weighing scales and in most times they use eye judgement to estimate carcass weight specially in remote and rural areas. The situation also applies in most developing countries.
The importance of carcass traits to the beef cattle industry is increasing, especially with the introduction of more detailed carcass specification systems and the payment of premiums for products satisfying the requirements of specific markets (Robinson et al 1993). Determination of carcass weight is important in estimation of carcass cash value as well as conducting studies and experiments. Different carcass measurements had been studied by many investigators as usefull predictors of carcass weight, grade, dressing percentage and composition (White and Green 1952; Preston and Willis 1974; Guma 1996 and Khogali 1999). Earlier, Bennett (1951) used temperate type of cattle and derived a formula for calculating the dressed carcass weight. The estimate equations reported by these authors helped to predict the live and carcass weights of temperate cattle, but not for tropical ones which are characterized by the presence of the hump.
The objective of this work is to investigate the relationship between carcass measurements and carcass weight and to formulate equations for Sudanese zebu cattle to predict carcass weight on the bases of one or more carcass measurements.
Carcass measurements were taken from 297 carcasses of cattle slaughtered at west Omdurman Abattoir (Ghanawa), Sudan. Carcass weights were taken using electronic weighing balance and recorded in kilograms. Carcass measurements were taken according to the procedure reported by Guma (1996), Khogali (1999) and Abdelhadi (2001) using a steel tape and a large metal caliper both of which were graduated in centimeters.
Carcass data were grouped according to carcass weight into three groups A, B and C following frequency distribution curve (Figure 1).
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All carcass weighing 172 kg or less were called “light weight carcasses” fell in group A, while group B cntained those ranging from 173 to 292 kg and were termed “medium weight carcasses”, however, group C contained carcasses weighing more than 292 or less than 385 kg were called “heavy weight carcasses”.
Carcass data were analyzed using Statistical Analysis System (SAS 1990) to calculate means, standard deviation and correlation coefficients. Regression analysis was also used to obtain the relationship between carcass weight and carcass measurements.
Carcass weights and carcass measurements are presented in table (1).
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Table 1. Carcass measurements of Baggara cattle |
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Measurement |
No. |
Mean |
SD |
CV |
Range |
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Carcass weight, kg |
297 |
233 |
47.3 |
20.3 |
113-384 |
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Heart girth, cm |
,, |
163 |
14 |
8.6 |
130-190 |
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Heart girth around the hump, cm |
,, |
179 |
13.9 |
7.8 |
135-210 |
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Abdominal circumference, cm |
,, |
147 |
10.3 |
7.0 |
111-177 |
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Carcass length, cm |
,, |
127 |
7.7 |
6.1 |
98-149 |
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Hind leg circumference, cm |
,, |
96.8 |
10.5 |
10.8 |
65-125 |
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Hind leg length, cm |
,, |
74.8 |
4.4 |
5.9 |
54-88 |
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Hind leg depth, cm |
,, |
23.0 |
2.7 |
11.7 |
15-31 |
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Hump circumference, cm |
,, |
81.2 |
11.6 |
14.3 |
20-110 |
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Hump height, cm |
, |
16.7 |
3.0 |
17.7 |
7-25 |
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Hump depth, cm |
,, |
19.1 |
3.6 |
19.0 |
9-28 |
Detailed measurements of carcass weight groups (A, B and C) are presented in Table 2.
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Table 2. Carcass weights (kg) and carcass measurements (cm) of Baggara cattle according to carcass weight groups. |
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Measurement |
Group A (113-171) kg |
Group B (174-292) kg |
Group C (293-284) kg |
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No. |
Mean |
SD |
C.V |
No. |
Mean |
SD |
C.V |
No. |
Mean |
SD |
C.V |
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Carcass weight |
23 |
139 |
19.6 |
14.1 |
243 |
231 |
27.2 |
11.8 |
31 |
325 |
22.5 |
6.9 |
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Heart girth |
,, |
137 |
27.8 |
20.2 |
,, |
164 |
8.3 |
5.1 |
,, |
177 |
8.9 |
5.1 |
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Heart girth around the hump |
,, |
152 |
8.2 |
5.4 |
,, |
179 |
10.5 |
5.8 |
,, |
197 |
8.9 |
4.5 |
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Abdominal circumference |
,, |
125 |
11.4 |
9.1 |
,, |
147 |
7.0 |
4.7 |
,, |
158 |
7.7 |
4.8 |
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Carcass length |
,, |
114 |
6.2 |
5.4 |
,, |
127 |
5.6 |
4.4 |
,, |
137 |
6.9 |
5.0 |
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Hind leg circumference |
,, |
78.1 |
11.9 |
15.2 |
,, |
97.8 |
7.6 |
7.8 |
,, |
104 |
13.3 |
12.8 |
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Hind leg length |
,, |
68.9 |
10.7 |
15.5 |
,, |
75.0 |
2.8 |
3.8 |
,, |
78.0 |
2.0 |
2.7 |
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Hind leg depth |
,, |
18.7 |
2.6 |
13.8 |
,, |
23.1 |
2.3 |
9.8 |
,, |
25.9 |
2.0 |
7.9 |
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Hump circumference |
,, |
63.6 |
5.8 |
9.1 |
,, |
82.8 |
8.6 |
10.6 |
,, |
89.0 |
15.5 |
17.4 |
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Hump height |
,, |
12.1 |
2.2 |
18.3 |
,, |
17.2 |
2.5 |
14.4 |
,, |
16.6 |
3.9 |
23.5 |
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Hump depth |
,, |
12.9 |
2.9 |
22.7 |
,, |
19.2 |
3.0 |
15.8 |
,, |
22.4 |
2.4 |
10.7 |
Carcass grouping indicated that medium weight carcasses of group B represented 82.2% of the total carcasses studied and had an average weight of 231 kg. However, group A which had the lightest carcass weight, represented 7.72 % and their average weight was 139 kg, while group C had the heaviest carcass weights with an average of 324.9 kg and represented 10.1% of all carcasses studies.
Table 3 shows the correlation coefficients between hot carcass weights and carcass measurements of all carcasses and carcass weight groups.
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Table 3. Correlation coefficients between hot carcass weight and carcass measurements of Baggara cattle |
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Measurement, cm |
Overall carcass weights, kg |
Carcass weight group |
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A |
B |
C |
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Heart girth |
0.66** |
0.40 ** |
0.56** |
0.19 (NS) |
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Heart girth around the hump |
0.79** |
0.44* |
0.62** |
0.40* |
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Abdominal circumference |
0.78** |
0.66** |
0.61** |
0.49** |
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Carcass length |
0.75** |
0.35 |
0.44** |
0.53** |
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Hind leg circumference |
0.57** |
0.85** |
0.49** |
0.26 (NS) |
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Hind leg length |
0.50** |
0.18 (NS) |
0.38** |
0.21 (NS) |
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Hind leg depth |
0.67** |
0.55** |
0.48** |
0.08 (NS) |
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Hump circumference |
0.61** |
0.69** |
0.51** |
0.26 (NS) |
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Hump height |
0.39** |
0.70** |
0.36** |
0.03 (NS) |
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Hump depth |
0.72** |
0.57** |
0.59** |
0.52** |
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* = P<0.05 ; ** = P<0.01; NS = Not significant |
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All correlation coefficients between carcass weight and the various carcass measurements were significant (P<0.001). Highly positive and significant (P<0.001) correlation coefficients were found between carcass weight and heart girth around the hump, abdominal circumference, heart girth, carcass length and hump depth which were 0.80, 0.78, 0.66, 0.75 and 0.72, respectively. However, medium and significant (P<0.001) correlation coefficients were found between carcass weight and hind leg (length, depth and hump circumference) which were 0.50, 0.67 and 0.61, respectively.
Regarding carcass weight groups A, B and C, the correlations between the hot carcass weight and linear carcass measurements were greater in group A (hind leg circumference and hump height), intermediate in group B (heart girth around the hump, abdominal circumferences, heart girth and hump depth) and low in group C, except carcass length and hump depth. According to table 3 the highest and significant correlations were found between heart girth, heart girth around hump, abdominal circumference, carcass length and hump depth.
Figure 2 shows the regression line and the regression equation of the hot carcass weight (Y) on carcass heart girth around the hump (x) for all measurements.
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It indicated that an increase or a decrease of one cm of carcass heart girth around the hump gave an increase or a decrease of 3.89 kg of carcass weight:
Y = 2.66x – 243.613 (±0.09), R2 = (0.62)
According to carcass weight grouping, only the regression lines of carcass measurement (x) for hind leg circumference (group A), carcass heart girth around the hump (group B) and carcass length (group C), with hot carcass weight (Y) were obtained as they had the highest correlation coefficients.
The regression equations were:
Group A: Y = 1.47x + 24.629 (± 0.28), R2 = (0.73)
Group B: Y = 1.5748x – 52.215 (± 0.08), R2 = (0.38)
Group C: Y = 1.7507x – 83.533 (± 0.20), R2 = (0.28)
The regression equation of carcass weight on hind leg circumference (group A), gave a high coefficient of determination (R2 = 0.73) which indicated the accuracy of using such measurement in estimation of light carcass weights of zebu cattle. The variation percentages between the actual and estimated carcass weights in groups A, B and C were 5.54, 9 and 8 %, respectively with an average of 7.50 %.
The mean values of the carcass heart girth, carcass length, hind leg circumference and hind leg length were higher than those reported by Gaili and Osman (1979), Guma (1996) and Khogali (1999) for the same breed. These differences could be attributed to the seasonal and nutritional factors.
Compared to foreign breeds, McGee et al (2007) reported longer carcass length of Holstein, Friesian and Charolais × Holstein- Friesian than Baggara zebu cattle which were [139, 134 and 132 vs. 127 cm], respectively. While the leg length for the same breeds was shorter in Holstein and Friesian compared to the present results [71.9 and 71.4 vs.74.8 cm]. Long leg length was found in Charolais × Holstein breed which was (76.7 cm). Hind leg depth was higher in the previous breeds compared to Baggara zebu cattle of the present study [28, 28.1 and 29.5 vs. 23cm], respectively. Indurain et al (2009) reported high values of length, round circumference and thickness 131, 121, 30.4 cm for Spanish bulls of average live weight 336 kg. These differences between breeds could be attributed to genetical differences.
The present findings showed that hot carcass weight and carcass heart girth around the hump were highly correlated (r = 0.80, P<0.001) which could be the best measurements to estimate the carcass weight of Zebu cattle. Payne (1990) reported that when live weight was known, an approximate estimation of the dressed carcass weight could be made according to the condition of the live animal. This agreed with Kempster et al (1982) who indicated the importance of conformation as an indicator of commercial value based on the assumption that carcasses with better conformation had advantages in terms of lean meat content, proportion of higher priced cuts and possibly greater muscle size or area. The correlation between hot carcass weight and carcass heart girth was lower than that reported by Khogali (1999) for the same breed. The latter author reported a high correlation coefficient of (r = 0.88). This variation might be due to the uniformity of live weights in the study of the latter author.
According to carcass weight grouping, the highest correlation was found in group A, between the hot carcass weight and hind leg circumference (r = 0.72, P<0.001). In general, these findings were in agreement with Khogali (1999) who reported a high correlation between cold carcass weight and hind leg circumference. Consequently greater accuracy can result from using this measurement for estimation of carcass weight of zebu cattle. The regression of carcass weight on carcass heart girth around the hump showed a straight line relationship. It was evident from the coefficient of determination (R2 = 0.62) in Figure 2, that the carcass heart girth around the hump could be a reliable measurement in estimation of hot carcass weight.
According to the carcass weight group A, B and C a straight line relationship existed between hot carcass weight and hind leg circumference, heart girth around the hump and carcass length with highly positive and significant (P<0.001) correlation coefficients (0.85, 0.62 and 0.53), respectively (Table 3). The R2 value was higher in group A (0.85), which clearly showed that the hind leg circumference was the best measurement for predication of hot carcass weight for light zebu cattle. The regression equation of this group, showed 5.5% variation for the estimated carcass weight (y) in which the hind leg circumference (x) ranged from 65 to 98 cm. Differences in carcass weights were observed at the same measurement of heart girth around the hump (Figure 2), this could be attributed to the high variation of carcass weights. Better results would be achieved in estimation of carcass weight if the animals were derived from pure breed.
From the view of the present result it could be concluded that, carcass heart girth around the hump, hind leg circumference and carcass length, respectively can be used to accurately estimate hot carcass weight of zebu cattle.
The authors express special thanks to the Administration of west Omdurman Abattoir (Ghanawa); thanks are also extended to their staff for their help in taking carcass measurements for this study.
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Received 25 August 2010; Accepted 19 September 2010; Published 5 January 2011
