Body and carcass linear measurements of goats slaughtered at different weights

S Attah*, A O Okubanjo, A B Omojola and A O K Adesehinwa**

Meat Science Laboratory, Department of Animal Science, University of Ibadan, Ibadan, Nigeria
abomojola@yahoo.com

^*Present Address: Department of Animal Production, University of Agriculture, Makurdi, Nigeria.

** Institute of Agricultual Research & Training, Obafemi Awolowo University,
PMB 5029, Moor Plantation, Ibadan. Nigeria.

Abstract

Body and carcass measurements were obtained from 9 each of Red Sokoto (RS) and West African Dwarf (WAD) male and female yearling goats. At the commencement of the experiment their initial body weight ranged between 5.47 and 8.82 kg. They were fed on a 16.8% crude protein concentrate diet and then slaughtered three per group at 10,15 or 20 kg body weight. Prior to slaughter, at the various predetermined slaughter weights, body measurements (height at withers, height at pelvis, width of chest , chest girth and width of pelvis) were carried out on each of the animals. After slaughter the hot carcass weight (HCW) was taken on the kill floor within 20 minutes post-mortem. The carcasses were chilled at 3C for approximately 24hr after which the various carcass measurements were carried out.

Body and carcass measurements that had to do with height and length of animals or their parts were significantly higher (P< 0.05) in the RS than the WAD. The males were significantly taller (P< 0.05) at 10 kg body weight. At 20 kg body weight, the males had significantly wider chest while the females had wider pelvis (P< 0.05). The width of pelvis, width of chest, chest girth, height at withers, height at pelvis and carcass depth of chest were at one stage of growth or the other found to be highly correlated with empty body weight (P< 0.05 - 0.001). The chest girth in all animals, width of chest in animals slaughtered at 10 and 20 kg body weights and the depth of chest (carcass) in animals slaughtered at 10 kg body weight were all highly correlated (P< 0.01) with dressing percentage.

Key Words: Body measurement, breed, carcass measurement, goats, sex

Introduction

Meat is a major source of animal protein in the human diet. In Nigeria, goats are kept mainly for meat although the skin is also valuable. Apart from taking live weight of meat animals, researchers also use other parameters such as body length, width of pelvis, height at withers and chest girths in order to adequately evaluate live animals. According to Srivastava et al (1968), body measurements are indices of skeletal development and indirectly help to determine carcass composition.

Another parameter that has been used over the years to estimate the amount of meat that could be obtained from slaughtered animals is carcass measurement. De Boer et al (1974) identified four types of linear carcass measurements. These include length of carcass, depth of chest, length of leg and width of leg.

In this study male and female goats of two breeds indigenous to West Africa were studied in order to determine their body and carcass measurements at three slaughter weights.

Materials and methods

Thirty six male and female goats of two breeds, the West African Dwarf (WAD) and the Red Sokoto (RS) were purchased in equal numbers by breed and sex from some goat farmers in Ibadan, South Western Nigeria. They were all purchased at about one and a half years of age with initial live weight range of between 5.47 and 8.82 kg. They were later assigned to a 2 x 2 x 3 factorial design and fed ad libitum with a 16.8% crude protein diet. Table 1 shows the composition of the experimental diet.

Table 1. Composition of experimental diet
Ingredient	Percentage
Maize	40.00
Dusa¹	29.00
Brewers Dry Grain	18.00
Groundnut cake	10.00
Bone Meal	1.00
Vit/Mineral Premix	2.00
Total	100.00
Determined Analysis
Moisture	8.00
Crude protein	16.80
Crude fibre	12.40
Ether extract	3.50
Nitrogen free extract	53.50
Ash	6.00
¹ By product of an alcoholic drink made from guinea corn

At the various predetermined slaughter weights of 10, 15 and 20 kg, body measurements namely height at withers, height at pelvis, width of chest, depth of chest, chest girth and width of pelvis were carried out using a measuring tape according to the method described by De Boer et al (1974).

When an animal reached a predetermined weight it was fasted for 24 hours, weighed and taken to the Department of Animal Science, University of Ibadan abattoir for slaughter. After slaughter the head, the skin and the feet were removed. The carcass was then eviscerated. The hot carcass weight (HCW) was taken on the kill floor within 20 min post-mortem.

The carcasses were chilled at 3ºC for approximately 24hr after which the cold carcass weights (CCW) were obtained. The carcass was split into two halves along the vertebral axis using a meat saw. The length of carcass, depth of chest, length of leg, maximum width of leg and width of leg from medial splitting surface were then measured following the procedure described by De Boer et al (1974).

Means and standard errors were determined on all data according to the following classifications: breed x weight level, sex x weight level and breed x sex. The data were subsequently subjected to analysis of variance appropriate to the design and Duncan's multiple Range Test (Steel and Torrie 1980) for separation of means. Data were then analysed by the regression procedure of statistical analysis system of Barr and Goodnight (1976). Individual animals were considered as experimental units.

Results and discussion

The data obtained on the experimental animals are summarized in Tables 2, 3 and 4. All the body and carcass measurements that had to do with height and length of animals or their parts such as height at withers, height at pelvis, carcass length and length of leg were significantly higher (P< 0.05) in the Red Sokoto (RS) than the West African Dwarf (WAD) (Tables 3 and 5). This was expected because the former is the taller of the two breeds. However, measurements like chest girth, width of chest and depth of chest (carcass) that related to fatness were generally higher in the WAD.

Table 2. Means and standard errors of body and carcass measurements by breed and slaughter weight
Variable	Slaughter weight (kg)
	10		15		20
	WAD	RS	WAD	RS	WAD	RS
Height at withers, cm	35.13±1.51^c	46.91±0.69^a	40.64±0.33^b	47.83±0.43^a	41.38±0.40^b	49.25±0.41^a
Height at pelvis, cm	39.36±1.74^d	50.07±0.64^b	45.29±0.49^c	51.33±0.39^b	47.29±0.34^c	59.50±0.64^a
Width of pelvis, cm	20.19±0.13^c	20.60±0.22^c	23.53±0.49^b	22.55±0.44^b	25.73±1.27^a	23.23±0.70^b
Depth of chest (live), cm	21.30±0.48^b	19.09±0.67^b	24.05±0.72^a	20.02±0.68^b	25.41±0.52^a	22.08±0.68^ab
Chest girth, cm	51.68±0.31^bc	50.40±0.08^c	58.64±0.55^a	53.93±0.32^b	58.25±1.72^a	55.13±0.59^ab
Width of chest, cm	17.87±0.36^b	16.22±0.10^b	29.25±0.85^a	26.98±0.13^a	30.13±0.78^a	27.52±0.46^a
Carcass length, cm	35.93±0.77^c	41.15±0.62^a	39.15±0.32^b	45.62±0.14^a	39.45±0.55^b	46.20±0.46^a
Hot carcass weight, kg	3.73±0.07^c	3.39±0.07^c	6.08±0.14^b	5.56±0.14^b	10.25±0.48^a	9.70±0.31^a
Empty body weight, kg	9.31±0.08^c	8.91±0.07^c	13.50±0.11^b	13.49±0.02^b	17.96±0.24^a	18.13±0.09^a
Chilled carcass weight, kg	3.47±0.06^c	3.09±0.05^c	5.79±0.15^b	5.11±0.10^b	10.00±0.48^a	9.38±0.30^a
Chilling loss, kg	0.27±0.01^c	0.30±0.02^b	0.31±0.06^b	0.45±0.08^a	0.25±0.03^c	0.33±0.04^b
Percent chilling loss	7.32±0.27^a	8.84±0.33^a	5.08±0.97^b	7.99±1.35^a	2.45±0.29^c	3.34±0.36^c
Dressing percentage¹	40.02±0.51^c	37.99±0.70^c	45.03±0.75^b	41.17±1.03^c	56.88±2.40^a	53.55±1.87^a
Depth of chest (carcass), cm	16.12±0.20	15.94±0.24	17.28±0.72	16.75±0.40	18.30±0.91	17.57±0.59
Length of leg, cm	24.43±0.31^b	28.45±0.55^a	23.78±0.58^b	28.46±0.42^a	24.04±0.57^b	28.70±0.59^a
Maximum width of leg, cm	4.68±0.15	4.93±0.34	4.95±0.12	5.13±0.14	5.48±0.48	5.88±0.36
Width of leg from medial splitting surface, cm	3.90±0.27	4.10±0.20	3.98±0.15	4.23±0.11	3.95±0.37	4.11±0.41
¹Based on empty body weight ^abcMeans in the same row without common superscripts are different at P<0.05.

Table 3. Means and standard errors of body and carcass measurements by sex and slaughter weight
Variable	Slaughter weight, kg
	10		15		20
	M	F	M	F	M	F
Height at withers, cm	43.44±2.26	38.60±3.03	44.72±1.77	43.76±1.50	45.78±1.82	44.85±1.77
Height at pelvis, cm	47.30±1.83^a	42.13±2.98^b	48.97±1.33^a	47.65±1.45^a	51.47±1.72^a	50.33±1.62^a
Width of pelvis, cm	20.77±0.25^c	20.22±0.07^c	22.05±0.24^c	24.03±0.28^b	22.35±0.34^c	26.60±0.90^a
Depth of chest (live), cm	21.42±0.43^bc	18.97±0.62^c	23.60±0.92^a	20.48±0.89^bc	24.91±0.70^a	22.58±0.91^ab
Chest girth, cm	51.41±0.41^b	50.67±0.21^b	57.08±1.24^a	55.49±0.92^a	58.13±1.42^a	55.25±1.20^a
Width of chest, cm	17.51±0.49^b	16.58±0.29^b	28.60±0.96^a	27.63±0.47^a	29.73±0.83^a	27.92±0.69^a
Carcass length, cm	38.75±1.44	38.33±1.26	42.68±1.44	42.10±1.49	43.45±1.62	42.20±1.55
Hot carcass weight, kg	3.64±0.10^c	3.48±0.09^c	6.08±0.13^b	5.56±0.15^b	10.20±0.40^a	9.75±0.43^a
Empty body weight, kg	9.11±0.15^c	9.11±0.06^c	13.60±0.06^b	13.39±0.06^b	18.35±0.11^a	17.74±0.14^a
Chilled carcass weight, kg	3.33±0.10^c	3.22±0.10^c	5.68±0.19^b	5.21±0.14^b	9.82±0.40^a	9.53±0.43^a
Chilling loss, kg	0.31±0.01	0.27±0.01	0.40±0.06	0.36±0.09	0.35±0.03	0.23±0.02
Percent chilling loss	8.48±0.48^a	7.69±0.34^a	6.68±1.16^a	6.38±1.50^a	3.46±0.31^b	2.33±0.26^b
Dressing percentage¹	39.86±0.50^c	38.15±0.79^c	44.66±0.78^b	41.55±1.24^b	55.88±2.21^a	54.54±2.30^a
Depth of chest (carcass), cm	16.36±0.08	15.70±0.23	17.88±0.57	16.15±0.30	18.89±0.67	16.98±0.64
Length of leg, cm	26.65±0.98	26.23±1.02	26.00±1.21	26.24±1.11	26.15±1.32	26.59±1.04
Maximum width of leg, cm	4.90±0.25	4.70±0.28	5.20±0.13	4.88±0.11	5.83±0.34	5.53±0.49
Width of leg from medial splitting surface, cm	4.08±0.22	3.93±0.26	4.18±0.13	4.03±0.15	4.21±0.39	3.85±0.38
¹Based on empty body weight ^abcMeans in the same row without common superscripts are different at P<0.05..

The male animals were generally taller in both breeds than their female counterparts, the differences being significant (P< 0.05) in animals slaughtered at 10 kg body weight. Both sexes have reached close to the peak height at withers for their class at 10 kg live weight with only insignificant increase in height to 20 kg weight. Indeed, Hall (1991) noted that height at withers rarely changes significantly with age.

Table 4 shows the effect of breed x sex interaction. There was no significant effect of this interaction as this table follows a similar pattern with those showing the breed and sex effects (Tables 2 and 3). The height at withers observed in both breeds here are generally lower than the ones recorded for the same breeds by Ngere et al (1979). While those workers used mature animals, the animals used in this work were not fully mature even at 20 kg body weight. However, the higher heights in male animals observed here were also reported by those workers.

Table 4. Means and standard errors of body and carcass measurements by breed and sex
Variable	Breed/Sex
Variable	WADM²	WADF³	RSM⁴	RSF⁵
Height at withers, cm	40.32±0.57^b	37.78±1.51^c	48.97±0.22^a	47.03±0.55^a
Height at pelvis, cm	42.68±0.68^b	42.26±1.75^c	52.80±0.67^a	51.12±0.80^a
Width of pelvis, cm	21.89±0.42^b	24.40±1.23^a	21.56±0.18^b	22.82±0.66^ab
Depth of chest (live), cm	24.77±0.65^a	22.41±0.63^b	21.85±0.45^b	18.94±0.48
Chest girth, cm	57.62±1.42^a	54.76±1.97^ab	53.45±0.79^b	52.84±0.75^b
Width of chest, cm	26.62±2.08	24.88±1.97	23.94±1.90	23.20±1.80
Carcass length, cm	38.50±0.80^b	37.85±0.65^b	44.75±0.89^a	43.90±0.93
Hot carcass weight, kg	6.89±1.00	6.48±0.96	6.38±0.95	6.04±0.93
Empty body weight, kg	13.85±1.31	13.32±1.19	13.52±1.36	13.50±1.30
Chilled carcass weight, kg	6.60±1.00	6.24±0.97	5.97±0.94	5.74±0.93
Chilling loss, kg	0.30±0.02^ab	0.26±0.04^b	0.41±0.04^a	0.31±0.05^ab
Percent chilling loss	5.04±0.73	4.86±0.96	7.37±0.95	6.07±1.14
Dressing percentage¹	48.14±2.73	46.48±2.76	45.46±2.41	43.01±2.69

Body and carcass linear measurements of goats slaughtered at different weights

S Attah*, A O Okubanjo, A B Omojola and A O K Adesehinwa**

Abstract

Introduction

Materials and methods

Determined Analysis

Results and discussion

Variable

Variable

Variable