MATERIALS AND METHODS

Animals and management: Two equal groups of Barki lambs and Zaraibi kids (n = 10 each), born in small ruminants farm of Cairo University during 4 weeks of autumn 2008 were used. Youngs of each species were kept with their mothers in a separate semi-open (4x5 m) pen attached with a (5x8 m) yard. Lambs and kids were weaned at 3 months of age and their mothers were moved out of the pen. Youngs were weighed every 2 weeks after over night fasting. Free access to water and mineral blocks were available.

Feeding: From 3 weeks of age up to weaning, lambs and kids suckled their mothers freely. A green fodders, Egyptian clover (Trifolium alexandrinum), was available all the time to both youngs and dams. An average allowance of 100 g/head/day of a ground grain mixture (35% yellow corn, 35% barley and 30% soybean meal ) was given as a creep feeding. Mothers were fed on 500 g/head/day of concentrate feed mixture (40% yellow corn, 30% decorticated cotton seed meal, 25% wheat bran, 3% limestone, 1% sodium chloride and 1% common salt). After weaning till slaughter at one year of age, youngs were fed according to their live body weight and a daily routine of farm NRC (1981, 1985) on Concentrate Feed Mixture (CFM ) consisted of (65% yellow corn, 10% cotton seed meal, 5% soybean meal,15% wheat bran, 2% limestone,1.5% common salt, 1% minerals mixture and 0.5% sodium bicarbonate). Final 2 months before slaughter as suggested Gaili and Ali (1985), both lamb and kid received daily about 800 and 500 g of CFM during the first month, respectively. While, in the second month, they were received daily about 1200 and 650 g of CFM, in the same order. In addition, lambs and kids were fed ad libitum on Egyptian clover (Trifolium alexandrinum). When green roughage was not available, clover hay was given, in average 425 g for lamb and 250 g for kid during the last 2 months before slaughter.

Experimental procedure: At 12 months of age, lambs and kids were fasted for about 18 h before slaughtering. Pre-slaughtering body weight and body measurements were recorded just before bleeding. Body measurements were estimated using a measuring tape.

The following body measurements were estimated:

Body length: Distance between the point of shoulder and pinbone.

Height at withers: Vertical distance from withers to the floor.

Heart girth: Circumference of the body just behind the forelegs.

Paunch girth: Circumference of the body just before the hinleges.

Round circumference: Circumference of the round just under the body floor.

Antemortem and postmortem examination of live sheep and goats and their carcasses did not show any marked abnormality. Each carcass was deskinned and decapitated. External offals (head, skin and feet) were removed. Internal offals (heart, lung and trachea, liver, kidneys, spleen and testis) were separated from dressed carcass and weighed. Also, full digestive tract was removed. Heart, kidneys and gut fats were separated and weighed. Carcasses were weighed hot (about 1 h after slaughtering). Fat-tail was removed from lambs carcasses and weighed. Each dressed carcass was then longitudinally split into approximately two equal halves. Carcass measurements were taken on the left half side as suggested by Hadjipanayiotou and Koumas (1994), Sen et al. (2004), Abdel-Moneim (2009a, b) and Liméa et al. (2010). These measurements were carcass width at the 3^rd rib and at the 7^th rib, round length, round circumference, loin length and carcass length. Carcass measurements were taken using a measuring tape to nearest 0.5 cm. The left side of carcass was then cooled at 4°C for 24 h. The chilled half of each carcass was weighed and divided into six cuts according to Atti and Ben Hamouda (2004) and Abdel-Moneim (2009a, b). These carcass cuts were round, loin, shoulder, neck, flank and thoracic region (ribs and brisket). Dressing percentage, based on pre-slaughter body weight, was calculated. Longissimus dorsi area at 10^th rib was measured in cm² using a digital planimeter (El-Gallad et al., 1988; Abdel-Moneim, 2009a). The 10^th rib cut was separated into its physical components (lean meat, fat and bone) and weighed separately. Body weight at slaughtering (12 months of age) averaged 40.2 and 23.3 kg for Barki lambs and Zaraibi kids, respectively.

Statistical analysis: The SAS statistical package (SAS, 2004) was utilized for data analysis. Data of body measurements of Barki ram lambs and Zaraibi male kids and their carcass characteristics were analyzed using the following model:

where:

Significant differences among means were detected using Duncan's Multiple Range Test. Simple correlation coefficients between body measurements and weights of body and carcass traits, for each species, were calculated and tested for significance.

RESULTS AND DISCUSSION

Pre-slaughtering body measurements: Significant differences in body length, height at withers, heart girth, paunch girth and round circumference before slaughtering were found between the two species (Table 1). The height at withers of Barki yearlings was significantly (p<0.05) higher (67.9 cm) than that of Zaraibi kids (64.6 cm) (Table 1).

Table 1:	Effect of species on body measurements (cm) before slaughtering
Within species, means of each trait not followed by the same letter differ significantly from each other (p<0.05), *p<0.05, **p<0.01

Body length and round circumference were significantly less (Table 1) for Zaraibi kids and paunch girth and heart girth were significantly higher for Barki lambs.

Weight of some internal offals and weight of fat stores: Differences between Barki lambs and Zaraibi kids in all studied internal edible offals weights, except testis weight were significant (p<0.01) (Table 2). In accordance to our results, El-Khidir et al. (1998) found that differences in some internal offals such as liver, lung, diaphragm and trachea, spleen and kidneys of Sudanese desert lambs and kids were significant (p<0.05). While, no significant differences were found in testis. However, no significant difference in heart weight between Indian lambs and kids was observed by Sen et al. (2004).

It is interesting that no significant differences existed between all fat stores of the studied lambs and kids, with the exception of mesentric fat weight which was significantly (p<0.01) higher in sheep presumbly due to its comparatively longer length (Table 3). Our results receive confirmity from Sen et al. (2004) who found that Indian lambs deposited relatively more (p<0.05) depot (non-carcass) fat than that of Indian kids. However, different results were reported by El-Khidir et al. (1998) as they found that mesentric fat weight was greater (p<0.05) in total fat stores of Sudanese desert kids than that of lambs.

Table 2:	Effect of species on weight of some internal edible offals (g)
Within species, means of each trait not followed by the same letter differ significantly from each other (p<0.05), ns: Not-significant, **p<0.01

Table 3:	Effect of species on weight of fat stores (g)
Within species, means of each trait not followed by the same letter differ significantly from each other (p<0.05), ns: Not-significant, **p<0.01, (1)Fat-tail-weight included

Carcass weight and measurements: Hot carcass weight, dressing percentage and carcass measurements except loin length were significantly higher for Barki lambs than Zaraibi kids (Table 4). These results receive confirmity from previous ones. Sen et al. (2004) found that Indian yearling sheep had higher (p<0.05) hot carcass weight (14.9 kg) than Indian male goats (10.1 kg). The comparatively higher dressing percentage of Barki lambs might arise from inclusion of the fat-tail (1.1 kg, Table 4), in one side and to the heavier fat content of the carcass on the other. These findings are in harmony with the observations reported by Tshabalala et al. (2003) on Dorper and Damara sheep as compared to Boer and Indigenous goats. The higher dressing percentages of Dorper and Damara sheep were associated with significantly heavier carcasses (p<0.05) compared to the goats. These heavier sheep carcasses contained significantly (p<0.05) more fat, which partly explains the higher (p<0.05) dressing percentages obtained for Dorper and Damara sheep than goats. In the meantime, Sen et al. (2004) reported that Indian yearling sheep had higher (p<0.05) dressing percentage (52.1%) than Indian male (49%) goats. The lowest dressing percentage of goats might be attributed to higher moisture content and less fat percentage in chevon than mutton. Similar result was obtained by Gaili and Ali (1985) who reported that Sudanese desert sheep had significantly (p<0.01) heavier carcasses than Sudanese desert goats at an equally adjusted empty body weight. This might imply that Sudanese sheep had a higher dressing percentage than Sudanese goats. The authors also found that Sudanese goats had less (p<0.05) carcass fat but tended to have more carcass bone than Sudanese sheep. The same trend was observed by Hogg et al. (1992) in New Zealand goats and Tshabalala et al. (2003) in Boer and Indigenous goats compared to New Zealand, Dorper and Damara sheep. The soft tissue (fat and muscle) of goats contained more moisture and minerals than sheep, while sheep had more fat. On the other hand, Sen et al. (2004) showed that Indian goat meat had significantly (p<0.001) more moisture (74.2%) and less fat (3.2%) than Indian sheep meat (68.9 and 8.5%, respectively). Contrarily, El-Khidir et al. (1998) reported that Sudanese desert goats had significantly greater carcass weight and dressing percentage than Sudanese sheep. Concerning carcass measurements, results showed no significant differences between sheep and goats in loin length (Table 4). Carcass length, carcass width at shoulder at 3^rd rib, carcass width at loin at 7^th rib and round length and circumference were all significantly (p<0.01) higher in Barki lambs than in Zaraibi kids (Table 4).

Table 4:	Effect of species on carcass weight (kg) and carcass measurements (cm)
Within species, means of each trait not followed by the same letter differ significantly from each other (p<0.05), ns: Not-significant, *p<0.05, **p<0.01 (1), (2)Fat-tail weight included

Carcass cuts and eye muscle (Longissimus dorsi) area: Table 5 shows that weight of the left side cold carcass of Barki lambs significantly (p<0.05) excelled that of Zaraibi kids (10.3 vs. 5.4 kg). However, in another study (El-Khidir et al., 1998) the situation was reversed as cold carcass side weight of Sudanese goats was significantly (p<0.01) heavier than that of Sudanese sheep. All carcass cuts weights, except flank weight were markedly and significantly (p<0.01) heavier in Barki lambs than Zaraibi kids (Table 5). Weight of flank cut was heavier for Zaraibi kids but did not reach significant level (Table 5). In other sheep and goats breeds (Indian breeds), Sen et al. (2004) reported that neck and shoulder portion was heavier (p<0.01) in goats than sheep (26.2 vs. 22.9%) but difference for wholesale cuts, except neck and shoulder, as a percentage of chilled half carcass tended to be small and non-significant. Concerning eye muscle (Longissimus dorsi) area and its components, it is apparent (Table 6) that Barki lambs significantly (p<0.05) excelled Zaraibi kids in area of eye muscle (14.5 vs. 8.0 cm²). This could be due to their higher pre-slaughter weight as longer carcass invariably have greater eye muscle area. Similar result was arrived at for Indian sheep and goats by Sen et al. (2004).

Table 5:	Effect of species on weight of carcass cuts (kg)
Within species, means of each trait not followed by the same letter differ significantly from each other (p<0.05), ns: Not-significant, **p<0.01 (1)Fat-tail weight removed

Table 6:	Effect of species on Longissimus dorsi area (cm2) and components of eye muscle
Within species, means of each trait not followed by the same letter differ significantly from each other (p<0.05), ns: Not significant, *p<0.5, **p<0.01

In view of the greater eye muscle area of Barki lambs, weights of lean, fat and bone were heavier (Table 6). But the difference did not reach a significant level for lean (Table 6). However, Shehata and Mokhtar (2005) reported that lean meat percentage in eye muscle of Baladi male kids was higher than that of Barki ram lambs (57.7 vs. 52.1%). Meanwhile, fat percentage in Baladi kids was lower than that of Barki lambs (18.9 vs. 28.6%). On the other hand, it appears (Table 6) that species of animal exerted a highly significant (p<0.01) effect on fat: bone ratio. Longissimus dorsi muscle of Barki lambs significantly (p<0.05) excelled Zaraibi kids in fat: bone ratio (1.2 vs. 0.6). Meanwhile, there were no significant differences in lean: fat and lean: bone ratios of Barki lambs and Zaraibi kids (Table 6). Similar finding was observed by Shehata and Mokhtar (2005) on Barki lambs and Baladi kids.

Relationships among body measurements, body weight and carcass traits of Barki lambs and Zaraibi kids: Data in Table 7 show that fasted body weight of Barki lambs was positively correlated with paunch girth. Meanwhile, positive and significant correlation coefficient was found between shoulder weight and paunch girth. This result partly agrees with that of Younas et al. (2013) who found that body weight of Hissardale sheep was positively and significantly correlated with all body measurements. The authors also indicated that body measurements can be used for estimation of body weight of animals in the field where scales are not usually available. It may be used as selection criteria as well. No consistent pattern of correlation coefficients was found among other traits studied (Table 7). Similar result was obtained for Red Karaman lambs by Yaprak et al. (2008) and Abdel-Moneim (2009b) for Barki lambs, both reported that height at withers, body length and heart girth circumference were not significantly correlated with dressing percentage. By contrast, Lavvaf et al. (2012) observed that chest girth and rump width were suitable factor for predicting hot carcass weight in each of Afshari and Zandi sheep, respectively.

As for Zaraibi kids, Table 8, fasted body weight as well as hot carcass weight were positively correlated with heart girth, paunch girth and round circumference. This result partly agrees with that of Rahman (2007) who found positive and significant (p<0.01) correlation coefficients between live body weight in 12 months old Black Bengal goats and each of body length, withers height and heart girth. On the other hand, shoulder weight and Longissimus dorsi area were positively correlated with heart girth, paunch girth and round circumference (Table 8). Neck weight and thoracic region were found to be positively correlated with both heart girth and paunch girth. Moreover, loin weight of Zaraibi carcasses was positively and significantly associated with round circumference (Table 8). But dissimilar result was reported by Abdel-Moneim (2009b) who stated that only round circumference of Barki ram lombs was positively and significantly (p<0.05) correlated with neck weight. It is stricking that no correlation coefficients was found between any weight of the studied traits and either body length or height at withers (Table 8). Contrarily, Attah et al. (2004) showed that empty body weight of both Red Sokoto and West African Dwarf yearling goats was positively and significantly (p<0.05) correlated with each of height at withers and height at pelvis. Additionally, dressing percentage of Zaraibi kids was found to be positively correlated with only heart girth (Table 8). Similarly, Attah et al. (2004) reported that chest girth of Red Sokoto and West African Dwarf goats was positively and significantly (p<0.01) correlated with dressing percentage. Accordingly, it may be suggested to use heart girth as an indication of dressing percentage when selecting for higher dressing percentage. Furthermore it could be seen from Table 8 that total fat stores weight of carcass were positively and significantly (p<0.05) correlated with each of heart girth (r = 0.73) and paunch girth (r = 0.67).

Table 7:	Correlation coefficients between body measurements, body weight and carcass traits of Barki lambs
*p<0.05

Table 8:	Correlation coefficients between body measurements, body weight and carcass traits of Zaraibi kids
*p<0.05, **p<0.01

In view of the attained results it could be suggested that paunch girth and heart girth were significantly highest for Barki lambs. However, body length and round circumference were significantly less for Zaraibi kids. Differences between Barki lambs and Zaraibi kids in all studied internal edible offals weight, except testis weight, were significant. Hot carcass weight, dressing percentage and carcass measurements except loin length were significantly higher for Barki lambs than Zaraibi kids. All carcass cuts weight, except flank weight, were markedly and significantly heavier in Barki lambs than Zaraibi kids. Eye muscle (Longissimus dosri) area and its components (lean, fat and bone) of Barki lambs excelled that of Zaraibi kids.

On the other side, it could be observed that fasted body and shoulder weights of Barki lambs were positively and significantly correlated with only paunch girth. However, in Zaraibi kids, Longissimus dorsi area, total fat stores, fasted body, shoulder, neck and thoracic region weights were positively correlated with both heart girth and paunch girth. Additionally, dressing percentage of Zaraibi kids was positively correlated with heart girth.

CONCLUSION

The obtained results revealed significant differences between Barki lambs and Zaraibi kids in all body measurements, weight of internal offals (except testis), carcass weight, dressing percentage, carcass cuts weight (except flank weight) in favour of Barki lambs. Consequently it might be recommended to raise Barki lambs for meat production rather than Zaraibi kids. Zaraibi breed is considered the best milk producing goat breed in Egypt. Hence it seems reasonable to genetically improve its potentialities towards milk production. Our results also showed that although eye muscle area and components were significantly higher in Barki lambs, no significant species differences were observed in lean or lean to fat or lean to bone. The might reflect similarity in qualitative traits of meat of Barki and Zaraibi breeds. On the other side, the study indicated significant and positive correlations between paunch girth and body weight of both species. Accordingly, paunch measuring could be used to estimate body weight under field conditions. Additionally, heart girth and round circumference can be used to predict body weight as well as hot carcass weight.

ACKNOWLEDGMENT

The author would like to thank Prof. Dr. G.M. Ashmawi, Professor of Sheep and Goats Production, Faculty of Agriculture, Cairo University for his kind assistance during this study.