CARCASS QUALITY OF CRIOLLO CORDOBES AND ANGLO NUBIAN SUCKLING KIDS

common dairy breed, are destined for meat production (Maubecin, 1973). Argentine goat meat production is based mainly on extensive systems by grazing on natural prairies with shrubs and forest, and scarce o non-existent feed supplementation (Maubecin, 1976). Currently, the demand for meat from goats has increased and meat from young animals is considered a delicacy. For this reason, kids are slaughtered at lowest age/weight (30-65 days old and 6-12 kg liveweight, Arias and Alonso, 2002). The information on the carcass characteristics in suckling kids from Criollo Cordobes and Anglo Nubian goat breeds is not well documented. Several studies have previously been carried out on carcass traits of Creole goats (Maubecin, 1976; Rossanigo et al., 1995), and very few on the Criollo Cordobes (De Gea et al., 2005b). Also, there is no available information about the carcass characteristics of Anglo Nubian kids slaughtered a low weight.

Argentine goat meat production is based mainly on extensive systems by grazing on natural prairies with shrubs and forest, and scarce o non-existent feed supplementation (Maubecin, 1976).Currently, the demand for meat from goats has increased and meat from young animals is considered a delicacy.For this reason, kids are slaughtered at lowest age/weight (30-65 days old and 6-12 kg liveweight, Arias and Alonso, 2002).The information on the carcass characteristics in suckling kids from Criollo Cordobes and Anglo Nubian goat breeds is not well documented.Several studies have previously been carried out on carcass traits of Creole goats (Maubecin, 1976;Rossanigo et al., 1995), and very few on the Criollo Cordobes (De Gea et al., 2005b).Also, there is no available information about the carcass characteristics of Anglo Nubian kids slaughtered a low weight.

MATERIAL AND METHODS
The animals, suckling intact males of the Criollo Cordobes (CC) and Anglo Nubian (AN) breeds, were purchased from two local farmers.The production system was extensive: the adults were fed on pastures

SUMMARY
The objective of this study was to assess the carcass characteristics of two goat breed types reared under extensive system.Forty male kids, 20 Criollo Cordobes and 20 Anglo Nubian, were used.The animals were slaughtered at 60±2 days old (group I) and at 90±3 days old (group II).The carcass yield and fatness was significantly higher in Anglo Nubian than in Criollo Cordobes kids.Breed and age at slaughter significantly affect carcass conformation, some carcass measures and indices, and non-carcass components.

INTRODUCTION
Currently, the production of goat meat is located in the Argentine northwest, being Criollo Cordobes goat (70%) the most common breed of goats in this region.They are bred mostly for meat production.The male kids of Anglo Nubian breed, the most without concentrate supplements, and the kids were nursing milk from their mothers and left to graze with their dams.At birth, 20 males from each breed were randomly allocated to two groups: I (slaughtered at 60±2 days old) and II (slaughtered at 90±3 days old).When kids reached the slaughter age, they were transported to the abattoir (5 km away).Slaughter live weight (SLW) was recorded immediately prior to slaughter.Each group was slaughtered in 1 day, after a 12-h fast.Kids were stunned with a captive bolt pistol and slaughtered by bleeding.Hot carcass weight (HCW) and weight of non carcass components (blood, head, skin, feet, gastro-intestinal tract, some visceral organs, fat depots) were recorder within 1 h post-mortem.Tail, thymus, lateral portion of the diaphragm, kidneys, perinephric and pelvic fats, and testes were retained in carcass.After chilling (24 h at 4ºC), cold carcass weights (CCW) and empty body weights (EBW, live weight minus the weight of digesta) were recorded.Then, each carcass was evaluated for conformation (scale from poor= 1 to good= 3), subcutaneous fatness (scale from 1= low to 5= very high), meat colour (1= pale; 2= pink; 3= red) and fat colour (1= white; 2= cream; 3= yellow) using the scoring system suggested by Colomer-Rocher et al. (1987).The internal fat cover was subjectively assessed using a scoring system, taking the pelvic-renal fat as a whole (1= low; 2= medium; 3= high).The carcass percentages were calculated as follows: HCW/SLW (%)= (hot carcass weight x 100)/ slaughter live weight; HCW/EBW (%)= (hot carcass weight x 100)/ empty body weight; CCW/SLW (%)= (cold carcass weight x 100)/ slaughter live weight; CCW/EBW (%)= (cold carcass weight x 100)/ empty body weight.
After chilling, the left half of each carcass (CLSW) was weighed and physically dissected into five primal cuts (shoulder, leg, ribs, flank and neck) according to Colomer-Rocher et al. (1987).Primal cuts were weighed and grouped into three categories: extra (leg and ribs), first (shoulder) and second (neck and flank).The tail, testes, kidney, pelvic-perirenal fat in the carcass left side were removed before jointing and weighed.The shoulder was separated into dissectible fat (subcu-taneous+intermuscular), muscle, bone and other tissue (major blood vessels, ligaments, tendons and fascias).
Statistical analysis of data were performed using the GLM procedure of SAS (SAS, 1997), in a 2 x 2 factorial arrangement with breed-type (CC and AN) and age (group I and group II) as main effects.Empty body weight was used as a covariate in the analysis of carcass measurements, non-carcass components and dressing percentages; hot carcass weight was used as a covariate in the analysis of primal cuts and dissectible tissues.Least squares means (LSM) and their standard errors were computed and tested for treatments differences.No significant interactions were noted for the parameters evaluated in the present study, therefore, only main effects are presented and discussed.The analysis of the qualitative variables was conducted using bivaried contingency tables, and chi-square tests.

RESULTS AND DISCUSSION
Average weight values at slaughter from CC and AN kids (table I) are comparable to those reported for suckling kids in Argentina (De Gea et al., 2005b;Domingo et al., 2008;Zimmerman et al., 2008).The EBW, HCW and CCW increased with the increase of the age at slaughter.
Chilling losses (table I) were higher than those reported by Marichal et al. (2003) in kids slaughtered at similar live weight.With the age at slaughter increased, percentages of chilling losses were slightly greater.The increase of body surface/fatness ratio, due to low deposition of subcutaneous fat, might be the main reason for these results.
Values obtained from carcass percentage are comparable to those obtained in Creole kids and their crosses (Zimmerman et al., 2008;Domingo et al., 2008), and within those found in a different genotypes at similar carcass kid weight (Santos et al., 2007).The lower dressing obtained by Meneses et al. (2004) can be explained by their greater body weight (30 kg) and age (6 months), and therefore the further development of the digestive tract (12.5% vs. 7-8%).The dressing percentage was higher (p<0.05) in AN kids than CC kids (50-58% vs. 47-55%).These differences can be attributed to a higher milk production from their mothers and therefore their greater growth rate.The lower visceral percentage (table V) and the higher degree of fat cover (table IV) from carcasses of AN kids could be the main reasons for these differences between breeds.
The carcass percentages did not change with the increase in body weight,which disagree with the findings of Owen et al. (1982).Marichal et al. (2003) recorded an increase in the dressing percentage in kids slaughtered at 6 to10 kg.The results of the

Criollo Cordobes
Anglonubian present study contrast with the general assertion that while kids consume milk, dressing percentage and their subcutaneous fat increases with the increasing of maturity.In this study, a heavier slaughter weight did not significantly increase (p>0.05)carcass fatness, this might be the cause of variation between this study and most published papers.
There were significant differences in some carcass measures and indices among breeds and age groups (table II).The results show that the carcasses from AN kids are longer and less compact than the CC kids due to the larger size of the AN breed, in agreement with Dhanda et al. (2003a).Heavier kids have longer carcasses and an improved carcass compactness index, which supports the findings of Peña et al. (2007).The rib eye area, higher than that found by Perez et al. (2001) in Creole kids slaughtered at 8-12 kg of body weight, showed a significant increase with slaughter weight.Likewise, the average values of ribeye area/ empty body weight ratio were higher (0.7 vs. 0.4-0.5)than those obtained in kids of various genotypes (Dhanda et al., 2003a;Peña et al., 2007).
There were significant differences between breeds for carcass conformation and fatness, in agree with Peña et al. (1994) and Oman et al. (2000).AN kids had better (p<0.05)scores than did CC kids.However, our data do not agree with Dhanda et al. (2003b) who showed that genotype does not affect carcass conformation.The scores of carcass conformation and subcutaneous fatness were lower than those obtained by Sanz et al. (1995) in kids slaughtered at 2 months old, and the score of muscle colour is lower than that obtained by Becerril-Herrera et al. (2006) in Creole male kids slaughtered at 7 kg live weight.All the variables increased with slaughter weight, being colour the exception.
Table IV shows the effect of breed and age at slaughter on visceral components.The percentage contribution of fifth quarter were similar to those reported for different breeds at similar live weight (Pérez et al., 2001;Argüello et al., 2007), and different than those obtained by Gallo et al. (1997)  carcass percentages (table I).
The fifth quarter, as percentage of EBW, and percentages of skin, subproducts and stomach decreased (p>0.05) and those of the visceral organs and fat depots increased (p>0.05) with increasing EBW.In opposition to that, Marichal et al. (2003) reported a significant increase in the contribution of gastro-intestinal tract as a percentage of the empty body weight; the diet between studies (milk vs. milk + concentrate) could be the main reason for these differences.Peña et al. (2007) recorded a significant decrease in the percentage of internal organs, whereas the percentage of stomach increased.The weight range considered and diet may be the main causes of these differences.
Fat depots percentage was not significantly different (p>0.05) for age at slaughter.In contrast, Peña et al. (2007) recorded significant increases in the omental and mesenteric fat contents with increased SLW.The level of food and slaughter weight range considered in both studies may be the main causes of the differences.
Cuts of half carcasses arranged from greatest to smallest were: leg (32%), ribs (22%), shoulder (21%), flank (11%) and neck (9%).Grouped by commercial categories, the extra cuts represented 54%, first 21% and second 20% of left half carcass weight, respectively.The trend of best yield observed in the cuts is in agreement with the reports of Perez et al. (2001) for Creole goats.The proportion of joint were in the same order as those obtained in previous studies (Monte et al., 2007;Zimmerman et al., 2008) in different goat breed and crosses.However, the percentages of leg and shoulder were higher than those obtained by Perez et al. (2001) in Creole kids reared with goat milk or milk substitute and slaughtered at 9 kg of EBW.These differences are likely due to different jointing procedures.There were no significant differences among slaughter weights for the percentage contribution of primal cuts, tail, kidney, thymus, diaphragm, testis and pelvic-renal fat (table V), in agreement with Perez et al. (2001) and Argüello et al. (2007), while the contribution to carcass weight of flank and pelvic-renal fat is higher in AN goat kids, and the percentage of pieces of extra category is lower.Differences between breeds in pelvic-renal fat deposition may be due to the quantity and quality of milk suckled by kids.Pérez et al. (2001) established that milk affects the proportion of pelvic-renal fat.
The correlation between the fat content of the shoulder and the other fatty deposits studied (table VII), yields a high correlation coefficient with the pelvic-renal fat.This fat depot can be a good predictor of carcass fat content, in agreement with Colomer-Rocher et al. (1989).
Means values of percentage of muscle, bone and fat to shoulder weight (table VI) were 65.6%, 26.5% and 6.3%.The lean content was higher to that reported for various other breeds of goat (Oman et al., 2000;Todaro et al., 2004;Zimmerman et al 2008) whilst the dissectible fat was lower.Bone carcass proportions also differed from the values found by Marichal et al. (2003) and Peña et al. (2007) in kids slaughtered at similar carcass weight, respectively.The lower fat content could be explained by the low nutritional level of the diets of goats and therefore their kids (Oman et al., 2000).Monte et al. (2007) working with AN crosses kids slaughtered at 14 kg carcass weight recorded mean values of contribution to shoulder weight of 62%, 15%, 8% for muscle, bone and fat, respectively.Dhanda et al. (1999) recorded percentages of 62-64% for muscle, 5-7% for fat and 24-28% for bone in five goat crosses slaughtered as Capretto.We found more similarities with the results recorded by Dhanda et al. (2003b), Argüello et al. (2007), and Santos et al. (2007).One of the reasons for the differences in tissue composition may be the joint of reference (Gallo et al., 1997;Zimmerman et al., 2008).Another reason may be the slaughter weight and diet: high vs. low weights and high energy vs. low energy diets alter the composition tissue.Genotype may be another cause of the differences in the tissue composition of carcass.Comparing goats of different mature body sizes at the same live weight may indicate differences which are related to the stages of maturity rather than breed per se (Dhanda et al., 2003b).
Distribution of carcass tissues is important in determining carcass quality.Breed influenced (p<0.05) the muscle content, muscle/fat and muscle/bone ratios.CC kids had higher values than AN kids at the same carcass weight.These differences can be partially attributed to mature body size (Mahgoub and Lu, 1998), which is higher in AN goat breed.These results show that carcasses from CC kids, at similar slaughter weight, are leaner compared with carcasses of AN kids.
There were no significant (p>0.05)differences among slaughter weight in percentage of muscle, bone, fat and remainder, despite of a higher assessment of subjective subcutaneous fatness (table III).However, the contribution of muscle and bone on shoulder weight tends to be lower when slaughter weight, while fat remains more or less constant over the various slaughter weights.These results do not support the findings of Dhanda et al. (1999) and Peña et al. (2007).The muscle/ bone ratio tended to be higher and the muscle/fat ratio lower when SLW weight of kids was high.The early deposition of bone and muscle in relation to fat, might be the reason for these results.
The rate of maturity of CC kids is higher than for AN kids, which is why they produce a greater dissected fat of shoulder/pelvicrenal fat ratio in comparison with the AN kids (19.5 vs. 7.6).These values also confirm that goats tend to store a great portion of their fat internally, rather than in subcu-taneous+intermuscular sites (Zimmerman et al., 2008).
The internal fat/carcass fat ratio was 9.37 ± 0.69 in CC kids, and increased with slaughter weight (8.57± 0.79 in group I and 10.01 ± 1.06 in group II), in agreement Gibb et al. (1993) who suggest that dairy goat breeds tend to store more fat in visceral depots, rather than as carcass adipose tissue.In AN kids was 12.15 ± 0.76, 11.45 ± 1.14 and 13.20 ± 0.77, respectively.The subcutaneous fat developing later than pelvic-renal fat produces a decrease of subcutaneous fat/pelvic-renal fat ratio with increasing slaughter weight (20.92 ± 2.00 vs. 18.41 ± 1.66 in CC kids and 8.33 ± 0.84 vs. 6.56 ± 0.87 in AN kids).
Table VII shows the principal correlation between empty body weight, carcass compactness and tissue distribution.The carcass conformation was not significantly correlated with any on the traits studied, except for empty body weight.These results are in disagreement with those pointed by Marichal et al. (2003), who noted that carcass with high conformation present more fat, lower bone content and better muscle/ bone ratio.

CONCLUSIONS
CC and AN goats are breeds with characteristics which make them suitable for profitable meat production.Within the weight range considered, their lean is pink and their carcasses have a good conformation and an adequate fatness.The higher proportion of muscle and moderate proportion of carcass fat (subcutaneous+intermuscular) indicate the potential of the both breeds as a source of lean meat.
Results obtained in this study showed that breed and slaughter weight influenced some carcass traits.The Anglo Nubian kids produced carcasses with better conformation and higher fatness; whereas the carcasses from Criollo Cordobes kids have a higher content in muscle and lower proportion of fat.
The carcass compactness index and subjective carcass conformation increased significantly and fifth quarter decreased as slaughter weight increased.However, the proportion of cut and tissue composition of the shoulder do not differ.
It would seem from the data presented that there is some advantage to be gained in terms of dressing out percentage, carcass compactness and yield of edible visceral, if male CC kids and AN kids are slaughterer at a higher live weight.However there is little or no advantage in terms of carcass jointing and carcass composition.The cost of growing the goats to higher weights is greater, and generally their price is lower.From these results it is recommended male kids to be slaughtered at 60 days old.The highest fatness of AN kids allows slaughter at lower live weights than those CC kids.

Table II .
Least-squares means (± S.E.) of carcass measures (cm) and indices for CriolloCordobes and Anglo Nubian kids. (Medidas e índices de la canal en cabritos de las razas Criollo Cordobés y Anglo Nubiana).

Table III .
Dhanda et al. (2003b)tered at higher weight/ age, and byDhanda et al. (2003b)in different genotypes.CC kids had significantly heavier (p<0.05)subproducts percentage and lower (p<0.05)fat depots than AN kids, which might be the reason for the differences in Carcass grade scores and percentage of carcasses in each class for Criollo Cordobes and Anglo Nubian kids.(Valoración subjetiva de canales de cabritos de las razas Criollo Cordobés y Anglo Nubiana).

Table V .
., Carcass weight (kg) and percentage contribution, in relation to half-carcass weight, of primal cuts (least-squares means±S.E.) of carcasses from Criollo Cordobes and Anglo Nubian kids.(Despiece de la canal de cabritos de las razas Criollo Cordobés y Anglo Nubiana).

Table VII .
Pearson correlation values between empty body weight, carcass compactness and tissue distribution.(Correlaciones entre peso vivo vacío, compacidad de la canal y composición tisular