ABSTRACT - Effect of sex on carcass characteristics and lamb meat quality of crossbred lambs (Gentile di Puglia X Val di Belice), were analysed. Eighteen lambs distributed in two groups (male and female), after weaned at 30 days, were slaughtered at 70 days of age. Dressing proportion and physical characteristics of carcass were significantly different (P<0.05), between males and females. Sex affected pH 24h in the muscles while color parameters were similar in both sexes. INTRODUCTION - Some rustic breeds have been selected in the southern regions of the Italy due to very hard feed and environmental conditions. Gentile di Puglia breed has been originated, by Merinos breed substitution on autochthonous breeds and is known for its adaptation to the local environment (hills and mountains) hard conditions. Another typical native local breed from the South Italy is Val di Belice. The breed is also adapted to live on arid soils and produce lot milk that is employed for the production of traditional fresh cheese. In Italy lambs are slaughtered very young, and less frequently, after a short fattening period, generally under intensive husbandry conditions. Many factors influence lamb meat quality such as breed (Purchas et al., 2002;) and sex (Dransfield,et al. 1990;). Meat quality and acceptability is determined by its physicochemical characteristics. Our aim is to use the effect that meat-type rams (Gentile di Puglia) produce on a milk-type sheep (Valle del Belice) in order to improve lamb meat quality. MATERIALS AND METHODS - The study was conducted with eighteen crossbred lambs (Gentile di Puglia x Val di Belice), distributed in two groups (male and female), after weaned at 30 days, received commercial concentrate and cereal straw ad libitum. All lambs were slaughtered at 70 days of age. After slaughter, carcass weight was determined and the carcasses were then chilled at 4°C for 24h in a conventional chiller, dressing (D) and shrink losses (SL) were evaluated. The pH values have been releved, using a glass electrode, on Semimembranosus (Sm), Longissimus dorsi (Ld) and Biceps femoris (Bf) muscles at slaughtering (pH1), after refrigeration to +4°C for 24 (pH24), 48 (pH48) and 72 hours (pH72). On a sample of Ld muscle the color was estimated by the Hunter Lab system using a colorimeter Minolta CR200 (illuminant D 65), which measured the values of Lightness (L), Redness (a) and Yellowness (b) by making 5 readings for each meat sample, approximately 2.5 cm thick, after refrigeration to +4°C for 24, 48 and 72 hours. Tenderness was measured using a Warner Bratzler shear device applied to an Instron 5544 and expressed as the cutting force (kg/cm2). In order to evaluate losses due to cooking, samples were weighed before and after cooking, in a convector oven at an inside temperature of the sample of 60° C over 30 minutes, measured by a diving (sinking) probe thermometer. Cooking loss was considered as a percent of the initial weight. Data were analyzed for variance using the GLM procedure of SAS. RESULTS AND DISCUSSION - Table 1 shows effect of sex on carcass characteristics and some quality aspects. Significant differences (P < 0.05) in dressing, cooking loss, raw and cooked meat tenderness were found between males and females. Our findings did not agree with previous report and meat of females was more tender (1.56 vs 1.74; P < 0.05) in raw and cooked meat (2.03 vs 2.12; P < 0.05). Sex did not influence the carcass weight. Females showed less capacity to release water than males with a lower cool loss % (P < 0.01). These results agree with those reported by Vergara et al.(1999). Results for pH and color are presented in Tables 2 and 3. Sex influence significantly the pH values 24 h after slaughter (P < 0.05) with values ranged from 5.44 to 5.77 in the three muscles (Ld, Sm and Bf) indicating that the animals were not stressed at time of slaughter. These values agree with the findings of Devine et al . (1993), within the normal pH range, assuming that an ultimate pH greater than 5.8 is regarded as undesirable. The CIE colour (lightness, redness, yellowness) are also listed in Table 2. No significant effect of sex was observed for these traits in Ld muscle. Color parameters were similar in both sexes, although females had slightly lower a* values than males, but differences were not significant. However, Teixeira et al. (2005) found an effect of sex on lightness, with males having significantly higher values than females, which, as suggested by Thompson et al.(1979), could be that females are darker than males at equal slaughter weight due to their greater precociousness. The current study has shown that the sex in Merino lambs modify few characteristics of the meat quality. Table 1 - Productive performance and physical traits MaleFemaleSignificance Carcass weight (g)11,916.6713,283.33NS Dressing (%)61.2262.83* Cool loss (%)2.451.95** Cooking loss (%)36.1934.59* Raw meat tenderness (kg/cm2)1.7451.567* Cooked meat ten.ss (kg/cm2)2.1232.035* MaleFemaleSignificance pH1 Sm6.346.46NS Ld6.356.46NS Bf6.396.30NS pH24 Sm5.67 5.77 ** Ld5.445.64* Bf 5.715.52* pH48 Sm5.745.61NS Ld5.485.57NS Bf 5.615.51NS pH72 Sm5.34 5.61 * Ld5.645.52NS Bf5.485.41NS Table 3 - Ld muscle color MaleFemaleSignificance Color24 L38.5442.35 NS a15.2815.08NS b13.4614.49NS Color48 L35.5938.72NS a12.1711.23NS b14.5215.28NS Color72 L39.6139.40NS a12.3511.65NS b16.4216.52NS REFERENCES - 1.Purchas, R. W. et al. (2002). Effects of age at slaughter and sire genotype on fatness, muscularity, and the quality of meat from ram lambs born to Romney ewes. New Zealand of Agricultural Research, 45,77-86. 2.Dransfield, E. et al. (1990). Carcass and eating quality of ram, castrated ram and ewe lambs. Animal Production, 50, 291-299. 3.Vergara, H., Molina, A. and Gallego L.(1999). Influence of sex and slaughter weight on carcass and meat quality in light and medium weight lamb produced in intensive systems, Meat Science, 52, 221-226. 4.Devine, C. E. et al. (1993). The effect of growth rate and ultimate pH on meat quality of lambs. Meat Science, 35, 63-77. 5.Teixeira, A. et al. (2005).Lamb meat quality of two breeds with protected origin designation. Influence of breed, sex and live weight. Meat Science, 71, 530-536. 6.Thompson, J. et al. (1979). Carcass characteristics of heavy weight crossbred lambs. II. Carcass composition and partitioning of fat. Australian Journal of Agriculture Research, 30, 1207-1214.
Influence of sex on some quality aspects of lamb meat
Facciolongo AM;
2012
Abstract
ABSTRACT - Effect of sex on carcass characteristics and lamb meat quality of crossbred lambs (Gentile di Puglia X Val di Belice), were analysed. Eighteen lambs distributed in two groups (male and female), after weaned at 30 days, were slaughtered at 70 days of age. Dressing proportion and physical characteristics of carcass were significantly different (P<0.05), between males and females. Sex affected pH 24h in the muscles while color parameters were similar in both sexes. INTRODUCTION - Some rustic breeds have been selected in the southern regions of the Italy due to very hard feed and environmental conditions. Gentile di Puglia breed has been originated, by Merinos breed substitution on autochthonous breeds and is known for its adaptation to the local environment (hills and mountains) hard conditions. Another typical native local breed from the South Italy is Val di Belice. The breed is also adapted to live on arid soils and produce lot milk that is employed for the production of traditional fresh cheese. In Italy lambs are slaughtered very young, and less frequently, after a short fattening period, generally under intensive husbandry conditions. Many factors influence lamb meat quality such as breed (Purchas et al., 2002;) and sex (Dransfield,et al. 1990;). Meat quality and acceptability is determined by its physicochemical characteristics. Our aim is to use the effect that meat-type rams (Gentile di Puglia) produce on a milk-type sheep (Valle del Belice) in order to improve lamb meat quality. MATERIALS AND METHODS - The study was conducted with eighteen crossbred lambs (Gentile di Puglia x Val di Belice), distributed in two groups (male and female), after weaned at 30 days, received commercial concentrate and cereal straw ad libitum. All lambs were slaughtered at 70 days of age. After slaughter, carcass weight was determined and the carcasses were then chilled at 4°C for 24h in a conventional chiller, dressing (D) and shrink losses (SL) were evaluated. The pH values have been releved, using a glass electrode, on Semimembranosus (Sm), Longissimus dorsi (Ld) and Biceps femoris (Bf) muscles at slaughtering (pH1), after refrigeration to +4°C for 24 (pH24), 48 (pH48) and 72 hours (pH72). On a sample of Ld muscle the color was estimated by the Hunter Lab system using a colorimeter Minolta CR200 (illuminant D 65), which measured the values of Lightness (L), Redness (a) and Yellowness (b) by making 5 readings for each meat sample, approximately 2.5 cm thick, after refrigeration to +4°C for 24, 48 and 72 hours. Tenderness was measured using a Warner Bratzler shear device applied to an Instron 5544 and expressed as the cutting force (kg/cm2). In order to evaluate losses due to cooking, samples were weighed before and after cooking, in a convector oven at an inside temperature of the sample of 60° C over 30 minutes, measured by a diving (sinking) probe thermometer. Cooking loss was considered as a percent of the initial weight. Data were analyzed for variance using the GLM procedure of SAS. RESULTS AND DISCUSSION - Table 1 shows effect of sex on carcass characteristics and some quality aspects. Significant differences (P < 0.05) in dressing, cooking loss, raw and cooked meat tenderness were found between males and females. Our findings did not agree with previous report and meat of females was more tender (1.56 vs 1.74; P < 0.05) in raw and cooked meat (2.03 vs 2.12; P < 0.05). Sex did not influence the carcass weight. Females showed less capacity to release water than males with a lower cool loss % (P < 0.01). These results agree with those reported by Vergara et al.(1999). Results for pH and color are presented in Tables 2 and 3. Sex influence significantly the pH values 24 h after slaughter (P < 0.05) with values ranged from 5.44 to 5.77 in the three muscles (Ld, Sm and Bf) indicating that the animals were not stressed at time of slaughter. These values agree with the findings of Devine et al . (1993), within the normal pH range, assuming that an ultimate pH greater than 5.8 is regarded as undesirable. The CIE colour (lightness, redness, yellowness) are also listed in Table 2. No significant effect of sex was observed for these traits in Ld muscle. Color parameters were similar in both sexes, although females had slightly lower a* values than males, but differences were not significant. However, Teixeira et al. (2005) found an effect of sex on lightness, with males having significantly higher values than females, which, as suggested by Thompson et al.(1979), could be that females are darker than males at equal slaughter weight due to their greater precociousness. The current study has shown that the sex in Merino lambs modify few characteristics of the meat quality. Table 1 - Productive performance and physical traits MaleFemaleSignificance Carcass weight (g)11,916.6713,283.33NS Dressing (%)61.2262.83* Cool loss (%)2.451.95** Cooking loss (%)36.1934.59* Raw meat tenderness (kg/cm2)1.7451.567* Cooked meat ten.ss (kg/cm2)2.1232.035* MaleFemaleSignificance pH1 Sm6.346.46NS Ld6.356.46NS Bf6.396.30NS pH24 Sm5.67 5.77 ** Ld5.445.64* Bf 5.715.52* pH48 Sm5.745.61NS Ld5.485.57NS Bf 5.615.51NS pH72 Sm5.34 5.61 * Ld5.645.52NS Bf5.485.41NS Table 3 - Ld muscle color MaleFemaleSignificance Color24 L38.5442.35 NS a15.2815.08NS b13.4614.49NS Color48 L35.5938.72NS a12.1711.23NS b14.5215.28NS Color72 L39.6139.40NS a12.3511.65NS b16.4216.52NS REFERENCES - 1.Purchas, R. W. et al. (2002). Effects of age at slaughter and sire genotype on fatness, muscularity, and the quality of meat from ram lambs born to Romney ewes. New Zealand of Agricultural Research, 45,77-86. 2.Dransfield, E. et al. (1990). Carcass and eating quality of ram, castrated ram and ewe lambs. Animal Production, 50, 291-299. 3.Vergara, H., Molina, A. and Gallego L.(1999). Influence of sex and slaughter weight on carcass and meat quality in light and medium weight lamb produced in intensive systems, Meat Science, 52, 221-226. 4.Devine, C. E. et al. (1993). The effect of growth rate and ultimate pH on meat quality of lambs. Meat Science, 35, 63-77. 5.Teixeira, A. et al. (2005).Lamb meat quality of two breeds with protected origin designation. Influence of breed, sex and live weight. Meat Science, 71, 530-536. 6.Thompson, J. et al. (1979). Carcass characteristics of heavy weight crossbred lambs. II. Carcass composition and partitioning of fat. Australian Journal of Agriculture Research, 30, 1207-1214.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
