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The use of lambs from crossing of local with specialized sheep breeds for meat production may lead to higher meat deposition and a smaller fat amount in the carcass, with a more adequate nutritional profile for human consumption. This study investigated the performance, carcass and meat characteristics of lambs from the Morada Nova and Santa Inês locally adapted hair breeds and crosses between Dorper × Morada Nova and Dorper × Santa Inês slaughtered at approximately 35 kg. Morada Nova lambs showed lower (p < 0.05) performance compared to the other genetic groups resulting in a higher age at slaughter (p < 0.05). Crossbred Dorper × Santa Inês and Dorper × Morada Nova lambs showed better characteristics for meat production with better (p < 0.05) conformation as well as leg and carcass compacteness index. Dorper × Santa Inês have a fatty acid profile that is more suitable for human consumption than Dorper × Morada Nova lambs do (p < 0.05); however, both had lower (p < 0.05) intramuscular lipid content (as measured by ether extract levels from Longíssimus lumborum) compared with purebred lambs. Therefore, when the objective is to obtain lean meat, with improved nutritional profile to reduce risks of cardiovascular disease, the use of breeds and crosses that reduce animal slaughter age, such as the ½ Dorper × ½ Santa Inês crossbred, is an interesting alternative.

The replacement of diet soybean meal protein with crambe cake protein (0%, 22%, 44% and 66%) was investigated to evaluate the effect on lamb performance and meat quality, as well as the extent to which erucic acid was incorporated into the meat. The inclusion of increasing levels of crambe cake resulted in poorer lamb performance, as demonstrated by a linear decrease in final liveweight and carcass weight. There was also an increase in plasma blood concentrations of aspartate transaminase and alanine transaminase, indicating hepatic injury. Reduced ether extract concentration of meat was observed, leading to higher shear-force values and a linear decrease in meat luminosity. The fatty acid profile of meat was drastically modified, presenting a reduction in total saturated and polyunsaturated fatty acid concentrations, particularly in the concentration of α-linoleic acid. Additionally, the total monounsaturated fatty acid concentration in meat decreased, while the concentration of erucic acid increased from 0.11% of total fatty acids in Longissimus lumborum samples from lambs fed diets with no inclusion of crambe cake, to 3.70%, 5.82% and 8.04% of total fatty acids in those from lambs fed diets where 22%, 44% and 66%, respectively, of the soybean meal protein was replaced with crambe cake protein. Therefore, the concentration of erucic acid in fatty acid profile of meat was higher than concentration deemed safe for human consumption.

O objetivo deste estudo foi avaliar as características da carcaça e da carne de cordeiros Morada Nova, Santa Inês e ½ Ile de France x ½Texel terminados em confinamento. Avaliou-se peso e proporção dos cortes cárneos, medidas de dimensão da carcaça e cor, maciez, perdas por cocção e pH final da carne de 10 animais da raça Morada Nova, 6 Santa Inês e 10 ½ Ile de France ½Texel. Os animais foram terminados em confinamento em baias coletivas, alimentados ad libitum com 50% de silagem de milho e 50% de ração concentrada, e abatidos precocemente com aproximadamente seis meses de idade. Análises de variância foram realizadas pelo PROC GLM do SAS (SAS Inst., Inc., Cary, NC) e as médias comparadas pelo teste de Tukey a 5% de significância. Os cordeiros Morada Nova apresentaram valores de 14,1 kg; 13,9 kg; 0,240 kg/cm; 56,2 cm e 35,8 cm para peso de carcaça quente e fria, índice de compacidade, circunferência de quadril e circunferência de perna, respectivamente, sendo estes menores (P<0,05) aos verificados nos animais Santa Inês (19,4 kg; 18,8 kg; 0,283 kg/cm; 64,6 cm e 40,0 cm) e ½ Ile de France ½Texel (18,6 kg; 18,2 kg; 0,305 kg/cm; 65,4 cm e 41,6 cm). O rendimento de carcaça quente e fria não diferiu (P>0,05) entre os grupos genéticos avaliados. A nota para cobertura de gordura e conformação foi superior (P<0,05) nos cordeiros ½ Ile de France ½Texel (2,4 e 3,0) e o comprimento da carcaça foi superior nos cordeiros Santa Inês (66,3 cm). Cordeiros ½ Ile de France ½Texel tiveram menor (P<0,05) proporção de pescoço e maior de pernil (9,10% e 33,1%) em relação aos cordeiros Morada nova (10,3% e 30,4%) e Santa Inês (10,9% e 31,6%). O peso de paleta, pernil, costeleta, costela e fralda foi menor (P<0,05) nos animais Morada Nova (1,306 kg; 2,127 kg; 0,999 kg; 0,775 kg e 0,433 kg, respectivamente) em relação aos animais Santa Inês (1,820 kg; 2,972 kg; 1,355 kg; 0,959 kg e 0,509 kg) e ½ Ile de France ½Texel (1,791 kg; 3,007 kg; 1,212 kg; 1,016 kg e 0,563 kg). O pescoço foi mais pesado nos cordeiros Santa Inês (1,038 kg) que diferiu (P<0,05) dos demais grupos genéticos (0,725 kg para Morada Nova e 0,830 kg para ½ Ile de France ½Texel). Cordeiros ½ Ile de France ½Texel apresentaram carne com maior luminosidade (37,4) em relação a cordeiros Morada Nova (33,5) e Santa Inês (31,7). Cordeiros dos grupos genéticos avaliados, quando abatidos aos seis meses de idade, resultam em carne semelhante de boa qualidade, contudo, cordeiros Morada Nova apresentam menor peso de carcaça e de cortes cárneos assim como menor dimensão da carcaça.

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We evaluated carcass traits from twenty 6-month-old Santa Ines lambs under tropical grazing (Andropogon gayanus) receiving condensed tannin from Acacia mearnsii once a week for 13 weeks to control endoparasites. Ten animals were treated with tannin (TG) and the remainder (10 animals) received a diet without tannin (CG). At slaughter, the following measurements were taken: live weight, carcass weight, half-carcass weight, carcass length, fat cover, skin weight and thickness, weight of thoracic and abdominal organs, scrotum and commercial cuts. The 12 th rib was removed for determination of muscle, fat and bone percentages, as well as their chemical analysis. Skin thickness was greater and commercial cuts (loin and rib/belly) were lower in TG. Animals that received tannin had a lower percentage of ether extract and higher protein in the 12 th rib. Condensed tannin from Acacia mearnsii did not impair carcass trait quality but decreased ether extract and increased protein content.