Abstract The lamb meat tenderness acceptance threshold has been little studied and has never been evaluated for the Brazilian population. So, this study aimed to find the maximum acceptable shear force for Brazilian lamb meat consumers. Three muscles were previously tested and chosen Longissimus thoracis et lumborum (LTL), psoas major and semimembranosus muscles received different treatments in the post-slaughter period (Hot deboning followed by cooling on ice, Standard carcass cooling and Ageing), aiming to create samples with varying levels of tenderness, which were evaluated by acceptance tests and descriptive analysis of tenderness by a trained team. Sarcomere length, myofibril fragmentation index, proximate composition, weight loss and pH analyses were performed to observe the biochemical phenomena in each treatment's meats. Variations caused in samples by treatments were more significant than differences inherent to the different muscles. Pearson and Multiple Factor correlation analyses indicated positive correlations between sarcomere length, myofibril fragmentation index and the scores assigned in sensory tests by 140 panelists and a trained team. Both groups noted that the differences between the meats in terms of tenderness and the sarcomere length also influenced the perception of juiciness observed by the groups. The maximum shear force indicated as acceptable for lamb meat was 44.1 N. The results obtained are important to guide the lamb meat producer for certain practices in the post-slaughter moments, avoiding actions that lead to sarcomere shortening and encouraging the production of aged meats.

ABSTRACT The experiment aimed to analyze the economic viability of using high-energy diets and the supplementation of chromium propionate or calcium salts of palm oil in the diet of ewes from the late gestation until the end of lactation. Seventy-two ewes of Santa Ines × Dorper crossbreeds were allocated to five treatments: CTL (n = 14) with 100% of NRC recommendation for metabolizable energy per kg dry matter intake (ME/kg DMI), LOW (n = 14) with 90% ME/kg DMI, HIGH (n = 15) with 110% ME/kg DMI, Cr (n = 15) HIGH diet plus chromium propionate, and FAT (n = 14) HIGH diet plus calcium salts of palm oil. Based on the performance data, a short-term analysis was performed for a module of 1000 ewes, evaluating costs, revenues, and profitability, and long-term analysis was performed by an additional cash flow of 120 months. The CTL and FAT treatments were not viable due to higher costs and lower revenues, and they also had a negative net present value (NPV) and internal rate of return (IRR). The LOW treatment, despite lower costs and positive profitability, had a negative NPV (-$872.90) and IRR (1.85%) that was below the discount rate, making it unprofitable in the long run. The HIGH and Cr treatments were considered feasible because they had lower unit costs and higher profitability, in addition to a high NPV ($64,894.11 and 104,902.05, respectively) and a higher IRR (9.03% and 13.65%, respectively) than the discount rate. The use of high-energy diets, with added chromium propionate, promoted better performance and, consequently, better economic return.

ABSTRACT: Intake is a multifactorial process that is influenced by animal type, environmental factors, and diet characteristics. Sheep, especially, have specific eating habits, with a greater selection of ingested feed compared to cattle. Thus, predictive equations for dry matter intake (DMI) must constantly be reviewed. The objective of this study was to combine different adjustment factors to develop one continuous adjustment factor for predicting the DMI of pregnant, dry, and lactating ewes. The equations evaluated for non-lactation ewes accounts for metabolic body weight and weight gain, and the equation for lactating ewes includes milk production and its fat content. The database used in this study was pooled from hair sheep ewes, two to four years old, with controlled feeding, during the pregnancy and lactating physiological phases. For the overall predictions (gestating and lactating ewes), the adjusted DMI prediction had greater accuracy but lower precision than the unadjusted DMI prediction. However, adjusting DMI increased the adequacy of the prediction as the mean square error of prediction difference (ΔMSEP) decreased (p = 0.0328). Similarly, for gestating ewes, the adjusted predicted DMI had a lower ΔMSEP than the unadjusted predicted DMI (p < 0.001). For lactating ewes, no difference was detected between the adjusted and unadjusted predicted DMI based on the ΔMSEP statistics (p = 0.3672), but the assumption that peak milk was 28 days (default) worsened the predictability of the adjusted predicted DMI as it had lower precision and accuracy. Adjustments for predicted DMI of dry and lactating ewes are necessary to increase adequacy and precision.

RESUMO A maciez da carne é um atributo importante para os consumidores do mundo todo. Porém, ainda faltam estudos sobre sua importância na área de carne de cordeiro para consumidores brasileiros. O objetivo do estudo foi verificar a avaliação dos consumidores em relação à carne de cordeiro com força de cisalhamento elevada. Oito cordeiros foram abatidos com 32,5 ± 2,5kg de peso vivo e 5 a 6 meses de idade. O músculo Longissimus dorsi das meias carcaças foi distribuído aleatoriamente em quatro diferentes processamentos postmortem: Carne Endurecida (CE), obtido pelo encurtamento pelo frio, Carne Fresca (CF), maturada por 3 (M3) e 7 (M7) dias postmortem . As variáveis medidas foram comprimento do sarcômero, força de cisalhamento (FC), índice de fragmentação miofibrilar (IFM)e testes sensoriais de aceitação afetiva com escala hedônica de nove pontos para textura, suculência e qualidade global. O processamento postmortem para CE resultou em menor sarcômero e maiores valores de FC (p <0,05) em comparação com outras amostras, enquanto estas não diferiram entre si. O IFM foi maior para M7 em relação à CE (p <0,05), enquanto CF e M3 apresentaram valores intermediários que não diferiram. Noteste sensorial, as amostras de CE receberam escores menores (p <0,01) para todos os atributos comparados aos demais tratamentos, que não diferiram entre si. Os consumidores avaliaram negativamente a carne que apresentou alta FC. Porém, estudos devem ser realizados para elucidar o impacto de diferenças menores, em faixas intermediárias de FC, na avaliação do consumidor.

SUMMARY Meat tenderness is a major attribute for consumers worldwide. However, few studies investigate the importance of lamb meat tenderness for Brazilian consumers. This study assessed consumers’ evaluation of lamb meat with high shear forces. Eight lambs were slaughtered at 32.5±2.5kg of live weight and 5 to 6 months of age. The Longissimus dorsi muscle from both half carcasses was randomly assigned to four different postmortem processes: Tough Meat (TM), obtained by cold shortening, Fresh Meat (FM), Aging for 3 (A3) and 7 (A7) days postmortem . The variables measured were the sarcomere length, shear force (WBSF) and myofibrillar fragmentation index. We also applied the sensory analysis using affective acceptance tests with hedonic scale of nine points to measure texture, juiciness and overall quality of the meat. The postmortem processing for TM resulted in shorter sarcomere and greater shear values (p <0.05) compared to all other samples, while FM, A3 and A7, did not differ between the samples. Myofibrillar fragmentation was greater for A7 compared to TM (p <0.05), while FM and A3 showed intermediate values that did not differ between the treatments. In the sensory analysis, TM samples received significantly lower scores (p <0.01) for all attributes compared to other treatments and the attributes were not different between the post rigor processes. Consumers identified and evaluated negatively the meat samples with high WBSF. However, further studies are needed to elucidate the impact of smaller differences in WBSF, at intermediate values, on consumers’ evaluation.

ABSTRACT. This study aimed to assess the influence of lamb finishing systems on zootechnical performance, as well as on carcass and meat quality. The experiment was conducted at the APTA’s experimental farm. Thirty-three lambs were used - both sexes, initial age of 90 ± 3 days, Texel with Santa Inês, each animal being one experimental unit, with 6 males and 5 females per treatment. Treatments consisted of: lambs finished on pasture, in semi-feedlot or in feedlot. The lambs were slaughtered with average live weight of 35 kg. Weight gain and carcass measures were taken by ultrasound. After slaughter, carcass conformation and yield, pH, temperature, color, water retention capacity and tenderness were measured. Animals finished on pasture had lower weight gain, were slaughtered at an older age, with lighter carcass weight, smaller loin area, lower shank compactness index, besides lighter shoulder and shank weights, compared to the other production systems (p < 0.05). There was no difference between the semi-feedlot and the feedlot systems for the assessed characteristics. In conclusion, production systems affect animal performance, as well as carcass and meat quality, especially when it comes to important production aspects, such as slaughter age and yield of premium cuts.

Vinte e dois cordeiros machos não castrados, Dorper x Santa Inês, com aproximadamente 90 dias de idade e peso vivo médio inicial de 27,0±4,4kg, foram alimentados com uma dieta com elevada proporção de concentrado com 20% de pelete proteico-mineral (Grano Entero(r)), 5% de feno de capim coast-cross e 75% de milho, na forma de milho grão inteiro (MGI), milho grão moído (MGM) ou milho grão úmido (MGU), para avaliação de desempenho no confinamento por um período de 14 dias de adaptação às dietas e às instalações e de 65 dias de confinamento. Em seguida, os animais foram abatidos com peso vivo médio final (PVF) de 47,97±5,13kg e o conteúdo gástrico foi avaliado para quantificação de protozoários, e foi realizada avaliação papilar. O delineamento experimental foi o de blocos casualizados. Não houve diferença entre os tratamentos (P&gt;0,05) quanto ao ganho de peso médio diário, eficiência alimentar, ingestão diária de matéria seca, características da carcaça e da carne. Os animais tratados com MGI tiveram maior conteúdo gástrico, menor pH ruminal, maior AP (% da superfície de absorção) e maior área papilar em comparação com os outros tratamentos. Os animais tratados com MGI tiveram melhores resultados para o peso final, mas para os demais parametros estudados não foi observada diferença.

Twenty-two males not neutered, Dorper x St. Agnes, with approximately 90 days of age and average live weight of 27.0±4.4kg were fed with a diet wich contained high concentrate with 20% protein pellet-mineral (Grano Entero (r)), 5% grass hay coast-cross and 75% corn in the form of whole kernel corn (MGI), ground corn grain (MGM) or high moisture corn (MGU) for performance evaluation in confinement for a period of 14 days of adaptation to the diets and facilities and 65 days of confinement. Then the animals were slaughtered at average final weight (PVF) of 47.97±5.13kg and gastric content was evaluated for quantification of protozoa, and a papillary review was conducted. The experimental design was in randomized blocks. There was no difference between treatments (P&gt;0.05) for average daily weight gain, feed efficiency, daily dry matter intake, carcass characteristics and meat. MGI-treated animals had higher gastric contents, the lower ruminal pH greater AP (% of surface absorption) and the larger papillary area was compared with other treatments. Animals treated with MGI had better results for the final weight gain, but for the other parameters studied, no difference was observed.

Machos e fêmeas, Santa Inês puros (SI) e cruzados de matrizes Santa Inês com reprodutores das raças Texel (TxSI), Ile de France (IFxSI) e Bergamácia (BxSI), terminados em confinamento e abatidos aos 15, 25, 35 e 45kg de peso vivo. Após o abate, foram tomados os pesos das vísceras e analisado o crescimento alométrico. O pulmão dos machos BxSI cresceu em taxas mais elevadas que SI e TxSI. A tráqueia/esôfago dos machos SI e TxSI cresceu mais lentamente que dos IFxSI e BxSI. Os rins dos machos BxSI cresceram mais rápido comparado aos dos TxSI e IFxSI. O fígado das fêmeas TxSI cresceu em taxas mais elevadas quando comparadas às fêmeas dos outros grupos genéticos. Os machos e fêmeas do grupo TxSI apresentaram taxas de crescimento maiores para rúmen/retículo, respectivamente, comparado aos grupos SI e BxSI.

Males and females, including purebred Santa Inês lamb (SI) and crosses between Santa Inês dams and Texel (TxSI), Ile de France (IFxSI) and Bergamasca (BxSI) sires were feedlot finished and slaughtered at 15, 25, 35 and 45kg live weight. After slaughter, the following non- carcass components were weighed and calculated the allometric growth. Lungs of BxSI males grew faster than those of SI and TxSI. Trachea/esophagus in SI and TxSI males grew slower than IFxSI and BxSI. Kidneys BxSI males grew faster than TxSI and IFxSI. Livers of female TxSI lamb grew more rapidly than those of females in the other genetic groups. In both males and females, the rumen/reticulum grew faster in the TxSI group than SI and BxSI groups.

Avaliou-se a influência dos níveis nutricionais da ovelha antes do parto, da idade à desmama e do sistema de terminação sobre as fibras musculares e a qualidade da carne dos cordeiros. Utilizaram-se matrizes mestiças Ile de France × Bergamacia criadas a pasto. As ovelhas foram divididas em dois grupos: um com suplementação alimentar 30 dias antes do parto e outro sem suplementação. Os animais (ovelha e cordeiros) foram subdivididos de acordo com a idade à desmama (45 ou 60 dias de idade) e os cordeiros desmamados foram submetidos a três sistemas de terminação: confinamento com dieta completa; confinamento somente com feno; e confinamento somente no pasto. O abate dos cordeiros foi realizado aos 30 kg de peso vivo ou aos 150 dias de idade. As características de carcaça analisadas foram morfofisiologia da fibra do músculo longissimus dorsi, fragmentação miofibrilar pós-morte (maturados nos dias 0, 3 e 7 pos mortem) e redução do pH e da temperatura da carne pós-abate. Não houve efeito da suplementação às ovelhas ou da idade à desmama sobre nenhuma das características avaliadas. A composição em fibras de contração lenta e oxidativa, contração rápida e oxidativa ou contração rápida e glicolítica não foi alterada pelos fatores em estudo, mas a área transversal das fibras foi menor nos cordeiros terminados com feno, assim como os valores de pH, temperatura e as medidas dos fragmentos de miofibrila. Com o aumento do tempo de maturação de 0 para 3 e 7 dias post mortem, houve redução do comprimento dos fragmentos de miofibrilas. O sistema de terminação de cordeiros em confinamento somente com feno interfere mais intensamente na qualidade da carne que o sistema de terminação a pasto ou em confinamento com dieta completa.

The study verified the influence of different nutritional levels of the dams, before parturition, the weaning age of the lambs and the finishing system on lamb muscle fiber morphology and meat quality. Ile-de-France × Bergamacia crossbred dams grazing on natural grassland were divided into two groups: 1) nutritional supplement 30 days before the parturition (SUPL), and 2) no nutritional supplement (NS). These groups were further subdivided by weaning age of the lambs, which corresponded to either 45 or 60 days. The weaned lambs from each of the previous groups were also divided into different finishing systems: confined and fed a complete diet (CD), confined and fed hay (H) and kept on grassland (P). The lambs were slaughtered at 30 kg live weight (CD and P), or at 150 days of age (H). The carcasses were cooled at 4ºC/24h. The analyzed variables were: longissimus dorsi muscle fiber morphophysiology, post mortem myofibrillar fragmentation (at 0, 3 and 7 days post mortem), meat pH and temperature. There was no effect of supplementation of dams or weaning age of the lambs for the evaluated variables. The frequency of slow-oxidative (SO), fast-oxidative-glycolytic (FOG) and fast-glycolytic (FG) muscle fiber types was not altered by the treatments, but the fiber cross-sectional area was smaller for the lambs finished only on hay, and the meat pH values and temperature were lower and the myofibrill fragment dimensions were smaller. As time maturation increased from 0 to 3 and 7 days post mortem, there was a decrease in the length of the myofibrill fragments. The diet of the lambs which were maintained confined and fed only with hay was nutritionally inferior when compared with all the others, and this changed the quality of the meat compared to the finishing systems on grassland or confined and fed complete diet.

O experimento foi realizado com o objetivo de avaliar o efeito da suplementação da ovelha 30 dias antes do parto, da idade à desmama (45 ou 60 dias) dos cordeiros e do sistema de terminação (em confinamento dieta total ou feno) ou a pasto sobre o perfil de ácidos graxos do músculo Triceps brachii de cordeiros machos não-castrados. O animais foram abatidos com 30 kg de peso corporal ou aos 150 dias de idade. Os cordeiros terminados em confinamento alimentados com feno foram abatidos pela idade e os demais pelo peso corporal. Os teores dos ácidos graxos C15:0, C16:0, C17:0, C16:1, C18:1 e C18:3 no músculo diferiram entre os sistemas de terminação dos cordeiros. O músculo dos cordeiros alimentados com dieta completa apresentou maiores valores de C16:0, C16:1 e C18:1, enquanto o músculo daqueles alimentados com feno e em pastagem apresentou maiores teores de C18:3. A dieta alterou o perfil de ácidos graxos no músculo dos cordeiros. A suplementação das ovelhas 30 dias antes do parto e a idade a desmama não afetaram o perfil de ácidos graxos.

The objective of this work was to evaluate the supplementation of ewes 30 days before lambing, of the weaning age (45 or 60 days) of lambs and of the finishing system (on confinement - full diet or hay) or in grass on the profile of Tríceps brachii muscle fatty acid of no castrated male lambs. The animals were slaughter with 30 kg body weight or at 150 days-old. The lambs finished on confinement fed were slaughtered by age and the others by body weight. The content of fatty acids C15:0, C16:0, C17:0, C16:1, C18:1 and C18:3 were different among the lambs finishing systems. The muscle of lambs fed full diet shown highest values of C16:0, C16:1 and C18:1, while the muscle those fed hay or grass shown highest values of C18:3. The diet affected the fatty acid profile of muscle of lambs. The ewes supplementation 30 days before lambing and the weaning age did not affect the fatty acid profile.

Objetivou-se avaliar o efeito da suplementação no pré-parto e da idade à desmama sobre o desempenho de cordeiros terminados em confinamento. Foram utilizadas 44 matrizes mestiças Ile de France × Bergamácia acasaladas com cordeiro Ile de France mantidas em pastagem de Panicum maximum cv. Tanzânia, em sistema de pastejo rotacionado, até 30 dias antes do parto, quando foram separadas em dois grupos. No pré-parto, apenas o primeiro grupo (SUPL) recebeu suplementação (1% peso vivo) com dieta balanceada. Após o parto, ambos os grupos, com (SUPL) e sem suplementação (NS), receberam suplementação. Por sorteio, metade dos cordeiros de cada grupo foi desmamada aos 45 dias e a outra metade, aos 60 dias de idade. Após a desmama, os cordeiros foram mantidos em confinamento com dieta balanceada e abatidos aos 30 kg de PV, após jejum de sólidos de 16 horas. O peso e a condição corporal ao parto das ovelhas diferiram entre os grupos, o que não ocorreu ao desmame. Os peso ao nascimento e ao desmame, o ganho de peso do nascimento ao desmame e do desmame ao abate, o período em confinamento e a idade ao abate não diferiram entre os cordeiros. O peso ao desmame e o ganho de peso do desmame ao abate foram influenciados pela idade à desmama (os cordeiros apresentaram 0,20 kg aos 45 dias e 0,15 kg aos 60 dias de idade). A suplementação proporcionou melhor condição corporal às ovelhas e a desmama aos 45 dias promoveu melhor desempenho aos cordeiros.

The objective of this trial was to evaluate the effect of ewe pre-partum supplementation and weaning age on performance of lambs. Forth-four Ile de France x Bergamasca ewes that were mated with Ile de France rams were used in this trial. Animals were maintained in a rotational grazing system of Panicum maximum (cv. Tanzânia) pasture until 30 days before parturition. Ewes were then divided in two groups: supplemented (SUPL) and not-supplemented (NS); animals on the SUPL group were supplemented (1% of body weight [BW]) with a balanced diet according to NRC (1985) requirements. After parturition, both groups were supplemented. Half of lambs from the SUPL and NS groups were weaned at 45 days of age and the other half at 60 days of age. After weaning lambs were feedlot fed with a diet balanced according to NRC (1985) model. Lambs were slaughtered when they reached 30 kg of BW after 16 hours of solids fasting. Both BW and body condition score of ewes at parturition differed between SUPL and NS groups while the same was not observed at weaning. Birth weight, weaning weight, weight gain from birth to weaning and from weaning to slaughter, days in feedlot, and slaughter age all were not different in lambs born from ewes of the SUPL or NS groups. However, significant differences were observed for weaning weight and weight gain from weaning to slaughter between groups of animals weaned at 45 or 60 days of age.

Cento e três cordeiros, machos e fêmeas, Santa Inês puros (SS) e cruzas com Texel (TS), Ile de France (FS) e Bergamácia (BS) foram utilizados no estudo do crescimento alométrico dos cortes. Os animais foram confinados em gaiolas individuais e abatidos aos 15, 25, 35 e 45 kg de PV. Após abate e resfriamento da carcaça, foram feitos os cortes: pescoço, costela/fralda, costeleta, lombo, paleta e perna, sendo esses dois últimos sem os braços, para avaliação do crescimento alométrico individual em relação ao corpo vazio (PCVZ). O crescimento alométrico do pescoço foi isogônico em todos os grupos, à exceção do grupo Santa Inês x Bergamácia (crescimento heterogônico positivo), comprovando que esse corte cresce de forma semelhante ao PCVZ. Os machos TS e FS apresentaram ritmo de crescimento do pescoço menor que o dos machos BS. A costela/fralda, em todos os grupos, teve crescimento lento entre os pesos avaliados, observando-se que, nos grupos TS e FS o ritmo de crescimento foi maior que no grupo SS. Nos machos, o desenvolvimento da paleta foi semelhante ao PCVZ, enquanto, nas fêmeas, foi lento em relação ao PCVZ. O desenvolvimento da costeleta e do lombo foi lento em todos os grupos, à exceção das fêmeas FS, nas quais acompanhou o PCVZ; os coeficientes alométricos de costeleta nesses animais foram menores que nos demais outros grupos. O desenvolvimento da perna foi similar ao PCVZ nos machos SS, TS e FS e nas fêmeas FS, porém, foi menos intenso nos machos BS e nas fêmeas SS, TS e BS.

This study was conducted using 103 male and female lambs from the following genetic groups: purebred Santa Inês (SS) and crossbreds of Santa Inês x Texel (TS), Santa Inês x Ile de France (FS), and Santa Inês x Bergamacia (BS). Animals were slaughtered at one of the following body weights: 15, 25, 35 or 45 kg. After slaughter and cooling of the carcasses, the following cuts were made: neck, rib/flank, short ribs, loin, blade, and hindlimb. The alometric growth of each cut in relation to the empty body weight (EBW) was measured. The alometric growth of the neck was isogonic (b=1) for most genetic groups and accompanied EBW growth. However, for BS lambs the growth was heterogonic (b>1) or slow growth. TS and FS male lambs showed slower neck growth rate compared to the BS lambs. The rib/flank had slow growth for all groups but TS and FS lambs showed greater growth rate than the SS animals. For males, the blade development followed the EBW while females had a slower growth rate. The development of short ribs and loin was slow for all groups, except on FS female lambs, in which both short ribs and loin growth followed that of EBW; the alometric coefficients obtained for short ribs were lower on FS female lambs compared to those of the remaining genetic groups. The development of hindlimb accompanied the EBW for SS, TS and FS males and also for FS female lambs.

Objetivou-se avaliar a composição centesimal da carne de cordeiros da raça Santa Inês (SI x SI) e de seus mestiços com Texel (T x SI), abatidos com diferentes pesos vivos. O músculo biceps femoris foi utilizado para as análises de umidade, de proteína bruta (PB), de extrato etéreo (EE) e de cinzas. O delineamento foi inteiramente casualizado, com 16 tratamentos, em esquema fatorial 2x2x4, com dois grupos genéticos, dois sexos (14 machos e 13 fêmeas em cada grupo) e quatro pesos de abate (15, 25, 35 e 45 kg PV), sendo os dados analisados com auxílio Proc GLM do programa estatístico SAS. A umidade diminuiu com o peso de abate, variando de 76,09 a 74,31%, e os machos apresentaram valores maiores em relação às fêmeas. A PB teve comportamento quadrático, variando de 20,27 a 21,36%. Com o aumento do peso de abate, o teor de EE elevou, variando de 0,95 a 3,78%, sendo que SI x SI tiveram maior teor de EE. Os machos, de ambos os grupamentos genéticos, tiveram menor teor de extrato etéreo. Houve declínio do teor de cinzas com o avanço do peso, e as fêmeas apresentaram os maiores valores. Conclui-se que o peso de abate alterou a composição centesimal da carne de cordeiros, de modo que os animais mais pesados apresentaram menor teor de umidade e de cinzas e maior teor de EE. O sexo e o grupo genético influenciaram o teor de EE, indicando a possibilidade de abate em pesos diferentes, conforme o sexo e a raça.

The objective of this study was to evaluate the meat centesimal composition of Santa Ines pure breed and Santa Ines vs Texel crossbreed lambs, slaughtered at different body weights. Thirteen males and fourteen females from both breeds were selected. The muscle biceps femoris was used to determine water, crude protein, crude extract and minerals contents. The experiment was arranged randomly, with 16 traits in a 2x2x4 factorial scheme with two genetic groups, two genders (14 males and 13 females in each group) and four slaughter weights (15, 25, 35 e 45 kg of body weight). Data was analyzed by Proc GLM of SAS program. It was observed that the water content decreased as the slaughter weight increased, ranging from 76.09 to 74.31%. The males had higher water content values when compared to the females. The crude protein showed a quadratic behaviour, ranging from 20.27 to 21.36%. As the slaughter weight increased, the value of crude extract content also increased, ranging from 0.95 to 3.78%. The SIxSI animals presented higher ether extract content. In both genetic groups, the males presented lower ether extract content. The minerals content decreased as the slaughter weight increased and the females presented higher values when compared to the males. It was concluded that, as slaughter weight increased, the ether extract content also increased, while water and minerals content decreased and the crude protein content showed a linear decrease. The meat of female lambs presented higher contents of ether extract and less water content when compared to the meat of male lambs. The SIxSI lambs presented higher ether extract content when compared to TxSI lambs.

O trabalho foi desenvolvido com o objetivo de estudar o efeito do sexo dos animais, do grupo genético e do peso de abate no desempenho de animais confinados. Foram utilizados 103 cordeiros, machos e fêmeas, Santa Inês puros (SS) e cruzas Santa Inês com Texel (TS), Ile de France (FS) e Bergamácia (BS), confinados em gaiolas individuais. Mediram-se a dieta fornecida e as sobras diárias, para cálculo do consumo de matéria seca (MS), energia metabolizável (EM), proteína digestível (PD) e fibra em detergente neutro (FDN). Os cordeiros foram abatidos em quatro pesos: 15, 25, 35 e 45 kg de peso vivo. Avaliaram-se o ganho de peso diário (GPD), o número de dias no confinamento (ND), a conversão alimentar (CA) e o consumo de MS, PD, EM e FDN, nas três fases de crescimento: 15 a 25 kg (1), 25 a 35 kg (2) e 35 a 45 kg (3). Também foram avaliados as idades de abate (IA), o peso do corpo vazio (PCVZ) e rendimento de carcaça (RC). Aos 35 e 45 kg, os cordeiros TS e FS apresentaram IA inferiores e as cordeiras SS, IA superiores. O ND dos cordeiros BS de 35 a 45 kg foi maior que dos TS. Aos 35 e 45 kg, o PCVZ dos cordeiros TS e FS foram menores. Os melhores GPD foram dos cordeiros TS, seguidos do FS e SS. Os consumos de MS, PD, EM e FDN foram semelhantes entre os grupos genéticos, nas fases 1 e 2 de crescimento. Verificou-se que os cordeiros TS tenderam a aumentar o consumo, com o incremento de peso, enquanto os outros grupos tenderam a diminuir. A CA elevou-se com o aumento de peso, com exceção dos machos FS. Os machos não apresentaram diferenças na CA entre os grupos genéticos, entretanto, as fêmeas TS e FS apresentaram valores melhores. Aos 35 e 45 kg, as fêmeas apresentaram maiores RC que os machos. Aos 35 kg, os melhores RC foram dos machos TS.

The work was carried out to evaluate the effect of animal sex, genetic group and slaugher weight on fedlot lambs performance. One hundred and three male and female lambs, purebred Santa Inês (SS) and crosses between Santa Inês and Texel (TS), Ile de France (FS) and Bergamacia (BS) were fedlot in individual cages. Diet and orts were daily collected to calculate the intakes of dry matter (MS), metabolizable energy (EM), digestible protein (PD) and neutral fiber detergent (FDN). The lambs were slaughtered at four weights: 15, 25, 35 and 45 kg of live weight. Weight gain (GPD), number of days in confinement (ND), feed:gain ratio (CA) and intakes of MS, PD, EM and FD were analyzed during three growing phases: 15 to 25 kg (1), 25 to 35 kg (2) and 35 to 45 kg (3), for each genetic group and each sex. The slaughter age (IA) and the empty body weight (PCVZ) were also analyzed. At high weights, TS and FS male lambs showed inferior IA, and the female lambs, superior IA. ND of BS lambs from 35 to 45 kg was superior than TS lambs. From 35 to 45 kg, PCVZ of TS and FS lambs was inferior. The best GPD was observed for TS lambs, followed by FS and SS. The intakes of MS, PD, EM and FDN were similar among the genetic groups, during the phases 1 and 2. TS lambs intake tended to increase as body weight increased, whereas the other groups showed tended to decrease. CA increased as slaughter weight increased. The males did not show differences in CA among the genetic groups, but TS and FS females showed better results. At 35 and 45 kg, the females showed superior RC than the males. At 35 kg, the TS males showed better RC than the other groups.

Foram utilizados 103 cordeiros, machos e fêmeas, Santa Inês puros (SS) e cruzas Santa Inês com Texel (TS), Ile de France (FS) e Bergamácia (BS), confinados em gaiolas individuais. Os cordeiros foram abatidos em quatro pesos: 15,0; 25,0; 35,0 e 45,0 kg de peso vivo. Após o abate e resfriamento da carcaça, foram feitos os seguintes cortes e calculadas as porcentagens em relação ao peso da carcaça fria: pescoço (PP), costela/fralda (PCF), costeleta (PC), lombo (PL), paleta (PPA) e perna (PPE), sendo esses dois últimos sem os braços. Os pescoços praticamente não variaram com o aumento dos pesos de abate. Os pescoços dos cordeiros TS e FS foram menores, comparados aos dos cordeiros SS e BS, na maioria dos pesos de abate estudados. A paleta também não variou com o aumento dos pesos de abate, havendo tendência para diminuição. Aos 45 kg, os cordeiros TS e FS apresentaram PPA maiores em relação aos cordeiros SS e BS. Nos outros pesos de abate, praticamente não houve diferenças para PPA entre os grupos genéticos. A costela/fralda elevou-se com o aumento dos pesos de abate, sendo que, em pesos de abate elevados, os cordeiros TS mostraram maiores proporções. Para a PC, praticamente não houve diferenças entre os pesos de abate. As fêmeas FS, entretanto, aos 35 e 45 kg, apresentaram menores PCF que os machos FS. O lombo tendeu a elevar-se com o aumento dos pesos de abate, mas foram detectadas diferenças para os animais abatidos aos 15 kg, em relação aos outros pesos de abate. Entre os grupos genéticos, praticamente não houve diferenças para PL. As pernas diminuíram com o aumento dos pesos de abate. Aos 35 kg de peso vivo, os cordeiros machos TS e as fêmeas FS obtiveram melhores PPE em relação aos outros grupos genéticos.

One hundred and tree male and female lambs, pure Santa Inês (SS) and crosses between Santa Inês and Texel (TS), Ile de France (FS) and Bergamacia (BS), were used. They were confined in individual cages. The lambs were slaughtered at four weights: 15.0, 25.0, 35.0 and 45.0 kg live weight. After slaughter and cooling of the carcasses, the following cuts were made: neck (PP), rib/flank (PCF), rack (PC), loin (PL), shoulder (PPA) and leg (PPE), these last two without the arms. Necks practically did not vary with the increase of slaughter weights. Necks of TS and FS lambs were smaller, compared to the SS and BS lambs, in most of the studied slaughter weights. Shoulders also did not vary with the increase of slaughter weights with a tendency to decrease. At 45 kg, TS and FS lambs presented greater PPA in relation to SS and BS lambs. In other slaughter weights, pratically there were no considerable PPA differences between the genetic groups. Rib/flanks increased with the increase of slaughter weights, and, in higher slaughter weights, the TS lambs showed greater proportions. For CP, there was practically no difference among slaughter weights. Ile de France females, however, at 35 and 45 kg, showed PCF smaller than FS males. Loins tended to increase with the increase of slaughter weights, but differences were detected in the animals slaughtered at 15.0 kg, in relation to the other slaughter weights. Among the genetic groups there was no difference for the PL. Legs decreased with the increase of slaughter weights. At 35 kg live weight, the male TS and the female FS lambs obtained better PPE in relation to the other genetic groups.

Propôs-se avaliar os parâmetros de qualidade pH, cor, perda de peso por cozimento (PPC) e força de cisalhamento (FC) no músculo Longissimus dorsi (LD) e Semimembranosus (SM) de 13 cordeiros machos e 14 fêmeas Santa Inês puro (SI x SI) e o mesmo número de animais Texel x Santa Inês (T x SI), abatidos com 15, 25, 35 e 45 kg PV. A carcaça foi resfriada por 24 horas a 2ºC, realizando-se, durante este período, as medidas de pH. Retiraram-se os músculos LD e SM para as análises de cor, PPC e FC. Utilizou-se um DIC, fatorial 2x2x4, e as médias foram analisadas pelo Proc GLM do programa estatístico SAS. As medidas de pH foram analisadas em parcela subdividida. A queda do pH no LD e SM foi mais acentuada para os animais mais leves. A carne das fêmeas T x SI apresentou pH final maior que a dos machos e cordeiros SI x SI. A luminosidade diminuiu e a intensidade da cor vermelha elevou-se com o aumento do peso de abate. A carne dos machos e dos cordeiros SI x SI apresentou coloração mais vermelha e menos luminosa no LD e SM. A PPC foi menor na carne dos cordeiros mais pesados; no músculo LD, dos machos houve menor perda de água que nos das fêmeas. Os machos tiveram carne mais dura e, com o aumento do peso de abate, houve diminuição de FC, sendo maior para o T x SI para o músculo LD e Santa Inês puro para o músculo SM.

The objective of this study was analyze the colour, pH, weight loss by cooking (PPC) and shear force (FC) of the Longissimus dorsi (LD) and semimembranosus (SM) muscles of Santa Inês (SI x SI) and Texel x Santa Inês (T x SI) lambs, slaughtered at different live weights. Thirteen males and fourteen females were slaughtered at 15, 25, 35 and 45 of live weight. The carcasses were kept during twenty-four hours at 2ºC and during that time the pH was measured. A completely randomized design in a latin square (2x2x4) arrange for analyse of colour, PPC and FC was used. Split plot arranged was used for the pH values analysis. The decrease of pH of both muscles (LD and SM) was greater in the lighter animals. T x SI females meat showed higher pH values than SI x SI males lambs. The lightness values increased and darkness was lower when the slaughter weight increased. The muscles (LD and SM) of the SI x SI males were reader and darker. The PPC was lower in the heaviest animals and in the LD muscle it was lower in the female lambs. Male lambs muscles lost more water were harder than of the females muscles. The decrease of the FC was related to the increase in the slaughtering weight, and this effect was higher in the LD muscle of T x SI animals and in the SM muscle of the SI x SI animals.