ABSTRACT: Bos taurus indicus temperament is variable and affects beef tenderization. Our objective was to investigate temperament and performance of non–castrated Nellore and identify groups based on Longissimus lumborum (LL) pH decline as well as beef characteristics produced by those groups. We investigated 94 animals with a subset of carcasses (n = 24) selected based on LL pH at 24 h postmortem (pm) to represent two groups: resistant to pH decline (> 5.8 called pH–Res; n = 10) and normal (< 5.7 called pH–Nor; n = 14). Steaks were fabricated from the LL muscle and randomly assigned to aging (2, 7, 14, and 21 days). Sarcomere length, cooking loss, myofibrillar fragmentation index (MFI), and Warner–Bratzler shear force (WBSF) were determined. Data on temperament were investigated in a multivariate approach, while beef data were compared between groups using the analysis of variance. Rectal temperature at the beginning of the finishing phase and total weight gain were greater and related to animals in the pH–Res group (p < 0.01 and p = 0.03, respectively). Temperature and pH decline curves, sarcomere length, and cooking loss revealed that pH–Res produced beef with lower quality compared to the pH–Nor group. Results for MFI and WBSF did not show differences between groups within each time pm; however, overall steaks from pH–Res were tougher (p = 0.06). Incidence of LL pH between 5.8 and 5.9 at 24 h pm did not compromise the tenderization rate or extension; however, it affected the water holding capacity in this population of Nellore cattle.

RESUMO Sistemas de produção baseados em pastagens e alimentos alternativos podem ser utilizados para reduzir cerca de 20% os custos de produção do leite caprino.O objetivo deste trabalho foi avaliar a influência da substituição do milho e do farelo de soja do concentrado, pela raspa de mandioca e alfafa, respectivamente, sobre o consumo, fermentação e degradabilidade ruminal de cabras adultas Saanen confinadas, vazias, secas e canuladas no rúmen. O experimento foi conduzido no delineamento em quadrado latino, com as dietas: milho triturado e farelo de soja; raspa de mandioca e farelo de soja; milho triturado e alfafa; raspa de mandioca e alfafa. Foram avaliados: consumo, parâmetros ruminais, produção de ácidos graxos de cadeia curta (AGCC) e cinética da degradação das dietas. A inclusão da raspa de mandioca e da alfafa não influenciou o consumo e a produção de amônia. O pH ruminal e as produções de AGCC foram influenciados pelos tempos de colheita,apresentando um pH elevado (6,29) na primeira mensuração (7 h 00) e diminuindo em seguida, influenciando dessa forma as produções de AGCC ao longo do dia. O ácido acético e a produção total de AGCC foram influenciados pelas dietas, sendo os maiores valores para a dieta mandioca/alfafa (68,03 e 93,64 mM 100 mM-1, respectivamente) e os menores valores para a dieta milho/soja (55,40 e 76,03 mM 100 mM-1, respectivamente).A degradabilidade dos nutrientes foi influenciada pelas dietas, sendo que as com mandioca e mandioca/alfafa apresentaram as maiores degradabilidades efetivas(57,57 para 0.02 h-1 e 53,49 para 0.05 h-1; 57,25 para 0.02 h-1 e 53,26 para 0.05 h-1, respectivamente), demonstrando que a mandioca e a alfafa podem substituir o milho e o farelo de soja dos concentrados, sem alterar o consumo e o ambiente ruminal das cabras, melhorando a produção de ácido acético e a degradabilidade da dieta.

ABSTRACT Pasture-based production systems and alternative foods can be used to reduce goat milk production costs by around 20%.The objective of this study was to examine the effect of substituting the corn and soybean meal of the concentrate with cassava chips and alfalfa, respectively, on the feed intake, fermentation, and rumen degradability parameters of adult, dry, empty, rumen-cannulated Saanen goats reared in a feedlot. The experiment was conducted as a Latin square design in which the following diets were tested: ground corn and soybean meal; cassava chips and soybean meal; ground corn and alfalfa; and cassava chips and alfalfa. The following variables were evaluated: feed intake, rumen parameters, short-chain fatty acid (SCFA) production, and feed degradation kinetics. Inclusion of cassava chips and alfalfa did not influence feed intake or ammonia production. Rumen pH and SCFA production were influenced by the collection times, presenting a high pH (6.29) at the first measurement (07 h 00) and then decreasing, thus influencing SCFA production throughout the day.Acetic acid and total SCFA production were influenced by the diets, with the highest values for the cassava/alfalfa diet (68.03 and 93.64 mM 100 mM-1, respectively) and the lowest values for the corn/soybean diet (55.40 and 76.03 mM 100 mM-1, respectively).Nutrient digestibility was also influenced by diets, with those containing cassava and cassava/alfalfa, providing the greatest effective degradability (57.57 to 0.02 h-1 and 53.49 to 0.05 h-1; 57.25 to 0.02 h-1and 53.26 to 0.05 h-1, respectively). This finding demonstrates that cassava and alfalfa can substitute the corn and soybean meal of concentrates without changing feed intake or the ruminal environment of goats. Rather, this substitution improves acetic acid production and diet digestibility.

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.

The objective of this work was to analyze the interrelations among weights and carcass measures of the longissimus lumborum muscle thickness and area, and of sternum tissue thickness, measured directly on carcass and by ultrasound scan. Measures were taken on live animals and after slaughter to develop models of multiple linear regression, to estimate the composition of shoulder blade, from selected variables in 89 kids of both genders and five breed groups, raised in feedlot system. The variables considered relevant and not redundant on the information they carry, for the common factor analysis, were used in the carcass composition estimate development models. The presuppositions of linear regression models relative to residues were evaluated, the estimated residues were subjected to analysis of variance and the means were compared by the Student t test. Based in these results, the group of 32 initial variables could be reduced to four variables: hot carcass weight, rump perimeter, leg length and tissue height at the fourth sternum bone. The analysis of common factors was shown as an effective technique to study the interrelations among the independent variables. The measures of carcass dimension, alone, did not add any information to hot carcass weight. The carcass muscle weight can be estimated with high precision from simple models, without the need for information related to gender and breed, and they could be built based on carcass weight, which makes it easy to be applied. The fat and bones estimate models were not as accurate.