Twenty-seven animals (½ Angus - ½ Nellore) were fed for four months with one of the following diets: without addition of essential oils (E0.0), with 3.5 (E3.5) or 7 (E7.0) g/animal/day of an essential oil blend (oregano, garlic, lemon, rosemary, thyme, eucalyptus and sweet orange). Chemical composition, fatty acid profile and meat color were evaluated in Longissimus muscle. In addition, the effects of aging (one, seven and 14days) on the meat water holding capacity, texture and lipid oxidation were evaluated. Essential oils had no effect on chemical and fatty acid composition, meat color, water holding capacity or texture, but an inclusion of 3.5g/day decreased lipid oxidation. The addition of 7.0g/animal/day had a pro-oxidant effect on meat during aging and resulted in higher values for lipid oxidation at 14days of aging. Aging significantly affected thawing losses and texture. A dose of 3.5g/animal/day could be recommended in feedlot animals, but greater doses could have a pro-oxidant effect.

RESUMO -A composição corporal e as exigências de macroelementos minerais (Ca, P, Mg, Na e K) para ganho de peso de bovinos de quatro raças zebuínas (Gir, Guzerá, Mocho-Tabapuã e Nelore) foram estimadas com 63 animais não-castrados, com idade média de 24 meses e 366 kg de PVinicial. Dezesseis animais das raças Gir, Guzerá e Mocho-Tabapuã e 15 da raça Nelore foram usados. Quinze animais, quatro das raças Gir, Guzerá e Mocho-Tabapuã e três da Nelore, foram abatidos ao início do estudo e os demais, distribuídos em três grupos, com três animais de cada raça e alimentados individualmente, ad libitum, com ração contendo 50% de concentrado na matéria seca, até atingirem peso de abate de 405, 450 e 500 kg, respectivamente. Equações de regressão do logaritmo do conteúdo corporal de macroelementos minerais, em função do logaritmo do corpo vazio (PCV), foram ajustadas para estimar os composição corporal dos constituintes para qualquer PCV, dentro do intervalo incluído na pesquisa (250 a 450kg). Pela derivação destas equações, a composição do ganho de PCV foi obtida. Animais das quatro raças não diferiram quanto à composição corporal de macroelementos minerais e às exigências líquidas para ganho de peso. Houve decréscimo na concentração dos cinco macroelementos no PCV e no peso ganho, com a elevação do PCV. As exigências líquidas estimadas para ganho de PCV, para os cinco macrominerais, foram inferiores aos valores fixos sugeridos pelo ARC (1980). Os requerimentos líquidos estimados de Ca e P para ganho de peso de um bovino não-castrado de 400 kg PV foram 16 e 24% inferiores, respectivamente, aos propostos pelo AFRC (1991). Palavras-chave: macroelementos minerais, exigências, raças zebuínas Body Composition and Macrominerals (Ca, P, Mg, Na and K) Requirements of Bulls, from Four Zebu BreedsABSTRACT -The body composition and macrominerals requirements for weight gain of four Zebu breeds (Gyr, Guzera, MochoTabapuã and Nellore) were estimated using 63 bulls averaging 24 months of age and 366 kg initial LW. Sixteen animals from Gir, Guzera e Mocho-Tabapuã breeds and 15 from Nellore breed. Fifteen animals, four animals from Gyr, Guzera and Mocho-Tabapuã breeds and three from Nellore breed, were slaughtered at the beginning of the trial. The remaining animals were distributed into three groups, containing three animals from each breed, which were individually fed a diet containing 50% concentrate as dry matter base, to reach the target live weight of 405, 450 and 500 kg, respectively. Regression of the log the of body composition of macrominerals, on the log of empty body weight (EBW), was fitted to estimate the total body composition of those constituents for any EBW inside the range included in this research (250 to 450 kg). By derivation of those regression, the composition of gain was rejusted. The animals from the four breeds did not differ regarding to body composition of macroelements minerals, as for the net requirements for weight gain. There were decreases in the concentration of the five macrominerals in the EBW and in ...

Forty-four feedlot-finished Nellore cattle were used to evaluate the impacts of temperament on performance, meat and carcass traits, and serum concentrations of hormones, proteins, enzymes, and immunoglobulins. Individual temperament was assessed at feedlot entry (d 0), 67 d, and 109 d, utilizing chute score (CS; 5-point scale) and exit velocity (EV). Temperament scores were calculated averaging CS and EV scores, and cattle were subsequently classified according to their temperament (an average of ≤3 = adequate temperament [ADQ], or an average of >3 = excitable temperament [EXC]). At the end of the experiment (d 109), all 44 animals were slaughtered, and 16 were randomly selected for final empty body weight (EBW) estimation. Blood samples were collected at 0, 67, and 109 d and analyzed for serum variables (cortisol, insulin, haptoglobin, total protein, lactate, creatinine kinase [CK], lactate dehydrogenase [LDH], and IgA). The incidence of carcass bruises was verified immediately after the hide was removed. Carcass pH was obtained at 0 and 24 h postmortem. Samples of the LM were collected for meat quality analyses. Cattle classified as ADQ had greater final BW ( = 0.03), final EBW ( = 0.02), metabolic weight ( = 0.03), ADG ( = 0.02), feed efficiency ( = 0.03), HCW ( = 0.02), cold carcass weight ( = 0.02), and LM area ( < 0.01) compared to that of the EXC cohorts. Cattle classified as ADQ tended to have a lower percentage of cooler shrink ( = 0.06) compared to that of EXC cattle. No temperament effects were detected for initial BW ( = 0.70), DMI ( = 0.14), cold dressing percentage ( = 0.98), or backfat thickness ( = 0.29). Cattle classified as ADQ had greater marbling ( = 0.02) and meat fat content ( = 0.05) compared with that of EXC cattle. No temperament effects (> 0.05) were detected for unsaturated fatty acid (UFA), SFA, MUFA, PUFA, and n-6:n-3 ratio. For blood parameters, EXC cattle had greater values of cortisol ( = 0.04) and haptoglobin ( = 0.05) and tended ( = 0.06) to have reduced serum insulin concentration compared with ADQ cattle. Both temperament groups had similar serum concentrations of IgA ( = 0.25) and total protein ( = 0.84). Cattle classified as EXC presented greater amounts ( = 0.05) of carcass bruises. In conclusion, an EXC temperament impaired feedlot performance, carcass characteristics, and meat quality traits in finishing Nellore cattle.

Essential oils are natural extracts from plants which can be included in cattle diets as an alternative to additives, such as ionophores, to improve the shelf life of meat. The aim of this study was to evaluate the sensory acceptability of meat from 57 crossbred (1/2 Angus–1/2 Nellore) animals of different sexes [heifers n = 30, and young bulls n = 27], finished in feedlot with isoenergetic and isonitrogenous diets, which differed in the level of supplementation (0.0, 3.5 or 7.0 g/animal/day) with a commercial mix of essential oils (Mixoil®) from seven plants: oregano, garlic, lemon, rosemary, thyme, eucalyptus and sweet orange. The Longissimus thoracis muscle, aged for 24 h, was evaluated by 120 consumers who scored tenderness acceptability, flavour acceptability and overall acceptability using a hedonic 9-point scale. The inclusion of essential oils affected tenderness acceptability and flavour acceptability (P ≤ 0.01), with a tendency (P < 0.10) for overall acceptability. Meat from heifers was more appreciated by consumers than that from young bulls in all attributes (P ≤ 0.001), however, different groups of consumers had different preferences. The inclusion of a mix of essential oils in beef diets was well accepted by consumers, and could improve the acceptability of meat from young bulls, when is added at a concentration of 3.5 g/animal/day during the last 4 months of fattening.

RESUMO -Com a finalidade de estudar as características da carcaça, nove animais Gir, nove Guzerá, nove Nelore e nove Mocho-Tabapuã não-castrados, com idade média de 24 meses e pesos vivos médios iniciais de 357,6; 362,0; 368,6; e 376,4 kg, respectivamente, foram usados neste estudo. Em cada raça, os animais foram distribuídos aleatoriamente em baias individuais, recebendo ração contendo 50% de concentrado na matéria seca à vontade e divididos em três pesos de abate (categorias 405, 450 e 500 kg PV). No abate, determinou-se o peso de corpo vazio. Não houve diferenças entre raças ou pesos de abate para as variáveis estudadas, exceto para rendimento de alcatra completa. Para esta característica, houve efeito de interação entre raça e categoria, sendo que o rendimento decresceu em animais Gir com a elevação do peso de abate, o que não ocorreu nas demais raças. Não houve diferenças entre as raças com relação à composição física. O peso de abate não influenciou a composição física da carcaça e a área de olho de lombo, mas influiu no comprimento de carcaça e na espessura de gordura.Palavras-chave: área de olho de lombo, bovino de corte, características de carcaça, composição física, comprimento, espessura de gordura, zebuínos Productive Performance of Four Zebu Breed Beef Cattle Slaughtered at Different Stages of Maturity. 2. Carcass TraitsABSTRACT -With the aim to study carcass traits, nine Gyr, nine Guzera, nine Nellore and nine Mocho Tabapuã bulls, averaging, respectively, 357.6, 362.0, 368.6, and 376.4 kg of initial live weight and 24 months of age were used in this study. The animals from each breed were randomly assigned to individual pens and were full fed a diet containing 50% concentrate, dry matter basis, until the slaughter weights (405, 450 and 500 kg LW). At slaughter the empty body weight was determined. There were no differences among breeds or slaughter weights on the traits studied, except for whole "alcatra" cut yield. For this trait there was a interaction effect between breed and category. The yield decreased in Gyr breed, as slaughter weight increased, but did not change in the other breeds. There were no differences among breeds regarding to any one of the physical composition. Slaughter weight did not influence carcass physical composition and loin eye area, however affected the carcass length and back fat thickness.