RESUMO A composição da carne bovina é influenciada diretamente pela gordura da dieta, principalmente em ruminantes, devido à biohidrogenação ruminal, que promove alterações no perfil de ácidos graxos dietéticos e afeta a qualidade da carne. Foram avaliadas às composições sensoriais, químicas e de ácido graxo da carne, da gordura intramuscular e subcutânea, de 40 machos Nelore terminados em dieta de confinamento contendo caroço de algodão (CSB) e subproduto de soja (SOB) como fontes de gordura de subprodutos agroindustriais. CSB, não alterou o pH da carne, força de cisalhamento, composição química ou perfil de ácido graxo subcutâneo em comparação com a dieta SOB. Diferenças foram observadas na cor amarela e vermelha da carne bovina, com baixa e alta inclusão de CSB na dieta; a inclusão de SOB na dieta levou a um aroma intensamente desagradável em carnes envelhecidas e cozidas. Em relação ao perfil de ácido graxo da carne bovina, CSB com 3% de gordura dietética produziu bifes com menor proporção de C 17: 0 , tendo 1.359 e 3.238 g / 100 g de ácido graxo intramuscular, enquanto CSB com 5% de gordura dietética levou a um aumento de C 18: 2n- 6 , com 0,298 e 0,132 g / 100 g de ácido graxo intramuscular em bifes de animais alimentados com CSB e SOB, respectivamente. CSB produziu cor vermelha bovina mais intensa, aroma desagradável e maior teor de ácido linoléico; entretanto, a cor e o aroma da carne produzida em bovinos alimentados com CSB na dieta foram menos intensos e semelhantes aos observados em bovinos alimentados com SOB; estes poderiam, portanto, ser recomendados para uso como subprodutos agroindustriais na dieta de bovinos de corte.

ABSTRACT Beef composition are directly influenced by the dietary fat, particularly in ruminants, due to rumen biohydrogenation, which promotes alterations in the dietary fatty acid (FA) profile and affects the meat quality. Beef sensorial, chemical, and FA compositions of intramuscular and subcutaneous fat were evaluated, from 40 Nellore males finished on feedlot diet based, containing cottonseed (CSB) and soybean by-product (SOB) as agro-industrial by-product fat sources. CSB as a fat source, did not alter the beef pH, shear force, chemical composition, or subcutaneous FA profile compared with the SOB diet. Differences were observed at yellow and red beef color, with low and high CSB diet inclusion; on the contrary, inclusion of SOB in the diet led to an intensely unpleasant aroma in aged and cooked meats. Regarding beef FA profile, CSB with 3% dietary fat produced steaks with a lower proportion of C 17:0 , having 1.359 and 3.238 g/100 g of intramuscular FA, whereas CSB with 5% dietary fat led to an increase in C 18:2 n -6 , with 0.298 and 0.132 g/100 g of intramuscular FA in steaks from animals fed with CSB and SOB, respectively. CSB produced more intense red beef color, unpleasant aroma, and higher linoleic acid content; however, the color and aroma of the meat produced from cattle fed with CSB in the diet were less intense and were like those observed in cattle fed with SOB; these could therefore be recommended for use as agro-industrial by-products in beef cattle diet.

ABSTRACT This study examined the replacement of maize and soybean meal with cassava chips and alfalfa grazing, respectively. Twelve lactating Anglo-Nubian goats were kept on a Panicum maximum cv. Tobiatã pasture. The experiment was laid out in a Latin square design in which the following diets were tested: ground maize + soybean meal, cassava chips + soybean meal, ground maize + alfalfa grazing, and cassava chips + alfalfa grazing. The evaluated variables were feed intake, daily weight gain, milk yield and composition, and feeding behavior of the goats as well as production costs. Cassava chips and grazed alfalfa influenced the intakes of dry matter, crude protein, neutral detergent fiber, and total digestible nutrients. However, milk yield, body weight, and body score did not change. There was no diet effect on the proportions of protein, solids-not-fat, somatic cell count, or urea nitrogen in the milk. Treatments influenced the levels of fat, lactose, and total solids in milk, with the highest fat levels achieved with diets containing alfalfa. Grazing, rumination, and idle times and time spent interacting with other goats were not influenced by diets. The evaluated feedstuffs improved feed efficiency and reduced production costs. Therefore, cassava chips and alfalfa can replace certain ingredients without impairing the production performance of goats, but rather improving the profit of the producer.

RESUMO O experimento foi conduzido para avaliar a cana-de-açúcar in natura em substituição à silagem de milho no consumo de matéria seca, parâmetros ruminais e cinética de degradação de forragens e concentrado em cabras adultas em mantença. Quatro cabras não lactantes canuladas no rúmen foram utilizadas em um delineamento em quadrado latino 4 × 4 com a substituição de 0, 33, 67 e 100% da silagem de milho por cana-de-açúcar. A substituição da cana-de-açúcar pela silagem de milho não afetou o consumo de matéria seca, o ganho de peso diário e o pH ruminal. Foi observado efeito quadrático para a concentração de nitrogênio amoniacal com concentração máxima de 74,43% de inclusão da cana, e também para ácidos graxos de cadeia curta, com concentrações máximas de acetato e butirato de 0,59 e 32,70% de inclusão da cana, respectivamente. A concentração mínima de propionato foi verificada em 10,36% de inclusão de cana-de-açúcar. No entanto, a relação acetato: propionato diminuiu linearmente com o aumento do teor de cana-de-açúcar. Não foi observado efeito de diferentes ambientes ruminais sobre a degradabilidade da matéria seca da forragem e da fibra em detergente neutro. A degradabilidade da matéria seca foi de 66,79% para a cana-de-açúcar e 72,62% para a silagem de milho após 96 h de incubação. A fibra em detergente neutro foi 37,10 e 51,82% para cana-de-açúcar e silagem de milho, respectivamente, após 96 h de incubação. Em conclusão, a cana-de-açúcar pode ser usada como substituto da silagem de milho na alimentação de cabras adultas de manutenção, sem alterar o consumo de matéria seca e a degradabilidade da forragem, aumentando a produção de propionato.

ABSTRACT The trial was conducted with the objective to evaluate fresh sugarcane as a replacement for corn silage on dry matter intake, ruminal parameters (pH, short chain fatty acids, and ammonia nitrogen concentration), and degradation kinetics of forages and concentrate in maintenance adult goats. Four nonlactating ruminally cannulated goats were used in a 4 × 4 Latin square design with the replacement of 0, 33, 67, and 100% of corn silage by sugarcane as the independent variable. The substitution of sugarcane for corn silage did not affect dry matter intake, daily weight gain, or ruminal pH. A quadratic effect was observed for ammonia nitrogen concentration with a maximum concentration at 74.43% of sugarcane inclusion, as well as for short chain fatty acids, with maximum concentrations of acetate and butyrate at 0.59 and 32.70% of sugarcane inclusion, respectively. The minimum concentration of propionate was verified on 10.36% of sugarcane inclusion. However, the acetate:propionate ratio linearly decreased with increased sugarcane content. No effect was observed of different rumen environments on forage dry matter and neutral detergent fiber degradability (effective and potential degradability, soluble and potential degradable fractions). Dry matter degradability was 66.79% for sugarcane and 72.62% for corn silage after 96 h of incubation. Neutral detergent fiber was 37.10 and 51.82% for sugarcane and corn silage, respectively, after 96 h of incubation. In conclusion, sugarcane can be used as a replacement for corn silage in maintenance adult goats feed without altering dry matter intake and forage degradability while increasing propionate production.

ABSTRACT The objective of this study was to evaluate the inclusion of vegetable oils in goat kid diets on performance, carcass traits, and meat composition, quality, and fatty acid profile. Forty-eight Anglo Nubian kids were evaluated in a completely randomized experimental design with four treatments, namely, control diet and diets including 2.5% canola, sunflower, or soybean oils. The animals were slaughtered at 30 kg live weight and performance, carcass and meat quality, centesimal composition, and fatty acid profile were evaluated. The treatments did not influence carcass yield or meat color. Among the saturated fatty acids, only caprylic, palmitic, and heptadecanoic acids differed among the treatments, whereas total saturated fatty acids decreased in the sunflower oil treatment. Monounsaturated fatty acids were not influenced by lipid supplementation. Among the polyunsaturated fatty acids (PUFA), linoleic acid was highest in the sunflower oil-treated group. Total PUFA were higher for the soybean oil-supplemented group, but similar to that achieved with sunflower oil. The highest omega-6 content was obtained with dietary inclusion of sunflower oil, whereas conjugated linoleic acid, atherogenicity index, and hypocholesterolemic:hypocholesterolemic ratio improved with the inclusion of sunflower and soybean oils. Supplementation with vegetable oils improves the fatty acid profile of kid meat without affecting animal performance. Better results are obtained with sunflower and soybean oils; therefore, it is up to the producer to choose the diet according to its cost.

ABSTRACT The objective of this study was to evaluate the intake and ruminal parameters of goats fed diets supplemented with vegetable oils. Four rumen-cannulated Saanen goats were allocated to four treatments, which consisted of a control diet and diets with the inclusion of 30 g of canola, sunflower, or soybean oils per kilogram of diet dry matter (DM). The experiment lasted 40 days, which were divided into four 10-day periods. Forage intake was estimated using chromium oxide as an external marker, and supplement intake was determined as the difference between the daily amount supplied and orts. Rumen fermentation parameters were evaluated from samples of rumen fluid collected every 2 h, for 12 h. Rumen pH and short-chain fatty acid and ammonia nitrogen concentrations were measured. There was no effect of lipid supplementation on DM intake. Ether extract intake was highest in the treatments with oil inclusion, and the highest acid detergent fiber intake was obtained with the diet containing canola oil. The pH was highest in the group fed soybean oil and responded quadratically to the collection times. Total short-chain fatty acid and acetic acid concentrations also responded quadratically to the collection times. Propionic and butyric acid concentrations and acetic:propionic acid ratio showed a cubic behavior with the increasing collection times. Canola, sunflower, or soybean oils can be included at 30 g/kg of the diet DM as a strategy to increase the energy density of goat diets.

ABSTRACT We aimed to evaluate the inclusion of three sources of vegetable oil in the diet of lactating goats on production in 120 days of lactation and the effect of these sources and lactation stage on fortnightly composition and fatty acid profile of goat milk at 20, 50, 80, and 110 days of lactation. A completely randomized design was adopted and 32 Anglo Nubian goats were used, distributed in four treatments: control diet and diets with inclusion of 30 g/kg of dry matter of diet of canola, sunflower, or soybean oil. The dairy production was 182.75 kg, and there was no difference for treatments. Among the constituents, only urea nitrogen was influenced by treatment and presented lower content for control treatment. Day of lactation had an effect on lactose. Defatted dry extract and somatic cell count had a quadratic effect with minimum values around 100 and 33 days of lactation, respectively. The content of urea nitrogen, also with a quadratic effect, was higher at 93 days of lactation. For protein, there was an interaction between treatments and period and, at the end of lactation, its content was increased. The inclusion of vegetable oils promoted reduction in total saturated fatty acids (SFA) and increased the total content of monounsaturated fatty acids (MUFA) and conjugated linoleic acid. The proportions MUFA:SFA and PUFA:SFA, the atherogenicity and thrombogenicity indexes, and the relation hypocholesterolemic fatty acids:hypercholesterolemic fatty acids improved with oil addition in animal diets. The addition of vegetable oil to diets for lactating goats improve the fatty acid profile with no impairment on milk production and composition, and the milk from early stages of lactation has better nutritional quality of the lipid fraction.

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.

ABSTRACT This study was conducted to investigate the effect of selective feeding habits on the quality of the ingested diet and the effect of feed restriction on the selectivity and behavior of goats in feedlots. Differences were found only in the amount of feed given to the animals, with a difference in the amount of feed rejected as a function of the nutritional level. Higher levels of orts were measured for those animals that received the ad libitum diet. For the composition of orts, differences were measured only in the ether extract fraction. Animals fed the ad libitum diet increased their intake of ether extract and energy, crude fiber, neutral detergent fiber, and acid detergent fiber. Thus, they had a preference for consuming the fibrous and energetic portions of the diet to the detriment of the mineral matter. The granulometry influenced the leftovers for the male and female treatments only in the diet that contained the 2.00- and 0.063-mm sized particles, with larger leftovers for the females. There were statistical differences as a function of feeding level for time spent in rumination, with stereotypical behavior, and in time spent standing up or lying down. As a function of sex, the differences were the same variables, including the time spent with agonistic behavior. Animals that received the ad libitum diet had a greater gain and final weight, whereas the animals that received the 60% restricted diet had the lowest performance, as did the females. Feed restriction changed the natural feeding behavior of goats, with smaller feed particles preferred. The feed restriction and sex also influenced the time spent on nonproductive activities, and the animals became more restless, with females having a higher social behavior than males.

The objective of this experiment was to evaluate levels of replacement (0, 33, 67 and 100%) of corn silage with fresh sugarcane in dairy-goat diets on the ingestive behavior of these animals. Eight lactating Alpine goats (after lactation peak) with a live weight of 51.95±3.29 kg were distributed into two 4 × 4 Latin squares according to their milk production. Animals were placed in individual pens where they received diets ad libitum, twice a day, with a roughage:concentrate ratio of 40:60, during 72 days of experiment. The evaluated variables were time spent feeding (TSF), ruminating (TSR), idle (TSI) and chewing (TSC), dry matter intake (DMI), neutral detergent fiber intake (NDFI), feeding efficiency of dry matter (FEDM) and neutral detergent fiber (FENDF), rumination efficiency of dry matter (REDM) and neutral detergent fiber (RENDF), number of ruminal boli per day (NRB) and number of rumination chews per day (NRC). The different treatments had no effect on TSF or TSR. However, a linear effect was observed on TSC. There was a linear effect on TSI, in which the highest value was observed in the treatment with 0% of sugarcane inclusion. A quadratic effect was observed on dry matter intake, with minimum point of 2.14 kg/day for 68.04% of sugarcane inclusion; however, NDFI was not affected by the different treatments. There was no effect of treatments on FEDM, although a quadratic effect was observed on FENDF, wherein the lowest value was observed in the treatment with 67% of sugarcane inclusion. There was no effect of different levels of corn silage replacement on REDM, RENDF, NRB or NRC. Sugarcane can be replaced with corn silage without changing the times spending on feeding and rumination.

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.

Este trabalho foi realizado com o objetivo de avaliar a influência do grupo racial e da condição sexual nas características da carcaça de caprinos jovens criados em confinamento. Foram utilizados 91 animais, 52 machos e 39 fêmeas, pertencentes a cinco grupos raciais: Alpino, ½Boer + ½Alpino, ½Anglo Nubiano + ½Alpino, ¾Boer + ¼Alpino, e ½Anglo Nubiano + ¼Boer + ¼Alpino. Foi tomado o peso ao jejum, no dia do abate, após 24 horas de jejum de sólidos. Foram tomadas medidas biométricas e de carcaça, objetiva e subjetivamente. O grupo racial influenciou a altura de cernelha, o comprimento interno e externo da carcaça e o comprimento de perna, que foram maiores nos animais Alpinos, bem como a largura do peito, o escore corporal, os índices de compacidade da carcaça e da perna e a cobertura de gordura da carcaça, que foram melhores nos animais com grau de sangue Boer. Animais machos tiveram maior altura de cernelha, medidas da estérnebra com ultrassom, comprimento interno da carcaça, comprimento de perna, profundidade dos tecidos na altura da 3ª e 4ª estérnebras tomadas na carcaça. Nas demais características corporais avaliadas, não foram encontradas diferenças entre grupos raciais e sexo dos animais. O cruzamento do grupo Boer com Alpino reduz o comprimento das carcaças e aumenta a cobertura de gordura e a quantidade de tecidos depositados, mas não influencia o desempenho do animal.

This study was carried out with the objective of evaluating the influence of breed groups and sexual conditional on carcass traits of young goats raised in feedlot. It was used 91 animals, 52 males and 39 females, belonging to five breed groups: Alpine, ½Boer + ½Alpine, ½Nubian + ½Alpine, ¾Boer + ¼Alpine and ½ Anglo-Nubian + ¼Boer + ¼Alpine. On the slaughter day, the shrunk weight was measured after 24 hours of solid fasting. Biometric and carcass measures were objectively and subjectively taken. Racial group influenced withers, internal and external carcass length, and leg length, which were greater for Alpine animals, as well as chest width, body condition score, carcass and leg compactness index and fat thickness on carcass, which were better in animals with Boer blood degree. Male animals showed greater withers, measures of sternebrae by ultrasound, internal carcass length, leg length, tissue depth height between 3rd and 4th sternebrae measured on carcass. On the other body evaluated characteristics, it was not found any differences among breed groups and sex of the animals. Crossing Boer with Alpine reduces carcass length, and increases fat thickness and deposited tissue, however, it does not change animal performance.

Este estudo teve como objetivo avaliar a qualidade da carne de cordeiros terminados em regime de confinamento que receberam dietas com diferentes teores de concentrado. Foram utilizados 18 cordeiros ½ Ile de France ½ Santa Inês não castrados, com peso inicial de aproximadamente 15 kg, distribuídos em dois lotes, representados pelo tratamento 1 (T1) animais que receberam na dieta relação volumoso:concentrado de 35:65 e (T2) cordeiros que receberam relação volumoso:concentrado de 65:35 até atingirem 32 kg de peso corporal em regime de confinamento, peso pré-determinado para o abate dos animais. Os cordeiros do tratamento 1 e 2 apresentaram valores similares de pH, força de cisalhamento, perdas por cocção e capacidade de retenção de água da carne, com valores médios de 5,70, 1,03 kgf/cm², 35,20 e 59,31%, respectivamente. A relação volumoso:concentrado não influenciou na qualidade centesimal da carne dos cordeiros alimentados com dietas mais concentradas ou mais volumosas, para umidade, proteína, extrato etéreo e matéria mineral. Concluiu-se que os cordeiros terminados em confinamento recebendo diferentes teores de concentrado na dieta apresentaram qualidade da carne similar; portanto, a escolha da dieta vai depender do custo dos ingredientes no momento do confinamento.

The objective of this study was to evaluate the meat quality of lambs terminated in confinement and fed diets with different concentrate contents. 18 non-castrated ½ Ile de France ½ Santa Inês lambs were used. Their initial weight was approximately 15 kg and they were divided into two separate groups represented by Treatment 1 (T1) - animals fed with diets containing the ratio voluminous:concentrate 35:65 - and Treatment 2 (T2) - lambs fed with diets containing the ratio voluminous:concentrate 65:35 until reaching 32 kg of body weight in confinement, which is the pre-established weight for slaughtering. T1 and T2 lambs presented similar values for pH, shear force, losses due to cooking and water retention capacity; the average values found were 5.70, 1.03 kgf/cm², or 35.20, and 59.31%, respectively. The voluminous:concentrate ratio did not influence the centesimal quality of meat of lambs fed with more concentrated or more voluminous diets for humidity, protein, ethereal extract, and mineral matter. It can be concluded that lambs terminated in confinement fed with different concentrate contents diets presented similar meat quality; therefore, the diet choice depends on the cost of the ingredients at the time of the confinement.

Objetivou-se avaliar o efeito da suplementação com cromo complexado à molécula orgânica do suplemento no desempenho produtivo, nas características de carcaça e na qualidade da carne de bovinos terminados em regime de pastagem. Foram utilizados 18 bovinos Nelore e 18 F1 Brangus × Nelore castrados, com 16 meses de idade, mantidos com suplementação mineral protéica, com ou sem cromo complexado à molécula orgânica e abatidos aos 22 meses de idade. O ganho médio diário de peso vivo (GMD) não diferiu entre grupos genéticos, entretanto animais mantidos com suplemento contendo cromo apresentaram maior GMD (494 g) em comparação aos demais (420 g). A adição de cromo orgânico no suplemento não promoveu alterações na área de olho-de-lombo (63,42 cm²) e na espessura de gordura subcutânea do dorso (5,46 mm) e da garupa (5,58 mm), tomados por meio do ultra-som. O peso médio de carcaça quente foi 235 kg e o rendimento médio de carcaça quente, 52,09%, com superioridade do suplemento contendo cromo (238 kg e 52,9%) em relação ao controle (231 kg e 51,2%). Animais Nelore e F1 Brangus × Nelore apresentam potencial similar de produção de carne a pasto. A suplementação mineral protéica com adição de cromo complexado à molécula orgânica aumenta o ganho de peso e o rendimento de carcaça, mas não influencia os parâmetros qualitativos da carne.

The present work was aimed to evaluate the effect of mineral protein supplementation with addition of chromium attached to the organic molecule on the productive performance, carcass traits and beef quality in steers finished under grass conditions. For this, 18 Nellore and 18 F1 Brangus × Nellore steers were used, with 16 months of average initial age and slaughtered at 22 months, distributed equally into two treatment of mineral protein supplementation with and without addition of chromium attached to the organic molecule. There was no observed difference between genetic groups regarding the average daily gain (ADG). However, animals supplied with chromium showed better ADG (494 g) than control animals (420 g). There was no observed difference between experimental treatments regarding the rib eye area, subcutaneous fat thickness at the back and rump measured through ultrasound, reaching final mean values of 63.42 cm²; 5.46 and 5.58 mm, respectively. It was observed an average of 235 kg for hot carcass weight and 52.09% for dressing percentage, with a superiority for the chromium treatment (238 kg and 52.9%) versus control (231 kg and 51.2%), and without difference between genetic groups. Nellore and F1 Brangus × Nellore steers show equal beef production potential under grass conditions. Mineral protein supplementation with chromium attached to the organic molecule increases the weight gain and dressing percentage, not influencing the beef quality parameters evaluated in this study.