Twenty-eight Brangus cattle were used to determine the effect of copper and selenium supplementation on performance, feed efficiency, composition of fatty acids in Longissimus dorsi (LD) muscle, and cholesterol concentration in serum and in LD muscle and enzymes activities, reduced glutathione (GSH) and oxidized glutathione (GSSG). The treatments were: i) Control, without copper (Cu) and selenium (Se) supplementation; ii) Se, 2 mg Se/kg of dry matter such as sodium selenite; iii) Cu, 40 mg Cu/kg of dry matter such as copper sulfate; iv) Se/Cu, 2 mg Se/kg of dry matter such as sodium selenite and 40 mg Cu/kg of dry matter such as copper sulfate. LD muscle fatty acid composition was not influenced by the treatments (p>0.05). The serum concentration of cholesterol was not influenced by the treatments (p>0.05), however, the concentration of cholesterol in LD was lower in cattle supplemented with copper and selenium (p<0.05). Oxidized glutathione and reduced glutathione increased (p<0.05) with Cu, Se and Se/Cu supplementation. The supplementation of copper (40 mg/kg DM) and selenium (2 mg/kg DM) altered the metabolism of lipids in confined Brangus cattle, through a decrease in cholesterol deposition in the LD, possibly by changing the ratio between reduced glutathione/oxidized glutathione. Copper and selenium supplementation improved animal performance and feed efficiency (p<0.05) when compared to the control group, providing advantages in the production system, while also benefiting consumers by reducing cholesterol concentration in the meat.

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Milk and its derivatives are important foods that contribute to daily nutrient requirements and improve consumers’ health. This study evaluated the effects of supplementing the diet of lactating dairy cows with sunflower oil (SFO), selenium, and vitamin E on the milk’s fatty acid profile and fat oxidative stability as well as the acceptability of the milk by consumers. For this purpose, 32 Jersey dairy cows were allocated to four treatment groups for 60 days, as follows: C (control diet); A (3.5 mg/kg DM (dry matter) organic selenium + 2000 IU vitamin E/cow per day); O (4% SFO DM); OA (equal doses of A and O treatments). The inclusion of SFO decreased the contents of 10:0, 10:1, 11:0, 12:0, 12:1, 14:0, and 9c-14:1 fatty acids as well as odd- and branched-chain fatty acids (13:0, iso 13:0, anteiso 13:0, 15:0, iso 15:0, and 17:0). There was also a tendency for 8:0 and 16:0 fatty acid concentrations to decrease when SFO was included in the cows´ diet. SFO decreased the concentration of 10:0 to 15:0 fatty acids in milk. The sum of the conjugated linoleic acids (CLAs), conjugated alpha-linolenic acid intermediates (CLnAs; 18:3 ω6 + 18:3 ω3), and 22:0 fatty acids in milk tended to increase, and there were significant increases in 18:0 and 9c11t-18:2 with SFO. In terms of the effects of SFO on the health-related lipid indices, the atherogenicity index tended to decrease and h/H tended to increase. When cows were supplemented with antioxidants, the concentration of 20:2 fatty acids decreased, the 6 + 7 + 8 + 9t-18:1, 16t-18:1, 20:0, 22:2, and 24:0 fatty acid concentrations increased, and there was a trend for the 22:1 ω9 fatty acid concentration to increase with antioxidants plus oil. There was a tendency for ω6 fatty acids and ω6/ω3 to increase with milk treated with antioxidants plus oil. The oxidative stability of milk was not influenced by the presence of SFO or antioxidants in the diet of dairy cows. Consumers desired the color and mouthfeel of the milk that was treated with SFO. Cows fed with 4% sunflower oil produced milk with an improved fatty acid profile for human nutrition, containing a higher CLA content and an improved ratio of hypocholesterolemic and hypercholesterolemic fatty acids, without increasing the milk’s susceptibility to oxidation. The milk was also rated as being more acceptable by consumers.

RESUMO -O presente trabalho foi realizado com o objetivo de estudar a substituição do milho em grão moído pela polpa cítrica no concentrado de 28 bezerros da raça holandesa (PC) durante a fase de aleitamento. O delineamento experimental foi em blocos ao acaso, sendo os blocos formados de acordo com a ordem de chegada dos animais. Os animais foram abatidos ao final do experimento. Foram empregados quatro tratamentos: 0, 15, 30 e 45% de polpa cítrica na ração, em substituição ao milho. Todos os animais receberam o colostro por três dias na fazenda de origem. Além do concentrado, os bezerros receberam diariamente quatro litros de leite integral no primeiro mês, divididos em duas refeições, e três litros no segundo mês, em uma única refeição. O concentrado foi oferecido aos bezerros a partir do quarto dia de vida. Todos os bezerros foram mantidos em abrigos individuais. Os parâmetros avaliados foram: ganho de peso diário, consumo de matéria seca, conversão alimentar, aumentos da altura na cernelha e do perímetro torácico, volume e peso dos compartimentos estomacais, desenvolvimento papilar, contagem de protozoários, pH ruminal e incidência de diarréias. Não houve diferença significativa entre tratamentos para os parâmetros estudados. Concluiu-se que a polpa cítrica pode substituir o milho em grão moído na dieta peletizada contendo 5% de leite em pó, para bezerros desmamados precocemente, com bons resultados.Palavras-chave: bezerros, concentrado inicial, polpa cítrica Substitution of the Corn Grain Ground by Citric Pulp in the Early Weaning of Dairy CalvesABSTRACT -The present study was carried out to study the substitution of the ground corn grain by the dried citrus pulp in the starter diet of 28 Holstein calves in an early weaning system. The experimental design was in completely randomized blocks, with the blocks formed in accordance to the arrival order of the animals. The animals were slaughter at the end of the experiment. The experiment consisted on four treatments: 0, 15, 30 and 45% of citrus pulp in the diet, in substitution of the ground corn grain. The calves received the colostrum for three days in the original farm. Besides the concentrate, the calves received four liters of whole milk in the first month, divided in two meal, and three liters in the second month. The concentrate was fed ad libitum fed to the calves from the fourth life day. All calves were kept in individual houses. The evaluated parameters were: average daily gain, dry matter intake, feed:gain ratio, increases of the withers height and of the heart girth, volume and weight of the stomach compartments, development of rumen papillas, number of protozoa, pH and incidence of diarrhea. There was no significant difference among treatments. The dried citrus pulp can substitute the ground corn grain in the diet of early weaned calves, with good results. cidindo com a escassez de forragens. Devido a essas facilidades e aos possíveis custos menores que o milho, e por ser um alimento de boa palatabilidade e alta digestibilidade, a polpa cítrica e...

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-In order to evaluate the effect of environmental temperature on ruminal fermentation and on mineral levels of growing ruminants, it was used 12 male calves (initial average weight 82.9 ± 7.7 kg, 100 days of age), were employed in a randomized block design (by weight) experiment, with repeated weight measurement and two environmental temperatures: thermoneutral (24°C) and heat-stressed (33°C), during 38 days. The animals exposed to 33°C presented lower dry matter ingestion, lower T 3 (triiodothyronine) serum level, higher ammoniacal nitrogen (NH 3 -N) level in the rumen liquid, and higher rectal and body temperatures during all the experimental period when compared to the animals kept in thermoneutral environment (24°C). The animals kept under heat stress environment (33°C) presented higher calcium serum level, which was the highest on 31st day and the lowest on the 38th day of the experiment; phosphorus level was the lowest during all the experimental period; sodium level was lower on the 17th, 31st and 38th experimental days. Potassium and zinc levels were lower after 24 days; copper level was lower until the 24th day; magnesium level was higher until the 17th day, if compared to the ones from the animals kept in thermoneutral environment (24°C). The heat-stressed animals presented higher levels of ammoniacal nitrogen in the ruminal liquid and a decrease in the phosphorus, sodium, potassium and zinc serum levels. These results show the necessity of changes on feed management to ruminants in temperatures over the thermal comfort limits so that performance loss is decreased.Key Words: ammoniacal nitrogen, dry matter ingestion, heat stress, macromineral, micromineral, volatile fatty acids Mudança na fermentação ruminal do alimento e na concentração sérica de minerais em animais mantidos em ambientes de alta temperatura RESUMO -Para verificar o efeito da temperatura ambiente na fermentação ruminal do alimento e nas concentrações de minerais em bovinos em crescimento, foram utilizados 12 bezerros machos (peso médio inicial de 82,9 ± 7,7 kg com 100 dias de idade), durante 38 dias, em delineamento experimental de blocos ao acaso, com medidas repetidas no tempo e duas temperaturas ambiente: ambiente termoneutro (24°C) e ambiente de estresse por calor (33°C). Os animais expostos à temperatura de 33°C tiveram ingestão menor de matéria seca, menor nível sérico de T 3 (triiodotironina), maior concentração de nitrogênio amoniacal (NH 3 -N) no líquido ruminal e maior temperatura retal e corporal em todo o período experimental em comparação àqueles animais mantidos no ambiente termoneutro (24°C). Os animais em ambiente de estresse por calor (33°C) apresentaram maior concentração de cálcio no soro, que foi maior aos 31 dias de experimentação e menor aos 38 dias. A concentração de fósforo nesses animais foi menor durante todo o período experimental e a de sódio, menor aos 17, 31 e 38 dias de experimentação. As concentrações de potássio e zinco foram menores depois de 24 dias; a de cobre menor até 24 dias; e a de magné...

Quatorze bezerros com quatro meses de idade, foram distribuídos em dois tratamentos, sendo um controle e um com suplementação de 0,4 mg de cromo orgânico por kg/M.S de ração basal. A ração basal foi constituída de 52% de feno de coastcross e 48% de concentrado à base de fubá de milho e soja extrusada, e foi oferecida ao animais durante 98 dias. Foi efetuado o controle diário da ingestão de alimentos. Na última semana foi realizado um teste de tolerância à glicose, com os animais em condições de conforto térmico. Para os grupos controle e tratado , o ganho em peso (1,330 e 1,320 kg/dia), a eficiência alimentar (0,24 e 0,25 kg) e a conversão alimentar (4,13 e 4,07 kg), foram semelhantes. Apesar de o grupo tratado apresentar tendência de eliminar a glicose mais rapidamente, os grupos não diferiram entre si.

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