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ResumoO milho cultivado para forragem requer cuidados especiais de manejo do solo. A exportação de nutrientes pela silagem pode causar redução na fertilidade do solo, com consequente redução na produtividade e qualidade nutricional das culturas posteriores. O objetivo do trabalho foi avaliar os teores de macronutrientes nos fragmentos de plantas de milho (colmo, folhas, brácteas mais sabugo e grãos) no estádio de ensilagem, na planta inteira (forragem na ensilagem) e nos grãos maduros; mensurar a exportação dos nutrientes do solo pela colheita da forragem ou pelos grãos. Posteriormente, foram empregadas duas dietas para bovinos confinados, uma a base de silagem e outra baseada em grãos, para mensurar o potencial de retorno dos nutrientes para o solo via esterco, e contabilizar o balanço final dos nutrientes. Os teores de N, P, K, Ca e Mg na forragem foram, respectivamente: 1,37; 0,24; 0,81; 0,2 e 0,22%; e nos grãos: 1,8; 0,28; 0,34; 0,12; e 0,11%. A adubação realizada foi suficiente para suprir a remoção de nutrientes quando se colheu somente grãos, gerando déficits ao solo de 93 kg ha -1 de N e 84 kg ha -1 de K quando se colheu a forragem. Os estercos de animais alimentados com silagem + concentrado, comparativamente à dieta sem volumoso (80% de grãos), reciclaram diferentes quantidades (kg ha -1 ) de N (276,28 vs 59,37), P (128,12 vs 33,37), K (58,32 vs 5,38), Ca (177,7 vs 78,89) e Mg (43,64 vs 11,81) para a área cultivada. Os sistemas de produção avaliados apresentaram capacidade de manter os teores de nutrientes no solo com a reposição via esterco, podendo incrementar a fertilidade e reduzir custos com fertilizantes minerais nos cultivos sucessivos. O sistema que utilizou silagem apresentou déficit de 25 kg ha -1 de K, provavelmente pela quantidade insuficiente aplicada, cuja recomendação normalmente é feita visando a produção de grãos. Palavras-chave: Esterco bovino, dieta 100% concentrado, silagem, teor de macronutrientes, Zea mays L. AbstractThe maize cultivated for forage requires special care with soil management. The nutrients exportation by silage might cause reducing of soil fertility, with consequent decrease of yield and nutritional quality of posterior crops. The aim of this work was assess levels of macronutrients in maize plant fragments (stem, leaves, bracts plus cob and grains), at stage of ensilage, in entire plant (silage forage) and in the

O objetivo do estudo foi avaliar o desempenho e as características da carne e da carcaça de novilhos não castrados terminados em confinamento com dieta composta de silagem de milho e concentrado com e sem inclusão de Sacharomyces cerevisie. O confinamento teve duração de 210 dias. Foram utilizados 36 novilhos, destes 18 eram animais Canchim (5/8 Charolês, 3/8 Nelore) e 18 eram animais Brangus (1/2 Angus, 1/2 Canchim), com idade média de 8 meses, peso vivo médio inicial de 250 kg. O delineamento experimental foio inteiramente casualizado, composto por dois tratamentos com seis repetições, em baias com três animais. Não foram constatados efeitos positivos da inclusão de leveduras vivas secas sobre o consumo de matéria seca e sobre o comportamento de novilhos terminados em confinamento. Verificou-se efeito positivo no desempenho dos animais confinados sobre as características relacionadas ao ganho médio diário (1,235 vs. 1,099 kg/dia) e a conversão alimentar (7,22 vs. 7,95 kg de matéria seca ingerida para kg de ganho de peso),demonstrando a eficácia na utilização sobre o tratamento controle. A inclusão de leveduras vivas secas à dieta não gerou alterações nas características da carcaça, na qualidade da carne e nos componentes de rendimento da carcaça na produção de novilhos de corte superjovens.

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Lysolecithin is an antiinflammatory emulsifier associated with improved apparent digestibility of total dietary fat and improved feed efficiency in dairy cattle. However, it is unknown if lysolecithin (LYSO) improves performance in calves. Moreover, since many conventional milk replacers use vegetable-sourced fat (e.g., palm oil), nutrient absorption and fecal score may be affected in neonatal calves. Thus, the objective of this study was to evaluate the effects of LYSO supplemented in milk replacer on performance, metabolites, and gut health of preweaned dairy calves. Holstein calves (n = 32) with adequate passive transfer were assigned in pairs (16 blocks) balanced by birth weight, date of birth, and sex at 1 d of age to randomly receive either LYSO (mixed in 2 milk replacer feedings at a rate of 4 g/d Lysoforte, Kemin Industries Inc., Des Moines, IA) or a milk replacer control (nothing added). Both treatments were fed 6 L/d milk replacer [22.5% crude protein, 16.2% crude fat (vegetable oil fat source) on a dry matter basis with 14% solids] by bucket in 2 daily feedings for 56 d. Calves were individually housed in wooden hutches and offered a commercial calf starter (24.6% crude protein and 13.9% neutral detergent fiber) and water by bucket ad libitum. Feed refusals and calf health was assessed daily. Weights and blood metabolites (glucose, total serum protein, albumin, creatinine, triglycerides, and cholesterol) were sampled weekly, and calves completed the study before weaning at 56 d of age. The effects of LYSO on calf average daily gain, feed efficiency, and blood metabolites were evaluated using a linear mixed model with time as a repeated measure, calf as the subject, and block as a random effect in SAS (SAS Institute Inc., Cary, NC). The effect of LYSO to improve the odds of abnormal fecal score was evaluated using a logistic model. Supplementation of LYSO increased average daily gain (control 0.28 ± 0.03 kg; LYSO 0.37 ± 0.03 kg; least squares means ± standard error of the mean) and increased feed efficiency (gain-to-feed; control 0.25 ± 0.03; LYSO 0.32 ± 0.03). Similarly, LYSO calves had a higher final body weight at d 56 (control 52.11 ± 2.33 kg; LYSO 56.73 ± 2.33 kg). Interestingly, total dry matter intake was not associated with LYSO despite improved average daily gain (total dry matter intake control 1,088.7 ± 27.62 g; total dry matter intake LYSO 1,124.8 ± 27.62 g). Blood glucose, albumin, creatinine, triglycerides, and cholesterol were not associated with LYSO. Indeed, only total serum protein had a significant interaction with LYSO and age at wk 5 and 6. Moreover, control calves had a 13.57 (95% confidence interval: 9.25-19.90) times greater odds of having an abnormal fecal score on any given day during the diarrhea risk period from d 1 to 28. The inclusion of LYSO as an additive in milk replacer in a dose of 4 g/d may improve performance, and calf fecal score, preweaning. Further research should investigate the mechanisms behind the effects of LYSO on fat digestibility in calves fed 6 L/d of mil...

Tropical grass hay feeding is related to improved ruminal health; however, it may decrease energy intake. On the other hand, whole-flint corn grain may be an alternative fiber source in the diet of dairy calves. Forty-two Holstein calves were used in a randomized block design, considering sex, birth date, and weight at 21 d of age, when the supply of whole-flint corn grain or tropical grass hay started. Three component-fed solid diets were compared: (1) starter concentrate only during the preweaning and starter concentrate with free choice of chopped Tifton-85 hay postweaning (SC), (2) starter concentrate with free choice of chopped Tifton-85 hay pre-and postweaning (SCH), and (3) starter concentrate with free choice of whole-flint corn grain pre-and postweaning (SCW). The animals were evaluated from 21 to 84 d of age. Calves were managed equally during the first 21 d, fed with 6 L/d of whole milk and a commercial starter concentrate (46% nonfiber carbohydrates, small particles, and pelleted) ad libitum. After that, milk feeding was reduced to 4 L/d until gradual weaning at 56 d of age. At 56 d of age, 4 animals per treatment were randomly chosen to be slaughtered for digestive tract weight evaluation and to collect tissue for histological analysis of the ruminal wall, duodenum, and cecum, whereas the other 30 animals were weaned and evaluated for a further 22 d when the SC diet also received hay ad libitum. Feed intake was measured daily. Weight gain and metabolic indicators of intermediate metabolism were evaluated weekly. Ruminal fluid was collected at wk 6, 8, 10, and 12 of age. The SCH diet increased the total and starter dry matter intake, and consequently, the average daily gain and body weight at 56 d of age. The SCW diet promoted an increase in propionate and decreased acetate-to-propionate ratio. Morphometric variables were affected by the SCH diet. The postweaning performance was unaffected by solid diets; however, the SCW diet decreased ruminal and fecal pH. Feeding hay, starting at 21 d of age, can stimulate early solid diet intake, promoting better performance and ruminal and intestinal development, when a highly fermentable and small particle pelleted starter is fed.

The weaning process may cause intense stress for dairy calves, even when low volumes of liquid diet are fed. Management tools that increase the intake of solid feeds, such as gradual weaning, can provide better physiological and metabolic conditions through better adoption of gradual weaning is not effective in improving performance when a calf has low intake 3 wk before weaning is complete, but it reduced vocalization on d 2 postweaning.

This study aimed to evaluate mechanical and chemical methods of forage dehydration in the production of black oat pre-dried silage (Avena strigosa Schreb) under different dehydration times. The experiment was conducted in a randomized block experimental design with five replications and arranged in a 2 x 6 factorial scheme. We assessed two methods of dehydration, mechanical and chemical, over six dewatering times, being made at 0, 3, 6, 9, 12, and 15 days after cutting or application of glyphosate. Harvest took place at 88 days after emergence, at pre-flowering. We evaluated dry biomass production at harvest, dry matter losses during dehydration in the field, losses during ensiling, gauging effluent output, and pre-dried silage chemical composition. There was an interaction between dehydration method and harvest time for most of the production characteristics. Chemical dehydration showed an enhanced dry matter recovery at the field level, however, unsuitable for pre-dried silage. The longer the dehydration period, the lower the losses for both analyzed methods; nevertheless, the chemical method reached unsatisfactory DM contents to produce good quality silage. Key words: Avena strigosa Schreb. Bromatology. Winter cereals. Conserved forage. Dry matter recovery. ResumoObjetivou-se avaliar a interferência dos métodos mecânico e químico de desidratação da forragem na confecção de silagem pré-secada de aveia-preta (Avena strigosa Schreb), sob diferentes tempos de desidratação. O experimento foi realizado em delineamento de blocos ao acaso, com 5 repetições, em esquema fatorial 2 x 6, sendo dois métodos de desidratação, mecânico e químico, sobre seis tempos de desidratação, sendo 0, 3, 6, 9, 12 e 15 dias após o corte ou aplicação do herbicida glifosato. A colheita se deu aos 88 dias após emergência, em estádio de pré-florescimento. Foram avaliadas produção de fitomassa seca no momento da colheita, perdas de fitomassa seca durante a desidratação à campo, perdas durante a ensilagem, com aferição da produção de efluentes, além da composição bromatológica da silagem pré-secada. Houve interação entre método de desidratação x época de colheita, para a maioria