In order to integrate and analyze knowledge on the use of protein supplements and protein nutrition of lactating dairy cows, we compiled a review of 108 studies published throughout the world, but principally in the Journal of Dairy Science between 1985 and 1997. In 29 comparisons from 15 metabolism trials, soybean meal was replaced by high amounts of rumen undegradable protein (RUP) as a supplement; the benefits were not consistently observed for flow to the duodenum, essential amino acids, or lysine and methionine. High RUP diets resulted in decreased microbial protein synthesis in 76% of the comparisons. However, fish meal provided a good balance of lysine and methionine when calculated as a percentage of total essential amino acids. In 127 comparisons from 88 lactation trials that were published from 1985 to 1997, researchers studied the effects of replacing soybean meal with high RUP sources, such as heated and chemically treated soybean meal, corn gluten meal, distillers grains, brewers grains, blood meal, meat and bone meal, feather meal, or blends of these sources; milk yield was significantly higher in only 17% of the comparisons. Fish meal and treated soybean meal accounted for most of the positive effects on milk yield from RUP; corn gluten meal resulted in mostly negative results. The percentage of fat in milk was depressed more by fish meal than by other RUP sources. Protein percentage was decreased in 28 comparisons and increased in only 6 comparisons, probably reflecting the decrease in microbial protein synthesis, as was observed for diets high in RUP. The data strongly suggest that increased RUP per se in dairy cow diets, which often results in a decrease in RDP and a change in absorbed AA profiles, does not consistently improve lactational performance.

Two experiments were conducted to evaluate the performance responses of finishing feedlot cattle to dietary addition of essential oils and exogenous enzymes. The treatments in each experiment consisted of (DM basis): MONsodium monensin (26 mg/kg); BEO-a blend of essential oils (90 mg/kg); BEO+MON-a blend of essential oils plus monensin (90 mg/kg + 26 mg/ kg, respectively); BEO+AM-a blend of essential oils plus exogenous α-amylase (90 mg/kg + 560 mg/kg, respectively); and BEO+AM+PRO-a blend of essential oils plus exogenous α-amylase and exogenous protease (90 mg/kg + 560 mg/kg + 840 mg/kg, respectively). Exp. 1 consisted of a 93-d finishing period using 300 Nellore bulls in a randomized complete block design. Animals fed BEO had higher DMI (P < 0.001) but similar feed efficiency to animals fed MON (P ≥ 0.98). Compared with MON, the combination of BEO+AM resulted in 810 g greater DMI (P = 0.001), 190 g greater average daily gain (P = 0.04), 18 kg heavier final body weight (P = 0.04), and 12 kg heavier hot carcass weight (P = 0.02), although feed efficiency was not significantly different between BEO+AM and MON (P = 0.89). Combining BEO+MON tended to decrease hot carcass weight compared with BEO alone (P = 0.08) but not compared with MON (P = 0.98). Treatments did not impact observed dietary net energy values (P ≥ 0.74) or the observed:expected net energy ratio (P ≥ 0.11). In Exp. 2, five ruminally cannulated Nellore steers were used to evaluate intake, apparent total tract digestibility of nutrients, and ruminal parameters in a 5 × 5 Latin square design. Feeding BEO increased the total tract digestibility of CP compared to MON (P = 0.03). Compared to MON, feeding the combination of BEO+MON increased the intake of CP (P = 0.04) and NDF (P = 0.05), with no effects on total tract digestibility of nutrients (P ≥ 0.56), except for a tendency (P = 0.09) to increase CP digestibility. Intakes of all nutrients measured, except for ether extract (P = 0.16) were greater in animals fed BEO+AM when compared with MON (P ≤ 0.03), with no differences on total tract nutrient digestibilities (P ≥ 0.11) between these two treatments. In summary, diets containing the BEO used herein enhanced DMI of growing-finishing feedlot cattle compared with a basal diet containing MON without impair feed efficiency. A synergism between BEO and AM was detected, further increasing cattle performance and carcass production compared to MON.

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Quatro vacas lactantes, em arranjo fatorial 2x2, no delineamento Quadrado Latino 4x4, receberam os seguintes tratamentos: milho moído grosso; milho floculado; moído grosso + polpa cítrica; floculado + polpa cítrica. A floculação (efeito processamento) aumentou as digestibilidades aparentes (%) no trato total da MS, MO, amido e proteína, reduziu a concentração de N-NH 3 ruminal, a proporção de acetato, mas aumentou propionato. A floculação tendeu a aumentar eficência alimentar percentual e produção de proteína do leite. Inclusão de polpa não afetou a ingestão de MS e aumentou digestibilidade de fibra. Inclusão de polpa aumentou a digestibilidade do amido (%) no tratamento moído grosso. Amonia ruminal e proporção de propionato não foram afetadas pela inclusão de polpa, mas houve significativo aumento de acetato. Houve interação processamento x polpa sobre concentração de glicose plasmática. Produção de leite corrigida, eficiência alimentar, percentual e produção de gordura do leite aumentaram com a inclusão de polpa.

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RESUMO -Objetivou-se avaliar dois intervalos de pastejo de pastos de capim-elefante (Pennisetum purpureum Schum.): um intervalo variável, quando o dossel atingisse 95% de interceptação da radiação fotossinteticamente ativa, e um intervalo de pastejo fixo, de 26 dias. O delineamento experimental foi o inteiramente casualizado com medidas repetidas no tempo.O intervalo de pastejo, a altura do dossel no pré e pós-pastejo, a interceptação da radiação fotossinteticamente ativa e o índice de área foliar foram maiores quando aplicado o intervalo de pastejo fixo. Não houve efeito dos intervalos de pastejo sobre as massas de forragem, de folhas e de colmos no pré e pós-pastejo nem sobre a densidade volumétrica do dossel no pré-pastejo. A massa de material morto foi menor no intervalo de pastejo variável em comparação ao intervalo fixo, tanto no pré quanto no pós-pastejo. Os teores de fibra em detergente neutro e fibra em detergente ácido nos pastos manejados em intervalo variável foram menores que naquela com intervalo fixo. A aplicação de intervalo de pastejo variável, por permitir redução do tempo de descanso do pasto, tem efeitos positivos na qualidade da forragem.Palavras-chave: interceptação de luz, lotação rotacionada, manejo do pastejo, Pennisetum purpureum, período de descanso, valor nutritivo Productive and qualitative characteristics of elephant grass pasture grazed in fixed and intermittent intervals according to interception of active photosynthetic radiation ABSTRACT -The objective of this trial was to evaluate two intervals of grazing on elephant grass (Pennisetum purpureum Schum.) pasture. It was tested a variable grazing interval when it was observed an interception of 95% of active photosynthetic radiation by sward, and a 26-day fixed grazing interval. The experimental design was a complete randomized design with time repeated measurements. The interval of grazing, pre and post grazing sward heights, sward interception of active photosynthetic radiation and leaf area index were greater when the fixed pasture interval was applied. There was no effect of intervals of grazing on forage mass, leaf mass and stem mass in pre-or post-grazing neither for sward volumetric density in pre grazing. Dead material mass was lower for variable grazing interval than in fixzed grazing for both pre and post grazing. Neutral detergent fiber and acid detergent fiber contents were lower in the grazing managed in the variable interval than in the fixed grazing interval. The use of variable grazing interval intervals that promoted reduction in resting time of the pasture resulted in positive effects on forage quality.Key Words: chemical composition, interval between grazing, light interception, pasture management, Pennisetum purpureum, rotational grazing IntroduçãoO crescimento da planta forrageira é determinado pelas condições genéticas e ambientais (fertilidade do solo, características climáticas, etc), que podem potencializar ou limitar a produção de forrragem.Assim, o estabelecimento do ciclo de pastejo em dias fixos pode p...

RESUMO.Foram utilizadas quatro vacas Holandesas, no terço final de lactação, canuladas no rúmen, com o objetivo de comparar milho moído fino, moído grosso ou floculado, assim como a substituição parcial dessas fontes de amido por polpa de citrus peletizada. O delineamento experimental utilizado foi um Quadrado Latino 5 x 4. As dietas continham silagem de milho como volumoso exclusivo e os tratamentos testados foram: milho moído fino (MF), floculado (F), moído grosso (MG), moído fino + polpa de citrus (MFP) e floculado + polpa de citrus (FP). O tratamento MG resultou em menores produções de leite, gordura e proteína, enquanto que o tratamento MFP resultou em maiores produções de leite corrigido, gordura e proteína. As digestibilidades no trato total da MS, PB, FDN, FDA foram maiores para o tratamento FP, enquanto que o tratamento F teve efeito negativo na digestão de fibra. O pH ruminal foi menor para o tratamento FP. Os teores médios de Namoniacal e AGV totais ruminais não foram afetados pelos tratamentos. O tratamento F reduziu as concentrações molares de acetato e butirato, enquanto que a inclusão de polpa favoreceu a produção ruminal destes. A glicose plasmática não foi afetada, mas os teores de N-uréico foram superiores no tratamento MFP comparados com MG.Palavras-chave: digestibilidade, polpa de citrus, processamento de grão, vaca de alta produção. ABSTRACT. Starch sources with different degradabilities and their partialreplacement by citrus pulp for lactating dairy cows. Four late lactating Holstein cows, canulated in rumen, were used in a 5x4 Latin Square Design to compare coarsely ground, finely ground and flaked corn and the partial replacement of these starch sources by citrus pulp. All diets contained corn silage as forage source. The treatments were finely ground corn (MF), steam-flaked corn (F), coarsely ground corn (MG), finely ground corn+ citrus pulp (MFP), steam-flaked corn+ citrus pulp (FP). The MG treatment resulted in the lowest dry matter intake and lowest milk, fat and protein yields, while the FP treatment resulted in the highest dry matter intake, 3.5% fat corrected milk, fat and protein yields. The DM, CP, NDF and ADF total tract digestibility were high for FP, however F had a negative effect on fiber digestibility. The ruminal pH was low for FP. Ruminal ammonia and VFA were not affected by treatments. The F treatment reduced molar concentration of acetate and butyrate, while citrus pulp stimulated their ruminal production. Plasma glucose was not affected by treatments, however PUN was higher for MFP as compared to MG.

RESUMO -A suplementação de fontes de amido de maior digestibilidade e o uso de aditivos com atividade coccidiostática e promotora de crescimento podem melhorar o desempenho de bezerros leiteiros pré e pós desmama. O objetivo deste trabalho foi avaliar o efeito de concentrados contendo milho laminado a vapor ou floculado, com ou sem a adição de monensina, no consumo, ganho de peso e parâmetros sanguíneos de bezerras leiteiras, antes e após a desmama realizada a sexta semana de vida. Foram utilizadas 32 bezerras holandesas do nascimento a 12 semanas de vida, em um delineamento experimental do tipo blocos ao acaso, com arranjo fatorial 2 x 2. Do nascimento à desmama os animais receberam concentrado ad libitum até o consumo de 2 kg/d, quatro litros diários de leite e tiveram acesso livre à água. Após a desmama, realizada na sexta semana de vida, os animais continuaram recebendo 2 kg de concentrado e passaram a ter acesso a feno picado ad libitum. O tipo de processamento de grão ou a adição de monensina não afetaram o consumo médio de concentrado ou feno, assim como o peso final e o ganho de peso diário. As concentrações plasmáticas de glicose e ácidos graxos livres (AGL) médios do período experimental não foram afetadas pelos tratamentos; entretanto, as concentrações de n-uréico foram inferiores no plasma de animais recebendo concentrado com grãos laminados e monensina. Houve efeito da idade do animal nas concentrações plasmáticas de glicose, n-uréico e AGL. Somente os parâmetros glicose e AGL plasmáticos foram afetados pelo horário após o fornecimento do alimento. A inclusão de monensina ou de grão processados na dieta de bezerras leiteiras não resultou em melhor desempenho animal, antes ou após a desmama. Palavras-chave: ácidos graxos livres, desempenho, glicose, ionóforo, N-uréico, plasma Corn Processing (Steam-Flaked Vs. Steam-Rolled) and Monensin for Pre and Post Early Weaning Dairy CalvesABSTRACT -The supplementation of more digestible starch sources and feed additives with coccidiostatic and growth promoting activities may improve pre and post weaning calves performance. The objective of this trial was to evaluate the effects of concentrates containing processed grains (steam-flaked vs. steam-rolled), with or without monensin, on intake, weight gain and blood parameters of baby calves, before and after weaning at six weeks of life. Thirty-two female calves were utilized on a completely randomized block, with a 2 x 2 factorial arrangement. The animals received concentrate ad libitum up to 2 kg/d, plus 4 L of milk. Calves had free access to water. After weaning, at the sixth week of life, calves received concentrate and chopped hay. The treatments did not affect concentrate or hay intake, final live weight, average daily gain, plasma glucose and NEFA cocentration. PUN was lower on calves fed steam-rolled corn and monensin. There was a significant effect of age on glucose, PUN, and NEFA concentrations. Only glucose and NEFA were affected by time after feeding. Addition of monensin or processed grain to dairy cal...