Carla Maris Machado Bittar

Características agronômicas e bromatológicas de híbridos de milho para produção de silagem

The objective of this work was to establish correlations between quantitative and qualitative variables and to evaluate their influence on the corn quality for ensilage production. Data from the Corn Hybrids for Silage Evaluation Program were used (IAC/APTA/ESALQ). Pearson correlations between the variables were calculated. The digestible dry matter (DM) production was affected not only by forage and grain productions, but also by the whole plant and stem digestibility. The digestible dry matter production presented the highest correlation coefficients with the total dry matter production (0.85) and with the grain production at ensiling (0.60) and maturity (0.68), production of fresh forage (0.47) and with the plant ears index (0.48). The correlation coefficients between the digestible DM production and the whole plant digestibility (0.44) and the stem fraction (0.38) were lower than those observed for the DM production. The whole plant digestibility depended mainly on the stem digestibility (0.60) and on parameters related to the grains. It may be concluded that when specific information on corn hybrids is not available, those with higher production of grains at maturity are selected due to their elevated correlation with DM production and digestible DM.

Desempenho de vacas em lactação recebendo dietas com diferentes teores de amido total, acrescidas ou não de levedura (Saccharomyces cerevisiae)

Trinta e seis vacas da raca Holandesa (258 dias em lactacao) foram utilizadas para se avaliar a suplementacao com levedura (Levucell SC 20 da Lallemand) em dietas para vacas leiteiras com dois teores de amido (22 vs 32%). O mais baixo teor de amido foi obtido com a substituicao parcial (50:50) de milho finamente moido por polpa de citrus peletizada. Utilizou-se quadrado latino 4 x 4 repetido, com quatro periodos de 24 dias. Os primeiros 20 dias foram destinados a adaptacao dos animais e os ultimos quatro, a coleta de dados. Os parâmetros avaliados foram a ingestao de materia seca, a producao e composicao do leite e as concentracoes de glicose e nitrogenio ureico no plasma sanguineo. A ingestao de materia seca, a producao e composicao do leite e a concentracao de glicose plasmatica nao foram afetadas pelos tratamentos. O nitrogenio ureico no leite foi maior nos animais sob suplementacao com aditivo microbiologico. O nitrogenio ureico no plasma foi reduzido com a substituicao parcial do milho pela polpa citrica, que nao teve efeito negativo sobre o desempenho de vacas produzindo, em media, 19 kg de leite/dia.

Diet crude protein content and sources for lactating dairy cattle

O fornecimento de dietas com maior teor de proteina para aumentar o fluxo de aminoacidos para o intestino pode aumentar o desempenho lactacional. Compararam-se dietas para vacas em lactacao contendo 16% de proteina bruta (PB), adequada em proteina degradavel no rumen (PDR) e proteina metabolizavel (PM) (NRC, 2001) com dietas com maiores teores de PB (17,5%) . Quarenta e duas vacas (27 primiparas e 15 multiparas, com 172 dias em lactacao) foram utilizadas em um delineamento do tipo Quadrado Latino 3 ´ 3, com 14 repeticoes. A dieta controle continha 16% de PB e era adequada em PDR e PM de acordo com o NRC (2001). O teor de PB das dietas foi aumentado para 17,5% atraves do aumento no fornecimento de farelo de soja e de algodao (SBCS-17,5) para aumentar a PM, ou ureia (U-17,5) para aumentar a PDR. O experimento teve duracao de 60 dias com tres subperiodos. Os animais foram alimentados em grupo com racao completa e ordenhados duas vezes ao dia. O consumo de materia seca foi maior para a dieta U-17,5 (p 0,05) pelos tratamentos. O teor de proteina foi reduzido (p < 0,01) pelo maior fornecimento de ureia (U-17,5); enquanto maior producao de proteina do leite (p < 0,01) foi observada para o tratamento SBCS-17,5. Para vacas produzindo em torno de 29 kg d-1, aumentar o teor de PB para 17,5%, por meio do maior fornecimento de farelo de soja e de algodao, acima das recomendacoes do NRC (2001) para PDR e PM, resultou em aumentos na producao de leite, leite corrigido para gordura e de proteina do leite.

Desempenho e desenvolvimento do trato digestório superior de bezerros leiteiros alimentados com concentrado de diferentes formas físicas

The physical form of concentrate on the performance and rumen development on dairy calves was evaluated in this experiment. Twenty-two Holstein male calves, with 42.3 kg initial body weight, were individually housed, fed 4 L/d of liquid diet and starter concentrate in two physical forms (pelleted or coarsely ground). Starter concentrate intake was monitored daily and calves were weighted weekly, always after the morning liquid diet feeding. After 10 weeks, four calves from each treatment were slaughtered and rumen samples were taken for pH, rumen short chain fatty acids (SCFA) and N-NH3 concentration. Morphometric measurement of the forestomach was also evaluated. There was no effect of the physical form on starter concentrate intake, body weight, and daily gain. The physical form of the concentrate also had no effects on pH, SCFA or N-NH3 rumen concentration, nor on the morphometric measurements of the forestomach, except for rumen capacity and abomasum weight, which were higher for animals fed pelleted starter concentrate. Coarsely ground starter concentrate may be an alternative to reduced production costs since the physical form of the concentrate had no effect on performance or in the development of forestomach of dairy calves.

Efeito da adição de butirato de sódio, propionato de cálcio ou monensina sódica no concentrado inicial sobre parâmetros ruminais e de desenvolvimento do rúmen de bezerros leiteiros

O objetivo neste trabalho foi avaliar o efeito da inclusao de butirato de sodio, monensina sodica ou propionato de calcio no concentrado inicial sobre parâmetros ruminais e de desenvolvimento do trato digestorio superior de bezerros leiteiros. Quinze bezerros holandeses recem-nascidos foram fistulados no rumen e alojados em baias individuais ate a decima semana de vida, com livre acesso a agua, alimentados com leite (4 L/dia), em duas refeicoes, e concentrado a vontade contendo butirato de sodio (0,15%), monensina sodica (30 ppm) ou propionato de calcio (0,15%). A partir da quarta semana de vida dos animais, antes e 2 horas apos a alimentacao da manha, foram realizadas colheitas semanais de fluido ruminal para determinacao do pH, da concentracao de acidos graxos de cadeia curta (AGCC) e N-amoniacal. Ao completar 10 semanas, os animais foram abatidos para avaliacao do crescimento do trato digestorio superior. O pH ruminal apresentou diferencas, tanto entre horarios quanto entre os aditivos utilizados no concentrado inicial. As concentracoes de AGCC totais, bem como de cada acido graxo, nao foram afetadas pelos aditivos. Entretanto, o horario de colheita teve efeito sobre todos os parâmetros, exceto a concentracao molar de acido acetico. O peso total do trato digestorio superior, assim como o peso medio de cada compartimento e a capacidade maxima do reticulo-rumen, nao foram afetados pelos aditivos fornecidos no concentrado. Tambem nao foram observados efeitos dos aditivos sobre a altura, a largura e o numero de papilas do epitelio ruminal. A inclusao desses aditivos no concentrado inicial nao afeta os parâmetros ruminais ou de desenvolvimento do trato digestorio de bezerros em aleitamento.

Estimativa de energia metabolizável de rações com polpa cítrica em substituição ao milho para tourinhos em terminação

Seventy-two finishing Canchim bulls averaging 318 kg of initial body weight and 18 months of age were assigned to a completely randomized block design to evaluate the effects of replacing ground corn (GC) with dried citrus pulp (CP) on average daily weight gain, dry matter intake, feed efficiency, carcass yield, and Longissimus dorsi fat thickness. Diets contained forage (sugarcane silage) to concentrate ratio of 30:70 and the following levels of CP and GC: 100% GC (CP0), 50% GC + 50% CP (CP50), 25% GC + 75% CP (CP75), or 100% CP (CP100). The experiment lasted 130 days with 14 days for diet adaptation and 116 days for data and sample collection. Feed efficiency and net energy for maintenance and gain were all greatest on CP50 than on CP0 diet. Daily weight gain and DM intake were lower on CP100 and CP75 compared to CP50. No significant differences were observed for fat thickness and carcass yield across treatments. Based on the actual data, both the NRC (1996) and NRC (2001) models underestimated the energy value of CP compared to GC.

A survey of dairy calf management practices in some producing regions in Brazil

This study aimed to characterize the Brazilian dairy calves raising systems through a survey of major aspects of animal husbandry. One hundred seventy-nine producers and/or technicians were interviewed. The questionnaire addressed issues related to the management of the dry cow and the newborn, nutritional management of the liquid-feeding phase, housing, and health management. A third of newborn calves stay with their mothers for more than 24 h after delivery, and only 56% of the calves receive colostrum within the first 8 h of life. Four out of ten producers allow the calf to suckle colostrum directly from the mother. Regarding the liquid diet, 44 and 35% of the farms provide marketable milk and discard milk for the calves, respectively. It was possible to identify several areas of improvement in the raising system; for instance, greater attention could be given to dry cows and the monitoring of births and to the establishment of adequate protocols to evaluate colostrum quality and feeding management.

Evaluation of mannan-oligosaccharides offered in milk replacers or calf starters and their effect on performance and rumen development of dairy calves

The objective of this study was to evaluate the route of administration of mannan-oligosaccharides in the diet of dairy calves and their effects on performance and plasma parameters indicative of rumen development. Following birth, twenty-four male Holstein calves were used in a completely randomized design and assigned to the following treatments: Control; 4 g/d Bio-Mos® (Alltech Biotech.) added to starter concentrate; and 4 g/d Bio-Mos® mixed into milk replacer. Animals were housed in individual hutches with free access to water, and fed 4L/d of milk replacer until weaning at six weeks. Calves also received 23g/kg crude protein of starter concentrate ad libitum. Fecal scores were evaluated daily. Body weights, growth measurements and blood samples for glucose, urea-N and β-hidroxibutyrate analyses were taken weekly until 8 weeks of age. There were no significant effects of treatment or treatment × age interactions for mean starter concentrate intake, weight gain or body growth. However, there was a significant age effect for all parameters. Fecal scores were not affected by treatments. Also, plasma concentration of glucose, urea-N or β-hidroxibutyrate were not affected by treatment or the treatment × age interaction. However, urea-N and β-hidroxibutyrate concentrations significantly increased with age, suggesting adequate rumen development. Under the conditions of this study, there were no calf performance benefits when mannan-oligosaccharides were incorporated into milk replacer or calf starter concentrate.

Substituição do milho moído por casca de soja na ração de vacas leiteiras em confinamento

Trinta e seis vacas holandesas no terco medio da lactacao, 123 dias em lactacao (DEL), foram utilizadas para avaliar a substituicao do milho moido (MM) por casca de soja (CS) em racoes contendo silagem de milho como volumoso principal e polpa citrica como parte da fonte energetica. Foram avaliadas racoes com 0, 10 e 20% de substituicao do milho moido por casca de soja na racao, na MS da racao completa (%MS): CS 0 - 0% de CS e 20% de MM; CS 10: 10% de CS e 10% de MM; e CS 20 - 20% de CS e 0% MM. Caracteristicas de desempenho e metabolismo como consumo de MS, producao e composicao do leite, concentracoes de N-ureico no leite e niveis de glicose plasmatica foram avaliadas. As vacas foram distribuidas a um delineamento experimental em quadrado latino 3 ´ 3, com de 12 repeticoes e de acordo com a producao de leite, DEL e a paridade. A inclusao de CS nas racoes nao afetou o consumo de MS (22,84 kg/dia), a producao de leite (28,33 kg/dia) ou a producao de leite corrigida para 3,5 % gordura (28,48 kg/dia). No entanto, aumentou linearmente a producao total de gordura (kg/dia) e a decresceu linearmente a concentracao de N-ureico no leite. A substituicao do milho moido por casca de soja na alimentacao de vacas leiteiras pode ser uma alternativa interessante, desde que o preco do subproduto seja competitivo.

Replacing corn grain with corn gluten feed in the diet of feedlot lactating cows

Thirty mid lactating Holstein cows (159 DIM) were used to evaluate the substitution of ground corn with gluten feed (FGM-21) in total mixed diets containing corn silage as the main forage and citrus pulp as part of the energy source. Treatments were: no FGM-21 and 20% ground corn in total feed DM (FGM 0), 10% FGM-21 and 10% ground corn in total feed DM (FGM 10), and no corn and 20% FGM-21 in total feed DM (FGM 20). The parameters evaluated were: dry matter intake, milk yield and composition, milk urea N concentration, blood parameters and body condition score. Cows were randomly assigned in ten 3 × 3 Latin Squares, according to milk yield, days in lactation and parity. Treatments did not affect the daily dry matter intake (DMI) (21.19 kg/d), milk yield (24.88 kg/d), FCM yield (25.34 kg/d), milk fat content (3.62%), and milk total solids (11.86%). Inclusion of corn gluten feed affected milk protein, lactose and urea concentrations.