ABSTRACT
Recently, returning straw to the fields has been proved as a direct and effective method to tackle soil nutrient loss and agricultural pollution. Meanwhile, the slow decomposition of straw may harm the growth of the next crop. This study aimed to determine the effects of rumen microorganisms (RMs) on straw decomposition, bacterial microbial community structure, soil properties, and soil enzyme activity. The results showed that RMs significantly enhanced the degradation rate of straw in the soil, reaching 39.52%, which was 41.37% higher than that of the control on the 30th day after straw return. After 30 d, straw degradation showed a significant slower trend in both the control and the experimental groups. According to the soil physicochemical parameters, the application of rumen fluid expedited soil matter transformation and nutrient buildup, and increased the urease, sucrase, and cellulase activity by 10%‒20%. The qualitative analysis of straw showed that the hydroxyl functional group structure of cellulose in straw was greatly damaged after the application of rumen fluid. The analysis of soil microbial community structure revealed that the addition of rumen fluid led to the proliferation of Actinobacteria with strong cellulose degradation ability, which was the main reason for the accelerated straw decomposition. Our study highlights that returning rice straw to the fields with rumen fluid inoculation can be used as an effective measure to enhance the biological value of recycled rice straw, proposing a viable solution to the problem of sluggish straw decomposition.
Subject(s)
Animals , Rumen/metabolism , Agriculture/methods , Soil/chemistry , Microbiota , Bacteria/metabolism , Oryza/metabolism , Soil Microbiology , CelluloseABSTRACT
Avaliaram-se as doses de nitrogênio 0, 60, 120 e 240kg ha-1 sobre a composição bromatológica e os parâmetros da cinética de degradação ruminal da aveia branca obtida de dois anos de cultivo (2013-2014). Foram realizadas as análises de matéria seca, matéria mineral (MM), proteína bruta (PB), extrato etéreo, fibra em detergente neutro (aFDNmo), lignina, carboidratos solúveis (CHOs) e proteína insolúvel em detergente ácido (PIDA). Não foi observado efeito da adubação nitrogenada sobre as variáveis em nenhum dos anos de cultivo. As variáveis bromatológicas foram influenciadas pelos fatores ambientais. A cinética de degradação ruminal foi correspondente à composição bromatológica. No ano de 2013, foram observados valores superiores para as variáveis PB, MM, PIDA, CHOs e carboidratos não fibrosos, o que influenciou positivamente nos parâmetros da cinética de produção de gás in vitro, Vf 1 e k 2. A composição da cultivar em 2014 tendeu a maiores teores de aFDNmo, lignina e carboidratos totais e a valores superiores para os parâmetros Vf 2 e L. O parâmetro k 1 não foi significativo nos períodos avaliados. Em 2014 o valor nutritivo foi negativamente influenciado pelo atraso na semeadura e pela soma de períodos de restrição hídrica combinados com a elevação da temperatura.(AU)
Doses of Nitrogen were evaluated: 0, 60, 120 and 240kg ha-1 on the chemical composition and rumen degradation kinetics of white oats obtained from two consecutive years (2013-2014). For nutritional characterization the following parameters were analyzed: dry matter; ash, crude protein, ethereal extract, neutral detergent fiber, lignin, soluble carbohydrates and insoluble acid detergent protein. No effect of nitrogen fertilization was observed on the variables analyzed in any of the growing years. The nutritional variables were influenced by environmental factors that occurred in the respective experimental periods and the parameters of ruminal degradation kinetics corresponded to the effects in these compounds. In year 2013, higher values were observed for the variables crude protein, ash, insoluble acid detergent protein, soluble CHO and no fibrous carbohydrates, resulting in higher values also for the in vitro gas production kinetics, Vf1 and k2. Nutritional contents in 2014 tended to higher levels of NDF, lignin and total carbohydrates, and higher values for the parameters Vf2 and L. The parameter k1 was not significant in any of the experimental periods evaluated. In 2014 the forage has its nutritive value negatively influenced by the delay in sowing and the periods of water restriction combined with higher temperatures.(AU)
Subject(s)
Rumen/metabolism , Dietary Carbohydrates/metabolism , Avena/chemistry , Nitrogen , In Vitro Techniques , KineticsABSTRACT
Abstract In the Southern Hemisphere, ruminants are mostly raised in grazing systems where animals consume forage and are supplemented with low amounts of concentrates. Concentrates are usually given separately and are rapidly ingested. This practice leads to changing rumen environment conditions during the day, may alter the rumen microbial metabolism and could affect host performance. The native ruminal Prevotella bryantii strain 3C5 was administered every 48 h to wethers under experimental conditions simulating Southern-Hemisphere feeding to evaluate its potential as a rumen fermentation modulator. The inoculum potential was assessed on day 17. The ammonia nitrogen (NH3-N), volatile fatty acids and ruminal pH were monitored on a 24-h basis 19 days after the beginning of the experiment, and the microbial community structure was assessed by pyrosequencing. The administration of P. bryantii modified the fermentation products and daily pH values compared to the control. The NH3-N concentration in the rumen of treated animals was significantly higher than that of the untreated animals. Modification of the ruminal environment and fermentation pathways was achieved without altering the general structure of the microbial community or the potential methane production. P. bryantii 3C5 could be considered in potential probiotic formulations for ruminants in semi-intensive systems.
Subject(s)
Animals , Male , Rumen/microbiology , Prevotella/metabolism , Rumen/metabolism , Rumen/chemistry , Sheep , Prevotella/genetics , Digestion , Fatty Acids, Volatile/metabolism , Fermentation , Ammonia/metabolism , Hydrogen-Ion Concentration , Models, BiologicalABSTRACT
Objetivou-se avaliar o efeito da substituição do milho grão pelo gérmen integral de milho (GIM) na dieta de vacas lactantes, com cinco teores de inclusão do gérmen com base na matéria seca (MS) (0,0; 6,7; 13,5; 20,1 e 26,9 %). Foram utilizadas cinco vacas multíparas mestiças, com 490 kg de peso corporal, 100 dias pós-parto e produção média de 26 kg de leite/dia. Cada período experimental teve duração de 21 dias, sendo 13 dias para adaptação à dieta e oito dias para coleta de amostras. O experimento foi em quadrado latino, os modelos foram selecionados em que os regressores foram significativos e a falta de ajuste não significativa, adotando-se o nível de significância de 5%. As variáveis analisadas foram o consumo de matéria seca (CMS) (kg/dia de MS), a digestibilidade (%), o comportamento ingestivo (h/dia), tamanho médio de partícula (mm), a fração não degradável (%), parâmetros ruminais (mg/dL), produção de leite (PL) (kg/dia), composição do leite (%), eficiência alimentar (EA = PL/CMS), concentração de energia e energia de lactação (Mcal/kg). A substituição do milho grão pela inclusão do GMI não provocou alterações (P>0,05) no comportamento ingestivo, pH, N-NH3 , e fração não degradável. A produção de leite, quantidade de proteína, lactose, relação proteína: gordura e eficiência alimentar tiveram aumento (P<0,05). Foi verificada redução linear (P<0,05) na porcentagem de gordura e concentração de energia, assim como a % de butirato com o acréscimo de GIM na dieta. A dieta com a inclusão de 26,9% de GIM na MS não promoveu efeito negativo sobre as variáveis analisadas, dessa forma, o GMI, pode ser um substituto do milho na dieta de vacas lactantes.(AU)
The purpose of this study was to evaluate the effect of replacing corn grain with whole-grain corn germ (WGCG) in the diet of lactating cows with five levels of inclusion of germ based on dry matter (DM) (0.0; 6.7; 13.5; 20.1; and 26.9%). This study used five multiparous crossbred cows, with average 490-kg body weight, 100 days postpartum, and average production of 26 kg of milk/day. Each experimental period lasted 21 days, with 13 days for diet adaptation and eight days for the collection of samples. The experiment was carried out in a Latin square design, with the selection of models where the regressors were significant and non-significant lack of adjustment, adopting a 5% significance level. The study analyzed the following variables: dry matter intake (DMI) (kg/day DM), digestibility (%), ingestion behavior (h/day), mean particle size (mm), non-degradable fraction (mg/dL), milk production (MP) (kg/day), milk composition (%), feed efficiency (FE = MP/DMI), energy concentration and lactation energy (Mcal/kg). It was observed that the replacement of corn grain with WGCG did not cause changes (P>0.05) in the ingestion behavior, pH, N-NH3, and non-degradable fraction. Milk production, protein, lactose, protein:fat ratio and food efficiency presented an increase (P<0,05). A linear reduction (P<0.05) was observed in the percentage of fat and energy concentration, as well as the percentage of butyrate with the addition of WGCG in the diet. The diet with the inclusion of 26.9% WGCG in DM did not present any negative effects on the analyzed variables, thus, WGCG could be a substitute for maize in the diet of lactating cows.(AU)
Se evaluó el efecto de la sustitución del maíz grano por el germen integral de maíz (GIM) en la dieta de vacas lactantes, con cinco niveles de inclusión del germen con base en la materia seca (MS) (0,0; 6,7; 13,5, 20,1 y 26,9%). Se utilizaron cinco vacas multíparas mestizas, con 490 kg de peso corporal, 100 días posparto y producción media de 26 kg de leche/día. Cada período experimental tuvo una duración de 21 días, siendo 13 días para adaptación a la dieta y ocho días para la toma de muestras. El experimento fue en cuadrado latino, los modelos fueron seleccionados donde los regresores fueron significativos y la falta de ajuste no significativa, adoptando el nivel de significancia del 5%. Las variables analizadas fueron el consumo de materia seca (CMS) (kg/día de MS), la digestibilidad (%), el comportamiento de ingestión (h/día), tamaño medio de partícula (mm), la fracción no degradable (%), parámetros rúmiales (mg / dL), producción de leche (PL) (kg/día), composición de la leche (%), eficiencia alimentaria (EA = PL/CMS), concentración de energía y energía de lactancia (Mcal/ kg). La sustitución del maíz grano por la inclusión del GMI no provocó alteraciones (P>0,05) en el comportamiento de ingestión, pH, N-NH3, y fracción no degradable. La producción de leche, cantidad de proteína, lactosa, relación proteína: grasa y eficiencia alimentaria tuvieron aumento (P<0,05). Se verificó una reducción lineal (P<0,05) en el porcentaje de grasa y concentración de energía, así como e l % de butirato con el aumento de GIM en la dieta. La dieta con la inclusión del 26,9% de GIM en la MS no promovió efecto negativo sobre las variables analizadas, de esa forma, el GMI, puede ser un sustituto por maíz en la dieta de vacas lactantes.(AU)
Subject(s)
Animals , Female , Cattle , Rumen/metabolism , Infant Nutritional Physiological Phenomena , Cattle/metabolism , Zea mays , Fatty AcidsABSTRACT
Objetivou-se neste estudo fracionar os carboidratos e as proteínas e avaliar a cinética de degradação ruminal de rações contendo 0; 24; 48 e 72% de torta de girassol. Os carboidratos foram fracionados em A+B1, B2 e C, e as proteínas em A, B1+B2, B3 e C. Os parâmetros de cinética de degradação ruminal das rações foram estimados a partir do método semiautomático de produção cumulativa de gases in vitro. Foram utilizados quatro animais 1/2 Gir x 1/2 Holandês, machos e castrados, fistulados no rúmen, mantidos em pastagem e recebendo 1kg de ração concentrada, como doadores de inócuo ruminal. O ensaio foi realizado em delineamento em blocos ao acaso, com quatro rações e quatro períodos, e os resultados obtidos foram interpretados de acordo com a análise de variância e de regressão a 5% de significância. Houve efeito linear decrescente para o fracionamento de carboidratos totais e a fração A+B1, e efeito linear crescente sobre as frações B2 e C. Para as frações nitrogenadas, houve efeito linear crescente sobre a fração A, e efeito linear decrescente sobre as frações B1+B2 e C. Em relação à cinética de degradação ruminal in vitro, houve efeito decrescente sobre o parâmetro "a", e efeito quadrático sobre os parâmetros "b" e "c", com pontos de máxima, respectivamente, de 61,84 e 66,77% de torta de girassol. A inclusão da torta de girassol nas rações suplementares, nos teores estudados, influenciou nas frações dos carboidratos, das proteínas e nos parâmetros de degradação ruminal. Caso haja a disponibilidade desse ingrediente, ele pode ser adicionado à ração suplementar de bovinos sem prejuízo nos parâmetros nutricionais e metabólicos.(AU)
This work aimed to fractionate carbohydrates and protein and to evaluate ruminal degradation kinetics of rations containing 0; 24; 48 and 72% of inclusion of sunflower cake. The carbohydrates were fractionate in A+B1, B2 and C fraction, and protein in A, B1+B2, B3 and C. Rations ruminal degradation kinetics were realized with the "in vitro" semiautomatic gas production technique. Four male, castrated, 1/2 Gir x 1/2 Holstein were used, all of them fistulated in the rumen. This study was done in randomized block design with four rations and four periods. The results obtained were interpreted according to variance and regression analysis at 5% significance level. There is a decreasing effect for total carbohydrates fractionation and A+B1 fraction, and there is an increasing effect for B2 and C fraction. For nitrogen fractions there is an increasing effect on fraction A and negative linear effect on B1+B2 and C fractions. For "In vitro" ruminal degradation kinetics there is a decreasing effect for "a" parameter, and quadratic effect for "b" and "c" parameters with maximum points respectively 61.84 and 66.77% of sunflower seed meal. The inclusion of sunflower cake in supplementary feeding, the studied levels, influenced the fractions of carbohydrates, proteins and degradation parameters. If there is the availability of this ingredient, it can be added to the supplemental feed cattle subject to the nutritional and metabolic parameters.(AU)
Subject(s)
Animals , Animal Feed , Carbohydrate Metabolism , Kinetics , Rumen/metabolism , Ruminants/metabolismABSTRACT
This study aimed to describe the diagnosis of health problems and to evaluate the cost of their treatment for cattle raised in feedlots to be slaughtered or to be sold as sires for cow-calf systems. Bovine respiratory disease and digestive disorders were the main problems diagnosed in the feedlot for slaughter; the cost for treatment was high, accounting for 9.7 to 20.9 kg of live weight (LW) or the equivalent of 7 to 15% of total LW gained over the days on feed. Due to the high intake of starch-rich concentrate, rumen and fecal pH was lower, whilst rumen osmolarity and blood lactate were higher in cattle fed for slaughter. Cattle affected by digestive disorders spent on average four additional days in the feedlot. Diseases and cost of treatments were associated with lower average daily gain and considerable economic losses. Health problems commonly observed in the feedlots for slaughter were not observed in the feedlots for males to be sold as sires. The most likely reason for this observation was the more careful nutrition and prophylactic health management in sire production systems, which produce animals of much higher selling price. Results from this study suggest that health problems found in feedlots for slaughter may not only reduce animal productivity and proï¬tability, but also the welfare of the animals. The systemic understaffing of livestock cattle workers and veterinarians in large feedlots in Brazil results in under reporting of diseases and lack to understand epidemiological context and disease prevention.(AU)
No presente estudo coletou-se e se interpretou dados sobre os principais problemas sanitários, bem como a respeito dos custos com os tratamentos de bovinos de corte confinados em dois sistemas diferentes: o tradicional, isto é, aquele que objetiva produzir animais prontos para o abate e o sistema de produção de touros destinados à venda destes como reprodutores. A porcentagem de bovinos confinados para o abate e que adquiriram problemas sanitários foi consideravelmente maior do que nos sistemas que os confinam para a venda como futuros reprodutores. As pneumonias e os transtornos digestórios foram os principais problemas diagnosticados no confinamento para o abate e os custos com os tratamentos foram elevados e, em média, representaram entre 9,7 e 20,9 kg de peso vivo ou o equivalente de 7 a 15% das arrobas ganhas durante o período confinado. O crescimento exagerado e a aglutinação (paraqueratose) das papilas ruminais foram os principais achados macroscópicos nos rúmens dos bovinos confinados para o abate. Devido à maior ingestão de grãos, o pH ruminal e fecal foi sempre menor, enquanto que a osmolaridade ruminal e o lactato sanguíneo foi sempre maior nos animais confinados para o abate. O tempo de permanência no confinamento foi maior, em média 4 dias, para os animais que adquiriram qualquer problema digestório. Isso, aliado ao fato de também terem os menores ganhos de peso diários, pode resultar em um considerável prejuízo. Os ganhos de peso diários foram similares para os animais confinados (que ingeriram mais de 85% de concentrados) para o abate e para os que foram confinados para a venda como reprodutores, que consumiram cerca de 50% de concentrados em sua dieta.(AU)
Subject(s)
Animals , Cattle , Cattle Diseases/prevention & control , Digestive System Physiological Phenomena , Pneumonia/diagnosis , Rumen/metabolism , Weight Gain , Health SurveillanceABSTRACT
A compactação dos pré-estômagos é um transtorno digestivo resultante da ingestão de forragem de baixa qualidade, rico em lignina e com baixos níveis de energia e proteína digerível, associada ou não a restrição hídrica. O acúmulo de vegetais ricos em fibras indigeríveis pode levar também a formação de fitobezoares, causando transtornos digestivos e obstruções intestinais. Objetivou-se com este trabalho descrever os aspectos epidemiológicos e as alterações clínico-patológicas de um surto de alterações digestórias em bovinos alimentados com Agave sisalana. O rebanho acometido era formado por 22 animais adultos, criados de forma semiextensiva, que, devido a escassez de forragem, receberam no cocho, quase que exclusivamente, durante dois meses, o caule do A. sisalana cortado manualmente. Seis vacas apresentaram diminuição do apetite, distensão abdominal, redução dos períodos de ruminação e da produção de fezes. Um animal foi encaminhado ao Hospital Veterinário da Universidade Federal de Campina Grande. O diagnóstico presuntivo de compactação ruminal e obstrução intestinal foi dado pela epidemiologia, sinais clínicos e análise de fluido ruminal. Na necropsia observou-se rúmen, retículo e omaso repletos, com conteúdo fibroso e ressecado constituído por fibras de A. sisalana. No abomaso observou-se a presença de conteúdo pastoso e esverdeado a acastanhado. Em todos os pré-estômagos e no abomaso havia fitobezoares, que mediam entre 4 e 12 cm de diâmetro. No duodeno um fitobezoar obstruía parcialmente a luz do órgão, com a porção anterior repleta de conteúdo e a posterior vazia. Conclui-se que a alimentação com caules de A. sisalana por longos períodos causa compactação de pre-estômagos e formação de fitobezoares.(AU)
Indigestion due to compaction of the ruminal content is a digestive disorder resulting from low-quality forage intake, rich in lignin and with low levels of energy and digestible protein, with or without water restriction. The accumulation of plant residues rich in indigestible fibers can also lead to formation of phytobezoars, causing digestive disorders and intestinal obstructions. The objective of this paper was to describe the epidemiology and the clinical and pathological changes of an outbreak of indigestion and other digestive disorders in cattle fed Agave sisalana. The affected herd consisted of 22 adult cattle reared in a semi-extensive system, which ingested almost exclusively stalks of A. sisalana manually cut for two months. Six cows showed decreased appetite and rumination, abdominal distension, and reduced production of dried feces. One animal was referred to the Veterinary Hospital. The presumptive diagnosis of indigestion was made by the epidemiologic data, clinical signs, and laboratory evaluation. At necropsy, the rumen, reticulum and omasum were filled with fibrous and dried A. sisalana content. A viscous, greenish brownish content was present in the abomasum. Numerous phytobezoars were found in the pre-stomachs and abomasum measuring 4-12cm in diameter. One phytobezoar was partially obstructing the duodenum, with the cranial part of the organ filled with intestinal content, and the caudal portion was empty. It is concluded that the administration of A. sisalana stalks for long periods may cause indigestion due to ruminal compaction and formation of phytobezoars.(AU)
Subject(s)
Animals , Cattle , Asparagaceae/adverse effects , Asparagaceae/metabolism , Foreign Bodies/veterinary , Intestinal Obstruction/physiopathology , Intestinal Obstruction/veterinary , Rumen/metabolism , Bezoars/diagnosis , Bezoars/veterinaryABSTRACT
Objetivou-se avaliar o efeito de combinações de diferentes fontes de nitrogênio não proteico com fontes de carboidratos como suplemento para bovinos sobre o consumo, degradabilidade in situ, taxa de passagem e cinética ruminal em bovinos. Os tratamentos consistiram nos seguintes suplementos proteinados: CSUENC = casca de soja + ureia encapsulada; CSUREIA = casca de soja + ureia; MTAMIR = milho triturado + amireia; MTURENC = milho triturado + ureia encapsulada, MTUREIA = milho triturado + ureia. Os animais foram alimentados com feno de Brachiaria brizantha cv. Marandu como fonte de volumoso. O ensaio foi conduzido em delineamento quadrado latino 5x5 (cinco suplementos, cinco animais, cinco períodos). Não houve diferenças para consumo de nutrientes (P>0,05), exceto para consumo de proteína bruta g/kgPV0,75, em que se verificou maior consumo no tratamento CSUENC. Para frações fibrosas, foram obtidas maiores ingestões de fibra em detergente neutro, fibra em detergente ácido (kg/dia; % PV; g/kgPV0,75), hemicelulose (% PV; g/kgPV0,75) quando alimentados com CSUREIA em relação àqueles com MTUREIA (P<0,05). Os tratamentos constituídos pelos diferentes proteinados não afetaram a degradabilidade in situ das frações nutricionais (P>0,05), exceto para fração potencialmente degradável da celulose. A concentração de nitrogênio amoniacal no líquido ruminal foi influenciada pela composição dos proteinados (P<0,05), sendo superior para os tratamentos MTUREIA e MTURENC em relação à CSURENC. As combinações entre diferentes fontes de nitrogênio não proteico e de carboidratos nos diferentes suplementos não modificam o consumo e a degradabilidade da forragem. Dessa forma, a escolha dos ingredientes para formulação de proteinados deve ser realizada considerando-se disponibilidade e preços desses suplementos.(AU)
The aim of this study was to evaluate the effect of combinations of different sources of non-protein nitrogen with carbohydrate sources as supplement feed to cattle on intake, in situ degradability and passage rate. Treatments consisted of the following protein supplements: CSUENC= soybean hulls + encapsulated urea; CSUREIA = soybean hulls + urea; MTAMIR = ground corn + starea; MTURENC = ground corn + encapsulated urea; MTUREIA = ground corn + urea. The animals were fed with Brachiaria brizantha cv. Marandu as roughage. The experiment was conducted in a latin square design (five supplements, five animals, five periods). The treatments did not affect the intake of nutrients (P>0.05), although a higher intake of crude protein (g/kgBW0.75) was observed by animals fed with CSUENC. A higher intake of NDF, ADF (kg/day, %BW; g/kgBW0.75) and hemicellulose (% PV; g/kgBW0.75) was observed by animals fed with CSUREIA when compared to those with MTUREIA (P<0.05). The degradability of nutritional fractions was not affected by any of the treatments (P>0.05), except for the potentially degradable cellulose. The ammoniacal nitrogen concentration in rumen fluid was influenced by the protein source (P<0.05) and was higher for MTUREIA and MTURENC treatments in relation to CSURENC. The tested combinations of different sources of non-protein nitrogen with different carbohydrates did not affect the forage intake or degradability. Therefore, the choice of the ingredients for protein supplement formulation should be made considering other factors as availability and price of these supplements.(AU)
Subject(s)
Animals , Cattle , Rumen/metabolism , Dietary Proteins/administration & dosage , Kinetics , Dietary Supplements/analysis , Digestion/physiologyABSTRACT
This paper presents, from the perspective of technological development and production, the results of an investigation examining 61 clinical studies with vaccines conducted in Brazil between 1938-2013, with the participation of the Oswaldo Cruz Institute (IOC) and the Oswaldo Cruz Foundation (Fiocruz). These studies have been identified and reviewed according to criteria, such as the kind of vaccine (viral, bacterial, parasitic), their rationale, design and methodological strategies. The results indicate that IOC and Fiocruz have accumulated along this time significant knowledge and experience for the performance of studies in all clinical phases and are prepared for the development of new vaccines products and processes. We recommend national policy strategies to overcome existing regulatory and financing constraints.
Subject(s)
Animals , Animal Feed/adverse effects , Dietary Proteins/chemistry , Models, Biological , Proanthocyanidins/chemistry , Rumen/metabolism , Brassica rapa/chemistry , Chemical Precipitation , Dietary Proteins/metabolism , Fermentation , Fabaceae/adverse effects , Fabaceae/chemistry , Fruit/adverse effects , Fruit/chemistry , Molecular Structure , Molecular Weight , Osmolar Concentration , Plant Proteins/chemistry , Plant Proteins/metabolism , Proanthocyanidins/adverse effects , Proanthocyanidins/metabolism , Ruminants , Ribulose-Bisphosphate Carboxylase/chemistry , Ribulose-Bisphosphate Carboxylase/metabolism , Rumen/microbiology , Solubility , Stereoisomerism , Serum Albumin, Bovine/chemistry , Serum Albumin, Bovine/metabolismABSTRACT
A idade ao corte é considerada o principal fator a afetar o valor nutritivo das forragens. Objetivou-se avaliar e comparar a cinética de degradação ruminal da matéria seca (MS), proteína bruta (PB) e fibra insolúvel em detergente neutro (FDN) das silagens de capim Andropogon gayanus obtidas em três diferentes idades de corte (56, 84 e 112 dias). As amostras das silagens secas e trituradas (5 mm) foram incubadas em sacos de nylon no rúmen por 0, 6, 12, 24, 48 e 72 h. Os parâmetros da cinética de degradação das silagens de cada tratamento (3 silagens) em cada animal (5 vacas) foram determinados pelo modelo: y = a + b(1 − e −c(t−L)). Os parâmetros gerados pela equação foram analisados como blocos inteiramente ao acaso, sendo que as idades de corte foram inseridas como efeito fixo e os animais como efeito aleatório (blocos). A silagem da planta aos 56 dias de rebrote apresentou maiores (P<0,05) valores de degradabilidade efetiva da MS e da FDN calculada para a taxa de passagem de 2,0%/h. Todas as silagens apresentaram baixa fração solúvel (<25,4%) e degradabilidade efetiva (<40,1%) da proteína bruta com taxa de passagem de 2%. Foi observado maior (P<0,05) tempo de colonização da FDN para as silagens realizadas com as plantas aos 84 e 112 dias de crescimento em comparação com a silagem produzida aos 56 dias. Os resultados da cinética de degradação ruminal das silagens de capim Andropogon gayanus indicam que a planta ensilada aos 56 dias de rebrote apresentou melhor valor nutricional...
Maturity is considered the primary factor affecting the nutritive value of forages. The aim of this study was to evaluate and compare dry matter (DM), crude protein (CP) and neutral detergent fiber (NDF) ruminal degradation kinetics of Andropogon gayanus grass silages harvested at three stages of maturity (56, 84 and 112 d). Dried and ground silage samples (5 mm) were incubated in nylon bags inside the rumen for 0, 6, 12, 24, 48, 72 and 96 h to estimate the kinetics of ruminal DM, CP and NDF degradation. The ruminal kinetic parameters of the silages from each treatment (56, 84 and 112 d of regrowth) in each animal (5 cows) were determined by the model: y = a + b(1 − e−c(t−L)). The parameters generated by the model were analyzed as randomized block design, with grass regrowth age as the fixed effect and animal the as random effect (blocks). The grass silage ensiled with 56 days of regrowth had the highest (P<0.05) effective degradability of DM and NDF calculated for fractional rate of particulate passage of 2%/h. All silages had low CP soluble fraction (<25.4%) and effective degradability calculated for fractional rate of particulate passage of 2%/h (<40.1%). A greater (P<0.05) NDF lag time was observed for the silages ensiled with 84 and 112d compared to the silage produced with 56d of regrowth. The ruminal degradation kinetics of Andropogon gayanus grass silages showed that the grass ensiled with 56 days of regrowth had higher nutritional value...
Subject(s)
Animals , Cattle , Fermentation , Rumen/metabolism , Sorghum , Silage/analysis , Carbohydrates/administration & dosage , In Vitro Techniques , KineticsABSTRACT
Twelve healthy Santa Ines sheep, non-pregnant and non-lactating underwent a protocol of experimental induction of nervous ketosis for studying the symptoms in ketosis and Pregnancy Toxaemia (PT) disease. Eight animals were subjected to infusion of 150 mL of isopropanol (IPA) at 35% in the jugular vein and four sheep were treated identically with isotonic saline solution (NaCl 0.9%) during 40 minutes. The animals treated with IPA showed increased heart rate (HR) after 40 minutes of infusion and decreased ruminal movement from the 10 minutes infusion with IPA and remaining low up to 10 minutes from the end of the infusion. Ruminal atony appeared in three animals, which showed slight meteorism gas. Infusion of IPA caused the appearance of nervous symptoms as depression, staggering, adduction of hind limbs, head pressing, teeth grind and blindness almost always accompanied by a decreased pupillary reflex and nystagmus. All the animals exhaled ketosis breath with strong odor within few minutes of the start of induction that helped the elimination of the IPA from the organism. The present results strongly suggest that part of the nervous symptoms observed in PT may be derived from the action of IPA. These present findings open new perspectives for a better understanding of the pathogenesis of PT in sheep...
Doze ovelhas hígidas, não prenhes e não lactentes foram submetidas a um protocolo de indução experimental de cetose nervosa para a avaliação de sintomatologia nos quadros de cetose e Toxemia da Prenhez. Neste protocolo, oito animais foram submetidos a infusão de 150 mL de solução de isopropanol a 35% na veia jugular, constituindo o grupo Tratado (GT), e quatro ovinos foram tratados identicamente com solução salina isotônica (NaCl 0,9%), constituindo o grupo Controle (GC) no decorrer de 40 minutos. Os animais do GT apresentaram aumento da frequência cardíaca (FC) aos 40 minutos de infusão e redução no movimento ruminal a partir dos 10 minutos de infusão com isopropanol, o qual permaneceu diminuído ate 10 minutos do termino da infusão. A atonia ruminal ocorreu em três animais, que manifestaram em seguida leve meteorismo gasoso. A infusão de isopropanol provocou o surgimento de sintomas nervosos como, depressão e sonolência, cambaleios, adução de membros posteriores, pressão da cabeça em obstáculo, ranger de dentes e cegueira quase sempre acompanhada de diminuição do reflexo pupilar e nistagmo. Todos os animais exalaram forte odor cetótico com poucos minutos do inicio da indução, fato que ajudou a eliminação do isopropanol do organismo. Os presentes resultados sugerem que parte dos sintomas nervosos verificados na Toxemia da Prenhez possa ser oriunda da ação do isopropanol. Estes resultados abrem novas perspectivas para o melhor entendimento da patogenia da Toxemia da Prenhez em ovinos...
Subject(s)
Animals , Ketosis/veterinary , Clinical Diagnosis/veterinary , Sheep Diseases/diagnosis , Heart Rate , Rumen/metabolism , /administration & dosage , Ketone Bodies/analysis , Diet/veterinaryABSTRACT
Quarenta e três ovelhas foram distribuídas em quatro tratamentos em um delineamento de blocos casualizados. Os tratamentos consistiram no fornecimento de dietas de flushing, formuladas com farelo de soja (FFS) ou com glúten de milho e farelo de algodão (FGM+FA) por 28 dias antes da ovulação, seguido pelo fornecimento de dietas de flushing ou de uma dieta de mantença (DM) durante 28 dias após a ovulação: T1 - FFS antes e após a ovulação (n=12); T2 - FFS antes da ovulação e DM após (n=11); T3 - FGM+FA antes e após a ovulação (n=10); T4 - FGM+FA antes da ovulação e DM após (n=10). O ganho de peso e o peso final não diferiram (P>0,05) entre os animais dos tratamentos. O ECC final foi maior (P<0,05) nas ovelhas do tratamento T3 do que nas do tratamento T2. A concentração de N-ureico foi maior (P<0,05) nas ovelhas dos tratamentos T1 e T3 do que naquelas dos tratamentos T2 e T4. A taxa de gestação e a prolificidade não diferiram (P>0,05) entre os animais. As dietas de flushing antes da ovulação, seguidas pelo fornecimento destas mesmas dietas ou de uma dieta de mantença após a ovulação, não alteraram a taxa de gestação e a prolificidade.
Forty-tree ewes were assigned to four treatments in a randomized block design. The treatments consisted of two flushing diets, composed of soybean meal (SMF) or corn gluten and cottonseed meal (CG+CMF) furnished for 28 days before ovulation, and feeding with flushing diets or a maintenance diet (MD) for 28 days after ovulation: T1 - (SMF) before and after ovulation (n=12); T2 - SMF before ovulation and a MD after (n=11); T3 - CG+CMF before and after ovulation (n=10); T4 - CG+CMF before ovulation and MD after (n=10). The gain in BW and the final BW did not differ (P>0,05) between treatments. The final BC was higher (P>0,05) in ewes in T3 treatment than in those in treatment T2. The urea N concentration was higher (P<0,05) in ewes in treatments T1 and T3 than those in treatments T2 and T4. The pregnancy rate and prolificacy did not differ (P>0,05) between treatments. The flushing diets before ovulation and feeding with this same diet or a maintenance diet after ovulation did not alter the pregnancy rate and prolificacy.
Subject(s)
Animals , Ovulation , Sheep/metabolism , Pregnancy Rate , Animal Feed/analysis , Rumen/metabolism , Animal Nutritional Physiological Phenomena , Glutens/analysis , Soybean Proteins/analysisABSTRACT
Determinou-se a digestibilidade intestinal (DI) da proteína de vários coprodutos do biodiesel nas formas de farelo e torta. Foram avaliados oito coprodutos: tortas e farelos de pinhão manso, nabo forrageiro, tremoço, algodão. Os coprodutos foram incubados no rúmen por 16 horas, e os resíduos não degradados no rúmen submetidos à digestão enzimática com solução de pepsina e pancreatina para a determinação da DI. Ainda, nos resíduos da incubação ruminal, foram determinadas: degradabilidade da matéria seca (DR), proteína degradável no rúmen (PDR) e proteína não degradável no rúmen (PNDR). A digestibilidade intestinal da proteína para os coprodutos do biodiesel variou de 2,4 a 48,6%. Todos os coprodutos avaliados caracterizaram-se como alimentos de alto teor proteico, sendo considerados de alta PDR, e apresentaram baixa digestibilidade intestinal da proteína. A DI da proteína dos coprodutos do biodiesel na forma de torta foi maior em comparação com a dos farelos. A torta e o farelo de algodão apresentaram os maiores coeficientes de DI.
The objective of this research was to determine intestinal protein digestibility (ID) of some biodiesel by-products in the form of cakes and the meals. Eight by-products were: cakes and meals of physic nut, turnip, lupine, cotton cake, cottonseed meal. The by-products were incubated in the rumen for 16 hours, were the undegradable rumen residues were submitted to enzymatic digestion with pepsin and pancreatin solution for the determination of ID. In the incubation residues the following was also determined: dry matter degradability (RD), rumen degradable protein (RDP) and rumen undegradable protein (RUP). The intestinal protein digestibility of biodiesel by-products ranged from 2.4 to 48.6%. All the by-products evaluated in this study were characterized as high protein sources and were considered high-RDP. The by-products presented low intestinal protein digestibility. The ID protein of biodiesel by-products was higher in the cakes than the meals. The by-products evaluated, the cottonseed cake and meal presented the highest ID coefficients.
Subject(s)
Animals , Digestion , Ruminants , Rumen/metabolism , Proteins/analysis , ProteinsABSTRACT
Rumen-protected conjugated linoleic acid [CLA] may increase the protein to fat ratio in milk, and potentially improve the energy balance of early lactation cows. The objective of this study was to evaluate the production performance and blood metabolite changes in Holstein cows supplemented with four different doses of CLA postpartum in early lactation. Eight multiparous Holstein cows with at least 25 kg/day milk production were randomly chosen and were included in an experimental design with four three week periods [7 days of adaptation and 14 days of treatment and sampling]. The experiment was carried out with four levels of protected CLA supplement including 0, 50, 100, and 150 g per day per cow. Blood metabolites such as cholesterol and LDL-C content decreased significantly [p<0.05], but other metabolites such as HDL-C, VLDL-C, triglyceride and BHBA did not change [p>0.05]. Milk production increased significantly [p<0.05], and 100 g/day of CLA supplemented treatment resulted in the highest production compared with the other groups. Milk fat percentage of the treated cows was reduced significantly and followed a dose-dependent response. No significant results were observed with regard to the protein content, solids-non-fat and milk density of the milk [p>0.05]. The increased milk production, and decreased blood LDL-C and cholesterol levels indicate an improvement in the physiological state of the cows. Given the enrichment of produced milk using this supplement, it is highly recommended to provide these supplements in dairy cow diets
Subject(s)
Animals , Female , Rumen/metabolism , Dairying , Milk/metabolism , CattleABSTRACT
Avaliou-se a qualidade da silagem de grãos úmidos de milho com adição de soja crua, por meio de medidas de digestibilidade parcial e total em bovinos. Foram utilizados três animais mestiços Nelore x Red Angus, implantados com cânulas ruminal e duodenal. O delineamento experimental foi o quadrado latino 3x3, com os seguintes tratamentos: SGM66= 60 por cento de volumoso, 26,6 por cento de silagem de grãos de milho e 13,4 por cento de farelo de soja e milho moído; SGM33= 60 por cento de volumoso, 13,4 por cento de silagem de grãos de milho e 26,6 por cento de farelo de soja e milho moído, e GMS= 60 por cento de volumoso e 40 por cento de farelo de soja e milho moído. A digestão e a digestibilidade da matéria seca não foram influenciadas pela inclusão de SGM na dieta. A dieta SGM66 aumentou a digestibilidade de matéria seca no intestino em relação à dieta GMS. Não houve efeito da inclusão da silagem de grãos na digestão e na digestibilidade das frações fibra em detergente ácido e fibra em detergente neutro da ração, bem como no fluxo ruminal e intestinal do amido. A SGM66 melhorou a digestibilidade total da proteína bruta, mas não mostrou efeito sobre a digestibilidade total da matéria seca, da fibra e do amido e sobre o ambiente ruminal no que se refere à acidez e à concentração de amônia.
The quality of high moisture corn grain silage with addition of raw soybean grains was evaluated by measures of partial and total digestibilities in cattle. Three crossbred Nelore x Red Angus steers averaging 305kg of live weigth and fitted with ruminal and duodenal cannulas were used. The experimental design was a 3x3 Latin square, and the steers received the following treatments: HMGS66 = 60 percent roughage, 26.6 percent high moisture grain silage, and 13.4 percent soybean meal and ground corn; HMGS33 = 60 percent roughage, 13.4 percent high moisture grain silage, and 26.6 percent soybean meal and ground corn; and GC = 60 percent roughage and 40 percent soybean meal and ground corn. The digestion and digestibility of dry matter was not influenced by the inclusion of HMGS in the diet. HMGS66 increased intestinal dry matter digestibility in relation to GC. The inclusion of high moisture corn grain silage did not affect acid detergent fiber and neutral detergent fiber digestions and digestibilities. The diet did not affect total intake of starch, as well ruminal and intestinal flow of starch. HMGS66 improved total digestibility of crude protein, but did not show effect on total digestibilities of dry matter, fiber, starch, and pH and ammonia concentration in the rumen.
Subject(s)
Animals , Glycine max/adverse effects , Silage/analysis , Zea mays/adverse effects , Ammonia/adverse effects , Cattle , Rumen/metabolismABSTRACT
Different supplementary enzymes have used widely in diets for ruminants and non-ruminants over the past decade. The present study investigated the effect of feeding natuzyme [enzyme supplement] on feedlot performance, feed digestibility and rumen metabolites of Varamini male lambs. Twenty-four Varamini male lambs [initial body weight 22 +/- 1.5 Kg with 3 to 4 months age] used in a completely randomized design for 84 days. The lambs were randomly allocated to three rations of 1] without enzyme, control diet, 2] with 0.5 g/kg of feed natuzyme, 3] with 1 g/kg of feednatuzyme with 8 replication. Basal diet was formulated according to CNCPS for sheep. Daily dry matter intake and monthly average gain of lambs recorded and digestibility of basal diet measured with chromic oxide as external marker. At the end of examination, rumen liquid samples collected from lambs and its pH and ammonia nitrogen were measured. The results showed that diets did not make significant effect on the average daily gain, dry matter intake and feed conversion ratio in lambs. Meanwhile, digestibility of crude protein, ether extract, dry matter, organic matter, neutral detergent fiber and acid detergent fiber of basal diet, ruminal pH and ammonia nitrogen did not show difference between diets. We concluded that use of 0.5 or 1 g/kg of feed natuzyme did not make significant effect on the performance of Varamini male lambs
Subject(s)
Male , Animals , Enzymes , Digestion , Rumen/metabolism , Diet , Sheep , Chromium Compounds , Hydrogen-Ion Concentration , Ammonia , NitrogenABSTRACT
Determinaram-se as frações dos carboidratos não fibrosos, hidrolisáveis e rapidamente fermentáveis em diferentes dietas e estimou-se a digestibilidade aparente desses nutrientes em dois ensaios com equinos. No ensaio I, utilizaram-se quatro equinos em delineamento quadrado latino 4x4, que consumiram dietas compostas por: feno de tifton-85; feno de tifton-85 e feno de alfafa; feno de tifton-85, feno de alfafa e concentrado; feno de tifton-85 e concentrado. No ensaio II, utilizaram-se 15 equinos em delineamento inteiramente casualizado, que consumiram dietas com 5, 13 e 21 por cento de extrato etéreo, obtidos com a inclusão de diferentes proporções de óleo de soja. A inclusão de concentrado nas dietas aumentou a digestibilidade dos carboidratos não fibrosos e de suas frações, sem afetar a digestibilidade da fibra, enquanto, em dietas com 13 por cento de extrato etéreo, a digestibilidade das frações dos carboidratos fibrosos e a dos não fibrosos não foram afetadas. Nas dietas com 21 por cento de extrato etéreo, houve redução na digestibilidade da celulose e dos carboidratos não fibrosos e suas frações hidrolisáveis e rapidamente fermentáveis. A análise dos carboidratos não fibrosos é uma boa estimativa do valor nutricional dos alimentos, podendo ser incluída na avaliação da qualidade dos alimentos e dietas dos equinos.
The fractions of nonfiber carbohydrates, hydrolyzable carbohydrates, and rapidly fermentable carbohydrates of diets and the apparent digestibility of these nutrients were evaluated in horses in two digestion assays. In assay I, four horses in 4x4 latin square diets: tifton-85 hay; tifton-85 hay and alfafa hay; tifton-85 hay, alfafa hay, and concentrate; and tifton-85 hay and concentrate. In assay II, fifteen horses were used in a completely randomized design, diets with 5, 13, and 21 percent ether obtained with the inclusion of different proportions of soybean oil. Results showed that inclusion of concentrate in diets increased digestibility of nonfiber carbohydrates, hydrolyzable carbohydrates, rapidly fermentable carbohydrates, and total carbohydrates, without affecting digestibility of fiber. In diets with 13 percent of ether extract in function of soybean oil inclusion, digestibility of fiber and nonfiber carbohydrates fractions was not affected; however, in diets with 21 percent of ether extract, the digestibility of cellulose, nonfiber carbohydrates, hydrolyzable carbohydrates and rapidly fermentable carbohydrates were reduced. Analysis of nonfiber carbohydrates fractions is a good estimate of feeds nutritional value, and could be included in quality evaluation of feeds and diets given to horses.
Subject(s)
Animals , Dietary Carbohydrates/adverse effects , Soybean Oil/adverse effects , Rumen/metabolism , EquidaeABSTRACT
Avaliaram-se as dinâmicas de trânsito e degradação da fibra em detergente neutro (FDN) em bovinos alimentados com forragem tropical de baixa qualidade e compostos nitrogenados. Foram utilizadas cinco novilhas Holandês x Zebu fistuladas no rúmen. A alimentação volumosa basal dos animais foi constituída por feno de capim-braquiária (Brachiaria decumbens Stapf.), com 5,08 por cento de proteína bruta (PB), com base na matéria seca (MS), fornecido ad libitum. Os cinco tratamentos avaliados foram definidos de acordo com o nível de suplementação proteica (0, 3, 5, 7 e 9 pontos percentuais acima do nível de PB da forragem). Como fonte de compostos nitrogenados, empregou-se mistura de ureia:sulfato de amônia:albumina (4,5:0,5:1,0). O experimento foi estruturado segundo delineamento em quadrado latino 5 x 5. Os níveis médios de PB nas dietas foram de 5,28; 8,08; 9,82; 11,87 e 13,63 por cento, com base na MS. Verificou-se elevação linear (P<0,05) da fração potencialmente degradável da FDN até o nível de 8,62 por cento de PB, com platô estimado de 47,92 por cento da FDN. Verificou-se efeito quadrático (P<0,05) sobre a taxa de degradação da fração potencialmente degradável da FDN em função dos níveis de PB da dieta, com máxima resposta estimada sobre 13,39 por cento de PB. O fluxo ruminal de partículas fibrosas apresentou relação linear-response-plateau em função do nível de PB na dieta (P<0,05), com ponto crítico para o início do platô sobre 7,59 por cento de PB.
Rumen transit and degradation dynamics of neutral detergent fiber (NDF) in cattle fed low-quality tropical forage and nitrogenous compounds were evaluated. Five crossbred heifers fitted with rumen cannulae were used. The animals were fed ad libitum with signal grass (Brachiaria decumbens Stapf.) hay, which had crude protein (CP) content of 5.08 percent in dry matter (DM). The five treatments were defined according to the level of CP in the diet (0, 3, 5, 7, and 9 percentile points above the CP level of the roughage). The supplement was a mixture of urea, ammonium sulfate, and albumin (4.5:0.5:1.0, respectively). The experiment was carried out according to a 5 x 5 Latin square design. The average CP levels in the diets were: 5.28, 8.08, 9.82, 11.87, and 13.63 percent in DM basis. The potentially degradable fraction of NDF was linearly increased (P<0.05) by CP levels in diet until 8.62 percent CP. From this point, there was stabilization of estimates (47.92 percent of NDF). The degradation rate of potentially degradable NDF showed a quadratic response (P<0.05) to CP levels, with maximal response at 13.39 percent of CP. The ruminal rate of passage of fibrous particles showed a linear-response-plateau (P<0.05) according to CP levels in the diet, with plateau beginning at 7.59 percent of CP.
Subject(s)
Animals , Animal Nutritional Physiological Phenomena , Brachiaria/adverse effects , Cattle , Nitroso Compounds/adverse effects , Dietary Fiber , Rumen/metabolismABSTRACT
The aflatoxin B1 degrading abilities of two different ruminants were compared in this study. One set of experiments evaluated the aflatoxin B1 degradation ability of different rumen fluid donors (steers vs. goats) as well as the rumen fluid filtration method (cheese cloth filtered vs. 0.45 microm Millipore) in a 2 x 2 factorial arrangement. Additional studies examined aflatoxin B1 degradation by collecting rumen fluid at different times (0, 3, 6, 9 and 12 h) after feeding. Cannulated Holstein steers (740 +/- 10 kg bw) and Korean native goats (26 +/- 3 kg bw) were fed a 60% timothy and 40% commercial diet with free access to water. Rumen fluid from Korean native goats demonstrated higher (p < 0.01) aflatoxin B1 degradability than Holstein steers. However, filtration method had no significant influence on degradability. In addition, aflatoxin degradation did not depend upon rumen fluid collection time after feeding, as no significant differences were observed. Finally, a comparison of two types of diet high in roughage found aflatoxin degradability in goats was higher with timothy hay opposed to rice straw, although individual variation existed. Thus, our findings showed the aflatoxin degradability is comparatively higher in goats compared to steers.
Subject(s)
Animals , Male , Aflatoxin B1/chemistry , Body Fluids/chemistry , Cattle/physiology , Goats/physiology , Korea , Rumen/metabolismABSTRACT
Foram comparadas as estimativas da cinética da fase sólida do capim-elefante (Pennisetum purpureum, Schum.) picado, mordentado com cromo (Cr), obtidas do ajuste de dois modelos não-lineares (bicompartimental tempo-independente e multicompartimental tempo-dependente) a resultados de excreção fecal de vacas Holandês x Zebu em lactação. Utilizaram-se dados de dois experimentos realizados em anos diferentes com capim-elefante cortado aos 60 e 45 dias, e suplementado, 3,3kg/vaca/dia, base matéria natural, ou não com concentrados. Foram utilizadas quatro e três vacas, respectivamente, no primeiro e no segundo ano de experimentação, havendo sempre duas fases de coleta de dados, necessárias para permitir que cada vaca pudesse ser avaliada em cada tratamento. As taxas de passagem ruminal estimadas variaram de 3,0 a 3,2 por cento/h no modelo bicompartimental tempo-independente, e de 2,6 a 3,0 por cento/h no modelo multicompartimental tempo-dependente, enquanto as respectivas taxas de passagem pós-ruminal variaram de 4,9 a 7,4 por cento/h e de 7,4 a 10,9 por cento/h. Os tempos médios de retenção do capim-elefante no trato gastrintestinal das vacas variaram de 66,0 a 76,2h no modelo bicompartimental tempo-independente, e de 48,1 a 57,8h no modelo multicompartimental tempo-dependente. O processo de dependência de tempo imposto pelo modelo multicompartimental permitiu melhor ajuste aos dados de excreção fecal do Cr, em relação ao modelo bicompartimental.
Particulate kinetics estimates of chopped elephantgrass (Pennisetum purpureum, Schum.) mordanted with Chromium (Cr) were obtained and compared by the adjustment of two nonlinear models - age-independent double-compartmental model and age-dependent multicompartmental model - to a Cr faecal excretion dates of lactating crossbred Holstein x Zebu cows. Results from two trials carried out in different years with elephantgrass cut at 60 and 45 days of growth and supplemented, 3,3 kg/cow/day, wet basis, or not with concentrates were used. Four cows in the first and three cows in the second year were used and in each year there were two phases of collection of data, necessary to allow that each cow could be evaluated in each treatment. The ruminal particulate passage rates of chopped elephantgrass ranged from 3.0 to 3.2 percent/h in age-independent double-compartmental model, and from 2.6 to 3.0 percent/h in age-dependent-multicompartmental model, while that the respective post-ruminal passage rates ranged from 4.9 to 7.4 percent/h and from 7.4 to 10.9 percent/h. The total mean retention time of the elephantgrass in the gastrointestinal tract ranged from 66.0 to 76.2 h in age-independent double-compartmental model, and from 48.1 to 57.8 h in age-dependent-multicompartmental model. The implicit assumption of age-dependence for the multicompartimental model allowed better fit to the data of faecal excretion Cr than that one of the double-compartmental model.