RESUMO
This study was performed to investigate the nitrogen (N) and carbohydrate digestive traits of grazing heifers. The experiment was carried out at the Federal University of Lavras. The treatments were a Marandu palisadegrass (Urochloa brizantha [Syn, Brachiaria brizantha] Stapf. A. Rich. cv. Marandu) monoculture fertilised with 150 kg N/[ha â year] (FP) or Marandu palisadegrass mixed pasture with forage peanut (MP). The pastures were grazed by six rumen-cannulated zebu heifers. A double cross-over design was used in four periods. Nutritive value, intake and apparent digestibility of forage, ruminal traits and kinetics and N balance were evaluated. Apparent total-tract digestibility of dry matter (DM) and neutral detergent fibre (NDF) were greater for FP than for MP. There was no effect in apparent total-tract digestibility of N. The estimated intestinal digestibility of nutrients was greater on MP than FP. Even though N intake and faecal N output were greater on MP than FP, there was no effect in urine N output. The N balance tended to be greater on MP than FP. The forage peanut, which contains condensed tannins, decreased ruminal fibre degradation, apparent digestibility and ruminal protein degradation, increased N flow from the rumen. Inclusion of forage peanut in the mixed pasture decreased the ruminal fibre degradability but increased N retention by the animals.
Assuntos
Ração Animal , Fenômenos Fisiológicos da Nutrição Animal , Dieta , Digestão , Rúmen , Animais , Bovinos/fisiologia , Digestão/fisiologia , Ração Animal/análise , Feminino , Dieta/veterinária , Rúmen/fisiologia , Rúmen/metabolismo , Nitrogênio/metabolismo , Proteínas Alimentares/metabolismo , Estudos Cross-Over , Fertilizantes/análise , Valor Nutritivo , Arachis/química , Carboidratos da Dieta/análise , Carboidratos da Dieta/administração & dosagem , Carboidratos da Dieta/metabolismo , Brachiaria/química , Brachiaria/fisiologia , Poaceae/químicaRESUMO
This experiment was designed to evaluate the effects of different concentrate crude protein (CP) concentration on performance, metabolism and efficiency of N utilization (ENU) on early-lactation dairy cows grazing intensively managed tropical grass. Thirty cows were used in a ten replicated 3 × 3 Latin square design. The treatments consisted of three levels of concentrate CP: 7.9%, 15.4%, and 20.5% offered at a rate of 1 kg (as-fed basis)/3 kg of milk. The cows fed low and medium CP had negative balance of rumen degradable protein and metabolizable protein. Increasing CP tended to linearly increase DMI, 3.5% FCM and milk casein, and linearly increased the yields of milk fat and protein. Increasing CP linearly increased the intake of N, the concentration of rumen NH3 -N, and the losses of N in milk, urine, and feces. Increasing dietary CP linearly increased the molar proportion of butyrate but had no effect on the other rumen VFAs and no effect on microbial yield. In conclusion, feeding a concentrate with 20.5% of CP to early-lactation dairy cows grazing tropical grasses, leading to a 17.8% CP diet, tended to increase DMI, increased the yield of 3.5% FCM and the milk N excretion, and decreased ENU by 32%.
Assuntos
Fenômenos Fisiológicos da Nutrição Animal/fisiologia , Bovinos/metabolismo , Bovinos/fisiologia , Dieta/veterinária , Proteínas Alimentares/administração & dosagem , Suplementos Nutricionais , Herbivoria/fisiologia , Lactação/fisiologia , Leite/metabolismo , Poaceae , Rúmen/metabolismo , Clima Tropical , Animais , Feminino , Nitrogênio/metabolismoRESUMO
ABSTRACT: The aim of this study was to evaluate the effect of total replacement of raw whole soybean (RAW) for roastedwhole soybean (ROS) on the production performance of Holstein cows. Two experiments were carried out usinga simple reversal design where RAW has been completely replaced by ROS. In experiment 1, 22 cows (175±60 days in milk)were used, and the dietary inclusion level of RAW or ROS was 3.7% of dry matter (DM). In experiment 2, 16 cows (130±50 days in milk)were used, and thedietary inclusion level of RAW or ROS was 11% of DM. In both experiments, ROS increased milk production by 1.1kgday-1 without changing fat and protein production. Dry matter intake or milk urea nitrogenwere not affected by dietary soy source. In experiment 2, plasma glucose concentration was decreased, and allantoin/creatinine ratio in urine tended to decreasein ROS. Experiment 2 also evaluated the nutrient digestibility and ruminal degradation kinetics of crude protein in two soybean sources. Roasting had no effect on the digestibility of DM, organic matter, and neutral detergent fiber. Roasted whole soybean hadgreater fraction B and lower protein degradation rate than did RAW; this showed that heat treatment was effective in increasing therumen undegradable amino acid flowto the animal, which suggesteda potential mechanism of action for improved performance observed in ROS.
RESUMO: O objetivo deste estudo foi avaliar o efeito da substituição total de soja integral crua (SC) por soja integral tostada (ST) sobre o desempenho produtivo de vacas Holandês. Foram realizados dois experimentos com delineamento experimental de reversão simples nos quais a SC foi totalmente substituída por ST. No experimento 1, foram utilizadas 22 vacas (175±60DEL) e o nível de inclusão dietética de SC ou ST foi de 3,7% na matéria seca (MS). No experimento 2, foram utilizadas 16 vacas (130±50 DEL) e o nível de inclusão dietético de SC ou ST foi de 11% na MS. Em ambos os experimentos, ST aumentou a produção de leite em 1,1kgd-1, sem alterar as produções de gordura e proteína. O consumo de MS e nitrogênio uréico no leite não foram afetados pela fonte de soja dietética. No experimento 2, a concentração de glicose plasmática foi reduzida e a relação alantoína/creatinina na urina tendeu a ser reduzida por ST. O experimento 2 também avaliou digestibilidade de nutrientes e cinética de degradação ruminal da proteína bruta das duas fontes de soja. Não houve efeito da tostagem nas digestibilidades da MS, matéria orgânica e FDN. A ST apresentou maior fração B e menor taxa de degradação da proteína do que a SC, mostrando que o tratamento térmico foi efetivo em aumentar o fluxo de aminoácidosnão degradáveis no rúmen para o animal, sugerindo um potencial mecanismo de ação para a melhora no desempenho observada com ST.
RESUMO
The objective of this study was to evaluate in situ ruminal degradation kinetics in two experiments, which different levels of dehydrated jackfruit (0, 5, 10 and 15% in natural matter) and cassavas scraping (0, 7, 15 and 30 % in natural matter) in the elephant grass silage, were used. The two experiments were carried out at the Department of Animal Science, Federal University of Viçosa, Brazil, in the same period and followed the same protocol. A mixed model was used, in which was considered random effect of experiment and fixed effects of experimental treatment and interaction among treatments with experiments. Samples of 3 g of each silage treatment were incubated in the rumen of three steers by periods of 0, 3, 6, 12, 24, 36, 48, 72, 96 and 120 hours. Then, the potentially degradable fraction(B), indigestible fraction (I), degradation rate of potentially degradable fraction (c), lag time, and effective degradability (ED) at 2, 5 and 8% per hour, were evaluated. No effect of addition of additives in ensiling of Napier grass for the effective degradability (P> 0.05) was observed, presenting an intercept at 47.7, 40.7 and 34.9% for the passage rates of 2, 5 and 8 %/h respectively. There were significant interaction among experiments with treatments (P 0.05), which demonstrates that the inclusion of additives in elephant grass silage promoted different benefits within eac
Objetivou-se com este estudo avaliar a cinética de degradação ruminal in situ em dois experimentos, os quais utilizaram níveis de jaca desidratada (0, 5, 10 e 15% na matéria natural) e raspa de mandioca (0, 7, 15 e 30% na matéria natural) na ensilagem do capim elefante. Os dois experimentos foram realizados no Departamento de Zootecnia da Universidade Federal de Viçosa, no mesmo período e seguiram o mesmo protocolo. Foi utilizado um modelo misto no qual foi considerado o efeito aleatório de experimento e efeitos fixos de tratamento e interação tratamento com experimento. Amostras de 3 g de silagens de cada tratamento foram incubadas no rúmen de três novilhas por períodos de 0, 3, 6, 12, 24, 36, 48, 72, 96 e 120 horas. Em seguida avaliou-se a fração potencialmente degradável (B), a fração indigestível (I), taxa de degradação da fração potencialmente degradável (c), lag time, e degradabilidade efetiva (DE) a 2, 5 e 8%/hora. Não houve efeito da inclusão de aditivos na ensilagem do capim elefante sobre a degradabilidade efetiva (P>0,05), apresentando intercepto em 47,7; 40,7 e 34,9% para as taxas de passagem de 2, 5 e 8%/h, respectivamente. Houve efeito da interação experimentos com tratamentos (P 0,05), o que demonstra que as inclusões de aditivos à silagem de capim-elefante promoveram diferentes benefícios dentro de cada experimento. A inclusão de jaca desidratada aumentou
RESUMO
The objective of this study was to evaluate in situ ruminal degradation kinetics in two experiments, which different levels of dehydrated jackfruit (0, 5, 10 and 15% in natural matter) and cassavas scraping (0, 7, 15 and 30 % in natural matter) in the elephant grass silage, were used. The two experiments were carried out at the Department of Animal Science, Federal University of Viçosa, Brazil, in the same period and followed the same protocol. A mixed model was used, in which was considered random effect of experiment and fixed effects of experimental treatment and interaction among treatments with experiments. Samples of 3 g of each silage treatment were incubated in the rumen of three steers by periods of 0, 3, 6, 12, 24, 36, 48, 72, 96 and 120 hours. Then, the potentially degradable fraction(B), indigestible fraction (I), degradation rate of potentially degradable fraction (c), lag time, and effective degradability (ED) at 2, 5 and 8% per hour, were evaluated. No effect of addition of additives in ensiling of Napier grass for the effective degradability (P> 0.05) was observed, presenting an intercept at 47.7, 40.7 and 34.9% for the passage rates of 2, 5 and 8 %/h respectively. There were significant interaction among experiments with treatments (P 0.05), which demonstrates that the inclusion of additives in elephant grass silage promoted different benefits within eac
Objetivou-se com este estudo avaliar a cinética de degradação ruminal in situ em dois experimentos, os quais utilizaram níveis de jaca desidratada (0, 5, 10 e 15% na matéria natural) e raspa de mandioca (0, 7, 15 e 30% na matéria natural) na ensilagem do capim elefante. Os dois experimentos foram realizados no Departamento de Zootecnia da Universidade Federal de Viçosa, no mesmo período e seguiram o mesmo protocolo. Foi utilizado um modelo misto no qual foi considerado o efeito aleatório de experimento e efeitos fixos de tratamento e interação tratamento com experimento. Amostras de 3 g de silagens de cada tratamento foram incubadas no rúmen de três novilhas por períodos de 0, 3, 6, 12, 24, 36, 48, 72, 96 e 120 horas. Em seguida avaliou-se a fração potencialmente degradável (B), a fração indigestível (I), taxa de degradação da fração potencialmente degradável (c), lag time, e degradabilidade efetiva (DE) a 2, 5 e 8%/hora. Não houve efeito da inclusão de aditivos na ensilagem do capim elefante sobre a degradabilidade efetiva (P>0,05), apresentando intercepto em 47,7; 40,7 e 34,9% para as taxas de passagem de 2, 5 e 8%/h, respectivamente. Houve efeito da interação experimentos com tratamentos (P 0,05), o que demonstra que as inclusões de aditivos à silagem de capim-elefante promoveram diferentes benefícios dentro de cada experimento. A inclusão de jaca desidratada aumentou