Sebastião de Campos Valadares Filho

Influence of incubation time and particles size on indigestible compounds contents in cattle feeds and feces obtained by in situ procedures

The aim of this work was to evaluate the effects of in situ incubation time and particles size on the estimates of indigestible fractions of dry matter (iDM), neutral detergent fiber (iNDF), and acid detergent fiber (iADF) in cattle feeds and feces. Samples of corn grain, wheat bran, corn silage, elephant grass, sugarcane, signal grass hay, corn straw, and feces obtained from cattle fed high and low concentrate diets were used. The samples were ground through 1 mm, 2 mm, and 3 mm screen sieve and put in 4 × 5 cm non-woven textile bags (20 mg DM/cm² of surface). The samples were divided in three groups, being each group incubated in the rumen of a crossbred heifer. The incubation procedure was conducted three times with the change of groups among animals. The following incubation times were used: 0, 12, 24, 48, 72, 96, 120, 144, 168, 192, 216, 240, and 312 hours. The contents of iDM, iNDF, and iADF were evaluated sequentially in each bag. The degradation profiles were interpreted by a non-linear logistic model. The particles size did not influence the estimates of iNDF and iADF. However, the particles size altered the rumen degradation dynamic rates of DM for corn silage and corn grain; of NDF for sugarcane, corn silage, and corn straw; and ADF for sugarcane. For those samples, the particle size has been positively associated with the incubation time necessary to estimate the indigestible fraction. Incubation times of 240 hours for DM and NDF, and 264 hours for ADF were suggested for obtaining more accurate estimates of indigestible fractions. The use of 2 mm particle size can increase the precision of estimates.

Níveis de proteína em suplementos para terminação de bovinos em pastejo durante o período de transição Seca/Águas: digestibilidade aparente e parâmetros do metabolismo ruminal e dos compostos nitrogenados

The objective of this trial was to evaluate ruminal, intestinal, and total tract apparent digestibilities of nutrients as well as metabolism of ruminal and nitrogenous compounds in supplemented finishing cattle during the drought to rainy transition season. Five Holstein x Zebu steers averaging 304 kg of live weight and 24 months of age located in five paddocks (0.34 ha each) of Brachiaria decumbens were used in this trial. The supplements fed (4 kg/animal/day) contained ground corn, whole soybean, urea, ammonium sulfate, and minerals and were formulated to yield, on as fed basis, 12, 16, 20, and 24% of crude protein (CP). Four animals were assigned to a 4 x 4 Latin square with experimental periods lasting 21 days. The remaining animal was not supplemented and was used for comparative purposes (CONT). No significant differences in ruminal, intestinal, and total tract apparent digestibilities of dry matter, organic matter, and neutral detergent fiber were observed by increasing the CP contents of the supplements. Similarly, abomasal flows of total nitrogen, ammonia nitrogen, and microbial nitrogen (MICN) did not differ when the CP contents of the supplements were increased. However, concentration of ruminal ammonia nitrogen increased linearly by incrementing the CP content of the supplement from 12 to 24%. Microbial efficiency averaged 17.5 g of MICN/kg of organic matter fermented in the rumen (OMFR) across supplements and was higher than that of the CONT (10.6 g of MICN/kg of OMFR). In addition, it was observed a significant cubic effect for urinary excretion of urea by increasing the CP contents of the supplements.

Níveis de Proteína em Suplementos para Terminação de Bovinos em Pastejo Durante o Período de Transição Seca/Águas: Consumo Voluntário e Trânsito de Partículas

Avaliaram-se o consumo e os parâmetros da cinetica de trânsito de particulas em bovinos suplementados durante a fase de transicao entre os periodos seco e chuvoso. Foram utilizados cinco novilhos Holandes x Zebu com idade e peso medios iniciais de 24 meses e 304 kg, respectivamente, manejados em cinco piquetes de Brachiaria decumbens (0,34 ha). Foram fornecidos suplementos (4 kg/animal/dia), constituidos por fuba de milho, grao de soja integral, ureia, sulfato de amonia e mistura mineral, formulados para apresentarem niveis de 12, 16, 20 e 24% de proteina bruta (PB), com base na materia natural. O experimento foi conduzido em quatro periodos experimentais de 21 dias e analisado por delineamento em quadrado latino 4 x 4. O quinto animal, mantido sem suplementacao (controle), foi utilizado como medida de comparacao descritiva. A forragem selecionada pelos animais apresentou teores medios de PB e fibra em detergente neutro (FDN) de 109,9 e 564,4 g/kg de materia seca (MS), respectivamente. A variacao do nivel de PB dos suplementos nao alterou os consumos de MS, de materia orgânica e de FDN. O fornecimento de suplementos reduziu o consumo de pastagem e ampliou o consumo de MS total em relacao ao controle, com coeficiente medio de substituicao de 0,41. O nivel de PB dos suplementos nao afetou a taxa de passagem ruminal das particulas, cujo valor medio (0,034 h-1), foi superior ao observado no controle (0,029 h-1).

Evaluation of fecal recovering and long term bias of internal and external markers in a digestion assay with cattle

Objetivou-se estimar a recuperacao total e o vicio de tempo longo das estimativas de excrecao fecal obtidas com os indicadores externos oxido cromico e dioxido de titânio e com os indicadores internos materia seca indigestivel (MSi), fibra em detergente neutro indigestivel (FDNi) e fibra em detergente acido indigestivel (FDAi) em ensaio de digestao com bovinos alimentados com diferentes dietas. Foram utilizados 14 novilhos F1 Red Angus x Nelore, nao-castrados, com idade e peso medios de 12 meses e 287 kg. Os animais foram alimentados com silagem de capim-elefante, silagem de milho ou feno de capim-braquiaria, suplementados ou nao com 20% de mistura concentrada. O experimento foi constituido de dois periodos de 13 dias cada, segundo delineamento em quadrado latino 2 x 2, com agrupamento de sete quadrados. Os animais receberam diariamente 10 g de oxido cromico e 10 g de dioxido de titânio atraves de sonda esofagica. Nao foram observados efeitos de forragem, nivel de concentrado ou de sua interacao sobre as estimativas de recuperacao fecal, tanto dos indicadores internos quanto dos indicadores externos. As estimativas de recuperacao fecal media para o oxido cromico e para o dioxido de titânio foram de 99,50% e 101, 95%, respectivamente. Para os indicadores internos, observou-se recuperacao fecal media de 99,02; 98,87 e 102,07% para MSi, FDNi e FDAi, respectivamente. Em todos os casos, as recuperacoes fecais foram iguais a 100%. Todos os indicadores avaliados podem ser considerados isentos de vicio de tempo longo. Contudo, maior precisao e verificada para as estimativas de excrecao fecal obtidas com indicadores internos.

Fontes suplementares de proteína para novilhos mestiços em recria em pastagens de capim-braquiária no período das águas: desempenho produtivo e econômico

The performance was evaluated of beef crossbred Holstein-Zebu steers, supplemented with different protein sources on pasture of Brachiaria brizantha, cv. Marandu, during the wet season. The area was divided into paddocks of 1.5 ha, with an availability of dry matter and potentially digestible dry matter of 7.46 and 4.50 t/ha, respectively. Twenty-five animals with 229 kg initial weight and 12 months of age were distributed in a complete randomized design, with five treatments and five replications. The following treatments were evaluated: mineral mix (MM) control group; soybean meal (SM) + cottonseed meal (CM) and MM; SM and MM; ground soybean grain (GGS) and MM; whole soybean grain (WSG) and MM; supplied daily on the amount of 60, 510, 460, 560 and 560 g/animal, respectively. Even without statistical significance, the animals that received the supplement showed a gain of 211 g (23.78%) greater than the animals that received only mineral mix. The use of multiple supplements based on soybean meal and cottonseed meal provided 247g/animal/day greater than the mineral mix. The supplementation with protein sources may provide additional gain during the wet season. Multiple supplementation provided economic return regardless of the protein source evaluated in relation to the control group.

Crescimento, conversão alimentar e rendimento de carcaça de bezerros da raça holandesa alimentados com dietas contendo diferentes níveis de volumoso

This work was conducted aiming to evaluate the effect of different forage levels in the diet on the average daily dry matter intake (DMI), average weight gain (AWG), feed:gain ratio and carcass yield. Thirty-six pure Holstein bull calves, 60 days old with initial average live weight (LW) of 78 kg, were allotted in a completely randomized experimental design. The animals were ad libitum fed with diets contained 10, 25, 40, and 55% of forage, on the DM basis, using chopped coast-cross (Cynodon dactylon) grass, ground corn and soybean meal, which constitute diets with approximately 16% CP. Animals were weighed at each 28 days period, with more frequent weighing for the animals near to the pre stabilized slaughtering weights of 190 ± 10 and 300 ± 10 kg, for the groups 1 and 2, respectively. Forage levels of the diet for both groups did not affect the dry matter intake. There was increased linear effect of forage level on feed:gain ratio expressed as LW or empty body weight (EBW). The average weight gain expressed in LW and EBW decreased linearly in function of the levels of forage in the diet. The hot carcass weight and hot carcass dressing for animals in group 2 were not affected, while the hot carcass dressing of animals from group 1 decreased linearly with the level of forage in the diet. The average daily gain at 28 and 56 days for group 1 and at 28, 56, 84 and 112 days for group 2, reduced linearly with the increasing of forage levels in the diets. The animal performance for both groups was higher with the use of low levels of forage in the diets, but above five months of age, the use of higher forage levels was not harmful to the performance of the animals.

Composição corporal e exigências líquidas de energia e proteína de bezerros da raça holandesa alimentados com dietas contendo diferentes níveis de volumoso

The objective of this work was to evaluate the effects of different forage levels in the diet on the body composition, net energy for maintenance and weight gain and net protein requirements for weight gain. Fifty-two pure Holstein bulls calves; 60 days old with initial average live weight (LW) of 78 kg were used. Eight reference animals were slaughtered at the beginning of the feeding trial. Another group of eight animals were fed diet with 90% of forage and 10% of concentrate to meet the requirements slightly above maintenance (maintenance group). The remaining 36 animals were allotted in the treatments in a complete randomized experimental design, in four groups of nine animals, in function of forage levels in the diet: 10, 25, 40 and 55%, on the DM basis, using chopped coast-cross (Cynodon dactylon) grass, ground corn and soybean meal, which constitute diets with approximately 16% CP. Five animals from each treatment were slaughtered with 190 + 10 kg LW and four with 300 + 10 kg LW. The net energy (NE) requirement for maintenance was estimated from the regression equations between the logarithms of produced heat and the metabolizable energy intake (MEI), assuming MEI equal to zero. Regression analysis, of the logarithm of the amounts of fat, protein and energy, in function of the logarithm of empty body weight (EBW) were fitted. The energy requirement for maintenance was in average 110.46 kcal/kg.75. The amount of fat and the energy content of weight gain increased as the animal LW increased, for all forage levels of the diet and in overall. The net energy and protein requirements for 1 kg of EBW gain were 2.83 Mcal/day and 183.20 g/day, respectively. The net energy and protein requirements for weight gain of Holstein calves increased with the increase of the empty body weight.

In vitro degradation of neutral detergent fiber from high-quality tropical forage according to supplementation with protein and (or) carbohydrates

The objective was to evaluate the effect of protein and (or) carbohydrate supplementation on the rumen degradation of neutral detergent fiber (NDF) from high-quality tropical forage. The experiment simulated the supplementation of finishing cattle under grazing during the rainy season (70:30 forage to concentrate ratio, as dry matter basis). Samples of elephant grass (Pennisetum purpureum Schum.) cut after 21 days regrowth were used as basal forage. The concentrate used was formulated to contain 30% crude protein, using starch as the [...]

Composição bromatológica e digestibilidade in vitro da matéria seca de silagens de milho e sorgo tratadas com inoculantes microbianos

Avaliaram-se a composicao bromatologica e a digestibilidade in vitro da materia seca (DIVMS) de silagens de milho e sorgo, tratadas ou nao com inoculantes microbianos, em diferentes periodos de fermentacao. Utilizou-se um arranjo fatorial 6 x 2 x 3 (periodos de fermentacao x silagens x inoculantes), em delineamento inteiramente casualizado, para avaliacao dos teores de materia seca (MS) e proteina bruta (PB), e um arranjo fatorial 4 x 2 x 3 para avaliacao dos constituintes fibrosos e da DIVMS, ambos com tres repeticoes. Observou-se os efeitos da interacao periodo de fermentacao ´ silagem ´ inoculante sobre os teores de MS e da interacao inoculante ´ periodo, sobre os teores de PB das silagens. Constatou-se efeito da interacao triplice tambem sobre os teores de fibra em detergente neutro (FDN) e fibra em detergente acido (FDA). Estimaram-se teores minimos de FDN nas silagens de milho tratadas com os inoculantes Silobac e Maize-All, respectivamente, de 52,14 e 50,75%, aos 37,34 e 46,1 dias apos a ensilagem. Quanto a celulose, verificou-se, entre as silagens de milho, menores valores nas silagens tratadas, mas nao foi detectado efeito de inoculante nas silagens de sorgo. Os teores medios de hemicelulose foram influenciados por silagem, periodo e inoculante, registrando-se na silagem de milho (29,8%) valor maior que na de sorgo (28,4%). Houve efeito quadratico do periodo de fermentacao sobre a DIVMS da silagem de milho tratada com os inoculantes Silobac e Maize-All, estimando-se valores maximos de 71,1 e 71,7%, aos 42,29 e 50,3 dias de ensilagem, respectivamente. As DIVMS das silagens de sorgo, no entanto, nao foram influenciadas pelo periodo de fermentacao.

Efeitos da inclusão e dos tempos de exposição da cana-de-açúcar ao óxido de cálcio sobre os parâmetros digestivos e fisiológicos de novilhas nelores

It was aimed to evaluate the effect of inclusion and times of sugar cane exposition to whitewash on intake and total and partial digestibility of nutrients and ruminal parameters and to compare titanium dioxide and chromium oxide as markers to estimate fecal dry matter excretion and dry matter abomasal flow. It was used six rumen and abomasum cannulated Nellore females, with average body weight of 250 ± 19 kg, distributed in an incomplete 6 x 6 latin square design. The experiment was set in a 3 x 2 factorial scheme with three levels of whitewash (0; 0.5 or 1.0% natural matter) and two times of sugar cane storage (0 and 3 days). There was no effect of storage times neither interaction among levels of whitewash and storage times on the intake of nutrients. However, levels of whitewash linearly increased consumption of dry matter (DM), organic matter (OM) and non-fibrous carbohidrates (NFC).Storage times reduced total apparent digestibility of dry matter, organic matter and neutral detergent fiber corrected for ash and protein (NDFap), but they did influence ruminal apparent digestibility of the nutrients. The inclusion of whitewash increased the consumption of total digestible nutrients (TDN), but it did not affect total digestibility and ruminal digestibility of the nutrients. The markers produced similar results for the estimates of total and ruminal apparent digestibility of all the evaluated nutrients. Interactions for ruminal pH were observed. However, values of amonical nitrogen were only influenced by sampling times. Addition of whitewash does not affect preservation of sugarcane, but it positively influences consumption of DM, OM, and TDN of the animals. The markers produced similar estimative to total tract and ruminal apparent digestibility of all nutrients. Titanium dioxide and chromium oxide markers produce similar estimates of digestibility.