Cláudia Batista Sampaio

Rumen dynamics of neutral detergent fiber in cattle fed low-quality tropical forage and supplemented with nitrogenous compounds

The aim of this work was to evaluate the effects of supplementation with nitrogenous compounds on rumen dynamics of neutral detergent fiber (NDF) in cattle fed low-quality tropical forage. Five crossbred heifers with average live weight of 180 kg and 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 4.86% of dry matter (DM). The five treatments were proposed in order to raise the CP level of diets to 0, 2, 4, 6, and 8 percentile points above the CP level of the forage. 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 × 5 Latin square design, with five experimental periods. The average CP levels in the diets were: 5.19, 7.11, 8.60, 11.67, and 13.02% on DM basis. The potentially degradable NDF was linearly increased according to the CP levels in diet up to 6.97% of CP. From this point, there was stabilization of estimates (47.87% of NDF). The degradation rate of potentially degradable NDF was linearly increased with the CP levels in diets. The rumen flow of fibrous particles (L) showed a linear-response-plateau pattern according to the CP levels in diets. The plateau (maximum estimate) began on 7.24% of CP. The mean retention time in the rumen and the rumen fill effect of undegradable NDF were affect by the CP levels similarly to L, with plateau (minimum) beginning on 6.90 and 6.97% of CP, respectively.

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.

Evaluation of chromium concentration in cattle feces using different acid digestion and spectrophotometric quantification techniques

The objective of this work was to evaluate combinations between acid digestion techniques and spectrophotometric quantification to measure chromium concentration in cattle feces. Digestion techniques were evaluated based on the use of nitric and perchloric acids, sulfuric and perchloric acids, and phosphoric acid. The chromium quantification in the solutions was performed by colorimetry and by atomic absorption spectrophotometry (AAS). When AAS was used, the addition of calcium chloride to the solutions as a releasing agent was also evaluated. Several standard samples containing known chromium contents were produced (0, 2, 4, 6, 8 and 10g of chromium per kg of feces) using cattle feces obtained from three different animals to evaluate the accuracy of the different combinations of techniques. The accuracy was evaluated by adjusting a simple linear regression model of the estimated values on the actual values of chromium content in the standard samples. Regardless of the digestion technique, the chromium content estimates in the standard samples obtained by colorimetry were not accurate (P 0.05). The use of the digestion technique in phosphoric acid provided incomplete recovery of the fecal chromium (P 0.05) fecal chromium contents.

Efeito da combinação de óleo de soja e monensina na dieta sobre o consumo de matéria seca e a digestão em vacas lactantes

Four rumen fistulated lactating dairy cows were assigned to a Latin Square (4x4), with 21 days of experimental period, being the last three days for evaluation, to evaluate the effects of the combination of soybean oil and monensin in lactating dairy cow diets on dry matter intake, total and partial digestibility of the nutrients and ruminal fermentation and microbial synthesis. The animals were assigned to a factorial arrangement (2x2): presence (4% in total DM) or absence of soybean oil and presence (33 ppm) or monensin absence and were fed diets with 55% corn silage and 45% concentrate. For evaluation of the total and partial digestibility, feces samples and omasal digesta were collected, using ADFi and Cr2O3 as markers. The oil presence reduced dry matter intake, but allowed similar TND intake. The total digestibility of nutrients was not affected by treatments. The NDF ruminal digestibility was similar in the oil presence and in the monensin presence, but it was reduced in the combination of the two. The pH, the efficiency of microbial synthesis and the total of VFA of the rumen liquor were similar among the treatments. Interaction was observed between oil and monensin for N-NH3 concentration, being verified smaller value for the diets with oil only. The proportion of acetate was reduced either in the oil presence or in the monensin presence, but in different magnitudes, as well as in the combination of the two. The propionic acid concentration increased with monensin and with oil, and butyric acid decreased with oil. Acetate:propionate ratio was reduced either in the oil presence or in the monensin presence. The synthesis of microbial protein was reduced in the oil presence and still more when oil was associated to monensin. The soybean oil and monensin combination act about the same microbial population and the sensibility to the action of the monensin it is increased in the oil presence. The limitation intake by fill rumen effect, by reduction of NDF digestibility, or by higher energy content, does not justify alone the reduction in dry matter intake in diets with soybean oil, indicating that metabolic factor can be involved.

Avaliação dos teores de fibra em detergente neutro em forragens, concentrados e fezes bovinas moídas em diferentes tamanhos e em sacos de diferentes tecidos

Two experiments were carried out to evaluate the effects of particles sizes on contents of neutral detergent fiber (NDF) by using nylon bags F57 (Ankom®) and non-woven textile (NWT 100 g/m2). In the first experiment, to check contents of NDF obtained with each one of the textilles, quantitative filter paper (purified cellulose) was used as analytical standard. The material was processed in a 1 or 2 mm and put in the bags in a ratio of 20 mg of dry matter/cm2 of surface. The analyses were performed in a fiber analyser (Ankom220) and using a heat-stable a-amylase. No effects of particles sizes were found. In the second experiment, it was used samples of forage (signal grass hay, sugar cane, coastcross hay, corn straw, corn silage, and elephant grass at 50 and 250 days of growing after cutting), concentrate feeds (sorghum grain, gluten meal, citrus pulp, cottonseed meal, soybean meal, wheat bran, corn grain, whole soybean, and soybean hulls), and feces of cattle of animals fed diets containing 15 or 50% of concentrate. The samples were prepared, put in bags, and analyzed as described in the previous experiment. In both experiments, the smallest contents of NDF were found by using nylon bags, indicating loss of particles through the bag porosity. It is suggested grind of samples by using 1-mm screen sieve, which provides efficient extraction of cell content by the action of neutral detergent and a greater specific surface by the action of the heat-stable a-amylase enzyme. The use of particles ground at 2-mm overestimates NDF contents.

Centesimal composition and fatty acids of meat from lambs fed diets containing soybean hulls

The objective of this study was to evaluate the centesimal composition and fatty acids in meat from animals fed diets containing levels of soybean hulls. The experiment was conducted at UESB in Itapetinga-BA, Brazil. Twenty-five confined Santa Ines rams were used. Treatments consisted of different levels of substitution of corn by soybean hulls (0, 25, 50, 75 and 100%) and elephant grass silage as forage. The design was completely randomized. Samples of concentrate and silage were collected to evaluate the fatty acid composition. The experimental period lasted 110 days. After this period, the animals were slaughtered and samples of the longissimus muscle were collected and vacuum-packed for further analysis. The levels of total lipid and protein showed quadratic effect with the increase of soybean hulls in the diet, as the moisture increased linearly with inclusion. There was no effect of treatments on the percentage of ash. The composition of saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), PUFA/SFA and omega 6 (n-6) did not change, but increases in n-3 and reduction in the n-6:n-3 ratio were observed when the the amount of soybean hulls in the diet increased. The content of fatty acid conjugated linoleic acid (CLA) ranged from 3.0 to 4.0 g/kg at levels of substitution. The inclusion of soybean hulls in the diet increased CLA, the n-3 and decreased the n-6:n-3 ratio.

Fecal excretion patterns and short term bias of internal and external markers in a digestion assay with cattle

Objetivou-se avaliar o perfil de excrecao fecal e o vicio de tempo curto dos indicadores externos oxido cromico e dioxido de titânio e dos 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 × Nelore, nao-castrados, com idade e peso medios de 12 meses e 287 kg, mantidos em baias individuais. 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, segundo delineamento em quadrado latino 2 × 2, com agrupamento de sete quadrados. Os animais receberam diariamente 10 g de oxido cromico e 10 g de dioxido de titânio por meio de sonda esofagica. Foram realizadas coletas fecais pontuais (grab samples), diretamente do reto dos animais, nos horarios de 1h30, 3h00, 4h30, 6h00, 7h30, 9h00, 10h30, 12h00, 13h30, 15h00, 16h30, 18h00, 19h30, 21h00, 22h30 e 24h00. Nao foram observados efeitos das forragens ou dos niveis de concentrado sobre a dimensao do ciclo excretorio. O periodo fundamental do ciclo excretorio foi de 15,06 e 18,66 horas para o oxido cromico e dioxido de titânio, e de 9,93; 9,29 e 10,55 horas para MSi, FDNi e FDAi respectivamente. Verificou-se maior amplitude de oscilacao para os indicadores externos. Considerando-se conjuntamente as caracteristicas dos indicadores avaliados, recomendam-se delineamentos de amostragem fecal com o minimo de quatro coletas, distribuidas ao longo do dia ou somente no periodo diurno, para obtencao de estimativas de excrecao fecal isentas de vicio de tempo curto.

Effect of protein supplementation in the rumen, abomasum, or both on intake, digestibility, and nitrogen utilisation in cattle fed high-quality tropical forage

Effects of differing proportions of ruminal and abomasal protein infusion on intake, digestion, ruminal dynamics and the metabolic parameters of nitrogen (N) compounds were evaluated in beef bulls fed high-quality tropical forage (98.6 g crude protein, CP/kg dry matter) for ad libitum intake. Four Nelore bulls (280 ± 10 kg bodyweight) fitted with ruminal and abomasal cannulas were studied in a 4 × 4 Latin square. Treatments included: Control (no supplement) or 230 g/day of supplemental CP (as casein), with ratios of abomasal : ruminal infusion of 0 : 100, 50 : 50 or 100 : 0. Organic matter intake was not affected by treatments (P ≥ 0.30), though N intake increased by supplementation (P < 0.001). Total CP and organic matter digestibility were increased (P < 0.02) by protein supplementation. Nitrogen balance was 43% greater (P < 0.02) in the treatments with supplementation. Although supplementation did not affect (P = 0.98) the efficiency of absorbed N, a tendency towards a positive linear effect (P = 0.08) was observed when modifying the site of supplementation from the rumen to the abomasum. Supplementation increased (P < 0.01) ruminal ammonia-N, serum urea-N, urinary N and urea-N excretion, which subsequently decreased linearly (P < 0.01) by the displacement of supplementation from the rumen to the abomasum. The results indicate that protein supplementation, either in the rumen or abomasum produces similar effects on N retention. However, the metabolic mechanisms responsible for the improved N retention appear to differ between supplementation sites. Additionally, the efficiency of N utilisation increases with infusion of protein into the abomasum.

Ingestive Behavior of Heifers Supplemented with Glycerin in Substitution of Corn on Brachiaria brizantha Pasture.

The objective was to evaluate the ingestive behavior of crossbred heifers finished on a Brachiaria brizantha cv. Marandu pasture receiving four levels of glycerin in their supplementation. Thirty-six crossbred heifers with average initial weight of 264.83±3.83 kg and 20 months of age were distributed into a completely randomized design with four treatments and nine replications: control (0%), 4.82%, 10.12%, and 15.56% glycerin in the dry matter. The grazing time reduced linearly (p<0.05), whereas the time spent on activities like rumination, idleness, trough and total chewing time were quadratically affected (p<0.05). Bite rate and number of bites/day were quadratically influenced (p<0.05). The number of bites/swallowed cud and the number of bites/minute, however, increased linearly (p<0.05). Although the time spent on each cud and number of chews per cud were not affected (p>0.05). The number of rumination periods reduced linearly (p<0.05), whereas the number of grazing, idle and trough periods, and the times per grazing, idle, rumination and trough periods were quadratically affected (p<0.05). The feed and rumination efficiencies of the dry matter, non-fibrous carbohydrates, pasture dry matter and concentrate were quadratically affected (p>0.05) whereas the feed efficiency of neutral detergent fiber reduced linearly (p<0.05). Addition of glycerin in substitution of corn in supplements for animals managed on pastures does not influenced feed intake, but reduces the grazing time and increases the idle time. The supplementation also improves feed and rumination efficiencies.

Nutritional evaluation and ruminal fermentation patterns of kochia compared with alfalfa and orchardgrass hays and ephedra and cheatgrass compared with orchardgrass hay as alternative arid-land forages for beef cattle in two dual-flow continuous culture system experiments1

The objective was to evaluate the ruminal fermentation patterns of forage kochia (FK) compared with alfalfa hay (AH) and orchardgrass hay (OH) (Exp. 1), and ephedra (EPH) and immature cheatgrass (CG) compared with OH (Exp. 2), using a dual-flow continuous culture system. Two in vitro experiments were conducted, and in each experiment, treatments were randomly assigned to six dual-flow fermenters (1,223 ± 21 mL) in a replicated 3 × 3 Latin square design, with three consecutive periods of 10 d each, consisting of 7 d for diet adaptation and 3 d for sample collection. Each fermenter was fed a total of 72 g/d (DM basis) and treatments were as follows: Exp. 1: 1) 100% OH, 2) 100% AH, and 3) 100% dried FK. Exp. 2: 1) 100% OH, 2) 100% dried CG, and 3) 100% dried EPH. On day 8, 9, and 10, samples of solid and liquid effluent from each fermenter were taken for digestibility analysis, and subsamples were collected for NH3-N, VFA, and bacterial N determinations. Data were analyzed using the MIXED procedure of SAS. In Exp. 1, treatments did not affect DM, OM, and NDF digestibilities, total VFA and molar proportions of acetate, propionate, butyrate, and branched-chain VFA. True CP digestibility, ruminal NH3-N concentration, and total N, NH3-N, NAN, and dietary N flows (g/d) were greater (P < 0.05) for FK compared with the other forages. However, treatments did not affect bacterial efficiency. In Exp. 2, DM, OM, and CP digestibilities were greater (P = 0.01) for EPH, and NDF digestibility was greater (P < 0.05) for EPH and CG compared with OH. Ephedra had the highest (P < 0.05) pH and acetate:propionate ratio and the lowest (P < 0.05) total VFA concentration. Total VFA, ruminal NH3-N concentration, and NH3-N flow (g/d) were highest (P < 0.05) for CG. Total N flow and bacterial efficiency were highest (P < 0.05) for OH and CG, while the flows (g/d) of NAN, bacterial N, and dietary N were greater (P < 0.05) for OH compared with the other forages. Results indicate that when compared with AH and OH (Exp. 1), FK has similar ruminal fermentation patterns and may be an adequate alternative for beef cattle producers. Furthermore, when compared with OH (Exp. 2), immature CG may also be an adequate forage alternative. This is especially important for areas in which conventional forages may not grow well such as the U.S. arid-land. However, EPH should not be used as the sole forage due to its poor ruminal fermentation as evidenced by the lowest total VFA concentration and propionate molar proportion.