Apparent Digestibility Of Neutral Detergent Fiber Research Articles

Effects of sulfur and acidity on performance and digestibility in feedlot lambs fed dried distillers grains with solubles1

Negative interactions of the acidity and S content of dried distillers grains with solubles (DDGS) have not been quantified. The objectives of this study were to determine the effects of dietary S, dietary acidity, and their interactions on growth, feed efficiency, ruminal H2S concentration, and apparent nutrient digestibility in lambs fed DDGS-based diets. To neutralize acidity, the DDGS was untreated or treated with 2% NaOH. Dietary S content was adjusted with Na2SO4 to achieve a 0.2 percentage unit difference in dietary S. Experiment 1 included 72 ewe and wether lambs (BW = 24.9 ± 0.4 kg) penned by sex in 24 pens, blocked by BW, and allotted in a 2 × 2 factorial arrangement of treatments for a 60 d feeding trial. On a DM basis, diets were: i) 60% DDGS + 0% Na2SO4, ii) 60% DDGS + 0.88% Na2SO4, iii) 62% NaOH-treated DDGS + 0% Na2SO4, and iv) 62% NaOH-treated DDGS + 0.83% Na2SO4. There were no interactions (P ≥ 0.19) of dietary S concentration and NaOH treatment. Lambs fed DDGS treated with 2% NaOH had 4% greater (P = 0.05) final BW and tended (P ≤ 0.07) to have greater DMI and ADG than lambs fed untreated DDGS; however, NaOH treatment did not affect (P = 0.42) G:F. Increasing dietary S with Na2SO4 tended (P = 0.07) to reduce DMI; however, dietary S did not affect (P > 0.17) ADG, G:F, or final BW. Rumen H2S concentration in gas samples collected on d 32 and 60 were not (P > 0.17) affected by dietary S or NaOH treatment. Experiment 2 included 24 lambs (initial BW = 43.0 ± 4.4 kg) used to determine the effects of NaOH treatment of DDGS and sulfur (Na2SO4) supplementation on N retention and the apparent digestibility of NDF, ADF, and OM. Treatments were similar to those used in Exp. 1, except that dietary DDGS was reduced to 45% of DM. Intake of DM, NDF, ADF, and N was not affected (P > 0.16) by NaOH treatment of DDGS or dietary S (Na2SO4) content. Treating DDGS with 2% NaOH reduced (P = 0.05) NDF digestibility by 10% compared with lambs fed untreated DDGS. Urine pH for lambs consuming DDGS treated with 2% NaOH was increased (P = 0.01) 1.74 pH units compared with urine from lambs fed untreated DDGS. Nitrogen intake and retention were not affected (P > 0.35) by dietary S concentration or NaOH treatment of DDGS. For feedlot lambs, treating DDGS with 2% NaOH did not lower ruminal H2S concentrations, but tended to increase ADG and DMI. Although treating DDGS with 2% NaOH was an effective way to neutralize the acidity in DDGS, this treatment reduced NDF digestibility.

Effect of time of cutting and maceration on nutrient flow, microbial protein synthesis, and digestibility in dual-flow continuous culture1

Maceration and evening-cutting are 2 forage management techniques that have independently improved forage quality and nutrient utilization in ruminants, but have not been evaluated in combination. Using a dual-flow continuous culture fermenter system, this preliminary study was designed to evaluate the individual and combined effects of time of cutting and maceration on in vitro ruminal digestion, nutrient flows, and microbial protein synthesis. Forages were harvested as hay from a timothy (Phleum pratense L.)-birdsfoot trefoil (Lotus corniculatus L.) stand in the morning (AM) or evening (PM). Half of each morning- and evening-cut treatment was macerated (AM-M, PM-M). The chemical composition (DM, OM, CP, NDF, ADF), including nonstructural carbohydrates (NSC) and water-soluble carbohydrates (WSC), was determined for each of the 4 treatments (AM, AM-M, PM, PM-M). Forages were ground to 2 mm and allocated to separate fermenters at 60 g of DM/d in a 4 × 4 Latin square design. Fermenters were operated over four 10-d periods with the first 7 d for adaptation followed by 3 d of sampling. Evening-cutting enhanced the apparent digestibility of NDF (P = 0.02) and ADF (P = 0.006), with a tendency (P < 0.10) for improved true DM digestibility and microbial protein synthesis. Molar proportions of individual VFA were not affected (P > 0.10) by time of cutting, though evening-cutting increased (P = 0.02) total concentration of VFA. Maceration had no effect (P > 0.10) on true nutrient digestibility or microbial protein synthesis. An interaction of time of cutting and maceration (P < 0.05) was observed whereby maceration decreased true DM and OM digestibilities in evening-cut treatments, but had no effect in morning-cut treatments. Similarly, maceration reduced total N supply (P < 0.001) and molar proportions of acetate (P = 0.04) and increased molar proportions of propionate (P = 0.01) in evening-cut treatments with no effect on morning-cut treatments. These results indicate that independent use of evening cutting increased fiber digestibility and total VFA concentration, and independent use of maceration shifted molar proportions of VFA toward glucogenic fermentation. The combined use of these management techniques afforded no improvement for in vitro digestibility or metabolism when applied to morning-cut hay, and decreased nutrient digestibility when applied to evening-cut hay. Due to inherent limitations of in vitro systems, the results of this study should be interpreted with caution. Further in vivo studies are needed to support our conclusions.

Desempenho e digestibilidade aparente dos nutrientes em ovinos alimentados com dietas contendo bagaço de cana-de-açúcar tratado com óxido de cálcio

Foram estudados os efeitos da adição de 0,0; 0,75; 1,5 e 2,25% de óxido de cálcio no bagaço de cana-de-açúcar (com base na matéria natural) com o objetivo de avaliar o desempenho, o consumo de nutrientes e a digestibilidade aparente das dietas e dos nutrientes em ovinos mestiços da raça Santa Inês e raças nativas. Vinte e quatro ovinos, mantidos em total confinamento, foram distribuídos em delineamento inteiramente ao acaso, com quatro níveis de óxido de cálcio e seis repetições. Os animais foram mantidos em baias individuais, por 77 dias. Os primeiros 14 dias foram de adaptação e, então, seguiram-se três períodos de 21 dias de coleta de dados. Na determinação da digestibilidade, utilizou-se o método de coleta total de fezes, que foi realizada nos quatro últimos dias do período experimental. As fezes foram coletadas três vezes ao dia, às 7, 13 e 18 h. O uso do óxido de cálcio não influenciou os consumos de matéria seca, proteína bruta, fibra em detergente neutro, fibra em detergente ácido e nutrientes digestíveis totais, mas houve efeito linear sobre ganho de peso, com o aumento nas doses de óxido de cálcio, mas não sobre a conversão alimentar e os coeficientes de digestibilidade aparente da matéria seca, proteína bruta e fibra em detergente ácido. Entretanto, foi observado efeito quadrático para o coeficiente de digestibilidade aparente da fibra em detergente. A utilização do bagaço de cana hidrolisado com óxido de cálcio em níveis a partir de 1,5% da matéria natural promove melhoras no desempenho de ovinos e aumenta a digestibilidade apenas da fibra em detergente neutro.

Digestibilidade da dieta, parâmetros ruminais e desempenho de ovinos Santa Inês alimentados com polpa cítrica peletizada e resíduo úmido de cervejaria

Dois experimentos foram realizados com o objetivo de avaliar o efeito da substituição do milho por polpa cítrica peletizada e resíduo úmido de cervejaria sobre a digestibilidade aparente dos nutrientes da dieta, os parâmetros ruminais e o desempenho de ovinos. As dietas foram definidas pela substituição do milho (controle) pela polpa cítrica peletizada ou pela mistura de resíduo úmido de cervejaria e polpa cítrica. No experimento 1, para avaliação do consumo, da digestibilidade aparente dos nutrientes e dos parâmetros ruminais, foram utilizados 12 machos da raça Santa Inês canulados no rúmen, distribuídos em delineamento experimental de blocos completos casualisados, com três dietas e quatro repetições. No experimento 2, para avaliação do desempenho, foram confinadas 48 fêmeas, que foram alimentadas com as mesmas dietas do experimento 1. A substituição do milho pela polpa cítrica peletizada não influenciou o consumo nem a digestibilidade dos nutrientes da dieta, diferente da inclusão de resíduo úmido de cervejaria, que reduziu o consumo e a digestibilidade aparente dos nutrientes, com exceção apenas da FDN, cuja digestibilidade aparente foi similar entre as dietas. A inclusão de resíduo úmido de cervejaria na dieta reduziu as concentrações ruminais de acetato e propionato e aumentou a relação acetato/propionato e o pH ruminal. Em geral, não há diferença entre a dieta contendo milho e aquela contendo polpa cítrica em substituição total ao milho. A utilização de resíduo úmido de cervejaria, no entanto, reduz o ganho médio diário, o peso corporal final e a eficiência alimentar.

Effect of corn particle size and soybean meal treatment on performance of finishing beef steers fed corn-silage-based diets

In the first experiment, 39 medium-frame beef steers (456 ± 41 kg) were used in a 2 × 2 factorial arrangement of treatments to evaluate the effect of different feeding strategies to maximize energy and protein deposition on finishing performance and plasma amino acid profile of beef steers fed corn silage ad libitum for 99 d. To achieve this goal, steers were individually supplemented with either 6.6 kg DM d-1 of cracked corn (CC) or ground corn (GC) in combination with 540 g DM d-1 of either solvent extracted (SS) or lignosulfonate-treated soybean meal (Soypass® SP). Dry matter intake, average daily gain and feed to gain ratio were not affected by treatments or by their interaction (P &gt; 0.10). When compared with SS, SP tended to increase (P = 0.07) grade fat (1.3 and 2.2 ± 0.5 mm, respectively). The CC diets reduced the plasma concentration of branched-chained amino acids (P = 0.03) and leucine (P = 0.01), and tended to decrease that of isoleucine (P = 0.06) compared with the GC diets. No effect of diet was observed on plasma urea-N concentration. In the second experiment, four steers were used in a 4 × 4 Latin square design to evaluate digestibility and N balance of the diets used in exp. 1. Reducing particle size of corn increased apparent digestibility of starch (P = 0.01) and tended to reduce apparent digestibility of NDF (P = 0.07). In conclusion, formulating diets with ground or cracked corn in combination with solvent extracted or lignosulfonate-treated soybean meal does not appear to influence steer performance or digestion parameters.

Consumo, digestibilidade dos nutrientes e parâmetros ruminais em bovinos alimentados com silagem de capim-mombaça

Avaliaram-se o consumo, a digestibilidade aparente total e parcial dos nutrientes, o pH e a concentração de amônia ruminal em bovinos alimentados com silagem de capim-mombaça e concentrado nas seguintes proporções: 80:20, 65:35, 50:50 e 35:65, com base na matéria seca. Foram utilizados quatro animais Holandês x Zebu, com peso corporal médio inicial de 229kg, canulados no rúmen e abomaso, e distribuídos em quadrado latino 4x4. Os consumos de matéria seca (MS), matéria orgânica (MO), proteína bruta (PB), extrato etéreo (EE) e carboidratos totais (CHOT), expressos em kg/dia, e a digestibilidade parcial dos carboidratos não fibrosos (CNF) apresentaram comportamento linear crescente, com resposta platô nos níveis de concentrado de 54,1; 54,8; 52,9; 62,2; 55,2 e 52,7%. O consumo dos demais nutrientes, exceto da fibra em detergente neutro (FDN), e as digestibilidades aparente total de MS, MO e CNF e a parcial de MO aumentaram linearmente com o incremento do concentrado nas dietas. Não foram encontradas diferenças no consumo e nas digestibilidades aparente total e parcial da FDN. Para concentração de amônia e pH ruminal, observou-se efeito quadrático de tempo de amostragem, com valores máximos de 24,76mg/dL e 6,53 em 2,8 e 3,5 horas após a alimentação, respectivamente.

Effect of dietary concentrate on rumen fermentation, digestibility, and nitrogen losses in dairy cows

The objective of this experiment was to investigate the effect of level of dietary concentrate on rumen fermentation, digestibility, and N losses in lactating dairy cows. The experiment was a replicated 3×3 Latin square design with 6 cows and 16-d adaptation periods. Ruminal contents were exchanged between cows at the beginning of each adaptation period. Data for 2 of the diets tested in this experiment are presented here. The diets contained (dry matter basis): 52% (LowC; control) and 72% (HighC) concentrate feeds. Crude protein contents of the diets were 16.5 and 16.4%, respectively. The HighC diet decreased ruminal pH and ammonia concentration and increased propionate concentration compared with LowC. Acetate:propionate ratio was greater for LowC than for HighC. Rumen methane production and microbial protein synthesis were unaffected by diet. Dry matter intake was similar among diets, but milk yield was increased by HighC compared with LowC (36.0 and 33.2kg/d, respectively). Milk fat percentage and yield and total-tract apparent NDF digestibility were decreased by HighC compared with LowC. More ruminal ammonia N was transferred into milk protein with HighC than with LowC. Urinary N excretion, plasma urea N, and milk urea N concentration were not affected by diet. The ammonia emitting potential of manure was similar between LowC and HighC diets. Increased concentrate proportion in the diet of dairy cows resulted in reduced ruminal ammonia concentration and enhanced ammonia utilization for milk protein synthesis. These effects, however, did not result in reduced urinary N losses and only marginally improved milk N efficiency. Increasing dietary concentrate was not a successful strategy to mitigate enteric methane production and ammonia emissions from manure.

Effects of timing of corn silage supplementation on digestion, fermentation pattern, and nutrient flow during continuous culture fermentation of a short and intensive orchardgrass meal

Using a dual-flow continuous culture fermenter system, this study evaluated the effect of timing of corn silage supplementation on ruminal digestion and nutrient flows following a short and intensive orchardgrass herbage meal. Treatments included 28g dry matter (DM) of corn silage added either 9h (9BH; 0700h) or 1h (1BH; 1500h) before adding 42g DM orchardgrass herbage or no corn silage (control; 70g DM herbage). Herbage was fed as follows: 66% of the total herbage meal at 1600h, 22% at 1720h, and the remaining 12% at 1840h. Effluent was analyzed for organic matter (OM), crude protein (CP), and neutral detergent fiber (NDF). Purine concentrations in effluent and bacterial isolates were used to estimate the partition of effluent N flow into bacterial and nonbacterial fractions, and to calculate true OM digestibility. Fermenters were sampled for pH, volatile fatty acids (VFA), and NH3-N at 0730, 1100, 1530, 1600, 1720, 1840, and 2000h on d 10. Data were analyzed as a 3×4 Latin square experimental design. True digestibilities for OM (average of 78.5%) and CP (average of 84.6%), and apparent NDF digestibility (average of 82.7%) were not affected by treatment. Mean ruminal pH was lower for 9BH than for 1BH, averaging 5.6 and 6.5, respectively. Molar proportions of acetate were not affected by treatment. Propionate concentration was greater for 9BH than for 1BH, averaging 20.5 and 18.1mM, respectively. Diurnal patterns of pH, NH3-N, and acetate:propionate ratio were affected by treatment: 9BH had the lowest values for all measurements as the day progressed. The NH3-N concentration and effluent NH3-N flow were higher for 1BH (11.4mg/100mL and 0.26g/d, respectively) than for 9BH (8.8mg/100mL and 0.20g/d, respectively). Effluent NH3-N flow (as a % of total N flow) was the lowest for 9BH. Bacterial efficiency was not affected by treatments, with a mean of 10.5g of N/kg of OM truly digested. Under the same resource allocation (pasture plus supplement), a simple change in timing of corn silage feeding (9 rather than 1h before an orchardgrass herbage meal) may alter ruminal fermentation pattern. These changes could increase the glucogenic nutrient supply and improve N utilization by reducing ammonia N losses.

Use of chitosans to modulate ruminal fermentation of a 50:50 forage-to-concentrate diet in sheep1

The objective of this study was to investigate the effects of chitosan (CHI) on ruminal and cecal fermentation and on apparent digestibility in sheep. In a first trial, 4 ruminally fistulated sheep fed an alfalfa hay and concentrate diet formulated to meet 1.2 times their maintenance energy requirements were assigned to 2 treatments [no-additive control (CTR), or 136 mg/kg of BW of CHI] for 19 d in a 2 x 2 crossover design. Samples of ruminal fluid and feces were taken for VFA and NH(3)-N concentrations. At the end of each period of the crossover, ruminal fluid was used as inoculum for batch cultures (24 and 96 h), and the effects on rate and extent of gas production and on fermentation variables for starch, cellulose, and the same diet fed to the animals were calculated. In a second trial, 4 sheep fed the alfalfa hay and concentrate diet were assigned to 2 treatments (CTR and CHI), as for the first trial, but this time for 14 d in a 2 x 2 crossover design. Apparent digestibility was studied. In the first trial, in terms of ruminal fermentation, CHI did not affect (P = 0.12) total VFA concentration or acetate proportion, but increased propionate proportion (P = 0.004) and propionate-to-acetate ratio (C3:C2; P = 0.007) and decreased branched-chain VFA (BCVFA) proportion (P = 0.003) and NH(3)-N concentration (P = 0.045). In feces, CHI decreased total VFA concentration (P = 0.01) and acetate (P = 0.045) and butyrate (P = 0.025) proportions, and increased propionate (P = 0.04), valerate (P = 0.01), and BCVFA (P = 0.032) proportions and C3:C2 ratio (P = 0.045). In batch cultures, when starch was used as substrate, CHI decreased acetate proportion (P = 0.016) and methane production (P = 0.03) and increased propionate and valerate proportions and C3:C2 ratio (P < 0.001). When cellulose was used as substrate, CHI decreased in vitro OM digestibility (P = 0.033), total VFA concentration, propionate proportion (P < 0.001), C3:C2 ratio (P = 0.006), methane production (P < 0.001), NH(3)-N concentration (P = 0.019), and gas production rate (P = 0.002), and increased butyrate (P = 0.029) and BCVFA (P = 0.004) proportions and pH (P < 0.001). When the alfalfa hay and concentrate diet was used as substrate, CHI decreased butyrate (P < 0.001) and BCVFA (P = 0.008) proportions, methane (P = 0.005) and asymptotic gas production (P = 0.02), and gas production rate (P = 0.05). In the second trial, CHI decreased NDF apparent digestibility (P = 0.09). In conclusion, CHI shifted ruminal fermentation toward energetically more efficient routes, without reducing OM apparent digestibility.

The effects of concentrate added to pineapple (Ananas Comosus linn. Mer.) waste silage in differing ratios to form complete diets, on digestion, excretion of urinary purine derivatives and blood metabolites in growing, male, Thai swamp buffaloes

Four, male, growing Thai swamp buffaloes (197 +/- 5.3 kg and all 1 year old) were used to evaluate the effects of concentrate added to pineapple waste silage in differing ratios, to form a complete diet, studying in vivo digestion, the rate of passage, microbial protein synthesis and blood metabolites. Animals were fed ad libitum with 4 diets, using four combinations of pineapple waste silage (P) and concentrate (C), in the proportions (on a dry matter basis) of 0.8:0.2 (P80:C20), 0.6:0.4 (P60:C40), 0.4:0.6 (P40:C60) and 0.2:0.8 (P20:C80). The results showed that the intakes of dry matter (DM), organic matter (OM), nitrogen (N), the N-balance, urinary purine derivatives (PD) excretion, the ratios of allantoin to creatinine (CR), PD to CR, the plasma urea-N (PUN) and insulin increased in the animals, but the intake of neutral detergent fiber (NDF), the coefficient of whole tract, apparent digestibility of NDF, the transit time (TT) and the mean retention time (TMRT) decreased, when the proportion of concentrate in the diet increased. This study indicated that the proportion of P40:C60 in the diet produced the best efficiency of urinary PD excretion (mmol) per digestible OM intake (kg DOMI).

Supplementing Maize or Soybean Hulls to Cattle Fed Rice Straw: Intake, Apparent Digestion, In situ Disappearance and Ruminal Dynamics

Steers with ad libitum access to rice straw were assigned to four diets to evaluate the effects of maize or soybean hull supplementation on intake, in vivo digestibility, ruminal pH, VFA, ammonia-nitrogen (NH 3 -N) and in situ ruminal disappearance of feed nutrients by cattle consuming rice straw. Supplement treatments were: no supplement (RS); soybean meal at 0.127% BW (SBM); cracked maize at 0.415% BW plus 0.044% BW soybean meal (MAIZE); or soybean hulls at 0.415% BW plus 0.044% BW soybean meal (HULLS). The MAIZE and HULLS diets were formulated to provide approximately 4 MJ of NE m per kg of diet. Rice straw DMI was not affected (p = 0.34) by supplement. Apparent dry matter (DM) digestibility was greater (p<0.001) for MAIZE and HULLS (56.6 and 60.0%, respectively) than for steers consuming SBM or RS (51.8 and 44.4%, respectively). Apparent NDF digestibility was greater (p<0.0004) for HULLS than MAIZE (61.7 vs. 58.0%, respectively) and apparent ADF digestibility was greater (p<0.0008) for HULLS than MAIZE (61.1 vs. 49.2%, respectively). There was no difference in apparent hemicellulose digestibility (p = 0.43). Analysis of ruminal fluid collected 0, 2, 4, 6, and 8 h post-feeding revealed ammonia-nitrogen was greatest (p<0.05) for steers on SBM and HULLS diets at 2 h (24.08 and 22.57 mg/dl, respectively) and total volatile fatty acids was greatest (p<0.05) for HULLS at 4 h (230 mM/L). In situ disappearance, measured at 0, 2, 4, 6, 8, 16 and 24 h, indicated that SBM, MAIZE and HULLS tended to enhance the digestibility of DM and fiber components of rice straw. In situ disappearance of rice straw DM was greatest for SBM and/or HULLS from 4 to 24 h (p = 0.03). Rice straw NDF and ADF disappearance was enhanced by supplementation from 16 to 24 h (p<0.02). Rice straw DM, NDF and ADF disappearances at 24 h were similar for MAIZE and HULLS treatments. When feeding cattle rice straw diets, energy and protein-based supplements are essential. This study showed that fiber-based supplements are just as, if not more, effective as starch-based supplements in rice straw utilization. This study shows that soybean hulls, in spite of their high fiber content, are as efficient as maize for supplementing rice straw primarily because fiber in soybean hulls is highly digestible as shown by in vivo digestibility and in situ disappearance.

Substituição da silagem de milho pela silagem de rama de mandioca na alimentação de vacas leiteiras: consumo e digestibilidade dos nutrientes

The objective of the experiment was to study the effects of replacing corn silage (CS) with cassava foliage silage (CFS) – using the upper third of the foliage – on intake and nutrient digestibility. Twelve lactating dairy cows were used in a randomized block design to evaluated intake and digestibility. The levels of replacement of CS with CFS were 0, 20, 40 and 60%. The parameters studied were: dry matter intake (DMI), organic matter intake (OMI), neutral detergent fiber intake (NDFI), indigestible neutral detergent fiber intake (INDFI), apparent digestibility of dry matter (ADDM), apparent digestibility of organic matter (ADOM), apparent digestibility of crude protein (ADCP), apparent digestibility of neutral detergent fiber (ADNDF), apparent digestibility of total carbohydrates (ADTC) and apparent digestibility of non-fiber carbohydrates (ADNFC). The replacement of CS with different levels of the upper third of cassava foliage silage (CFS) had no effect in practically any of evaluated variables (p > 0.05). However, ADCP (p < 0.01) decreased as the levels of replacement were increased. The inclusion of CFS did not alter the intake or digestibility of nutrients, except for ADCP. In spite of the negative effect on the apparent digestibility of protein, CFS can partially replace CS in the diet of lactating dairy cows.

The interaction of harvesting time of day of switchgrass hay and ruminal degradability of supplemental protein offered to beef steers1,2

The objective of this study was to evaluate an interaction between harvest at 0600 (AM) vs. 1800 (PM) with high (HI) or low (LO) ruminal degradability of a protein supplement to change voluntary intake, digestion, or N retention by steers offered switchgrass (Panicum virgatum L.) hay. Black steers (255 +/- 14 kg of BW) were blocked by BW, and then randomly assigned (5 steers each) to AM/HI, PM/HI, AM/LO, or PM/LO treatment groups. Steers were group-housed in covered, outdoor pens with individual feeding gates. After adaptation and standardization, intake was measured for 21 d followed by a digestion trial (5 d of total collection). Steers were offered 767 (LO) or 825 (HI) g/d of supplement to provide 268 g of CP/d. Compared with AM, PM had greater (P = 0.01) concentrations of total nonstructural carbohydrate (TNC, 71 vs. 56 g/kg of DM), and lesser concentrations of NDF (760 vs. 770 g/kg of DM, P = 0.02), ADF (417 vs. 427 g/kg of DM, P = 0.02), and CP (55.9 vs. 58.6 g/ kg of DM, P = 0.07). Protein fractions A, B(2), and B(3) were similar for AM and PM, but HI contained more (P < 0.02) A (694 vs. 296 g/kg of protein) and less B(2) (174 vs. 554 g/kg of protein) fraction than LO. Harvest interacted with supplement to increase (P = 0.07) ad libitum digestible DMI for steers offered PM/HI (11.4 g/kg of BW daily) compared with steers offered PM/LO (10.2 g/kg of BW daily), but there was no difference for steers offered AM/LO or AM/HI (10.7 g/kg of BW). Apparent digestibilities of DM (594 vs. 571 g/kg of intake), NDF (591 vs. 562 g/kg of intake), ADF (585 vs. 566 g/kg of intake), and N (651 vs. 632 g/kg of intake) were greater (P < 0.04) for PM than for AM. Apparent digestibility of N was greater (P = 0.02) for HI (652 g/ kg of intake) vs. LO (631 g/kg of intake). Interactions between harvest and supplement for apparent digestibilities of NDF (P = 0.09) and ADF (P = 0.03) were due to no change or an increase in digestibility in response to increased ruminal degradability of supplement in steers offered PM harvest, whereas increased ruminal degradability of supplement decreased digestibility of NDF and ADF in steers offered AM harvest. Treatments did not affect hay intake (3.93 kg/d), N retained (15.8 g/d), or plasma urea N (5.25 mM) during ad libitum intake. Greater TNC in PM vs. AM harvest was not sufficient by itself to increase total voluntary DMI, but greater protein degradability interacted with harvest time to increase ruminal fiber digestibility and digestible DMI of beef steers offered PM vs. AM harvest.

Substituição total do milho e parcial do feno de capim-tifton por palma forrageira em dietas para vacas em lactação: consumo e digestibilidade

Para avaliação do consumo e da digestibilidade aparente dos nutrientes de dietas contendo diferentes níveis (0; 12,0; 25,0; 38,0 e 51,0%) de palma forrageira (Opuntia ficus indica Mill) em substituição total ao milho (Zea mays L.) e parcial ao feno de capim-tifton (Cynodon spp), foram utilizadas cinco vacas da raça Holandesa, distribuídas em quadrado latino 5 × 5. No início do experimento, os animais apresentavam 583 ± 7,07 kg de peso corporal (PC) e período de lactação em torno de 110 dias. Cada período experimental teve duração de 17 dias, dez dias para adaptação dos animais à dieta e sete dias para coleta de dados. O consumo de MS (kg/dia, %PC e g/kg0,75) e os consumos de MO, EE, PB, carboidratos totais (CT), FDN, FDA e NDT (kg/dia) diminuíram linearmente conforme aumentaram os níveis de palma forrageira na dieta. O consumo de CNF, no entanto, aumentou com a inclusão de palma forrageira na dieta. Os coeficientes de digestibilidade aparente de MS, MO, EE, PB, CT e CNF não foram influenciados pela inclusão de palma forrageira na dieta. Entretanto, o coeficiente de digestibilidade aparente da FDN reduziu linearmente com a inclusão de palma forrageira na dieta. A inclusão da palma forrageira nas dietas influenciou negativamente no consumo dos nutrientes e no coeficiente de digestibilidade da FDN.

Palma forrageira (&lt;em&gt;Opuntia ficus indica&lt;/em&gt; Mill) e uréia em substituição ao feno de capim tifton (&lt;em&gt;Cynodon&lt;/em&gt; spp) em dietas de vacas da raça holandesa em lactação. 1. Digestibilidade

The effect of five levels forage cactus and urea (0.0, 12.5, 25.0, 37.5 and 50%) in replacement of tifton hay in lactating Holstein cows diets, on the apparent digestibility of dry matter (ADDM), organic matter (ADOM), neutral detergent fiber (ADNDF), crude protein (ADCP), total carbohydrates (ADTC) and nonfiber carbohydrates (ADNFC) were evaluated. Five Holstein cows weighing on average 480 kg and with an average milk yield of 20 kg of milk/day were used in a 5x5 Latin square design. The DM, OM, TC and NFC apparent digestibility increased while NDF apparent digestibility decreased linearly and the CP apparent digestibility was not affected by the inclusion of forage cactus and urea. The total digestible nutrients of maintenance, digestible energy of lactation, metabolizing energy of lactation and liquid energy of lactation increased as the forage cactus and urea levels increased.

Effects of copper oxide bolus administration or high-level copper supplementation on forage utilization and copper status in beef cattle1

Two experiments were conducted to study effects of high-level Cu supplementation on measures of Cu status and forage utilization in beef cattle. In Exp. 1, eight steers randomly received an intraruminal bolus containing 12.5 g of CuO needles (n = 4) or no bolus (n = 4). Steers were individually offered free-choice ground limpograss (Hemarthria altissima) hay. On d 12 (Period 1) and d 33 (Period 2) steers were placed in metabolism crates, and total forage refused and feces produced were collected for 7 d. Daily samples of forage offered and refused and of feces excreted for each steer within period were analyzed for DM, ash, NDF, ADF, and CP. Liver biopsies were collected on d 0, 12, and 33. Copper oxide bolus administration resulted in greater (P < 0.03) liver Cu (DM basis) accumulation in Period 1 (556 vs. 296 mg/kg) and Period 2 (640 vs. 327 ppm). Apparent digestibilities of NDF and CP were greater (P < 0.04) for steers receiving no bolus in Period 2 (62.2 vs. 57.1% and 50.2 vs. 43.4% for NDF and CP digestibility, respectively). In Exp. 2, 24 crossbred heifers were assigned to individual pens and received a molasses-cottonseed meal supplement fortified with 0, 15, 60, or 120 ppm of supplemental Cu (Cu sulfate; six pens per treatment). All heifers were offered free-choice access to ground stargrass (Cynodon spp.) hay. Heifer BW and liver biopsies were collected on d 0, 42, and 84. Forage refusal was determined daily, and diet DM digestibility was estimated over a 21-d period beginning on d 42. Heifers consuming 120 ppm of supplemental Cu gained less (P < 0.05; 0.04 kg/d) than heifers consuming 15 (0.19 kg/d) and 60 ppm of Cu (0.22 kg/d), but their ADG did not differ from that by heifers consuming no supplemental Cu (0.14 kg/d; pooled SEM = 0.07). Heifers supplemented with 15 ppm of Cu had greater (P < 0.05) liver Cu concentrations on d 84 than those on the 0-ppm treatment and the high-Cu treatments (60 and 120 ppm). Forage intake was less (P = 0.07) by heifers receiving no supplemental Cu than by heifers on all other treatments (6.6 vs. 5.8 +/- 0.37 kg/d). Apparent forage digestibility was not affected by Cu treatment. These data suggest that high rates of Cu supplementation (Cu sulfate; > 60 ppm of total Cu) resulted in less liver Cu accumulation by beef heifers compared with heifers consuming diets supplemented with moderate dietary Cu concentrations (i.e., 15 ppm). As well, the administration of CuO boluses might depress the digestibility of forage nutrient fractions in steers.

Desempenho produtivo de vacas leiteiras alimentadas com diferentes proporções de cana-de-açúcar e concentrado ou silagem de milho na dieta

Objetivou-se avaliar o consumo, a digestibilidade aparente dos nutrientes, a produção e composição do leite e a variação do peso corporal de vacas lactantes alimentadas com dietas contendo diferentes proporções de cana-de-açúcar e concentrado ou silagem de milho. Foram utilizadas 12 vacas da raça Holandesa, distribuídas em três quadrados latinos 4 x 4, balanceados. As dietas experimentais foram formuladas à base de silagem de milho, na proporção de 60%, ou cana-de-açúcar corrigida com 1 % da mistura uréia+sulfato de amônio (9:1), nas proporções de 60, 50 e 40%. Não houve diferenças entre a dieta com 60% de silagem de milho e aquela com 40% de cana-de-açúcar para produção de leite (20,81 e 19,78 kg/dia), consumo de matéria seca e da maior parte dos nutrientes, digestibilidade aparente da maioria dos nutrientes e variação de peso. Entre as dietas à base de cana-de-açúcar, aquela com 60% foi a que promoveu o pior desempenho quanto à produção de leite (16,90 kg/dia), ao consumo de matéria seca e de nutrientes e à variação de peso, seguida da dieta com 50% de cana-de-açúcar, que apresentou resultados intermediários. A dieta com 40% foi a que proporcionou melhores resultados para estes parâmetros. As vacas alimentadas com a dieta contendo 50% de cana-de-açúcar apresentaram resultados semelhantes para consumo de FDN em comparação à dieta na proporção de 40%. As dietas com 60 e 50% de cana-de-açúcar apresentaram valores semelhantes para digestibilidades aparentes da FDN e carboidratos não-fibrosos. Não foram observadas diferenças entre os tratamentos para nenhum dos parâmetros de composição do leite.

Consumo e digestibilidade de subprodutos do processamento de frutas em ovinos

Esta pesquisa foi realizada objetivando-se avaliar o valor nutritivo de subprodutos do processamento de frutas. Foram estudados subprodutos de abacaxi, acerola, goiaba, maracujá e melão, utilizando-se 20 ovinos machos castrados, com peso médio de 34,5 kg. Adotou-se o delineamento experimental inteiramente casualizado, com cinco tratamentos (subprodutos) e quatro repetições. Os consumos de matéria seca (CMS) dos subprodutos de goiaba, maracujá e melão foram semelhantes, porém superiores ao CMS do subproduto de acerola. Os maiores consumos de proteína bruta (CPB) foram observados com maracujá e melão (g/animal/dia, g/UTM), enquanto acerola apresentou menor CPB. O subproduto de goiaba apresentou maior consumo de fibra em detergente neutro (CFDN) e fibra em detergente ácido (CFDA)e o de maracujá, maior coeficiente de digestibilidade aparente da matéria seca (DMS). Os subprodutos de acerola e goiaba apresentaram DMS inferior aos demais. Os coeficientes de digestibilidade aparente da proteína bruta dos subprodutos de maracujá e melão foram superiores aos demais subprodutos. Quanto aos coeficientes de digestibilidade da fibra em detergente neutro (DFDN) e da fibra em detergente ácido (DFDA), os subprodutos de acerola e goiaba mostraram-se inferiores, enquanto o subproduto de maracujá apresentou DFDA e DFDN superiores aos demais subprodutos. Não foram observadas diferenças para o balanço de nitrogênio entre os subprodutos estudados. Os resultados comprovaram que os subprodutos de abacaxi, maracujá e melão podem ser utilizados na alimentação de ruminantes, enquanto os subprodutos de acerola e goiaba apresentaram baixos coeficientes de digestibilidade, limitando sua utilização para ruminantes.

Performance of lactating dairy cows fed whole cottonseed with elevated concentrations of free fatty acids in the oil.

Twenty-four multiparous cows were used in a 10-wk randomized block design trial to evaluate the effects of feeding whole cottonseed (WCS) containing increasing concentrations of free fatty acids (FFA) in the oil on nutrient intake and digestibility, milk yield and composition, and select plasma metabolites. Two lots of WCS containing either 3 or 12% FFA were blended to provide WCS with 3, 6, 9, and 12% FFA. Cottonseeds were included in the wheat silage-based total mixed ration at 12.5% of dry matter (DM). There was no difference in intakes of DM, crude protein (CP), or neutral detergent fiber; yield of milk; or percentages of milk protein, lactose, or SNF. Milk fat percentage was lowest for the diet containing WCS with 6% FFA. Concentrations of individual milk fatty acids C6:0 decreased and C16:1 increased linearly as FFA in WCS increased. A cubic response was observed for concentrations of C8:0, C10:0, and C12:0 because of higher concentrations when diets contained WCS with 6% FFA than 3 and 12% FFA, which were higher than 9% FFA. Intake and apparent total tract digestibility of acid detergent fiber increased linearly as FFA concentration in WCS increased. Apparent NDF digestibility was highest for diets containing WCS with 3 and 6% FFA; CP digestibility was highest with WCS containing 3 and 9% FFA. Differences in milk fatty acid concentration and nutrient digestibility suggest minor changes in rumen fermentation; however, feeding WCS with up to 12% FFA did not negatively impact nutrient intake and digestibility or milk yield or composition.

Food intake and digestive efficiency in temperate wool and tropic semi-arid hair lambs fed different concentrate: forage ratio diets

This work was conducted to evaluate food intake and digestive efficiency of temperate wool and tropic semi-arid hair lambs, according to different concentrate: forage ratios in diet. Twenty-four lambs, averaging 90±1.8 days old and a mean body weight of 20±0.69 kg, 12 of them wool lambs, F 1 from Ideal×Ile de France crossing, and 12 others pure Santa Inês hair lambs, were distributed into a four replication 3×2 factorial arrangement consisting of three diets and two genotypes. Experimental diets consisted of: D1=60% concentrate mix (C) and 40% Cynodon sp. cv. Tifton-85 hay (F), D2=40% C and 60% F, and D3=20% C and 80% F. D1 was formulated for a daily gain of 300 g per animal. Increasing forage levels in diets resulted in linear reductions ( P<0.01) in DM, OM, CP, TCH and metabolizable energy (ME) intake, and a linear increase ( P<0.01) in NDF ingestion. Tropic semi-arid hair lambs had higher DM, OM, NDF, CP, and TCH intake than temperate wool lambs. Although there were no genotype effects in OM and GE coefficient of digestibility, hair lambs showed more efficient ( P<0.05) digestibility of DM, CP, NDF and TCH. Increases in forage levels of diets corresponded to a negative linear effect ( P<0.01) in the apparent digestibility of DM, OM, CP, TCH and GE, while apparent digestibility of NDF increased linearly ( P<0.01). Total endogenous nitrogen (fecal plus urinary N) for F 1 Ideal×Ilede France wool and Santa Inês hair lambs were, respectively, 182 and 312 mg/kg 0.75 per day. Thus, Santa Inês tropic semi-arid hair lambs showed to be more responsive than F 1 Ideal×Ile de France temperate wool lambs to low quality fibrous diets.