NDF Fractions Research Articles

Intake and digestion of wheat forage by stocker calves and lambs

Because wheat forage contains high concentrations of N, NPN, digestible DM, and water, beef cattle and sheep require an adaptation period before positive BW are seen. The objective of the present experiment was to determine the impact of length of exposure of lambs and steers to wheat forage on BW gains, N retention, and forage digestibility. Sixteen steer calves (average BW = 210 +/- 12 kg) and 20 wether lambs (average BW = 31.5 +/- 2.0 kg) were randomly assigned to 1 of 2 treatment groups. Group 1 grazed a wheat pasture for 120 d during the winter, whereas group 2 was wintered on dormant warm-season grass pastures plus warm-season grass hay and plant-based protein supplements. In the spring (April 5), all lambs and steers grazed wheat pasture for 14 d and were then housed in metabolism stalls and fed freshly harvested wheat forage to determine forage digestibility and N metabolism. Data were analyzed for lambs and steers separately as a completely randomized design, using the individual animal as the experimental unit. Lambs and steers grazing wheat pasture for the first time in the spring had less ADG during the first 14 d than lambs (80 vs. 270 g, respectively; P = 0.01) and steers (1.06 vs. 1.83 kg, respectively; P = 0.09) that had grazed wheat pastures all winter. Digestibility of DM, NDF, and ADF fractions and N metabolism of freshly harvested wheat forage by lambs and steers were not different (P > 0.10) between the 2 treatment groups. Less ADG during the first 14 d of wheat pasture grazing is most likely the result of less DMI by nonadapted animals and is not due to diet digestibility or N metabolism.

Effect of intake level and alfalfa substitution for grass hay on ruminal kinetics of fiber digestion and particle passage in beef cattle

Two experiments were conducted to evaluate digestion kinetics of alfalfa (Medicago sativa L.) substitution for grass hay in beef cattle. In Exp. 1, forage combinations evaluated in situ consisted of 0% alfalfa-100% big bluestem (Andropogon gerardi Vitman), 25% alfalfa-75% big bluestem, 50% alfalfa-50% big bluestem, and 100% alfalfa-0% big bluestem. Nonlinear regression was used to determine the immediately soluble fraction A, the potentially degradable fraction B, the undegraded fraction C, and the disappearance rate of DM and NDF. Dry matter fraction A increased linearly (P = 0.03), and DM and NDF fraction B decreased linearly (P = 0.01) with increasing alfalfa substitution. Rate of DM and NDF disappearance increased linearly (P </= 0.02) with increasing alfalfa substitution. In Exp. 2, treatments were arranged as a 2 x 2 factorial testing alfalfa substitution [none or 25% (as-fed basis)] to orchardgrass hay (Dactylis glomerata L.) and intake level [restricted to 1% of BW daily (DM basis) or ad libitum]. Nutrient intakes were lowest (P </= 0.05) by steers fed restricted diets, intermediate by steers fed orchardgrass ad libitum, and greatest by steers fed orchardgrass plus alfalfa ad libitum. Intake level and forage source had no effect (P >/= 0.23) on total tract apparent digestibility of all nutrients except CP. Steers fed orchardgrass plus alfalfa had 33% greater (P = 0.01) total tract apparent digestibility for CP than those fed orchardgrass alone. Lag time of DM and NDF disappearance was not affected (P >/= 0.20) by alfalfa supplementation or intake level. Rate of DM and NDF disappearance of orchardgrass was faster (P </= 0.01) in steers fed orchardgrass plus alfalfa, at both restricted and ad libitum levels of feeding, than in animals fed orchardgrass alone. Mean retention times of large and small particles of orchardgrass tended to be shorter (P </= 0.06) when steers consumed ad libitum vs. restricted diets. Small orchardgrass particles tended to have a faster (P = 0.09) rate of passage under ad libitum feeding conditions and with alfalfa addition. Ad libitum intake was associated with a shorter mean retention time of orchardgrass and faster rate of passage of small orchardgrass particles, whereas alfalfa addition increased the rate of passage of small orchardgrass particles and the rate of DM and NDF disappearance.

Physically effectiveness of beet pulp in dairy cows 2: Intakes, digestibility and chewing activity, and performance of Holstein dairy cows

Many non-forage fibrous sources (NFFS) such as beet pulp (BP) contain more NDF than some forage sources, and have been successfully used in dairy rations to replace a portion of the effective or physical effective fiber (peNDF) that is normally provided by forages. However, BP has limited forage replacement value and effectiveness factor of 0.40 (fraction of NDF) versus 1.0 for forages (Mertens, 1997). In addition, Mertens (1997) suggested that the physically effectiveness factor of ground and pellet were 0.40 and 0.30, respectively. However, the effects of BP when substituted with different feed sources in TMR are variable that depend on chemical composition, types and physical characteristics. The objective of this experiment was to measure the effects of three types of BP on intakes, digestibility, and chewing activity and performance of Holstein dairy cows.

Chemical composition and in situ dry matter and fiber disappearance of sorghum × Sudangrass hybrids1

Three sorghum x Sudangrass hybrids were planted in twelve 0.2-ha plots to test the effect of date of harvest and hybrid on plant maturity, DM yield, chemical composition, and in situ DM and fiber disappearance. Sweet Sunny Sue (a non-brown midrib (BMR) hybrid; nonBMR), NutriPlus BMR (a BMR hybrid; NP-BMR), and Dry Stalk BMR (a BMR hybrid; DS-BMR) were planted on 26 June 2003 at 22.4 kg of seed/ha. Beginning 34 d after planting, plant height and phenological growth stage were assessed weekly in 10 random, 0.5-m(2) quadrats per plot. Plants were clipped to 2.5 cm in height and analyzed for CP, NDF, and ADF using near-infrared spectroscopy. Composite samples harvested from each plot on d 34, 48, and 63 were incubated in the rumen of 3 steers to determine the in situ disappearance of DM and NDF in a 3 x 3 Latin square. Forage yield was greater (P < or =0.02) for nonBMR than NP-BMR on d 41 and 55 and tended (P = 0.08) to be greater on d 48. The DS-BMR hybrid produced more (P = 0.04) forage DM than the NP-BMR on d 48. When DM yield was regressed on growth stage at harvest, BMR hybrids were predicted to produce 265 kg/ha more DM (P < 0.01) than nonBMR, at the late-boot stage. At all harvest dates, NDF concentrations were less (P < or =0.02) for BMR than nonBMR. The DS-BMR had greater (P < or =0.02) NDF concentrations than NP-BMR on d 41, 48, 55, and 63. Detergent fiber concentrations were predicted to be greater (P < 0.01) in nonBMR than BMR when regressed on growth stage at harvest, but the magnitude of the differences in fiber concentration diminished with growth stage. The A fractions of DM and NDF were greater (P < 0.01) and the C fraction was less (P < 0.01) for BMR hybrids than nonBMR. The B fraction of DM was not affected (P = 0.15) by hybrid type. The B fraction of NDF was not different (P = 0.28) on d 34 but was greater (P < 0.01) on d 48 and 63 for BMR than nonBMR. Effective degradability of NDF and DM was greater (P < 0.02) for BMR than nonBMR on all harvest dates. The A fraction of DM was less for DS-BMR than NP-BMR (P < 0.01), but the B and C fractions of NDF and DM did not differ (P > 0.13) between BMR hybrids. This research indicates that forage chemical composition and ruminal in situ disappearance are improved in the BMR sorghum x Sudangrass hybrids tested compared with the nonBMR. Yield reductions are commonly reported for BMR hybrids, but predicted DM yields in the current study were not reduced if harvested at a similar phenological growth stage.

Acidogenicity Value and Rumen Acid Load of Common Zoo Animal Feeds

In ruminants, consumption of diets high in readily fermentable carbohydrates can result in a rapid increase in total ruminal acid load leading to a drop in ruminal pH and ultimately ruminal acidosis. Currently, there are no simple and rapid methods to determine the potential for a feedstuff or feed ingredient to cause ruminal acidosis. The objective of this study was to assess the acidogenicity value of some common feed used in zoos and determine if the associated acid-load could be estimated using this in vitro technique. Acidogenicity values of feed samples were determined after dissolution of Ca from CaCO3 powder added after 24 or 48h of incubation in a rumen liquor and buffer solution media. True acidogenicity value was negatively correlated with the NDF fraction (R2 = -0.63, P < 0.01 after 24h of incubation and R2 = −0.71, P < 0.01 after 48 h); positively correlated with the starch fraction (R2 = 0.66, P < 0.01 after 24h of incubation and R2 = 0.71, P < 0.01 after 48 h) and the sugar fraction (R2 = 0.51, P < 0.05 after 24h of incubation and R2 = 0.57, P < 0.05 after). Only the NDF fraction showed a significant (R2 = −0.60, P < 0.01, after 24h of incubation) correlation with rumen acid load. Since only a small amount of further rumen acid load accumulated after 24h of incubation, feeds need to be incubated for only 24h to estimate their acidogenicity. These results suggest this quick and simple in vitro technique, which eliminates animal factors, could be incorporated easily into captive herbivore feeding strategies to quickly rank feeds in terms of their potential to affect net rumen acid-load.

Degradabilidade &lt;em&gt;in situ&lt;/em&gt; de silagens de milho confeccionadas com inoculantes bacteriano e/ou enzimático

In situ degradability of corn silages prepared with bacterial and/or enzymatic inoculants. The objective of this work was to evaluate the effects of the bacterial and/or enzymatic inoculants on corn silage degradation. The in situ technique was used in four adult steers in a 4x4 latin square design. The evaluated treatments were: CS (control silage), SBI (silage with bacterial inoculant), SBEI (silage with bacterial and enzymatic inoculant) and SEI (silage with enzymatic inoculant). There was no difference among treatments i fraction (a), potential degradable fraction (b), fraction b rate of degradation (c), potential degradability (PD) and effective degradability (ED) of DM and OM. The ED of CP was higher in SEI treatment (63.13%) and lower in SBEI treatment (53.69%). The b fraction of NDF was higher for SBEI (74.13%) and lower for SBI (64.07%). The NDF indigestible residue (I) did not show any difference among treatments. The ADF b and I fraction and the c rate values did not show any difference among treatments.

Fermentation kinetics of the carbohydrate fraction of fresh forage, silage and hay of Avena sativa

SummaryThe aim of the present paper was to study the fermentation characteristics and kinetics of the carbohydrate fractions of fresh, ensiled and hay of oats (Avena sativa) using the Cornell Net Carbohydrate and Protein System (CNCPS) and the in vitro gas production technique (GPT). The whole forage and its NDF and EIR (ethanol insoluble residue) fractions were incubated in order to estimate the fermentation kinetics of carbohydrate fractions (A, B1 and B2) with the curve subtraction method. The carbohydrates fermentation kinetics estimated with the GPT agree with the three CNCPS carbohydrate fractions and explain some modification due to forage preservation methods. For all forages, the fermentation rate of the three CNCPS carbohydrate fractions showed the same ranking A &gt; B1 &gt; B2. Fermentation rate value (RM: 0.163, 0.057, 0.032 h-1 A, B1, B2 fraction for fresh oats; 0.106, 0.032, 0.016 h-1 for A, B1, B2 fractions of ensiled oats; 0.165, 0.051, 0.022 h-1 A, B1, B2 fraction for oats hay) could be used as kd in the CNCPS.

Ruminal degradability of corn forages depending on the processing method employed

The in sacco degradabilities of starch and fibre in corn were compared between kernel grains and the whole corn plant before and after ensiling using the nylon bag technique. The same plants were used, in order to exclude the effects of genotype or maturity at harvest. The incubation time course was carried out over 48 h on four cannulated dairy cows. The effective degradability of starch was lower in kernel grains (70.2%) than in the whole plant before (83.9%) and after (92.3%) ensiling. Starch degradation in whole plants was accelerated compared to kernel grains by a shift from the slowly degradable (from 61.3% to 31.9%) to the rapidly degradable fraction (from 35.9% to 65.6%) without significantly affecting the degradation constant rate (7.7 and 8.0% per h respec- tively for kernel grains and whole corn plants). The ensiling process improved starch degradation even further compared to whole fresh plants by significantly increasing the rapidly degradable frac- tion (80.7% versus 65.6%) and by a higher degradation constant rate (12.4% per h versus 8.0% per h). The fibre degradation was similar between grains and whole corn plants despite differences in their content and composition of NDF. However, ensiling significantly increased the rapidly degradable NDF fraction (15.2 versus 9.9%) and doubled its degradation constant rate (from 1.6% per h to 3.2% per h). This effect was probably due to improved hemicellulose degradation, because cellulose and lignin were not degraded differently between corn plants before and after ensiling. Mechanical crack- ing such as chopping at harvest improves ruminal starch degradation without altering fibre degra- dation but the ensiling process simultaneously increases the degradability of starch and fibres. ruminal degradation / corn processing / corn starch / corn fibres

Corn silage or high moisture corn supplements for beef heifers grazing temperate pastures: effects on performance, ruminal fermentation and in situ pasture digestion

Effects of replacing fresh pasture with corn silage (CS) or high moisture corn (HMC) on average daily gain (ADG) and rate of subcutaneous fat deposition (RFD) were evaluated in 48 Angus × Hereford heifers (196 ± 6 kg) under grazing conditions. Six additional heifers (284 ± 25 kg), fitted with ruminal cannulaes, were assigned to a replicated 3 × 3 Latin square in 15-days periods, to study the effect of supplementation on ruminal fermentation and in situ pasture digestion characteristics. All heifers were assigned to one of three treatments as follows: in T0 fresh pasture (800 g kg −1 grass and 20 g kg −1 legumes) was the sole component of the diet; whereas CS and HMC were included at 400 and 310 g kg −1 of the diet on a DM basis in T1 and T2, respectively. No differences in ADG (910 g/day, P = 0.34) or RFD (0.022 mm/day, P = 0.62) were detected among treatments. Total DM intake was higher in T2 (8.54 kg/day) when compared to T0 (7.24 kg/day) and T1 (6.68 kg/day). Average ruminal pH values were higher ( P < 0.01) in heifers that received CS (pH = 6.3) when compared to T0 (pH = 5.9) and T2 (pH = 5.8). Treatment by hour of sampling interactions were detected for rumen ammonia nitrogen concentration ( P < 0.02); being higher in T2 at hours 19 and 23, but similar among treatments for hours 3, 7, 11 and 15 of sampling. Total volatile fatty acid (VFA) concentrations and molar proportions of acetate and n-butyrate tended to differ among treatments, but molar proportion of propionate was similar among treatments. Potentially digestible fractions of pasture DM and NDF were higher in T1 ( P < 0.05). The rate of digestion of pasture NDF, degradable NDF fraction and effective degradability were decreased by HMC feeding ( P < 0.05). Supplementation of temperate pastures with CS or HMC permitted an increase in stocking rates from 4.2 in T0 to 7 (T1) and 6.2 heifers/ha (T2). Animal live weight gain increased from 320 in T0 to 499 (T1) and 467 kg ha −1 (T2), without affecting ADG or FDR of the animals. These results suggest that CS supplementation had a positive associative effect on high quality pasture digestion, being a more appropriate supplement than HMC to be used in grazing beef heifers.

Efeito dos tratamentos físicos e químicos no resíduo de lixadeira do algodão

O experimento foi conduzido no Departamento de Zootecnia (UFLA) e no Laboratório de Alimentos (UNIFENAS), com o objetivo de avaliar o valor nutritivo do resíduo de lixadeira do algodão pela composição bromatológica (PB, FDN, FDA) e pela degradabilidade da MS e da FDN. Os tratamentos foram: T1 - in natura (IN); T2 - pressão e vapor (127ºC/1,5 kgf/cm²/35min; PV); T3 - 4% hidróxido de sódio (por 24 horas; NaOH); T4 - 3% uréia (por 28 dias; U); T5 - 4% NaOH + 3% uréia (NaOH/U); T6 - PV + 4% NaOH (PV/NaOH); T7 - PV + 3% uréia (PV/U). Pelos resultados referentes à composição química, conclui-se que os tratamentos associados foram mais eficientes em aumentar o valor nutritivo do resíduo, sendo o tratamento NaOH/U o que apresentou os melhores resultados para PB, FDN e FDA. Os maiores valores para a degradabilidade efetiva da MS foram verificados para o resíduo tratado com PV, U, NaOH/U, PV/NaOH, PV/U, que também apresentaram maior fração solúvel e menor fração insolúvel potencialmente degradável (b). Os tratamentos U, PV/NaOH e PV/U apresentaram as maiores de degradabilidade efetiva da FDN e maior fração solúvel. Os tratamentos associados aumentaram a degradabilidade e o valor nutritivo do resíduo de lixadeira do algodão.

Metabolic and microbial responses in western crossbred and Meishan growing pigs fed a high-fiber diet.

Four Duroc x White composite crossbred (21.8 +/- 1.0 kg BW) and four 12-wk-old Meishan purebred (20.7 +/- 1.6 kg BW) growing barrows were used to determine the relative breed differences in metabolic and microbial responses to a high-fiber diet. The pigs were trained to consume 700 g of a diet containing 35% (as-fed basis) dehydrated alfalfa meal once daily. The pigs' daily intakes of DM, N, GE, NDF, and ADF were 610 g, 16.6 g, 2.64 Mcal, 150 g, and 88 g, respectively. On d 12 after surgical catheterization of the portal vein, ileal vein, and carotid artery, a 3-d total urine and feces collection was conducted. On d 24 after surgery, each pig was placed in an open-circuit calorimeter, and its catheters were connected to a system for simultaneous measurements of oxygen consumption by portal-drained viscera and by whole body, and the net portal absorption of VFA after a 24-h fasting and during a 5-h postprandial period. The VFA measured included acetic, propionic, isobutyric, butyric, isovaleric, and valeric acids. A second 3-d total urine and feces collection was conducted on d 30 after surgery. There were no differences (P = 0.13) between the first and second collections in apparent total-tract digestibility coefficients for nutrients and N retention of pigs. Compared with Duroc x White composite crossbred pigs, Meishan pigs had lower (P = 0.05) apparent digestibility coefficients for DM, N, NDF, hemicellulose, and N retention, but their portal-drained viscera used a greater (P = 0.05) fraction of whole-body oxygen consumption. No differences (P = 0.12) were found between Duroc x White composite crossbred and Meishan pigs in total viable bacteria and cellulolytic bacteria from fecal samples, in vitro digestibility of alfalfa NDF fractions by fecal inocula, whole-body oxygen consumption, net portal absorption of VFA, total energy of absorbed VFA, and the potential of absorbed VFA for meeting the energy needs for whole-body heat production. These results indicate that, in contrast to previous beliefs, the ability of Meishan growing pigs to utilize a high-fiber diet is not superior to that of Duroc x White composite crossbred growing pigs.

Degradabilidade in situ da matéria seca, proteína bruta e fibra em detergente neutro, de diferentes gramíneas, em novilhos suplementados com misturas múltiplas

Este experimento foi conduzido com o objetivo de avaliar o efeito de diferentes suplementos minerais sobre a degradabilidade da MS, PB e FDN em bovinos a pasto, nas dependências da Escola Agrotécnica Federal de Cuiabá, MT, entre julho e novembro de 2001 e dividido em três períodos, com intervalos de 28 dias. Foram utilizados doze novilhos de corte, castrados, com idade e peso médio de 18 meses e 240 kg, respectivamente, com raças e graus de sangue diversos, fistulados no rúmen. Pelo manejo diferido da pastagem, dividiu-se a área em seis piquetes, providos de comedouro coberto e bebedouro. Utilizou-se o pastejo rotacionado com quatorze dias de ocupação, e a taxa de lotação de 1 animal/ha. Os tratamentos foram: T0 - pastagem sem minerais (Testemunha); T1 - pastagem com sal mineralizado; T2 - pastagem com sal mineralizado + uréia; T3 - pastagem com sal mineralizado + uréia + milho; T4 - pastagem com sal mineralizado + uréia + farelo de soja e T5 - pastagem com sal mineralizado + uréia + milho + farelo de soja. A forragem foi obtida pela técnica de simulação de pastejo, homogeneizada, sendo retirada uma amostra composta seca em estufa para moagem. A forragem utilizada no ensaio de degradabilidade apresentou média de 8,4% PB e 77,2% FDN, em base de MS e foi incubada in natura com 37,2% MS. Para a degradabilidade ruminal, foi utilizada a técnica do saco de náilon. As amostras de forragem foram colocadas nos sacos, obedecendo-se à relação de 20 mgMS/cm2 de superfície, incubados no rúmen durante 0, 3, 6, 12, 24, 36, 48, 72 e 96 horas. A degradabilidade potencial e efetiva e a fração não degradável da MS, PB e FDN foram analisadas utilizando-se o delineamento em blocos ao acaso, com seis tratamentos e seis repetições pelo teste de Scott Knott. Os blocos foram organizados considerando cada animal fistulado. Pelos resultados obtidos, verificou-se que, para a degradabilidade efetiva da MS, houve diferença (P&lt; 0,07) entre os tratamentos e as taxas de degradação da PB e FDN da forragem não houve influências (P&gt;0,05) dos tratamentos. O fornecimento de fonte nitrogenada e/ou energética mostrou ser eficiente na degradabilidade efetiva da MS, em média, 6,8% maior do que os outros sem essas fontes.

Effect of Sodium Hydroxide plus Hydrogen Peroxide Treated Mustard (Brassica campestris) Straw Based Diets on Rumen Degradation Kinetics (In sacco), Fermentation Pattern and Nutrient Utilization in Sheep

Two experiments were conducted to determine the effect of alkaline hydrogen peroxide (AHP) treatment (1% NaOH+1.5% H 2 O 2 ; 1 AHPMS, 2% NaOH+1.5% H 2 O 2 ; 2AHPMS) on rate and extent of degradation of mustard straw (MS) in sacco in sheep, and its in vivo digestion and ruminal fermentation characteristics when fed to sheep with concentrate (200 g per sheep daily). The treatment of straw with 1 and 2% AHP increased its sodium content by 148 and 296% to that of untreated straw (UMS). There was significant decrease in NDF and hemicellulose contents of AHP treated straw and increase in cellulose and lignin contents. Phenolic acids like ferrulic, p-coumaric and o-coumaric significantly (p<0.001) reduced by AHP treatment of mustard straw. In first experiment the in sacco degradation of DM, OM and NDF was significantly (p<0.01) greater for 2 AHPMS than for UMS at all incubation periods. The disappearance of nutrient from I AHPMS and 2 AHPMS treated straws continue to increase up to 96 h whereas in UMS the peak disappearance was found at 48 h. By using the equation {(y=a+b) (i-e - c t )} the degradation rates (c) for DM, OM, and NDF were significantly higher for UMS than AHP treated straws. Level of alkali (1 and 2%) had significant effect on degradation characteristics (a, b, c and P 0 . 0 5 ) of DM and NDF fraction of MS. However, the effect was not pronounced on OM fraction of MS. In feeding experiment, the intake of nutrients for DM, OM, cell wall constituents and energy was higher on 2 AHPMS, whereas no effect on the digestibility of these nutrients was observed. The apparent nitrogen retention was higher (p<0.05) both in 1 and 2 AHPMS groups. Water intake by animals was significantly increased due to AHP treated mustard straw feeding. Rumen liquor pH was higher in 2 AHPMS fed animals. The NH 3 -N of rumen liquor was not affected by feeding of AHP treated MS based diets. Total VFA concentration was significantly (p<0.01) higher in UMS fed group. The fractional out flow rate of DM was higher (p<0.05) in animals fed on 2 AHPMS diets compared to UMS and IAHPMS fed groups. The population of large holotrichs was higher (p<0.05) on AHP treated MS fed diets compared to UMS. The study indicated that treatment of mustard straw with AHP changed its chemical composition towards a better feed. The nutritive value of 2% AHP treated mustard straw was better in terms of dry matter intake and apparent nitrogen retention. The higher in sacco DM, OM and NDF disappearance however, was not confirmed by in vivo data in this study.

Effects of Ammonia, Urea Plus Calcium Hydroxide and Animal Urine Treatments on Chemical Composition and In sacco Degradability of Rice Straw

This experiment was conducted to examine the effects on the composition and rumen degradation in sacco of rice straw treated with animal urine (1 l of 2.9 g N/kg DM straw) and urea plus calcium hydroxide (2% urea plus 0.5% Ca(OH)2/kg DM straw) as a cheap and relatively safe alternative for ammonia (3% ammonia solution/kg DM straw). Mold occurred in urine treated straw, but other treatments were apparently mold-free. All treatments significantly (p<0.05) increased CP content in the straw compared with untreated one. Ammonia-treated straw contained CP at about twice that in urine or urea-calcium hydroxide treated straw. NDF and hemicellulose contents decreased significantly (p<0.05) in all treatments, while ADF and cellulose showed no differences compared with untreated straw. The degradable fraction of DM, CP, NDF, hemicellulose and cellulose was significantly (p<0.05) increased for ammonia and urea-calcium hydroxide treatments than for urine treated or untreated straw except for CP of urine treated straw. Chemical treatment of rice straw increased the readily degradable fraction of CP, while it decreased the slowly degradable fraction for urine or urea-calcium hydroxide treated rice straw. The degradation rate of hemicellulose was significantly (p<0.05) increased for ammonia and urea-calcium hydroxide treatments compared to urine treated or untreated straw. However, no effect on cellulose degradation rate was found by any of the treatments. There was no improvement in the degradation kinetics caused by the urine treatment despite the improvement of the chemical composition. Although the improvement in rumen degradability was less in the urea-calcium hydroxide treatment than in the ammonia treatment, its use may be more desirable because it is less expensive to obtain, less hazardous nature, and readily available. For further improvement it is necessary to investigate the supplementation of slowly degradable nitrogen to urea- calcium hydroxide treated rice straw diet. (Asian-Aust. J. Anim. Sci. 2003. Vol 16, No. 3 : 368-373)

Chemical composition, ruminal kinetic parameters, and nutrient digestibility of ammonia treated oat hulls

A study was conducted to determine the effects of ammoniation (3 or 5% by dry weight) on the nutritive value of oat hulls. Ruminal nutrient kinetic parameters and degradability of untreated and ammoniated oat hulls were determined using two non-lactating cows fitted with rumen cannulas. Eighteen steers were used in a digestibility trial to determine nutrient utilization of three diets consisting of 100% barley silage, 50% untreated oat hulls plus 50% barley silage, and 50% ammoniated oat hulls plus 50% barley silage (DM basis). Ammoniation at both levels increased (P &lt; 0.05) total N and reduced (P &lt; 0.05) neutral detergent fibre levels of oat hulls. Most of the N added due to ammoniation was in the form of non-protein N. The results of the in situ trial showed that ammoniation at the 3% level increased the potentially degradable NDF and ADF fractions as well as their rates of degradation. Ammoniation at the 3% level improved (P &lt; 0.05) effective ruminal degradability of NDF and ADF of oat hulls by 41 and 35%, respectively. Dry matter intake was highest (P &lt; 0.05) for steers fed the ammoniated oat hull diets, intermediate for those fed the untreated oat hull diets and lowest (P &lt; 0.05) for those fed the 100% barley silage diet. Steers fed the ammoniated oat hull diet had higher (P &lt; 0.05) total tract digestibility of NDF and lignin relative to steers fed the untreated oat hull diet. However, total tract digestibility of dry matter was not affected by ammoniation. It was concluded that ammoniation is a viable method for improving the feeding value of oat hulls to ruminant animals. Relative to the 3% level, ammoniation at 5% resulted in a marginal improvement in the nutritive value of oat hulls. Key words: Ammonia treatment, oat hulls, ruminal degradation, nutrient utilization

Intake, digestion, and digestive characteristics of Neotyphodium coenophialum-infected and uninfected fescue by heifers offered hay diets supplemented with Aspergillus oryzae fermentation extract or laidlomycin propionate.

Tarentaise heifers fitted with a rumen cannula (539 +/- 7.5 and 487 +/- 15.7 kg avg initial BW in Exp. 1 and 2, respectively) were used in two Latin square metabolism experiments having 2 x 2 factorial treatment arrangements to determine the effects of supplementation with Aspergillus oryzae fermentation extract (AO) or laidlomycin propionate (LP) on intake, digestion, and digestive characteristics of Neotyphodium coenophialum-infected (IF) or uninfected (FF) tall fescue (Festuca arundinacea) hay diets consumed ad libitum. Heifers were housed in individual stanchions in a metabolism facility with ambient temperatures controlled to range between 26.7 and 32.2 degrees C daily. Total feces and urine were collected for 5 d following a 21-d dietary adaptation period. In situ DM and NDF disappearance and ruminal fermentation characteristics were also determined. In Exp. 1, DMI was 24% greater (P < 0.01) by heifers offered FF than by those offered IF (6.7 vs 5.4 kg/d). Heifers fed 2 g/d AO tended (P = 0.09) to consume 4% more DM than those fed a diet without AO. Degradable DM and NDF fractions of IF were greater (P < 0.01) than those of FF, but AO supplementation did not affect situ disappearance (P > or = 0.42). In Exp. 2, DMI was 18.9% greater (P < 0.01) by heifers offered FF than by those offered IF (6.6 vs 5.5 kg/d). Heifers fed LP (50 mg/d) consumed 10.6% less (P < 0.05) DM than those not fed LP (5.7 vs 6/5 kg/d). Digestibility of NDF tended to be greater (P = 0.08) and digestibility of ADF was greater (P < 0.05) from FF than from IF. Conversely, apparent N absorption (%) was greater (P < 0.05) from IF than from FF. Heifers fed LP had lower (P < 0.05) ADF digestibility than those not fed LP. In situ degradable DM and NDF fractions were greater (P < 0.01) from IF than from FF. Diets supplemented with LP had higher (P < 0.01) indigestible DM and NDF fractions than those without LP. Propionic acid and total VFA concentrations were greater (P < 0.05) from heifers offered FF than from those offered IF and from heifers fed LP than from those not fed LP. Therefore, it appears the major effect of N. coenophialum was a reduction in forage intake and total-tract fiber digestibility in certain situations. Response to the feed additives was similar whether heifers were offered IF or FF and no evidence was apparent that either additive would improve performance substantially by animals consuming low-quality fescue hay diets.

Use of the automated gas production technique to determine the fermentation kinetics of carbohydrate fractions in maize silage

As forage maize matures major changes occur in the proportions and nature of the carbohydrate fractions present and an assessment of these is important. This study used an automated in vitro gas production (GP) technique with samples of both whole maize silage (WMS) and isolated cell walls (as neutral detergent fibre; NDF) of maize silages (cv. Hudson) harvested at four increasing stages of maturity (dry matter contents 228, 273, 304 and 372 g kg −1). This provided an estimate of the fermentation characteristics of the NDF and by difference (WMS − NDF), the neutral detergent solubles (NDS). The conventional approach of incubating WMS resulted in small differences in GP values which were not related to the changes in the principal carbohydrate fractions. However, incubating the NDF fractions separately and calculating the NDS values produced strong relationships between the changes in the starch and cell wall contents and the gas asymptote values for the NDS ( r=0.72) and NDF ( r=0.83) fractions, respectively. The gas asymptote values for the NDF fraction were also highly correlated ( r=0.98) with NDF degradability of the WMS. The use of this approach in nutrition models needs consideration.

Contribution of storage and structural polysaccharides to the fermentation process and nutritive value of lucerne ensiled alone or mixed with cereal grains

The low content of water soluble carbohydrates (WSC) and the high buffering capacity usually constrains lucerne ( Medicago sativa) ensilability. However, there are other sources of readily fermentable substrate and positive effects of adding cereal grains to wet silages have been reported. An experiment was carried out to study the contribution of hemicellulose, cellulose and natural or added starch to the silage fermentation process, and in vitro digestibility and gas production. A crop of lucerne (10% blooming) was chopped, inoculated with lactic acid bacteria, and ensiled in microsilos with four treatments: alone (T0), or with 50 kg/t of sucrose (SU), barley (BRL), or maize (MZ). Microsilos were incubated for 47 days. Polysaccharide recovery was determined by the mass balance technique, and starch by dacron bag. Except for SU, all treatments were apparently limited by the amount of WSC needed to sustain good silage fermentation. As expected, SU produced an excellent fermentation but despite initial WSC differences, there were no significant differences with BRL for total fatty acids, lactic and acetic acid, total acidity, pH and NH 3-N. Fermentation characteristics of MZ were generally worse than BRL’s and similar to T0’s ones. Hemicellulose was extensively hydrolysed (T0: 59.5%; MZ: 38.1%; BRL: 48.8%; and SU: 46.8%). Cellulose was almost quantitatively recovered and starch recovery averaged 70% for T0 and BRL, and approximately 100% for MZ and SU. The type of cereal added affected starch recovery using the dacron bag technique (MZ: 77%; BRL: 47%; P<0.05). True dry matter digestibility was the same for all treatments (fresh lucerne: 81.3%; T0: 80.7%; MZ: 81.8%; BRL: 80.5%; and SU: 82.1%), and neutral detergent fibre digestibility (NDF-D) of silages was reduced in relation to the fresh material (fresh lucerne: 55.1%; T0: 48.8%; MZ: 51.9%; BRL: 45.3%; and SU: 46.7%). Although all silages showed a rapid in vitro fermentation pattern, gas production (48 h) of SU and BRL (265.4 and 260.5 ml/g DM) was greater than T0 and MZ (246.0 and 244.6 ml/g DM) ( P<0.05). It can be concluded that starch hydrolysis depends on the type of grain, and that starch from barley and legume cell wall components could supply additional fermentable substrate to the ensiling process. These data also showed that ensiling reduced NDF-D and suggest that labile NDF fractions removed during the ensiling process were later accessible during the in vitro fermentation.

Prediction of the standardized ileal true digestibility of amino acids from the chemical composition of oilseed meals in the growing pig

Digestibility experiments using growing pigs fitted with an ileorectal anastomosis were performed to measure the standardized ileal true digestibility (ITD) of amino acids in five cotton seed meals (CSM) and three palm kernel meals (PKM), differing in their level of non starch polysaccharides (NSP), as expressed by NDF content and the nitrogen content of NDF (N NDF). The NDF content in CSM ranged from 273 to 475 g kg −1 on dry matter (DM) and the crude protein content from 384 to 506 g kg −1 DM. The latter values were not correlated with the NDF content. For PKM, NDF varied from 592 to 686 g kg −1 and the crude protein content from 151 to 177 g kg −1. Results obtained for CSM clearly demonstrate a curvilinear relationship, except for methionine, between ITD of amino acids and NDF content. Furthermore, if the composition of the CSM as ash, fat, total nitrogen, nitrogen from NDF (N NDF) and total gossypol (TGOS) contents is known (g kg −1 DM), the quantity of digestible amino acid can be predicted for lysine, threonine and tryptophan with reasonable precision, but less for sulfur amino acids. As an example for lysine, dLys ( g kg −1 DM)=6.5116(1.0939)+0.1411 N(0.0158)−0.1673 NNDF(0.0091)−0.0124 NDF (0.0010) R 2=0.993. For PKM, the relationships were more difficult to assess because of a narrow range in NDF level and the heterogeneity of response between pigs, especially for the higher NDF contents. In addition, the current data confirmed that the nitrogen content in the NDF fraction of NSP, often considered in ruminant protein nutrition, could be also an useful predictor of true ileal digestible values for selected amino acids in the pig,

Effect of dietary fibre source on total tract digestibility, caecum volatile fatty acids and digestive transit time in the weaned piglet

Effects of the use of 200 g of either wheat bran, sugar beet pulp, soya bean hulls or alfalfa meal per kilogram diet on the digestive process of the weaned piglet were studied on 24 Duroc× Landrace male piglets, weaned at 28 days of age. Piglets had an initial mean live weight of 7.92(±1.1) kg and were randomly distributed in six successive blocks of four animals. The total tract apparent digestibility (TTAD) was 0.872, 0.887, 0.815 and 0.824 for energy and 0.847, 0.833, 0.665 and 0.795 for nitrogen for the wheat bran, sugar beet pulp, soya bean hulls and alfalfa meal diet, respectively ( P<0.01). The TTAD values for NDF were 0.615, 0.861, 0.721 and 0.593, and for ADF were 0.390, 0.779, 0.708 and 0.457 in diets based on wheat bran, sugar beet pulp, soya bean hulls and alfalfa meal, respectively ( P<0.01). The level of volatile fatty acids (VFAs) in the caecum contents changed from 3.80 to 4.96 mg g −1 when sugar beet pulp replaced soya bean hulls, respectively, the later producing a higher proportion of acetic acid ( P<0.05). The average molar proportions were 0.635, 0.245 and 0.10 for acetic, propionic and butyric acid, respectively. Soya bean hulls in the diet increased the level of total VFA by 15 or 30% when compared with the wheat bran or with the sugar beet pulp and the alfalfa meal, respectively ( P<0.05). For a constant nitrogen intake, the diet containing soya bean hulls supported the lowest nitrogen retention. The mean retention time was 51.5, 49.9, 56.9 and 37.7 h for diets based on wheat bran, sugar beet pulp, soya bean hulls and alfalfa meal, respectively ( P<0.01). In contrast to alfalfa meal, the soya bean hulls reduced the chromium excretion rate by 40% and delayed the inflexion point of the excretion curve by 11 h, and consequently the digestive transit time. In conclusion, sugar beet pulp has the highest degradation rate of NDF and ADF fractions. The inclusion of soya bean hulls leads to a decrease in the energy and nitrogen digestibility of the weaning diet. Finally, alfalfa meal was the most effective fibre source to regulate the digestive transit time.