• Asian-Australasian Journal of Animal Sciences
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• v.26 no.3
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• pp.358-365
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• 2013

A series of in vitro studies were carried out to determine i) the effects of enzyme and formaldehyde treatment on the degradation characteristics of carbohydrate and protein sources and on the synchronicity of these processes, and ii) the effects of synchronizing carbohydrate and protein supply on rumen fermentation and microbial protein synthesis (MPS) in in vitro experiments. Untreated corn (C) and enzyme-treated corn (EC) were combined with soy bean meal with (ES) and without (S) enzyme treatment or formaldehyde treatment (FS). Six experimental feeds (CS, CES, CFS, ECS, ECES and ECFS) with different synchrony indices were prepared. Highly synchronous diets had the greatest dry matter (DM) digestibility when untreated corn was used. However, the degree of synchronicity did not influence DM digestibility when EC was mixed with various soybean meals. At time points of 12 h and 24 h of incubation, EC-containing diets showed lower ammonia-N concentrations than those of C-containing diets, irrespective of the degree of synchronicity, indicating that more efficient utilization of ammonia-N for MPS was achieved by ruminal microorganisms when EC was offered as a carbohydrate source. Within C-containing treatments, the purine base concentration increased as the diets were more synchronized. This effect was not observed when EC was offered. There were significant effects on VFA concentration of both C and S treatments and their interactions. Similar to purine concentrations, total VFA production and individual VFA concentration in the groups containing EC as an energy source was higher than those of other groups (CS, CES and CFS). The results of the present study suggested that the availability of energy or the protein source are the most limiting factors for rumen fermentation and MPS, rather than the degree of synchronicity.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.1
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• pp.56-64
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• 2011

This study was conducted to evaluate the use of exogenous enzymes as a potential means of improving the ruminal digestion (i.e., degradability) of alfalfa hay and rice straw. Twenty six enzyme-additives were examined in terms of protein concentration and enzymic activities on model substrates. The exogenous enzymes contained ranges of endoglucanase, xylanase, ${\beta}$-glucanase, ${\alpha}$-amylase, and protease activities. Six of the enzyme additives were chosen for further investigation. The enzyme additives and a control without enzyme were applied to mature quality alfalfa hay substrate and subsequently incubated in rumen batch cultures. Five of the enzyme additives (CE2, CE13, CE14, CE19, and CE24) increased total gas production (GP) at 48 h of incubation compared to the control (p<0.05). The two additives (CE14 and CE24) having the greatest positive effects on alfalfa hay dry matter, neutral detergent fibre (NDF) and acid detergent fibre (ADF) degradability were further characterized for their ability to enhance degradation of low quality forages. The treatments CE14, CE24, a 50:50 combination of CE14 and CE24 (CE14+24), and control (no enzyme) were applied to mature alfalfa hay and rice straw. For alfalfa hay, application of the two enzyme additives, alone and in combination, increased GP compared to the control at 48 h fermentation (p<0.05), whereas only CE14 and CE14+24 treatments improved GP from rice straw (p<0.05). Rumen fluid volatile fatty acid concentrations throughout the incubation of rice straw were analyzed. Acetate concentration was slightly lower (p<0.05) for CE14${\times}$CE24 compared to the control, although individually, CE14 and CE24 acetate concentrations were not different from the control. Increases (p<0.05) in alfalfa hay NDF degradability measured at 12 and 48 h of incubation occurred only for CE14 (at 12 h) and for CE14+24 (at 12 and 48 h). Similarly, ADF degradability increased (p<0.05) with CE14 and CE14+24. As for rice straw, increased DM degradability was observed at 12 and 48 h of incubation for all enzyme treatments with an exception for CE14 at 12 h. The degradability of NDF was improved by all the enzyme treatments at either incubation time, while ADF degradability was only enhanced at 48 h. Overall, the enzymes led to enhanced digestion of mature alfalfa and there was evidence of improved digestibility of rice straw, an even lower quality forage.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.3
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• pp.351-359
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• 2015

Twelve multiparous Holstein dairy cows in mid-lactation were selected for a replicated $4{\times}4$ Latin square design with a $2{\times}2$ factorial arrangement to investigate the effects of corn and soybean meal (SBM) types on rumen fermentation, N metabolism and lactation performance in dairy cows. Two types of corn (dry ground [DGC] and steam-flaked corn [SFC]) and two types of SBM (solvent-extracted and heat-treated SBM) with different ruminal degradation rates and extents were used to formulate four diets with the same basal ingredients. Each period lasted for 21 days, including 14 d for adaptation and 7 d for sample collection. Cows receiving SFC had a lower dry matter (DM) and total N intake than those fed DGC. However, the milk yield and milk protein yield were not influenced by the corn type, resulting in higher feed and N utilization efficiency in SFC-fed cows than those receiving DGC. Ruminal acetate concentrations was greater and total volatile fatty acids concentrations tended to be greater for cows receiving DGC relative to cows fed SFC, but milk fat content was not influenced by corn type. The SFC-fed cows had lower ruminal ammonia-N, less urea N in their blood and milk, and lower fecal N excretion than those on DGC. Compared with solvent-extracted SBM-fed cows, cows receiving heat-treated SBM had lower microbial protein yield in the rumen, but similar total tract apparent nutrient digestibility, N metabolism measurements, and productivity. Excessive supply of metabolizable protein in all diets may have caused the lack of difference in lactation performance between SBM types. Results of the present study indicated that increasing the energy degradability in the rumen could improve feed efficiency, and reduce environmental pollution.

• Korean Journal of Agricultural Science
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• v.26 no.1
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• pp.58-64
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• 1999

The chemical composition and ruminal dry matter digestibilities of leaves, stems and roots of Aralia cordata Thunberg were determined and compared each other as a roughage sources for ruminants. The crude protein contents were higher for leaves(12.4%) than for leaves+stems (9.7%), stem(5.1%) and roots (3.8%) (P<0.05). The crude fat contents were higher for leaves (3.7%) than for roots (2.1%) and stems (1.3%) (P<0.05). The crude fiber contents were lower for roots (12.3%) than for leaves (15.0%), leaves+stems (27.7%) and stems (40.3%) (P<0.05), respectively. The contents of neutral detergent fiber were lower for leaves (30.2%) than for leaves+stems (42.0%), roots (50.8%) and stems (60.0%) (P<0.05), respectively. The contents of acid detergent fiber were lower for root(18.3%) than for leaves(21.4%). leaves+stems (37.5%) and stems (49.6%) (P<0.05), respectively. The calcium content of leaves(2.4%) were higher than those of stems and roots (0.97% and 0.69%), however the phosphorus contents were similar among leaves, stems and roots(0.25%, 0.19% and 0.35%). Ruminal dry matter digestibilities for 12, 24, 48 and 72hr of leaves(38.9%, 65.9%, 79.8% and 82.4%) and roots(38.9%, 59.8%, 77.6% and 78.5%) were higher than stems(31.1%, 44.1%, 49.5% and 52.6%). Furthermore the digestibilities of leaves were higher than those of alfalfa hay(37.4%, 48.8%, 67.8% and 71.8%) and although the digestibilities of stems which were the lowest among the parts were higher than those of acasia wood chip(12.6%, 18.2%, 21.6% and 24.3%).

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.11
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• pp.1564-1568
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• 2005

The objective of the study was to evaluate the use of n-alkanes to estimate DM intake and digestibility by beef cattle. Six steers were blocked (3 blocks, 2 animals/block) according to the body weight (279${\pm}$19 kg) and randomly allotted within blocks to two diets (3 steers/diet). A second trial was conducted with the same animals (321${\pm}$18 kg) after 36 days (d), using a switch back design. The diets consisted of two types of chopped sun-cured hay, alfalfa (Medicago sativa L) hay, or fescue (Festuca arundinacea Schreb) and alfalfa mixture, which were fed in equal amounts to steers. Animals were dosed with $C_{32}$ and $C_{36}$ alkanes, employing an intra-ruminal controlled-release device at the beginning of each trial. Hay intake per animal was measured from d 6 to 12 and sub samples were taken for chemical analysis. Rectal samples of feces were taken from each animal once/daily from d 8 to 14, freeze dried, and ground prior to alkane analysis. Alkanes were extracted from ground hay and feces. Feed intake was calculated from the dose rate of $C_{32}$ alkane and, the herbage and fecal concentrations of adjacent odd ($C_{33}$ or $C_{31}$) and even ($C_{32}$) chain length alkanes. Crude Protein, NDF, ADF, ash concentrations and In vitro dry matter digestibility (IVDMD) were 17.7, 42.2, 28.4, 7.9 and 71.7 for alfalfa, and 12.4, 56.5, 30.4, 6.9 and 69.1% for fescue/alfalfa mixture, respectively. For both diets, intake estimated from $C_{33}$:$C_{32}$ ratio was not different from the measured intake, but intake estimated from $C_{31}$:$C_{32}$ ratio was lower (p<0.05), than the measured intake for both diets. The average estimated forage intake from $C_{33}$:$C_{32}$ ratio was 4.86 and 0.69% below than the measured intake for alfalfa and, fescue/alfalfa mixed diets, respectively. The respective estimates with $C_{31}$:$C_{32}$ ratio were 9.59 and 11.33% below than the measured intake. According to these results, alkane $C_{33}$:$C_{32}$ ratio is better than alkane $C_{31}$:$C_{32}$ ratio for the estimation of intake by beef steers.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.10
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• pp.1443-1450
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• 2003

Crossbred (Bos taurus${\times}$Bos indicus) calves were used from birth till 14 weeks of age to evaluate three sources of protein that differed in ruminal degradability viz. groundnut cake alone (HD) or in combination with cottonseed meal (MD) and meat and bone meal (LD), when fed along with two sources of non-structural carbohydrates viz. raw (R) and thermally processed (P) maize. Twenty four new born calves were arranged in six groups in a $3{\times}2$ factorial design and fed on whole milk up to 56 d of age. All the different calves received calf startes along with green oats (Avena sativa) from 14 d of age onwards free-choice. A metabolism trial of 6d starters duration, conducted after 90 d of experimental feeding, revealed greater (p<0.05) digestibility of DM, OM, total carbohydrates, NDF and ADF in calves fed on the P diets than on the R diets promoting greater (p<0.05) metabolizable energy intake. The digestibility of NDF was higher (p<0.01) on LD diets where as calves on MD diets exhibited significantly lower digestibility of ADF (p<0.01). The retention of nitrogen per unit metabolic body size was significantly (p<0.05) higher on the LD-P diet than on the diet HD-P which, in turn, was higher (p<0.05) than that of HD-R. Nitrogen retention as percentage of intake was significantly greater (p<0.05) on LD-P than on LD-R diets (52.2 vs. 36.4%). Also, P fed calves utilized nitrogen more efficiently than the R fed as shown by retention of significantly greater proportions of intake (47.4 vs. 40.9%) and absorbed (65.8 vs. 59.5%) nitrogen. Calorimetric evaluation of the diets through open-circuit respiration chamber revealed that the dietary treatments had no impact on methane production by calves. The intake of DE and ME was improved (p<0.01) because of maize processing resulting in greater (p<0.01) retention of energy. The protein degradability exerted no influence on the partitioning or retention of energy. A significant interaction between cereal and protein types was evident with respect to retention of both nitrogen (p<0.01) and energy (p<0.05). In conclusion, no discernible trend in the influence of cereal processing was apparent on the dietary protein degradability, but the positive effect of cereal processing on energy retention diminished with the increase in dietary undegradability.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.11
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• pp.1705-1712
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• 2007

The effect of different tropical feed sources on rumen ecology, cellulolytic bacteria, feed intake and digestibility of beef cattle was investigated. Four fistulated, castrated male crossbred cattle were randomly allocated to a $4{\times}4$ Latin square design. The treatments were: T1) urea-treated (5%) rice straw (UTS); T2) cassava hay (CH); T3) fresh cassava foliage (FCF); T4) UTS:FCF (1:1 dry matter basis). Animals were fed concentrates at 0.3% of body weight on a DM basis and their respective diets on an ad libitum basis. The experimental period was 21 days. The results revealed that the use of UTS, CH, FCF and UTS:FCF as roughage sources could provide effective fiber and maintain an optimal range of ruminal pH and $NH_3-N$. Total viable and cellulolytic bacterial populations were enhanced (p<0.05) with UTS as the roughage source. Animals fed FCF had a higher rumen propionate production (p<0.05) with a lower cellulolytic bacteria count. Moreover, three predominant cellulolytic bacteria species, namely Fibrobacter succinogenes, Ruminococcus albus and Ruminococcus flavefaciens, were found in all treatment groups. Roughage intake and total DM intake were highest with UTS (2.2 and 2.5% BW, respectively) as the roughage source (p<0.05). Nutrient intake in terms of organic matter intake (OMI) was similar in UTS, CH and UTS:FCF treatments (8.0, 6.8 and 8.7 kg/d, respectively), while crude protein intake (CPI) was enhanced in CH, FCF and UTS:FCF as compared to the UTS treatment (p<0.05). Digestion coefficients of DM and organic matter (OM) were similar among treatments, while the CP digestion coefficients were similar in CH, FCF and UTS:FCF treatments, but were higher (p<0.05) in CH than in UTS. CP and ADF digestible intakes (kg/d) were highest (p<0.05) on the CH and UTS treatments, respectively. It was also observed that feeding FCF as a full-feed resulted in ataxia as well as frequent urination; therefore, FCF should only be fed fresh as part of the feed or be fed wilted. Hence, combined use of FCF and UTS as well as CH and FCF were recommended.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.7
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• pp.945-951
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• 2013

In vitro studies were undertaken to develop an appropriate fibrolytic enzymes cocktail comprising of cellulase, xylanase and ${\beta}$-D-glucanase for maize stover with an aim to increase its nutrient utilization in sheep. Cellulase and xylanase added individually to ground maize stover at an increasing dose rates (0, 100, 200, 400, 800, 1,600, 3,200, 6,400, 12,800, 25,600, 32,000, 38,400, and 44,800 IU/g DM), increased (p<0.01) the in vitro dry matter digestibility and in vitro sugar release. The doses selected for studying the combination effect of enzymes were 6,400 to 32,000 IU/g of cellulase and 12,800 to 44,800 IU/g of xylanase. At cellulase concentration of 6,400 IU/g, IVDMD % was higher (p<0.01) at higher xylanase doses (25,600 to 44,800 IU/g). While at cellulase doses (12,800 to 32,000 IU/g), IVDMD % was higher at lower xylanase doses (12,800 and 25,600 IU/g) compared to higher xylanase doses (32,000 to 44,800 IU/g). At cellulase concentration of the 6,400 to 32,000 IU/g, the amount of sugar released increased (p<0.01) with increasing levels of xylanase concentrations except for the concentration of 44,800 IU/g. No effect of ${\beta}$-D-glucanase (100 to 300 IU/g) was observed at lower cellulase-xylanase dose (cellulase-xylanase 12,800 to 12,800 IU/g). Based on the IVDMD, the enzyme combination cellulase-xylanase 12,800 to 12,800 IU/g was selected to study its effect on feed intake and rumen fermentation pattern, conducted on 12 rams (6 to 8 months; $20.34{\pm}2.369$ kg body weight) fed 50% maize stover based TMR. The total volatile fatty acids (p<0.01) and ammonia-N concentration was higher in enzyme supplemented group, while no effect was observed on dry matter intake, ruminal pH and total nitrogen concentration.

• Journal of Life Science
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• v.18 no.4
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• pp.515-521
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• 2008

This experiment was conducted to investigate effects of non-ionic or zwitterionic (+/-) surfactants on digestibility of rice straw, and changes of growth of rumen mixed microbes, pH, and gas production during in vitro fermentation. Also, during in vitro ruminal fermentation, microbial attachment on rice straw was investigated using scanning electron microscopy (SEM). Tween 80 or SOLFA-850 for non-ionic surfactant (NIS), and 3-(Dodecyldimethylammonio) propanesulfanate (DDAP) for zwitterionic surfactant (ZIS) was supplemented by 0.05% and 0.1% in Dehority's artificial medium containing Holtein rumen fluid, respectively, and the substrate for fermentation was rice straw passed through 1 mm screen. The experiment was composed of 7 treatments (two levels of two NISs, two levels of a ZIS) including the control, and 6, 12, 24, 48 and 72 hr of fermentation time with 3 replications per treatment. Treatment of Tween 80 increased in vitro DM digestibilities during 48 hr and 72 h post fermentations compared to the other treatments, whereas treatment of DDAP as a ZIS resulted in decreased DM digestibility than that of the control from 24 hr post fermentation (P<0.05). Gas production in vitro was greater (P<0.05) with addition of NIS than the control or ZIS, and increased as fermentation time elapsed. Rumen mixed microbial growth was greatest with addition of Tween 80 as NIS, and lowest when DDAP as ZIS was supplemented to the fermentation tube (P<0.05). In SEM observation, rumen microbial population attached on rice straw particle was greater with addition of NIS, but was less with addition ZIS compared with the control. In conclusion we could not found any positive effects of ZIS surfactants on rumunal fermentation characteristics and rumen microbial growth rates.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.9
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• pp.1295-1303
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• 2013

The aim of this study was to determine the effect of different physical forms and urea treatment of rice straw on feed intake, rumen fermentation, and milk production. Four, multiparous Holstein crossbred dairy cows in mid-lactation with initial body weight (BW) of $409{\pm}20kg$ were randomly assigned according to a $4{\times}4$ Latin square design to receive four dietary treatments. The dietary treatments were as follows: untreated, long form rice straw (LRS), urea-treated (5%), long form rice straw (5% ULRS), urea-treated (2.5%), long form rice straw (2.5% ULRS) and urea-treated (2.5%), chopped (4 cm) rice straw (2.5% UCRS). Cows were fed with concentrate diets at a ratio of concentrate to milk yield of 1:2 and rice straw was fed ad libitum. The findings revealed significant improvements in total DM intake and digestibility by using long and short forms of urea-treated rice straw (p<0.05). Ruminal pH was not altered among all treatments (p>0.05), whereas ruminal $NH_3$-N, BUN and MUN were found to be increased (p<0.01) by urea-treated rice straw as compared with untreated rice straw. Volatile fatty acids (VFAs) concentrations especially those of acetic acid were decreased (p<0.05) and those of propionic acid were increased (p<0.05), thus acetic acid:propionic acid was subsequently lowered (p<0.05) in cows fed with long or short forms of urea-treated rice straw. The 2.5% ULRS and 2.5% UCRS had greater microbial protein synthesis and was greatest when cows were fed with 5% ULRS. The urea-treated rice straw fed groups had increased milk yield (p<0.05), while lower feed cost and greater economic return was in the 2.5% ULRS and 2.5% UCRS (p<0.01). From these results, it could be concluded that 2.5% ULRS could replace 5% ULRS used as a roughage source to maintain feed intake, rumen fermentation, efficiency of microbial protein synthesis, milk production and economical return in mid-lactating dairy cows.