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1.
Fourteen Holstein steers (446 +/- 4.4 kg of initial BW) with ruminal, duodenal, and ileal cannulas were used in a completely randomized design to evaluate effects of whole or ground canola seed (23.3% CP and 39.6% ether extract; DM basis) on intake, digestion, duodenal protein supply, and microbial efficiency in steers fed low-quality hay. Our hypothesis was that processing would be necessary to optimize canola use in diets based on low-quality forage. The basal diet consisted of ad libitum access to switchgrass hay (5.8% CP; DM basis) offered at 0700 daily. Treatments consisted of hay only (control), hay plus whole canola (8% of dietary DM), or hay plus ground canola (8% of dietary DM). Supplemental canola was provided based on the hay intake of the previous day. Steers were adapted to diets for 14 d followed by a 7-d collection period. Total DMI, OM intake, and OM digestibility were not affected (P > or = 0.31) by treatment. Similarly, no differences (P > or = 0.62) were observed for NDF or ADF total tract digestion. Bacterial OM at the duodenum increased (P = 0.01) with canola-containing diets compared with the control diet and increased (P = 0.08) in steers consuming ground canola compared with whole canola. Apparent and true ruminal CP digestibilities were increased (P = 0.01) with canola supplementation compared with the control diet. Canola supplementation decreased ruminal pH (P = 0.03) compared with the control diet. The molar proportion of acetate in the rumen tended (P = 0.10) to decrease with canola supplementation. The molar proportion of acetate in ruminal fluid decreased (P = 0.01), and the proportion of propionate increased (P = 0.01), with ground canola compared with whole canola. In situ disappearance rate of hay DM, NDF, and ADF were not altered by treatment (P > or = 0.32). In situ disappearance rate of canola DM, NDF, and ADF increased (P = 0.01) for ground canola compared with whole canola. Similarly, ground canola had greater (P = 0.01) soluble CP fraction and CP disappearance rate compared with whole canola. No treatment effects were observed for ruminal fill, fluid dilution rate, or microbial efficiency (P > or = 0.60). The results suggest that canola processing enhanced in situ degradation but had minimal effects on ruminal or total tract digestibility in low-quality, forage-based diets.  相似文献   

2.
A rumen simulation technique (RUSITEC) apparatus with eight 800 ml fermenters was used to investigate the effects of replacing dietary starch with neutral detergent–soluble fibre (NDSF) by inclusion of sugar beet pulp in diets on ruminal fermentation, microbial synthesis and populations of ruminal cellulolytic bacteria. Experimental diets contained 12.7, 16.4, 20.1 or 23.8% NDSF substituted for starch on a dry matter basis. The experiment was conducted over two independent 15‐day incubation periods with the last 8 days used for data collection. There was a tendency that 16.4% NDSF in the diet increased the apparent disappearance of organic matter (OM) and neutral detergent fibre (NDF). Increasing dietary NDSF level increased carboxymethylcellulase and xylanase activity in the solid fraction and apparent disappearance of acid detergent fibre (ADF) but reduced the 16S rDNA copy numbers of Ruminococcus albus in both liquid and solid fractions and R. flavefaciens in the solid fraction. The apparent disappearance of dietary nitrogen (N) was reduced by 29.6% with increased dietary NDSF. Substituting NDSF for starch appeared to increase the ratios of acetate/propionate and methane/volatile fatty acids (VFA) (mol/mol). Replacing dietary starch with NDSF reduced the daily production of ammonia‐N and increased the growth of the solid‐associated microbial pellets (SAM). Total microbial N flow and efficiency of microbial synthesis (EMS), expressed as g microbial N/kg OM fermented, tended to increase with increased dietary NDSF, but the numerical increase did not continue as dietary NDSF exceeded 20.1% of diet DM. Results suggested that substituting NDSF for starch up to 16.4% of diet DM increased digestion of nutrients (except for N) and microbial synthesis, and further increases (from 16.4% to 23.8%) in dietary NDSF did not repress microbial synthesis but did significantly reduce digestion of dietary N.  相似文献   

3.
A study was conducted to determine the effects of stage of maturity on ensiling characteristics and ruminal nutrient degradability of oat silage. Oat was field grown and forage was harvested at the boot or soft dough stage and ensiled in mini-silos for 0, 2, 4, 8, 16 and 45 days. Two lactating Holstein cows fitted with ruminal fistulas were used determine ruminal nutrient degradability. Regardless of the stage of maturity, ensiled forages went through a rapid fermentation with a sharp decline in pH during the first 2 days of ensiling. Extensive proteolysis took place between 0 and 2 days as indicated by a reduction in true protein and neutral detergent insoluble protein (NDICP) and an increase in non-protein nitrogen (NPN). Chemical analysis of the 45 days silage showed that stage of maturity had no effect on neutral detergent fibre (NDF) and acid detergent fibre (ADF) of oat silage. However, oat harvested at the boot stage contained more crude protein (CP) and less starch than that harvested at the soft dough stage. Distribution of protein fractions showed that oat harvested at the boot stage contained lower NPN, NDICP and acid detergent insoluble protein than oat harvested at the soft dough stage. Results of the in situ incubation experiment indicated that oat harvested at the soft dough stage had lower ruminal dry matter (60.6 vs. 66.4%). CP (81.3 vs. 88.7%) and NDF (35.4 vs. 42.2%) degradabilities than oat harvested at the boot stage. It was concluded that chemical composition and ruminal nutrient degradability of oat silage are significantly influenced by stage of maturity.  相似文献   

4.
Four ruminally and duodenally cannulated steers (703.4 +/- 41 kg initial BW) were used in a 4 x 4 Latin square to evaluate the effects of field pea inclusion level on intake and site of digestion in beef steers fed medium-concentrate diets. Steers were offered feed ad libitum at 0700 and 1900 daily and were allowed free access to water. Diets consisted of 45% grass hay and 55% by-products based concentrate mixture and were formulated to contain a minimum of 12% CP (DM basis). Treatments consisted of (DM basis) 1) control, no pea; 2) 15% pea; 3) 30% pea; and 4) 45% pea in the total diet, with pea replacing wheat middlings, soybean hulls, and barley malt sprouts in the concentrate mixture. Experimental periods consisted of a 9-d dietary adjustment period followed by a 5-d collection period. Grass hay was incubated in situ, beginning on d 10, for 0, 2, 5, 9, 14, 24, 36, 72, and 98 h; and field pea and soybean hulls for 0, 2, 5, 9, 14, 24, 36, 48, and 72 h. Total DMI (15.0, 13.5, 14.1, 13.5 +/- 0.65 kg/d) and OM intake (13.4, 12.0, 12.6, 12.0 +/- 0.58 kg/d) decreased linearly (P = 0.10) with field pea inclusion. Apparent ruminal (17.5, 12.0, 0.6, 6.5 +/- 4.31%) and true ruminal CP digestibility (53.5, 48.7, 37.8, 46.2 +/- 3.83) decreased linearly (P < 0.10) with increasing field pea. Neutral detergent fiber intake (8.9, 7.9, 7.8, 7.0 +/- 0.3 kg/d) and fecal NDF output (3.1, 2.9, 2.6, 2.3 +/- 0.2 k/d) decreased linearly (P < 0.03) with increasing field pea. No effects were observed for microbial efficiency or total-tract digestibility of OM, CP, NDF, and ADF (P > or = 0.16). In situ DM and NDF disappearance rates of grass hay and soybean hulls decreased linearly (P < 0.05) with increasing field pea. Field pea in situ DM disappearance rate responded quadratically (P < 0.01; 5.9, 8.4, 5.5, and 4.9 +/- 0.52%/h, for 0, 15, 30, and 45% field pea level, respectively). Rate of in situ CP disappearance of grass hay decreased linearly (P < 0.01) with increasing field pea level. Field pea is a suitable ingredient for beef cattle consuming medium-concentrate diets, and the inclusion of up to 45% pea in by-products-based medium-concentrate growing diets decreased DMI, increased dietary UIP, and did not alter OM, NDF, or ADF digestibility.  相似文献   

5.
This study investigated the potential of vines from four sweet potato varieties (Tia Nong 57, Tia Nong 66, Ligwalagwala and Kenya) as alternative feed resources for ruminant livestock. The chemical composition [neutral detergent fibre (NDF), acid detergent fibre (ADF), crude protein (CP) and acid detergent insoluble nitrogen (ADIN)], in vitro ruminal nitrogen (N) degradability and in vitro ruminal biological activity of tannins in the vines, harvested at 70 and 110 days after planting (DAP), were determined. Variety and harvesting stage did not (p > 0.05) influence CP and NDF content of the vines. Concentration of CP ranged from 104.9 to 212.2 g/kg DM, while NDF ranged from 439.4 to 529.2 g/kg DM across harvesting stages and varieties. Nitrogen degradability (ND) at 70 and 110 DAP was highest (p < 0.05) in Ligwalagwala (743.1 and 985.0 g/kg DM, respectively). Treatment of vines with tannin‐binding polyethylene glycol (PEG) increased (p < 0.05) in vitro ruminal cumulative gas production parameters (a, b and c). The in vitro ruminal biological activity of tannins, as measured by increment in gas production parameters upon PEG inclusion, had a maximum value of 18.2%, suggesting low to moderate antinutritional tannin activity. Ligwalagwala vines, with highly degradable N, would be the best protein supplement to use during the dry season when ruminant animals consume low N basal diets and maintenance is an acceptable production objective. Tia Nong 66 and Kenya varieties, with less degradable N, may be more suitable for use as supplements for high‐producing animals such as dairy goats.  相似文献   

6.
Effects of increasing level of field pea (variety: Profi) on intake, digestion, microbial efficiency, and ruminal fermentation were evaluated in beef steers fed growing diets. Four ruminally and duodenally cannulated crossbred beef steers (367+/-48 kg initial BW) were used in a 4 x 4 Latin square. The control diet consisted of 50% corn, 23% corn silage, 23% alfalfa hay, and 4% supplement (DM basis). Treatments were field pea replacing corn at 0, 33, 67, or 100%. Diets were formulated to contain a minimum of 12% CP, 0.62% Ca, 0.3% P, and 0.8% K (DM basis). Each period was 14 d long. Steers were adapted to the diets for 9 d. On d 10 to 14, intakes were measured. Field pea was incubated in situ, beginning on d 10, for 0, 2, 4, 8, 12, 16, 24, 36, 48, 72, and 96 h. Bags were inserted in reverse order, and all bags were removed at 0 h. Ruminal fluid was collected and pH recorded at -2, 0, 2, 4, 6, 8, 10, and 12 h after feeding on d 13. Duodenal samples were taken for three consecutive days beginning on d 10 in a manner that allowed for a collection to take place every other hour over a 24-h period. Linear, quadratic, and cubic contrasts were used to compare treatments. There were no differences in DMI (12.46 kg/d, 3.16% BW; P > 0.46). Ruminal dry matter fill (P = 0.02) and mean ruminal pH (P = 0.009) decreased linearly with increasing field pea level. Ruminal ammonia-N (P < 0.001) and total VFA concentrations (P = 0.01) increased linearly with increasing field pea level. Total-tract disappearance of OM (P = 0.03), N (P = 0.01), NDF (P = 0.02), and ADF (P = 0.05) increased linearly with an increasing field pea level. There were no differences in total-tract disappearance of starch (P = 0.35). True ruminal N disappearance increased linearly (P < 0.001) with increasing field pea level. There were no differences in ruminal disappearance of OM (P = 0.79), starch (P = 0.77), NDF (P = 0.21), or ADF (P = 0.77). Treatment did not affect microbial efficiency (P = 0.27). Field pea is a highly digestible, nutrient-dense legume grain that ferments rapidly in the rumen. Because of their relatively high level of protein, including field peas in growing diets will decrease the need for protein supplementation. Based on these data, it seems that field pea is a suitable substitute for corn in growing diets.  相似文献   

7.
A ruminal fermentation trial and a steer growth trial were conducted to evaluate the effects of time interval of cottonseed meal (CSM) supplementation of predominantly meadow fescue grass hay (GH; CP = 6.6%) on nutrient digestion and growth performance of beef steers. The fermentation trial used four ruminally cannulated steers assigned to a 4 x 4 latin square design with dietary treatments of GH fed alone (C) or GH supplemented with 3 g CP/kg BW.75 daily as supplied by CSM every 12, 24 or 48 h. Nylon bags containing GH were inserted into the rumen on d 1 and 2 of each collection period and incubated for 12, 24, 48 and 96 h to measure NDF and ADF degradation. Subsequently, steers were fed Yb-labeled GH and fecal samples were collected to determine particulate passage rate (PR). Dry matter and NDF intake, mean NDF and ADF in situ disappearance and ruminal VFA concentrations were greater (P less than .05) when CSM was fed; however, the delivery of CSM at various times did not affect (P greater than .10) these variables. Supplemented diets tended (P = .08) to have faster PR compared with the C diet. In the growth trial, CSM supplemented steers consumed more digestible DM (P less than .05) and had greater (P less than .05) daily gain compared with C steers. Effects due to time of CSM supplementation were not observed for the variables measured in the present study.  相似文献   

8.
This experiment was carried out to study the effect of a directly fed exogenous fibrolytic enzyme on intake and digestion of DM, OM, protein, NDF, ADF, and hemicellulose of alfalfa and ryegrass hay by sheep. Four diets were randomly assigned to four ruminally cannulated lambs using a 4 x 4 Latin square design, repeated in time, with a factorial arrangement (2 x 2) of diets: 1) alfalfa hay; 2) alfalfa hay + exogenous fibrolytic enzymes (enzyme); 3) ryegrass hay; and 4) ryegrass hay + enzyme. Lambs consumed more DM and OM from alfalfa than from ryegrass hay (P < 0.001). The ADF intake was not different between the hays, but NDF intake was lower for alfalfa (P < 0.001). For both hays, the enzyme increased intake of DM (P < 0.01), as well as OM and CP (P < 0.05); however, NDF and ADF intake were not changed. Alfalfa hay had higher apparent digestibility of DM, OM, and CP (P < 0.001), but lower digestibility for NDF, ADF, and hemicellulose. The enzyme increased apparent digestibility of CP, hemicellulose (P < 0.05), and NDF (P < 0.10) for alfalfa. Also, for both hays, the enzyme improved N balance because lambs retained more N (P < 0.05). The enzyme increased (P < 0.05) total VFA concentration (3 and 6 h) for both hays. Results from this trial indicate that directly fed exogenous fibrolytic enzymes may change ruminal fermentation, intake, and digestibility of forages with different nutritive value.  相似文献   

9.
The objective was to evaluate effects of feeding sorghum-sudan- or alfalfa-based diets on intake, first compartment stomach characteristics, digestibility, nitrogen balance and energy metabolism in alpacas at low altitude (793 m). Six mature alpacas (42 ± 2.3 kg of body weight) were used in a replicated 3 × 3 Latin square experiment. The treatments were: sorghum-sudan diets (SSD), alfalfa hay diets (AHD) and fresh alfalfa diets (FAD), respectively. Alpacas were housed in metabolism crates and diets were fed for 21 days with 11 d of adaptation and 10 d of sampling. Alpaca was supplemented concentrate with 160 g per alpaca per day and forages were fed at 12 h intervals with water provided ad libitum. First compartment stomach pH and ammonia N were unaffected by forage source, whereas total VFA concentration was different between diets, with the least for FAD (46.8 mM), followed by AHD (51.8 mM) and the highest for SSD (56.1 mM). Ratio of acetate to propionate was greater for AHD and SSD than for FAD diets. The molar proportion of acetate decreased, whereas the molar proportion of propionate increased for FAD relative to AHD and SSD. Redox potential was lower for SSD than for FAD. Surface tension was greater for FAD than for SSD and AHD. Osmolality was lower for FAD than for SSD and AHD. First compartment pressure and methane production tended to be higher for FAD than for SSD (P < 0.06) and AHD (P < 0.07). Digestibilities of DM, OM and EE were not different between diets. However, the digestibility of CP was lower for AHD relative to SSD and FAD. Digestibilities of NDF and ADF were greater for SSD than for AHD and FAD. Intakes of gross energy (GE) and N were greater for AHD than for FAD and SSD. Digestible energy (DE) was the highest in AHD followed by SSD and FAD. Metablizable energy (ME) was different with the lowest for FAD (3.9 MJ/day), followed by SSD (5.4 MJ/day) and the highest for AHD (8.1 MJ/day). Energy retained was followed the same trend as ME. The results demonstrate variable responses of alpacas to feeding sorghum-sudan or alfalfa diets in terms of dry matter intake, first compartment stomach characteristics, digestibility, nitrogen balance and energy metabolism at low altitude.  相似文献   

10.
Tall fescue hay (H) supplemented with corn and urea (HU) or corn gluten meal (HCGM) and ammoniated tall fescue hay supplemented with corn (AH) or corn gluten meal (AHCGM) were fed to steers in two 4 X 4 Latin-square trials. Diets were fed to four Angus-Hereford steers (550 kg) at equal intakes in trial 1 and to four Hereford steers (350 kg) at ad libitum intakes in trial 2. Ammoniation reduced cell wall concentrations of p-coumaric acid and ferulic acid by 48 and 67%, respectively. Concentrations of other phenolics were also reduced. Apparent total tract digestibilities of vanillin, p-coumaric acid and ferulic acid were lower (P less than .05, .001 and .01, respectively) when nontreated hay was fed in trial 1, but were not different between hay types in trial 2. In trial 1, greater negative intestinal digestibilities of p-coumaric acid (P less than .001) and vanillin (P less than .05) occurred for steers fed HU and HCGM vs AH and AHCGM diets. Digestibilities of neutral detergent fiber (NDF) and acid detergent fiber (ADF) were greater (P less than .001) for steers fed ammoniated hay diets in both trials and greater (P less than .05) for HCGM vs HU in trial 1. More than 96% of the NDF and ADF digested by steers in trial 1 was digested in the stomach. Intakes of digestible NDF and ADF, but not indigestible NDF or ADF, were higher (P less than .001) for steers fed AH and AHCGM in trial 2. In situ dry matter disappearance rate of ammoniated hay was greater (P less than .05) than that of nontreated hay, but rate of cotton thread disappearance from bags suspended in the rumen of steers fed the various diets was similar among treatments. In both trials, feeding ammoniated hay resulted in higher (P less than .05) ruminal concentrations of acetate and higher (P less than 0.05) acetate:propionate ratios. Ruminal liquid dilution rates were lower (P less than .05) for steers fed AH and AHCGM in trial 1, but were not different in trial 2. Ruminal dry matter concentration and solids dilution rate were not affected by diet in either trial. The results are interpreted to indicate that increased intake of ammoniated hay is a result of increased rate and extent of fiber digestion.  相似文献   

11.
Total viable rumen bacteria counts through the use of colony-unit forming assays lack accuracy because they only include culturable bacteria capable of initiating cell division. Thus, bacterial counts can be underestimated. The use of fluorescent characteristics of cell membranes allows flow cytometry to enumerate and distinguish dead from live bacteria cells. The objective of this experiment was to investigate the viable and total ruminal bacteria counts when 3 levels of forage:concentrate in diets were fed at restricted levels with the addition of Saccharomyces cerevisiae (YC). Three cannulated post-pubertal Holstein heifers (age 18 ± 1.0 months) were fed corn silage (CS)-based diets in a 3-period (35 d) Latin square design. Heifers were fed the diets for 21 d with no yeast addition, followed by 14 d where yeast culture (YC) was added (1 g/kg as-fed basis); (Yea-Sacc1026, Alltech, Inc., Nicholasville, KY). A low concentrate (LC) TMR (80% CS, 20% concentrate; 12.4% CP, 35% NDF), a medium concentrate (MC) TMR (60% CS, 40% concentrate; 12.3% CP. 28% NDF), and a high concentrate (HC) TMR (40% CS, 60% concentrate; 12.6% CP, 25% NDF), were fed once per day. Rumen fluid was sampled − 2, 0, 2, 4, 6, 8, 10, 12 h after feeding. Samples were immediately stained with fluorescent dyes using the BacLight kit (Molecular Probes Inc., Eugene, OR) and analyzed with a Coulter XL-MCL single laser flow cytometer. Mean rumen viable bacteria counts linearly increased among treatments (4.96, 4.78, 6.73 × 1011 ± 0.53 × 1011 cells/ml; P = 0.02) for LC, MC and HC respectively, and YC addition increased number of viable bacteria cells (P < 0.01). Total and viable bacteria counts decreased for the first 2 h after feeding then increased 4 h post-feeding. Dietary concentrate level and YC can alter rumen bacteria counts as measured by this method.  相似文献   

12.
以3头装有瘤胃瘘管的干奶牛作为瘤胃液供体,用体外培养法研究不同日粮蛋白和中性洗涤纤维(NDF)水平对瘤胃发酵、消化和微生物蛋白合成的影响。采用2×3双因子完全随机设计,粗蛋白水平14%、16%和18%,NDF水平为32%和36%。体外发酵后2、4、6、12、24 h取瘤胃液测定pH、NH3-N浓度和微生物蛋白含量,发酵结束后测定饲料中干物质(DM)、NDF和酸性洗涤纤维(ADF)消化率。结果表明:随着蛋白水平升高,瘤胃发酵pH有增加趋势(P=0.079),显著提高NDF和ADF消化率和细菌蛋白合成量(P<0.05),但不影响DM消化率和原虫蛋白的合成量(P>0.05);日粮中NDF水平显著影响瘤胃pH、NH3-N浓度和ADF消化率(P<0.05),但不影响DM和NDF消化率以及微生物蛋白的合成量(P>0.05)。本试验条件下,日粮中16%CP和32%NDF组可在一定程度上促进瘤胃发酵,提高纤维消化率以及微生物蛋白的合成量。  相似文献   

13.
选用4头装有永久性瘤胃瘘管的初产奶牛采用4×4拉丁方设计，研究不添加油脂（CK）、添加4％豆油（LOC1）、4％胡麻油（LOC2）以及2％豆油+2％胡麻油（LOC3）对DM、OM、NDF、ADF瘤胃表观消化率及全肠道消化率的影响。结果表明：在60%高粗料日粮基础上添加4%豆油、亚麻油或二者的混合物，对奶牛干物质采食量没有影响。与对照组相比,添加油组DM、OM、NDF、ADF的瘤胃表观消化率和全肠道消化率都有降低的趋势，但差异不显著（P＞0.05），3个添加油组之间差异也不显著（P＞0.05）。  相似文献   

14.
Four ruminally and duodenally cannulated crossbred beef steers (397+/-55 kg initial BW) were used in a 4 x 4 Latin square to evaluate the effects of increasing level of field pea supplementation on intake, digestion, microbial efficiency, ruminal fermentation, and in situ disappearance in steers fed moderate-quality (8.0% CP, DM basis) grass hay. Basal diets, offered ad libitum twice daily, consisted of chopped (15.2-cm screen) grass hay. Supplements were 0, 0.81, 1.62, and 2.43 kg (DM basis) per steer daily of rolled field pea (23.4% CP, DM basis) offered in equal proportions twice daily. Steers were adapted to diets on d 1 to 9; on d 10 to 14, DMI were measured. Field pea and grass hay were incubated in situ, beginning on d 10, for 0, 2, 4, 8, 12, 16, 24, 36, 48, 72, and 96 h. Ruminal fluid was collected and pH recorded at -2, 0, 2, 4, 6, 8, 10, and 12 h after feeding on d 13. Duodenal samples were taken for three consecutive days beginning on d 10 in a manner that allowed for a collection to take place every other hour over a 24-h period. Linear, quadratic, and cubic contrasts were used to evaluate the effects of increasing field pea level. Total DMI and OMI increased quadratically (P = 0.09), whereas forage DMI decreased quadratically (P = 0.09) with increasing field pea supplementation. There was a cubic effect (P < 0.001) for ruminal pH. Ruminal (P = 0.02) and apparent total-tract (P = 0.09) NDF disappearance decreased linearly with increasing field pea supplementation. Total ruminal VFA concentrations responded cubically (P = 0.008). Bacterial N flow (P = 0.002) and true ruminal N disappearance (P = 0.003) increased linearly, and apparent total-tract N disappearance increased quadratically (P = 0.09) with increasing field pea supplementation. No treatment effects were observed for ruminal DM fill (P = 0.82), true ruminal OM disappearance (P = 0.38), apparent intestinal OM digestion (P = 0.50), ruminal ADF disappearance (P = 0.17), apparent total-tract ADF disappearance (P = 0.35), or in situ DM disappearance of forage (P = 0.33). Because of effects on forage intake and ruminal pH, field peas seem to act like cereal grain supplements when used as supplements for forage-based diets. Supplementing field peas seems to effectively increase OM and N intakes of moderate-quality grass hay diets.  相似文献   

15.
本试验旨在利用尼龙袋法比较不同品种全株玉米青贮前后瘤胃降解特性的差异.试验采用2×3双因素试验设计,选择玉米7367号、玉米7377号、玉米7387号3个全株玉米品种为研究对象,采用尼龙袋法比较3种全株玉米青贮前和青贮后的营养成分和瘤胃降解特性,旨在探讨适合河北省种植的全株玉米青贮品种.结果表明:1)青贮前玉米7377...  相似文献   

16.
试验旨在研究中药复方对日粮营养物质在山羊瘤胃内降解特性的影响。择6头健康的体重相近的安装有永久性瘤胃瘘管的周岁大足黑山羊羯羊,按3×3重复拉丁方试验设计,随机分为3组,1个对照组和2个处理组。对照组饲喂基础日粮,2个处理组分别在基础日粮上给每头羊日喂15 g复方Ⅰ和复方Ⅱ(由藿香、苍术、黄柏和生石膏等中药按不同比例组成)。采用瘤胃尼龙袋法对日粮精料和粗料干物质(DM)、有机物(OM)、粗蛋白质(CP)、中性洗涤纤维(NDF)及酸性洗涤纤维(ADF)在瘤胃内不同时间点的降解率进行测定,再根据动态降解率计算出降解模型参数及有效降解率。结果表明:复方Ⅰ能极显著提高精料DM和ADF及粗料DM、OM、NDF和ADF的有效降解率(P<0.01);复方Ⅱ能极显著提高精料DM及粗料DM、OM和ADF的有效降解率(P<0.01),显著提高精料ADF和粗料NDF的有效降解率(P<0.05)。研究结果提示,中药复方能改善山羊瘤胃降解能力,且复方Ⅰ作用效果优于复方Ⅱ。  相似文献   

17.
This study aimed to evaluate the effects of forage neutral detergent fiber (fNDF) levels on the voluntary feed intake, digestibility, ruminal fermentation and feeding behavior of goats fed diets with cactus pear. Five non‐lactating ruminally cannulated goats fed ad libitum were randomly assigned to a 5 × 5 Latin square design. Treatments consisted of levels of fNDF at 0, 109, 222, 339 and 463 g/kg of dry matter (DM) in cactus pear‐based diets. The intakes of DM and NDF were quadratically affected (p ≦ .045) by fNDF levels. Voluntary water intake (VWI) increased linearly as the fNDF levels increased in the diet. The digestibility coefficients of organic matter, NDF and ether extract and total digestible nutrients concentration were quadratically affected (p ≦ .048) by fNDF levels. The ruminal pH linearly increased (p = .001) with fNDF levels, ranging from 5.44 to 5.81 for diets containing 0 and 463 g fNDF/kg DM, respectively. The fNDF levels promoted a linear increase (p = .006) in chewing time, linearly decreased (p = .007) resting time and quadratically affected (p = .033) rumination time. The inclusion of fNDF in the diets provided favorable conditions for ruminal function, digestibility and feeding behavior in goats fed diets containing cactus pear.  相似文献   

18.
The objective of this study was to evaluate the effects of dietary crude protein (CP ) levels and 2‐methylbutyrate (MB ) supplementation on ruminal fermentation, bacterial populations, microbial enzyme activity and urinary excretion of purine derivatives (PD ) in Simmental steers. Eight ruminally cannulated Simmental steers, averaging 18 months of age and 465 ± 8.6 kg of body weight (BW ), were used in a replicated 4 × 4 Latin square design by a 2 × 2 factorial arrangement. Low protein (98.5 g CP /kg dry matter [LP ] or high protein (128.7 g CP /kg dry matter [HP ]) diets were fed with MB supplementation (0 g [MB ?] or 16.8 g steer?1 day?1 [MB +]). Steers were fed a total mixed ration with dietary corn straw to concentrate ratio of 50:50 (dry matter [DM ] basis). The CP  × MB interaction was observed for ruminal total VFA , molar proportions of acetate and propionate, acetate to propionate ratio, ammonia‐N, effective degradability of neutral detergent fibre (NDF ) and CP , microbial enzyme activity, bacterial populations and total PD excretion (p  < .05). Ruminal pH decreased (p  < .05), but ruminal total VFA concentration increased (p  < .05) with increasing dietary CP level or MB supplementation. Acetate molar proportion increased (p  = .043) with MB supplementation, but was not affected by dietary CP level. Propionate molar proportion decreased (p  < .05) with increasing dietary CP level or MB supplementation. Consequently, acetate‐to‐propionate ratio increased (p  = .001) with MB supplementation, but was not affected by dietary CP level. Ruminal ammonia‐N content increased (p  = .034) with increasing dietary CP level, but decreased (p  = .012) with MB supplementation. The effective degradability of NDF and CP increased (p  < .05) with increasing dietary CP level or MB supplementation. Microbial enzyme activity, bacterial populations and total PD excretion also increased (p  < .05) with increasing dietary CP level or MB supplementation. The results indicated that ruminal fermentation, nutrient degradability, microbial enzyme activity, ruminal bacterial populations and microbial protein synthesis improved with increasing dietary CP level or MB supplementation in steers.  相似文献   

19.
In vivo digestibility (eight animals) and solid particles passage rate measured by faecal Cr (four animals fistulated at the rumen) were determined on riverine buffalo bulls and Delle Langhe rams, given four diets at maintenance level (50 g/kg M0.75 per day of dry matter), according to a Latin square design, composed of a factorial combination of high and low NDF and of high and low protein undegradability. The diets were: L-30 = low NDF (530.0 g/kg DM), low undegradability of protein (29.6%, CP = 138.0 g/kg DM); L-40 = low NDF (537.0 g/kg DM), high undegradability of protein (41.0%, CP = 139.0 g/kg DM); H-30 = high NDF (583.0 g/kg DM), low undegradability of protein (28.3%, CP = 128.0 g/kg DM); H-40 = high NDF (NDF = 580.0 g/kg DM), high undegradability of protein (40.0%, CP = 128.0 g/kg DM). The digestibility of organic matter (66.68% vs. 64.32%, P < 0.05) and of the other analytical fractions (NSC, NDF, cellulose and hemicelluloses) was significantly higher in buffaloes with the exception of that of crude protein which was similar for the two species. Considering the diets within the species, the increased undegradable protein in the small intestine produces different effects: in the buffalo, it does not positively influence the digestibility of NSC but does increase that of cellulose, on the other hand in sheep it influences the digestibility of NSC. The post-ruminal digestibility of the undegraded protein, both in buffalo and sheep, is higher than that from protein of microbial origin. The passage rate of the marker of the solid particles, through the first compartment, k1 (2.86% h− 1 and 2.54% h− 1 for the buffalo and the sheep) and through the entire intestinal tract, MRT (57.50 and 58.88 h for the buffalo and the sheep) does not show significant differences in the two species. The passage rate of the marker of the solid particles in buffalo rumen, at variance with the structural carbohydrates of the diet, is more variable compared with that of the sheep.  相似文献   

20.
The study was conducted to examine the chemical composition of urea–molasses treated wheat straw (WS) fermented with cattle manure (CM) and its feeding value for growing buffalo male calves. Wheat straw treated with varying levels of urea (0%, 2% and 4%) and molasses (2% and 4%) was ensiled with 30% cattle manure (on dry matter basis) for different fermentation periods (20, 30 and 40 days). Fermented wheat straw (FWS) after each fermentation period was analyzed for pH, dry matter (DM), crude protein (CP), true protein (TP), ammonia nitrogen (NH3-N), acid detergent fiber (ADF) and neutral detergent fiber (NDF). Maximum pH, DM, CP, TP and NH3-N and minimum NDF contents were observed with 4% urea. The 4% molasses level increased the CP, TP and NH3-N contents of FWS, but pH, DM and NDF remained unchanged after 40 days of fermentation. The 4% urea × 4% molasses interaction resulted in maximum DM, CP, TP, NH3-N after 40 days of fermentation period and this combination was used for large scale production of FWS to evaluate its feeding value for calves. Four isonitrogen and isocaloric diets were formulated. The control FWS 0 diet contained no FWS while in FWS 15, FWS 25 and FWS 35 diets concentrate was replaced with 15%, 25% and 35% FWS, respectively. The diets were randomly allotted to four groups of 28 calves 9–12 months of age, seven in each group, in a randomized complete block design to examine the nutrient intake, digestibility, nitrogen balance and weight gain. An increased DM, organic matter (OM), CP and NDF intakes were observed in calves fed FWS diets compared to those fed FWS 0 diet. Nitrogen retention increased significantly with increasing the level of FWS. The DM, OM, CP and NDF apparent digestibilities were non-significant in calves fed different levels of FWS. A linear increase in weight gain was noticed in calves fed diets containing increasing level of FWS.  相似文献   

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