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1.
Naturally fauna-free (FF) wethers, equipped with ruminal and duodenal cannulas, were used in two groups of eight (Group A) and seven (Group B) animals in six consecutive experimental periods, each lasting for 28 d. The objective was to measure ruminal fermentation traits, and flows of nonammonia nitrogen (NAN), total amino acid (TAA), and bacterial nitrogen (BN) from the stomach after inoculation with individual ciliate protozoa species in each period. The wethers in both groups were fed a diet based on corn silage, haylage, and soybean meal, and they remained FF during the first period. At the beginning of each other period, the wethers were progressively inoculated intraruminally with one individual major species of ruminal ciliate protozoa or total fauna (TF). Thus, Group A was progressively inoculated (+) with Dasytricha ruminantium (DS), Polyplastron multivesiculatum (PP), Isotricha intestinalis (IS), Entodinium caudatum (EN) and TF-type A. Also, Group B was progressively inoculated (+) with IS, DS, Epidinium ecaudatum (EP), Eudiplodinium maggi (EU), and EN. Duodenal digesta and ruminal fluid were collected and sampled in each period on d 26 and 28, respectively, and subjected to chemical analyses. A significantly higher (P < .05) pH (6.4) in ruminal fluid of the Group A wethers was obtained when each DS, DS+PP, DS-PP-IS+EN, and TF population was present in the rumen than when the wethers were FF (6.2). In the Group B wethers, pH (6.1) was lower (P < .05) for the population of IS-DS-EP+EU than for other populations (6.2 to 6.3). The concentration of total VFA in ruminal fluid was higher (P < .05) in the Group B wethers when IS, IS+DS, or IS-DS+EP populations were present in the rumen than when the wethers were FF. The flow of NAN, TAA, and BN from the stomach to the intestinal tract was generally lower for different protozoa populations than for the FF period. Largest decreases (P < .05) in the flow of NAN, TAA, and BN occurred when EN was added into the rumen of wethers in the A and B groups, which already contained populations of DS-PP+IS and IS-DS-EP+EU, respectively. Holotrich protozoa had very little effect on the protein metabolism in the rumen, but cellulolytic protozoa (PP, EP, and EU) and EN decreased the efficiency of protein utilization by the ruminant host.  相似文献   

2.
Two experiments were conducted to determine the effect of increasing dietary K on macromineral bioavailability from a wheat straw-hay diet, and to monitor changes in the rumen that could affect mineral availability. In the first experiment, 12 mature wethers were used in a metabolism study to determine the effect of adding potassium chloride (KCl) to a supplement fed with a diet of 55% NH3-treated wheat straw and 45% bromegrass hay. In the second experiment, similar diets were fed to six wethers with ruminal and abomasal cannulae to determine the site of mineral absorption. Dietary K levels were 1, 2 and 3% of the diet dry matter. Increasing K tended to decrease (P less than .06) apparent absorption of Mg. Potassium absorption increased (P less than .01) with increasing dietary K, but retention was not altered. Quadratic effects (P less than .01) of K were observed for Ca and P apparent absorption and retention. Increased K lowered (P less than .05) plasma Mg in Exp. 1 but not in Exp. 2. Ruminal concentrations of K increased (P less than .01), and concentrations of Na decreased (P less than .05), as dietary K increased. Ruminal fermentation was influenced by dietary K level. Molar proportions of acetate in the rumen were increased (P less than .01) by the addition of K to the diet, while molar proportions of butyrate (P less than .01) and valerate (P less than .01) decreased linearly with increasing K. Time X treatment interactions were present for ruminal propionate, butyrate and NH3-N (P less than .01).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

3.
Three experiments were conducted in Granadina goats and Segure?a wethers fed at maintenance level to evaluate the effect of including a mixture of barley and a new by-product derived from olive oil extraction (two-stage dried olive cake) on ruminal degradation and passage kinetics (Exp. 1), fermentation pattern and protozoa population (Exp. 2), and urinary purine derivatives excretion (Exp. 3). Polyethylene glycol was supplied to the animals to evaluate the effects of tannins contained in the by-product. The experimental diets were as follows: alfalfa hay and alfalfa hay plus a concentrate, formulated with two-stage dried olive cake, barley, and a mineral-vitamin mixture either with or without the addition of polyethylene glycol to the drinking water. The inclusion of two-stage dried olive cake in the diet resulted in an increase of condensed tannins. Ruminal VFA concentration in goats and wethers increased (P < 0.05) and ammonia N (NH3-N) concentration decreased (P < 0.05). The inclusion of two-stage dried olive cake decreased (P < 0.001) urinary allantoin excretion only in wethers. Ruminal degradation profiles and fractional passage rates were similar in goats and wethers. The polyethylene glycol supply increased (P < 0.001) DM and N degradation rates in both animal species but did not modify the fractional passage rate. Ruminal fermentation patterns were also similar in goats and wethers and were affected by polyethylene glycol supply. In general, Entodiniomorphida and Holotricha protozoa counts were higher (P < 0.05) in the rumen of goats than of wethers. Protozoa count in wethers responded more to polyethylene glycol supply than in goats. The present work presents the first data obtained from a comparative study with sheep and goats concerning urinary excretion of purine derivatives. The excretion was similar in both animal species when fed alfalfa hay; however, polyethylene glycol affected only urinary allantoin excretion in wethers. Results suggest a greater sensitivity of wethers than of goats to two-stage olive cake condensed tannins.  相似文献   

4.
The effects of proteolysis on digestion and animal performance were studied using heat to inhibit proteolysis at ensiling. Alfalfa (Medicago sativa) was ensiled either after wilting for 24 h (control; C) or after heating (100 degrees C) in a crop dehydrator for 2 min (heated; H). In Exp. 1, eight wethers, cannulated in the rumen and duodenum, were given the silages to determine the effects of heat treatment of alfalfa on the digestion of silage. In Exp. 2, growing lambs had ad libitum access to the silages to determine the effects of heat treatment on intake, animal performance and body composition. Heat treatment inhibited protease activity; protein N accounted for 33.5 and 61.3% and ammonia N 15.5 and 5.1% of total N in C and H silages, respectively. Heat treatment reduced mean post-feeding ruminal ammonia N concentration (P less than .05), ruminal pH (P less than .05) and the acetate: propionate ratio (P less than .001) in ruminal fluid. Heat treatment increased duodenal flow of non-ammonia N (P less than .05) and amino acids (P less than .05), the amount of N absorbed (P less than .05) in the small plus large intestine and also increased the efficiency of microbial protein synthesis (P less than .05). In Exp. 2, although intake and gain were higher (P less than .001) for H-fed than for C-fed lambs, there were no differences (P greater than .05) in empty body composition. The results indicated that inhibition of proteolysis by heat treatment at ensiling can increase utilization of silage N within the rumen, increase voluntary intake and result in a higher rate of gain by lambs fed alfalfa silage.  相似文献   

5.
Three experiments were conducted to determine the influence of the presence of protozoa on copper (Cu) metabolism in sheep fed corn silage or corn silage supplemented with casein, fish meal or soybean meal. For each diet, eight rams were kept fauna-free; eight additional rams were faunated and housed separately from them. The faunated rams in all treatments grew faster and consumed more feed and, consequently, more Cu. However, they had a lower (P less than .01) ruminal Cu solubility and accumulated less Cu in their livers than the fauna-free rams when fed corn silage alone or in combination with soybean meal (insoluble, ruminally degraded protein). Such effects were not significant when corn silage was supplemented with fish meal (protein resistant to ruminal degradation). The presence of ciliate protozoa in the rumen had no effect on the accumulation of Cu in the liver of sheep fed corn silage supplemented with casein (soluble, ruminally degraded protein) and produced conflicting results on ruminal Cu solubility. Hence, the effect of protozoa on Cu metabolism is indirect and depends on the type of protein present in the diet.  相似文献   

6.
An in vitro wheat fermentation study (Exp. 1) was conducted to investigate the effect of pH (pH 7, 6, 5 and 4) on rumen lactate and VFA production. In another study (Exp. 2), lambs were fed high concentrate diets containing either no additions (control), 2% sodium bentonite, 2% limestone, 2% NaHCO3 or 10% alfalfa hay. The effect of these diets was determined on ruminal and systemic measurements before and after dietary adaptation. Effect of the control, bentonite, limestone and NaHCO3 treatments on nutrient digestibilities and mineral retentions after adaptation were also determined. Lactate production in the rumen fluid incubated at pH 7 or 6 was negligible. Reducing incubation pH from 6 to 5 resulted in accumulation of both total and L(+)-lactate, but further reduction to pH 4 did not result in an additional increase in lactate production. Variations in incubation pH or time did not affect the ratio of D to L isomers. Lowering the incubation pH to below 6 reduced total VFA production and increased the acetate to propionate ratio. In Exp. 2, the feeding of buffers or alfalfa hay was effective in maintaining a more normal feed intake and ruminal pH, and reduced ruminal lactate. Blood measurements were not affected by dietary treatment. When animals were adapted to the experimental diets, the dietary buffers did not influence rumen and blood measurements. Lambs fed 2% NaHCO3 digested more (P less than .05) organic matter, crude protein, N-free extract and starch, and 2% limestone increased (P less than .05) fiber digestibility. Dietary buffers tended to increase fecal pH and reduce fecal starch Magnesium retention with 2% bentonite, Ca retention with 2% limestone and Na and Mg retention with NaHCO3 were all increased (P less than .05).  相似文献   

7.
Three lamb metabolism experiments were conducted to investigate the effects of chronic administration of the novel urease inhibitor N (n-butyl) thiophosphoric triamide (NBPT) on ruminal N metabolism, fermentation, and N balance. In Exp. 1, ruminally cannulated wethers (n = 28; 45.0 +/- .9 kg) were administered one of seven doses of NBPT (0 [control], .125, .25, .5, 1, 2, or 4 g of NBPT daily) and fed a common cracked corn/cottonseed hull-based diet twice daily containing 2% urea at 2.5% of initial BW for the duration of the 15-d experiment. Overall, NBPT decreased (linear P < .0001; quadratic P < .001) ruminal urease activity, resulting in linear increases (P < .0001) in ruminal urea and decreases in ruminal NH3 N concentrations. However, the detection of an NBPT x day interaction (d 2 vs 15; P < .01) indicated that this depression in urea degradation diminished as the experiment progressed. Increasing NBPT linearly decreased (P < .01) total VFA concentrations on d 2 of the experiment, but it had no effect (P > .10) on d 15. Increasing NBPT had no effect (P > .10) on DM or ADF digestibilities, but it linearly decreased (P < .01) N digestibility. Supplementing NBPT produced a linear increase (P < .05) in urinary N excretion and a linear decrease (P < .01) in N retention. In Exp. 2, ruminally cannulated wethers (n = 30; 46.8 +/- .6 kg) were fed one of two basal diets (2.0 vs 1.1% dietary urea) at 2.5% of initial BW and dosed with either 0 (control), .25, or 2 g of NBPT daily for the duration of the 15-d experiment. There were no NBPT x dietary urea interactions (P > .10) for Exp. 2. Increasing NBPT depressed (linear and quadratic P < .0001) ruminal urease activity, producing linear (P < .0001) increases in urea N and linear decreases in NH3 N in the rumen. As in Exp. 1, an NBPT x day interaction (P < .05) was noted for urea, NH3 N, and total VFA concentrations; the maximum response to NBPT occurred on d 2 but diminished by d 15 of the experiment. Administration of NBPT did not influence (P > .10) DM, ADF, or N digestibilities in Exp. 2. In Exp. 3, wether lambs (n = 30; 26.4 +/- .7 kg) were subjected to the same treatment regimen as in Exp. 2 for a 14-d N balance experiment. Although several NBPT x dietary urea interactions (P < .05) were noted, increasing NBPT did not affect (P > .10) N digestibility. Administration of NBPT quadratically increased (P < .10) urinary N excretion, producing a linear decrease (P < .05) in N retention. These results suggest that although NBPT is capable of inhibiting ruminal urease short-term, the ruminal microflora may be capable of adapting to chronic NBPT administration, thereby limiting its practical use in improving the utilization of dietary urea.  相似文献   

8.
Two experiments were conducted to study the effects of alterations in ruminal pH and volatile fatty acid (VFA) concentrations on utilization of Mg and other minerals. In Exp. 1, two metabolism trials were conducted with 12 ruminally cannulated crossbred wethers fed 800 g/d of orchard-grass (Dactylis glomerata, L.) hay. After each feeding, wethers were ruminally infused with 500 ml (4.2 ml/min) or either 1) deionized water, 2) 40% (w/v) glucose solution, 3) .26 M propionic and .17 M butyric acid solution or 4) .35 M HCl. The pH of the VFA solution was adjusted to 6.8 with 10N NaOH. In Exp. 2, a metabolism trial was conducted with 12 ruminally cannulated crossbred wethers fed 600 g of orchard-grass hay and infused with a buffered VFA solution prepared as in Exp. 1 or with an unbuffered solution. In both experiments each trial consisted of a 5-d adaption period followed by four 5-d collections of feed, feces and urine. Compared with the glucose treatment, infusion of the buffered VFA solution produced similar acetic and propionic and higher (P less than .05) butyric acid concentrations (Exp. 1). The HCl solution produced changes in ruminal and pH values similar to those of the glucose infusion. In Exp. 1, apparent absorption of Mg was increased over twofold by the glucose infusion (P less than .05), but the other infusions had no effect. Apparent absorption of P was decreased (P less than .05) by HCl infusion, and K absorption was decreased by HCl and glucose infusions. In Exp. 2, infusion of the unbuffered VFA solution decreased apparent Mg absorption by 15.7%, compared with infusion of the buffered solution. These experiments suggest that the increased Mg absorption observed with carbohydrate supplementation is not due to alterations in ruminal pH or VFA levels.  相似文献   

9.
Three digestion experiments and one growth experiment were conducted to determine site, extent and ruminal rate of forage digestion and rate and efficiency of gain by cattle offered alfalfa haylage supplemented with corn or dry corn gluten feed (CGF). In Exp. 1, eight steers were fed alfalfa haylage-based diets with substitution of corn for 0, 20, 40 or 60% of haylage in a 4 X 4 latin square. Increasing dietary corn substitution increased (P less than .05) OM, NDF and ADF digestion by steers but decreased (P less than .05) rate of in situ alfalfa DM digestion. In Exp. 2, five heifers were fed alfalfa haylage-based diets with increasing dietary levels of CGF in a 5 X 5 latin square. Increasing dietary CGF increased (P less than .05) OM, NDF and ADF digestion by heifers. In Exp. 3 and 4, cattle were fed alfalfa haylage-based diets containing either 20 or 60% corn or CGF. In Exp. 3, supplementation increased (P less than .05) OM and NDF digestion but level X supplement source interaction (P less than .05) occurred, with added CGF increasing OM and NDF digestion more than added corn. In Exp. 4, supplementation improved (P less than .05) DM intake, daily gain and feed efficiency. Dry matter intake and daily gain were greater (P less than .05) for 60% supplementation than for 20% supplementation. Overall, whereas increasing the level of dietary supplement increased (P less than .05) OM, NDF and ADF digestion, only corn addition decreased (P less than .05) rate of in situ alfalfa DM digestion. Daily gains and feed efficiencies were similar in cattle fed either corn or CGF with alfalfa haylage.  相似文献   

10.
Sheep were used to determine the effects of dietary supplementation with readily-fermentable carbohydrates on Mg, Ca, K and P utilization. In each of two metabolism trials, 15 mature, crossbred wethers (average weight, 49.2 kg) were allotted to five dietary treatments consisting of 800 g/d of orchardgrass (Dactylis glomerata, L.) hay alone, or supplemented with 450 g/d of either glucose, sucrose, lactose or starch. Each trial consisted of a 5-d adjustment period, a 10-d preliminary period and a 10-d collection period. Compared with wethers fed hay alone, supplementation with each kind of carbohydrate to the diet decreased (P less than .05) fecal Mg excretion and increased (P less than .05) apparent absorption and retention of Mg. Apparent absorption of the Ca was lower (P less than .05) in wethers fed lactose and tended to be decreased by glucose, sucrose and starch supplementation. Calcium retention was lower (P less than .05) in wethers fed sucrose and lactose, compared with those fed hay alone. All types of supplementary carbohydrates depressed (P less than .05) apparent absorption and urinary excretion of K. Serum Mg and Ca were not affected and serum K was depressed (P less than .05) by carbohydrate supplementation. Ruminal fluid pH was decreased (P less than .05) by glucose and lactose supplementation, and addition of these carbohydrates tended to decrease molar proportions of acetate and increase those of propionate and butyrate, compared with sheep fed hay alone. Sucrose addition decreased (P less than .05) acetate and increased (P less than .05) butyrate molar proportions in the ruminal fluid.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

11.
The concentration of H2S and rate of feed digestion, VFA and methane production in the rumen were measured in sulphur deficient (-S) and S supplemented (+S) sheep while fauna-free (-P) and after refaunation (+P). The concentration of rumen H2S was increased by S supplementation but was not affected by the presence of protozoa. When fauna-free, -S sheep had reduced rates of feed digestion (30 v 48%/d), acetate synthesis (35 v 115 g/d) and methane synthesis (0.4 v 7.4 g C/d) compared to +S sheep and up to 36% (v/v) of total rumen gas was H2. When these sheep were given a single dose of 8.8 g Na2SO4, the proportion of methane increased and the proportion of H2 in rumen gas decreased. After refaunation of sheep, their rates of feed digestion, VFA production and methane production were higher and were not affected by the level of S. From this differential response to S deficiency by -P and +P sheep, it is concluded rumen protozoa increase the availability of S to other rumen microbes. This is probably because they degrade protein through to peptides and amino acids.  相似文献   

12.
Two experiments (4 X 4 Latin squares) were conducted, using four multiple-cannulated wethers (mean body weight, 65 kg), to determine effects of treating wheat straw (WS) with alkaline solutions (pH 11.5) of hydrogen peroxide (AHP; .26 g hydrogen peroxide/g WS) on site and extent of nutrient digestion in sheep. Diets contained either 33 to 37% (low WS) or 70 to 72% (high WS) AHP-treated (T) or non-treated (C) WS. Treatment of WS with AHP resulted in increased acid detergent fiber and cellulose concentrations and decreased acid detergent lignin (ADL) concentrations compared with non-treated WS. In Exp. 1, intakes were held constant at approximately 1,044 g dry matter (DM)/d. When fed AHP-treated WS diets, wethers digested more (P less than .05) DM, neutral detergent fiber (NDF) and cellulose in the stomach (54.8, 47.4, 51.6 and 20.0%; 65.6, 68.8, 51.5 and 37.2%; 66.6, 74.2, 45.2 and 40.7% of intake, respectively, for low WS-T, high WS-T, low WS-C and high WS-C diets) and in the total tract (83.0, 74.8, 68.4 and 50.0%; 81.8, 81.0, 53.9 and 42.1%; 85.2, 86.9, 50.2 and 47.6%, respectively, for the low WS-T, high WS-T, low WS-C and high WS-C diets), and had lower (P less than .05) ruminal pH than when fed the non-treated WS diets. In Exp. 2, the same wethers were fed diets similar to those fed in Exp. 1, but at ad libitum intake. Wethers consumed less (P less than .05) feed when fed the high WS-C diet than when fed the other three diets (2,234, 2,526, 2,271 and 1,297 g/d for the low WS-T, high WS-T, low WS-C and high WS-C diets, respectively). Digestibilities of DM, NDF and cellulose were higher (P less than .05) when sheep were fed the treated WS diets than when fed the non-treated WS diets (82.7, 70.7, 68.4 and 58.0%; 78.6, 72.9, 49.4 and 51.6%; 78.0, 84.0, 53.8 and 37.5%, respectively, for the low WS-T, high WS-T, low WS-C and high WS-C diets). Fluid and particulate dilution rates in the rumen were higher (P less than .08) when wethers consumed AHP-treated WS diets compared with non-treated WS diets (8.21, 8.56, 6.96 and 6.81%/h; 6.06, 6.73, 4.05 and 3.15%/h, respectively, for the low WS-T, high WS-T, low WS-C and high WS-C diets). The AHP treatment was successful in overcoming the major barriers to microbial degradation of WS in the gastrointestinal tract of wethers.  相似文献   

13.
Four rumen fistulated wether and beef steers were used to evaluate differences in dry matter digestibility (DMD) between cattle and sheep. They were fed either perennial ryegrass or switchgrass hay at an ad libitum or restricted level for four experimental periods. Significant ruminant species X forage and ruminant species X level of intake (P less than .05) interactions were observed for digestible dry matter. The steers digested the switchgrass 7 percentage units greater than the wethers while ryegrass was digested equally. Digestibility differences between the steers and wethers were 6 percentage units at the ad libitum level of intake and 1 unit at the restricted level of intake. Crude protein digestibility tended to be greater (P less than .10) for sheep with a 7 unit difference for switchgrass and a 3 unit difference for ryegrass. The mean ruminal solids retention time of the digesta was approximately (P less than .01) 50% greater (26.0 vs 17.4 h) in cattle, with no difference in ruminal liquid dilution rate (LD) between animal species. Total ruminal volatile fatty acid concentration differed (P less than .01) with level of intake; however, no influence due to intake on the molar proportion of acetate (P greater than .10) or propionate (P greater than .10) was evident in spite of a difference (P less than .01) in LD. Rumen pH (P less than .05) and osmolality (P less than .01) were affected by both level of intake and forage, with the ryegrass and high level of intake decreasing pH and increasing osmolality.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

14.
The intestinal supply of amino acids (AA) in sheep fed alkaline hydrogen peroxide-treated wheat straw (AHPWS)-based diets supplemented with soybean meal (SBM) or corn grain plus combinations of corn gluten meal (CGM) and blood meal (BM) was measured in a 5 X 5 latin square. Sheep (avg wt 45 kg) with ruminal, duodenal and ileal cannulas were fed diets containing 65% AHPWS supplemented with the following protein sources: soybean meal (SBM), corn gluten meal (CGM), blood meal (BM), 2/3 CGM:1/3 BM and 1/3 CGM:2/3 BM. Total nitrogen (N) flow at the duodenum was not affected (P greater than .05) by protein source. Flows of bacterial N and AA increased (P less than .05) and flows of nonbacterial N and AA decreased (P less than .05) when wethers were fed SBM vs corn plus other protein sources. When diets contained SBM, quantities of total AA at the duodenum were lower (P less than .05) and the profile of AA supplied to the intestine was altered substantially. Total flows of AA at the duodenum and total quantities of AA disappearing from the small intestine were similar (P greater than .05) for all diets containing BM and CGM, but flows and disappearance of valine, histidine, lysine and arginine increased linearly (P less than .05), whereas flows and disappearance of leucine, isoleucine and methionine decreased linearly (P less than .05) as BM replaced CGM in the diets. Results suggest that quantities of individual AA flowing to the duodenum and disappearing from the intestine of wethers fed AHPWS-based diets can be altered by source of dietary protein. Furthermore, feeding protein sources resistant to ruminal degradation in combination may improve the profile of AA supplied to the intestine.  相似文献   

15.
Two metabolism trials were conducted with 12 yearling crossbred wethers per trial (34 and 38 kg for trials 1 and 2, respectively). The wethers, equipped with ruminal, abomasal and ileal cannulae, were randomly allotted for each trial to the following treatments: 1) hay alone or hay supplemented with 2) .9% urea, 3) 1% urea and 6.5% molasses or 4) 1% urea and 5.2% corn. Two digestive flow markers were used: Cr2O3 powder and Co-ethylenediaminetetraacetic acid (Co-EDTA). Urea and Co-EDTA were infused continuously into the rumen via cannula. Daily dry matter (DM) intake averaged 517 g. Urea supplementation improved N retention (P less than .01). Apparent digestibility of DM, acid detergent fiber (ADF) and energy was not affected by treatment. Urea and carbohydrate supplementation increased ruminal propionic acid molar proportions (P less than .05). Apparent ruminal DM digestion accounted for 41% of the total DM degraded, whereas 77.4% of the digestible ADF was degraded in the rumen. Urea supplementation increased ADF digestion in the large intestine (P less than .01). Urea and carbohydrate supplementation resulted in a stepwise increase in N flowing with the liquid phase at the abomasum. Mean retention times of the solid and liquid phases of digestive contents were similar across treatments. Overall, benefits of supplementation of poor-quality fescue hay diets by small amounts of urea and readily available carbohydrates remain questionable for sheep fed at a fixed level of intake below maintenance.  相似文献   

16.
不同精料补饲水平对藏绵羊瘤胃内环境参数的影响   总被引：2，自引：0，他引：2  
选择1.2岁左右藏绵羊30只,随机分3组,采用单因子分组设计,以青干草为基础日粮,按每只150,300,450 g/d 3种精料水平补饲,研究不同精料补饲水平对藏绵羊瘤胃代谢参数变化规律的影响。结果表明;随精料补饲水平提高,藏绵羊瘤胃液pH值下降,NH3-N浓度、NH3-N浓度平均值、总挥发性脂肪酸(VFA)浓度显著增加(P<0.05)。在本试验条件下,从藏绵羊瘤胃内环境的稳定方面考虑,藏绵羊每日补饲精料300 g效果最佳。  相似文献   

17.
Two experiments were conducted to determine some of the factors that led to hypomagnesemic tetany associated with the feeding of two orchardgrass hays. Sixteen mature Columbia and Suffolk wethers (62 to 72 kg), four of which were fitted with ruminal and abomasal cannulae, were fed one of two tetany-prone orchardgrass hays or a non-tetany-prone bromegrass hay. In Exp. 1, 12 wethers were used in a completely random design metabolism experiment to measure apparent absorption and retention of macrominerals. In Exp. 2, four wethers with ruminal and abomasal cannulae were used in a completely random design experiment to monitor pre-intestinal mineral absorption and ruminal characteristics. This experiment was replicated once, with wethers remaining on their diets for 16 d in each replication. In the metabolism experiment, apparent absorption and retention of Mg as a percentage of intake were lower (P less than .01 and P less than .05) for one tetany-prone orchardgrass hay compared with the other orchardgrass hay. Pre-intestinal absorption of Mg in the cannulated wethers was greater (P less than .01) for the orchardgrass hays than for the bromegrass hay. Pre-intestinal Mg absorption was higher (P less than .01), both in terms of grams per day and a percentage of intake for the orchardgrass hay with the highest Mg content. In the noncannulated wethers, the percentage of water-soluble Mg in the feces was lower (P less than .01) for the tetany-prone hays, indicating that a decrease in Mg solubility in the intestine may have influenced Mg apparent absorption.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

18.
Olives leaves, accrued during the processing of olive harvests for oil extraction, are poor in N, rich in crude fat and ADF (1.19, 8.03 and 28.2 g/100 g of DM, respectively), and relatively low in condensed tannins (11.1 mg/g of DM). Three experiments were conducted in a 2 x 3 (two animal species: goats vs. wethers; and three experimental diets: olive leaves without or with polyethylene glycol supply and olive leaves supplemented with barley and faba beans) factorial design to evaluate ruminal degradation and passage kinetics (Exp. 1), fermentation pattern and protozoa population (Exp. 2), and urinary purine derivatives excretion (Exp. 3). Polyethylene glycol was supplied to evaluate the effects of condensed tannins contained in olive leaves. Ruminal degradability of CP was low in both goats and wethers, although goats showed higher (P < 0.05) values than wethers. Supplementation of olive leaves with barley and faba beans increased (P < 0.001) ruminal degradability of DM and CP. Both goats and wethers fed olive leaves showed similarly low particulate fractional passage rates (0.021 and 0.023/h, respectively). Ingestion of olive leaves promoted low NH3-N and VFA concentrations, which reflect poor microbial activity. These concentrations, especially that of VFA, increased when barley and faba beans were added. Ingestion of olive leaves affected ruminal protozoa: Entodiniomorphida showed low concentrations and Holotricha completely disappeared. When animals received a diet based on olive leaves, barley, and faba beans, Holotricha appeared in the ruminal liquor and Entodiniomorphida increased (P < 0.001). In goats and wethers fed olive leaves alone, urinary allantoin excretion was very low (163 and 164 micromol/kg BW0.75 in goats and wethers, respectively), and moderate values (352 and 389 micromol/kg BW0.75 in goats and wethers, respectively) were observed when a diet of olive leaves, barley, and faba beans was fed. The polyethylene glycol supply did not have an effect in goats or in wethers, indicating the lack of an effect of condensed tannins in olive leaves. Ingestion of olive leaves promotes a low microbial activity, although its supplementation with readily degraded carbohydrates and protein improves microbial activity and, as a consequence, increases its ruminal degradation. In general, for most of the measured variables, there were no animal species x diet interactions. Thus, goats and wethers had similar ruminal activities when fed diets based on olive leaves.  相似文献   

19.
Two digestion studies were conducted to evaluate the use of pretanned leather shavings as a component of a protein supplement. In Exp. 1, the in situ and in vitro disappearance of pretanned leather shavings and soybean meal was evaluated. Results revealed that less than 18.4% of the pretanned leather shavings was solubilized and disappeared when exposed to McDougall's buffer for 48 h, but there was 90.0% disappearance with 48-h exposure to a .1 N HCl/pepsin treatment and 97.0% disappearance with exposure to a two-stage digestion. In situ disappearance following 72 h in the rumen allowed 6.8% disappearance. Thus, leather shavings seem to be relatively indigestible in the rumen, but postruminal digestion may be possible. In Exp. 2, six Angus x Holstein steers, fitted with ruminal and duodenal cannulas, were used in a replicated 3 x 3 Latin square to evaluate ruminal and digestion effects of the following supplements combined with fescue hay at 1.7% of BW (DM basis): no supplementation (control); supplementation intraruminally with soybean meal at .07% of BW (as-fed basis); and supplementation intraruminally with a combination of soybean meal and pretanned leather shavings (17:8 ratio) at .05% of BW (isonitrogenous to soybean meal; as-fed basis). Ruminal fluid passage rate was greater and fluid turnover time was shorter in steers fed leather shavings than in those fed soybean meal (P = .10). Ruminal pH was lower (P = .04) for supplemented steers than for control steers and ruminal NH3 N concentration was greater (P = .01) in steers fed soybean meal than in those fed leather shavings. Total VFA concentration was increased (P = .02) by supplementation. Supplementation with soybean meal increased (P < .05) ruminal molar proportions of butyrate, valerate, and isovalerate compared with leather shavings. Duodenal OM flow and OM disappearing in the intestines were increased by supplementation (P < .10), but not by the type of supplement fed (P > .10). Ruminal digestion of OM and total tract OM digestion were unaffected (P > .10) by supplementation and the type of supplement fed. Flow and digestion of NDF were unaffected (P > .10) by the treatments. Flow of N and the quantity of N disappearing in the intestines were increased (P < .05) by supplementation but did not differ (P > .10) between supplementation groups. Microbial N flow, N utilization for net microbial protein synthesis, and ruminal N disappearance were unaffected (P > .10) by supplementation and the type of supplement provided. Combining pretanned leather shavings with soybean meal seemed to have no deleterious effects on digestion or fermentation and to allow for escape of some N to the lower tract.  相似文献   

20.
Soybean meal (SBM) treated with 70% ethanol at 80 C (ET), nontreated SBM (NT) or a ureacasein-corn mix (UC) was fed to steers fitted with ruminal and duodenal cannulae to study ruminal N metabolism. Sodium chloride (NaCl) was ruminally infused at 0 or 500 g/d. Nitrogen supplements provided approximately 70% of total dietary N. Experimental design was a 6 X 6 Latin square with a 3 X 2 factorial arrangement of treatments. Total duodenal N flows and non-ammonia, non-bacterial-N (NANB-N) flows were higher (P less than .05) when steers were fed SBM treatments compared with UC, and higher (P less than .05) when steers were fed ET compared with NT. Percentage of SBM-N escaping ruminal degradation was greater (P less than .05) when steers were fed ET compared with NT, and greater (P less than .05) when NaCl was infused into the rumen. Duodenal flows of total, indispensible and dispensible amino acids were increased (P less than .05) when steers were fed SBM treatments compared with UC, and greater (P less than .05) when steers were fed ET compared with NT. No differences in soluble N flows at the omasum were observed due to treatment. Bacterial protein comprised the majority of the N leaving the rumen. Both ruminal NaCl infusion and ethanol and heat treatment of SBM increased ruminal SBM-N escape.  相似文献   

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