In vivo prediction of extracellular and intracellular water in cattle and sheep using thiocyanate and urea

Two experiments were conducted in cattle and sheep to determine the earliest time for thiocyanate equilibration with extracellular water. In Exp. 1, nine animals were infused to determine marker concentrations and sampling times. In Exp. 2, five steers were infused and then exsanguinated for tissue analyses. Thiocyanate equilibrated 22 to 31 min after infusion with a pool size equivalent to expected extracellular water. Plasma thiocyanate half-life averaged 29 h. Tissue concentrations 24 or 48 h after thiocyanate infusion were 20 to 24% of those observed in plasma for heart muscle and kidney and 6 to 8% in liver and skeletal muscle. A procedure is proposed for the in vivo estimation of empty body water (urea dilution), extracellular water (thiocyanate dilution) and, by difference, intracellular water in cattle and sheep, requiring only three blood samples, an initial sample and two samples taken 12 and 28 min after intravenous infusion of a urea-thiocyanate solution.     

Within—country variation in the ability of ruminants to degrade DHP following the ingestion of Leucaena leucocephala—a Thailand experience

Goats fed Leucaena leucocephala (leucaena) at an experimental site in Thailand were shown to be excreting DHP in their urine. This was unexpected as earlier results from another site had shown that goats and cattle fed leucaena did not excrete DHP and so possessed DHP—degrading bacteria. Goats sampled near the earlier sample site excreted no DHP in their urine. Rumen fluid taken from these goats was successfully used to transfer DHP—degrading ability to the goats at the Experimental site some 350 km away that did not show the presence of DHP-degrading bacteria. Degradation of mimosine in-vitro and excretion of DHP in the urine ceased 72 hr after addition of rumen fluid and infusion with rumen fluid from protected goats, respectively. The situation in Thailand may not be unique. Countries where leucaena is fed should check that animals are protected. Fortunately, the ferric chloride urine test is simple to use and effective in detecting the problem and also the recovery after transfer of rumen fluid from protected animals.     

Evaluation of sodium thiosulfate as an extracellular water marker in cattle.

Two studies were conducted to determine whether sodium thiosulfate (THS) can estimate extracellular water (ECW) in beef cattle in conjunction with empty body water (EBW) estimation by urea space. Experiment 1 used 24 steers (366 kg) to determine the clearance parameters for THS and urea. Blood samples were taken over 1 h. A two-component curve, Y = A1ek1(t) + A2ek2(t), (t = hours after infusion) fit the clearance of both markers; intercepts (A1, A2) and clearance coefficients (k1, k2) were 44.8, 44.4, -25.8, and -2.24 mg/dL, respectively, for THS (r2 = .98, Sy.x = 2.72, animal effects removed and 24.4, 10.5, -21.7, and -.71 mg/dL, respectively, for urea (r2 = .98, Sy.x = 1.49). Sodium thiosulfate equilibrated with ECW 5 to 10 min after infusion. Experiment 2 consisted of 22 steers (483 kg) infused with a combination solution of 20% urea, 10% THS, and 4% sodium thiocyanate (SCN; equilibration time = 28 min); half the steers were implanted with estradiol. Empty body water increased with implantation (P less than .01). Extracellular water tended to increase in implanted steers as measured by THS (12 min, P = .14) and SCN (P = .10). The estimation of ECW at 12 min was not different (P greater than .2) from the SCN estimate at 28 min (SCN = 3.7 + .873 THS; r2 = .70; P less than .001). Sodium thiosulfate gave reasonable estimates of ECW (22 to 26% of BW) and required only 0- and 12-min blood samples.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effects of 10% hypertonic saline, 0.9% saline and hydroxy ethyl starch infusions on hydro-electrolyte status and adrenal function in healthy conscious dogs

The purpose of this study was to investigate the influence of different saline and colloid solutions on adrenal steroid secretion in dogs. Six healthy male Beagles underwent three infusion cycles: 10 min infusion of 30 ml/kg of NaCl 0.9%, 5 ml/kg of hydroxy ethyl starch, or 5 ml/kg of NaCl 10%. Plasma osmolality, hematocrit, total solids, cortisol and aldosterone levels were measured at 0, 5, 15, 30, 60, 120, 180 and 240 min after beginning infusion. Plasma ACTH levels were measured at 0, 15 and 240 min. An identical timing of sampling was applied during a control session omitting the fluid infusion. Osmolality, sodium, chloride and cortisol levels were found to be significantly higher with hypertonic saline solute compared to control. All fluid infusions lead to lowered plasma potassium, hematocrit, total solids and aldosterone values. ACTH concentrations did not show significant changes with any of the infusion cycles. The increase in cortisol levels suggests that hypertonic saline infusion could be interesting in critical care resuscitation, particularly in patients who are suffering from relative adrenal insufficiency.     

The rate and pattern of urea infusion into the rumen of wethers alters nitrogen balance and plasma ammonia

Changes in N balance, urinary excretion of purine derivative (PD), urea, creatinine and ammonia and plasma ammonia, glucose, urea, insulin and IGF‐1 were examined in four wethers (37 ± 2.6 kg BW). The animals were fitted with permanent ruminal catheters, fed lucerne hay (9.4 MJ/day; 23 g N/day; 7 g soluble N/day, 6 equal meals/day) and treated with contrasting rates of urea infusion into the rumen: first, a continuous infusion (CT), at 3.2 mg urea‐N/min for 10 days and then a discontinuous infusion (DT) at 156 mg urea‐N/min for 4 min; in 6 daily doses with the meals for 7 days. N balance was calculated from pooled samples of faeces and urine. Jugular blood samples were collected before and 1.5 h after the morning meal (M1) on days CT10, DT2, DT4 and DT6. N retention decreased during DT (p = 0.01) due to a significant increase of N excretion in urine (4 g/day; p = 0.009) and faeces (1 g/day; p = 0.02). Dry matter (p < 0.001) and N digestibility in vivo (p = 0.01) decreased significantly during DT. Urinary urea and PD excretion were not altered by treatment. Significant linear (p = 0.004) and quadratic (p = 0.001) effects were observed for plasma ammonia in M1 (from 170 CT10 to 235 μm DT2 and returned to 120 μm DT6). No changes were observed in plasma glucose, urea, insulin and IGF‐1. Results indicate that changes from CT to DT reduced N retention in sheep due to enhanced urinary N excretion, but it was not associated with changes in urinary urea or PD excretion; or plasma concentrations of insulin and IGF‐1. As the dry matter (DM) an N digestibility could account a 0.23 of the decrease in N retention; the largest fraction of the reduction in N retention remained unexplained by the results.     

人工唾液对绵羊瘤胃液相平衡、瘤胃发酵和微生物氮合成的影响

进行两个试验,研究灌注人工唾液对绵(?)平衡,瘤胃发酵和微生物蛋白质合成的影响。用尿液嘌呤衍生物总量作为供给宿主动物微生物氮的指标。试验1内,4只绵羊每天饲喂1kg以侧短干草为基础的配合日粮,采用4×4拉丁方(?),别向瘤胃中灌注0,1.5,3和4L/d单倍浓度的人工唾液(AS)。试验2内,3(?)每天饲喂与试验1成分相同的颗粒日粮1kg,采用3×4不完全拉丁方设计,分别(?)瘤胃中灌注0,4和8L/d单倍浓度和4L/d双倍浓度的人工唾液(DAS)。试验1发现,灌注人工唾液对瘤胃液体积、瘤胃液稀释率、发酵类型及微生物氮合成没有影响试验又发现,灌注8L/d AS和4L/d DAS显著提高瘤胃液稀释率和微生物氮的今成(P<0.05):但对瘤胃液体积没有显著影响(P<0.05)。4个处理的微生物氮合(?)效率分别为8.50,11.20,13.10和13.97g/kg可消化有机物(DOM)(S.E=(?) 95)。微生物氮合成效率与瘤胃液稀释率有相关关系。     

Nitrogen metabolism in the large intestine of ruminants. 6. Metabolism of intracecally administered 14C and 15N urea in sheep with simultaneous intracecal doses of heat-damaged hay

Two wethers (28 kg and 33 kg) were supplied with ileocaecal re-entrance cannulae and received a straw pellet ration rich in crude fibre (70.5% straw, 12% chopped sugar beet, 10% cereals, 2% urea, 3% NH4HCO3 and 2.5% of a mineral mixture). In a preliminary period 50% of the digesta flow was collected on 6 successive days for 18 h each. An amount of digesta sufficient for 24 h was apportioned for hourly application and stored at a temperature of -20 degrees C for the main trial. In the main trial the two animals received intracaecally the collected digesta with a supplement of ca. 6 g hay damaged by heat/kg LW(0.75) in hourly portions over 24 h (hay made up ca. 15 and 20% resp. of the DM amount). In addition, each digesta sample was supplemented with 14C and 15N labelled urea (19.7.10(6) Bq 14C urea and 364 mg 15N excess from 15N urea). About 9% of the applied 15N amount was microbially utilized; the utilization quota was thus lower than after the application of partly hydrolyzed straw meal (16% in a previous trial). The 14C activity from 14C urea was quickly eliminated in the form of CO2 in the respiratory gases (at the 18th hour after the end of the infusion 70% excreted as CO2). The half-lives for the urea resulting from the semi-logarithmic decrease of the atom-% 15N excess in the blood plasma were 7.9 and 7.7 resp. 23% and 34% resp. of the applied 15N excess were excreted in urine. The excretion of radioactive carbon in urine, however, was at 2.8% and 4.3% resp. of the applied amount very low 120 h after the beginning of the trial (96 h after the end of the infusion). On the whole one can conclude from this trial that hay damaged by heat has only a low stimulating effect on microbial activity in the large intestine.     

Methaphylactic effect of tulathromycin treatment on rumen fluid parameters in feedlot beef cattle

The aim of this study was to evaluate the effect of tulathromycin as a bovine respiratory disease (BRD) metaphylactic treatment on rumen fluid parameters in feedlot cattle in an intensive livestock production farm. One hundred beef cattle, immediately after housing, were divided in 2 equal groups: 50 animals with metaphylactic treatment against BRD (treated group; tulathromycin at 2.5 mg/kg BW) and 50 animals with placebo treatment (control group). Rumen fluid samples were collected from each animal by rumenocentesis in 3 periods: 1 d (T1), 8 d (T8), and 15 d (T15) after treatment. Rumen pH was determined by ruminal fluid using portable pH meter. Total volatile fatty acids (total VFA) were evaluated by high performance liquid chromatography (HPLC). All animals were singularly weighed at T1 and T15. Two-way analysis of variance (ANOVA) was applied to determine significant effects of treatment (treated group versus control group) and period (T1, T8, and T15) on rumen fluid parameters and body weight. No clinical signs of BRD or other related diseases were recorded during the periods of study from any animal. Statistically significant differences (P < 0.05) were found between treated group and control group for mean values of ruminal pH (6.02 versus 5.89) and total VFA (5.84 versus 5.13) at 8 d after treatment. The weight gain (Δ) showed an average increase of 8.6 kg in treated group (P < 0.05). The trends of ruminal pH and VFA values suggest an effect of tulathromycin as BRD metaphylactic treatment on the modulation of rumen fermentation, particularly 8 d after administration.     

Efficacy of the urea dilution technique in estimating empty body composition of pigs weighing 50 kilograms

The efficacy of the urea dilution technique in estimating the empty body composition of pigs weighing 50 kg was evaluated in three trials using 17 contemporary (Large White X Landrace X Hampshire X Duroc) and 8 Nebraska Gene Pool X contemporary pigs. Blood samples were collected via ear catheter before infusion (-60, -30 and 0 min) and at various times (3 to 90 min) after urea infusion (2.16 mmol/kg live BW), and analyzed for plasma urea. Backfat thickness of live pigs from the contemporary line was measured ultrasonically. Pigs then were killed by euthanasic injection, and total bodies (with gastrointestinal contents removed) were analyzed for water, protein and fat. In Trials 1 and 2, there were linear relationships (P less than .001) between chemically determined body water and fat and between body water and protein. Urea space was related (P less than .05) to empty body components with few exceptions, but regression coefficients for urea space in Trial 3 were different from those of Trials 1 and 2. Inclusion of additional independent variables with urea space improved estimation of empty body components. Although backfat alone did not estimate empty body components (except fat) as well as urea space alone, the addition of other common independent variables resulted in better estimates using backfat than urea space. The results of this experiment indicate that the urea dilution technique can be used to estimate the body composition of growing pigs. However, the accuracy obtained depended on the population of pigs being investigated and was no greater than the accuracy with appropriate equations based on backfat.     

Pharmacokinetics and clinical effects of pirfenidone administered intravenously in horses

OBJECTIVE: To characterize the plasma pharmacokinetics and clinical effects of pirfenidone administered IV in healthy horses. ANIMALS: 6 adult horses. PROCEDURES: A 15 mg/kg dose of pirfenidone was administered IV over 5 minutes. Physical variables were recorded and blood samples collected prior to infusion; 2.5 minutes after beginning infusion; at the end of infusion; and at 3, 6, 9, 12, 15, 20, 25, 30, 40, 50, 60, 75, and 90 minutes and 2, 2.5, 3, 4, 6, 8, 12, and 24 hours after completion of infusion. Plasma concentrations of pirfenidone and its metabolites were determined. RESULTS: Mild clinical effects, including tachycardia and muscle fasciculations, were observed during drug administration but stopped at the end of the infusion. Pirfenidone and 2 metabolites, hydroxypirfenidone and carboxypirfenidone, were detected by the end of the 5-minute infusion. Mean peak plasma concentration of pirfenidone was 182.5 micromol/L, detected at the end of the infusion. Mean peak plasma concentrations of hydroxypirfenidone and carboxypirfenidone were 1.07 and 3.4 micromol/L, respectively, at 40 minutes after infusion. No parent drug or metabolites were detected at 24 hours. Distribution of pirfenidone best fit a 2-compartment model, and the drug had mean +/- SEM elimination half-life of 86.0 +/- 4.7 minutes, mean body clearance of 6.54 +/- 0.45 mL/kg/min, and apparent volume of distribution at steady state of 0.791 +/- 0.056 L/kg. CONCLUSIONS AND CLINICAL RELEVANCE: Intravenous administration of pirfenidone was tolerated with transient adverse affects during infusion, and drug clearance was rapid.     

Procedural and mathematical considerations in urea dilution estimation of body composition in lambs

Two experiments (n = 46 and 56, respectively) were conducted to evaluate urea dilution as an estimator of body composition in lambs and to address certain procedural and mathematical considerations in this technique. In Exp. 1, 14 blood samples were taken over 240 min after urea infusion. The equation describing the urea clearance curve was: delta PUN = 9.7e-.1727(min) + 10.4e-.0021(min), pools 1 and 2, respectively (r2 = .99, P less than .001; individual lamb effects removed). In the combined experiments, urea space (US) was related to percentage of empty body water (PEBH2O) by the equation 31.7 + .471 US (empty body weight basis; r2 = .56, P less than .001). The regression equation indicates that the US-PEBH2O relationship in lambs is different from that reported in cattle, even though urea clearance kinetics are similar. Although the prediction equations appeared to be biologically valid, considerable error was associated with the composition estimates. The PEBH2O was predicted as well by live weight (r2 = .69; SEy.x = 3.0) as by US in these experiments. The two-sample method (T12 minus T0) to determine the change in marker concentration was shown to be related more closely (r2 = .56) to PEBH2O than the standard multisample extrapolation to T0 method (r2 = .0 and .38 for pools 1 and 2, respectively). An equilibration time of 9 to 12 min provided the best estimate of body composition in lambs.(ABSTRACT TRUNCATED AT 250 WORDS)     

Characteristics of water soluble markers for measuring rumen liquid volume and dilution rate

The utility of five water soluble markers (WSM) for measuring rumen liquid volume and dilution rate was examined in nine in vitro and in vivo experiments. The WSM tested included polyethylene glycol (PEG) and ethylenediaminetetraacetic acid (EDTA) complexes of Cr, Co, Fe and Yb. Feedstuffs incubated in vitro absorbed variable amounts of distilled H2O and autoclaved rumen fluid with roughages imbibing greater (P less than .05) amounts of fluid than feeds higher in starch. Liquid present in the feeds tested reached equilibrium with added WSM in about 20 min. Corn grain in the whole or ground form appeared to exclude 4 to 16% of the WSM while imbibing water. Cottonseed hulls reduced detectable PEG due to some water soluble substance present. The WSM tested did not produce different estimates of dilution rate (P = .65) and volume (p = .29) of steers fed either 80% whole shelled corn, 90% chopped alfalfa hay or 90% prairie hay diets. Ruminal liquid measured by hand removal was about 4% greater than volume estimated by WSM. The percentage of total ruminal water associated with solids varied from 27 to 86% among steers. Compared with steers fed an 80% whole shelled corn diet, steers fed equal dry matter from alfalfa hay had 15% more dry matter in the rumen, 21% larger liquid volume, 80% greater ruminal liquid dilution rate and 116% greater rate of liquid flow from the rumen. Dilution rate of ruminal liquid during feeding was examined with six steers fed a 90% chopped alfalfa hay diet once daily at 1.8% of body weight. Dilution rate estimated with Co EDTA increased by 166% during the 4 h after feeding. The WSM did not influence (P greater than .10) digestibility of dry matter with steers fed a 90% roughage or a 90% concentrate ration. Recovery of WSM administered via a rumen cannula ranged from 96.8 to 99.7% in feces and 1.2 to 3.4% in urine. All WSM examined appeared suitable for estimating rumen liquid volume and dilution rate for diets not containing cottonseed hulls.     

Response of one-humped camel (Camelus dromedarius) to intravenous glucagon injection and to infusion of glucose and volatile fatty acids, and the kinetics of glucagon disappearance from the blood

The effects of glucagon injection and infusion of glucose and volatile fatty acids were studied in one-humped camels. Twenty adult male camels were divided into four equal groups. The first group was infused with physiological saline and served as a control. The second group was injected with a single dose of glucagon, the third group was infused with glucose (50%) in sterile saline, and the fourth group was infused with a volatile fatty acid (VFA) mixture. In the first, third and fourth groups, sampling was performed before the beginning of infusions (control time), and at 15, 30, 60 and 120 min post-infusion. Plasma glucagon concentrations were monitored in the second group at 5, 10, 15, 20, 30, 45, 90, 105 and 120 min after injection. For glucagon injection, glucose concentration peaked at 15 min post-injection, and tended to decrease thereafter. Plasma glucose concentrations showed significant rises above the basal value at all times after glucose infusion. VFA infusion had no apparent effect on plasma glucose concentration. After injection of glucagon, the plasma lactate concentration dropped significantly at 15 and 30 min, then increased gradually until it reached the original concentration of lactate at 120 min. However, glucose infusion elevated the plasma lactate concentration only at the end of the infusion period. A decrease in plasma lactate was observed at 60 min after VFA infusion. The present investigation provides evidence that the glucagon level in camels is higher than that in other ruminants and in man, and suggests that this is a probable species specificity, which would explain the higher level of glucose in the blood of camels than in that of other ruminants. The disappearance curve of injected glucagon had, as in other ruminants, an exponential two-compartment function. The hormone was rapidly distributed and was eliminated with a high rate of clearance.     

The effects of 10% hypertonic saline, 0.9% saline and hydroxy ethyl starch infusions on hydro-electrolyte status and adrenal function in healthy conscious dogs

The purpose of this study was to investigate the influence of different saline and colloid solutions on adrenal steroid secretion in dogs. Six healthy male Beagles underwent three infusion cycles: 10 min infusion of 30 ml/kg of NaCl 0.9%, 5 ml/kg of hydroxy ethyl starch, or 5 ml/kg of NaCl 10%. Plasma osmolality, hematocrit, total solids, cortisol and aldosterone levels were measured at 0, 5, 15, 30, 60, 120, 180 and 240 min after beginning infusion. Plasma ACTH levels were measured at 0, 15 and 240 min. An identical timing of sampling was applied during a control session omitting the fluid infusion. Osmolality, sodium, chloride and cortisol levels were found to be significantly higher with hypertonic saline solute compared to control. All fluid infusions lead to lowered plasma potassium, hematocrit, total solids and aldosterone values. ACTH concentrations did not show significant changes with any of the infusion cycles. The increase in cortisol levels suggests that hypertonic saline infusion could be interesting in critical care resuscitation, particularly in patients who are suffering from relative adrenal insufficiency.     

Abomasal bacteria produce an inhibitor of gastrin secretion in vitro

Previously, proliferating microflora transferred with abomasal nematodes, were suspected to be the source of the gastrin inhibitor in some parasite excretory/secretory products. Aerobic cultures in HBSS of abomasal fluid from uninfected sheep became inhibitory during the static growth phase, unless antibiotics were present. Basal gastrin secretion was reduced by up to 90%. Rumen fluid and incubates and medium in which Streptococcus bovis and ovine rumen Actinomycete spp. had been grown also contained the inhibitor. Unlike abomasal cultures, rumen fluid and incubates also reduced the measurement of gastrin standards. Rumen incubates were less potent after exposure to pH 2-3, suggesting that inactivation normally occurs in the unparasitised abomasum. Contaminating bacteria which generate the gastrin inhibitor in parasite ES products are probably rumen organisms which survive in the abomasum and proliferate during subsequent incubation. Significantly, rumen bacteria have been shown to be capable of affecting the secretory activity of the gastric mucosa.     

Balance and urinary excretion of calcium, magnesium and phosphorus in response to high concentrate feeding and lactate infusion in lambs

Two experiments were conducted to investigate the influence of dietary concentrate level and iv lactate infusion on the urinary excretion and balance of Ca, Mg and P in lambs. In Exp. 1, six ruminal fistulated, crossbred wethers (25 kg) were fed diets of 0, 50 and 70% concentrate for 5-d periods (periods 1, 2 and 3, respectively) followed by 25 d on a 90% concentrate diet (periods 4, 5 and 6, respectively). Collections were made for all days except 6 to 10 and 16 to 20 on the 90% concentrate diet. Dry matter intakes increased with each increase in dietary concentrate until the initial period of 90% concentrate (period 4) when intakes were lowest. Intakes increased (P less than .05) during the latter two periods of 90% concentrate feeding compared with period 4. Rumen fluid pH decreased and rumen L (+) lactate increased with increasing concentrate intake. Blood pH and bicarbonate both decreased with increasing concentrate intake indicating a mild disturbance in acid-base balance. Plasma concentrations of Ca, Mg and P decreased with increased concentrate intake and were elevated (P less than .05) for periods 5 and 6 compared with period 4. Plasma alkaline phosphatase activity and urinary hydroxyproline excretion both increased (P less than .05) for periods 5 and 6. Four of the six animals were in negative Ca balance for the initial period of 90% concentrate feeding, but showed highest Ca retentions for periods 5 and 6. Magnesium and P balance appeared unaffected by increased concentrate intake. Disturbances in Ca metabolism appeared to be short-term and nondetrimental; the animals responded with increased growth and Ca retentions once adjusted to the high concentrate diet. In Exp. 2, four Hampshire ewes (32 kg) were used in a 4 X 4 Latin square design with treatments being saline (.9% NaCl, w/v), L (+) lactate, D (-) lactate and D, L-lactate infused iv in a saline solution to supply .6 mM/kg body weight of each isomer in 15 min. Plasma and urine samples were taken 0, .5, 1, 1.5, 3, 6 and 12 h from the start of infusion. Total urinary excretion of Ca (P less than .04) and Mg (P less than .02) were elevated for all lactate infusions as compared with saline. Total P excretion was greater (P = .06) for all lactate infusions compared with saline and was increased (P less than .05) for the D, L-lactate treatment as compared with the D- and L-lactate treatments.(ABSTRACT TRUNCATED AT 400 WORDS)     

Ground transport stress affects bacteria in the rumen of beef cattle: A real‐time PCR analysis

Transport stress syndrome often appears in beef cattle during ground transportation, leading to changes in their capacity to digest food due to changes in rumen microbiota. The present study aimed to analyze bacteria before and after cattle transport. Eight Xianan beef cattle were transported over 1000 km. Rumen fluid and blood were sampled before and after transport. Real‐time PCR was used to quantify rumen bacteria. Cortisol and adrenocorticotrophic hormone (ACTH) were measured. Cortisol and ACTH were increased on day 1 after transportation and decreased by day 3. Cellulolytic bacteria (Fibrobacter succinogenes and Ruminococcus flavefaciens), Ruminococcus amylophilus and Prevotella albensis were increased at 6 h and declined by 15 days after transport. There was a significant reduction in Succinivibrio dextrinosolvens, Prevotella bryantii, Prevotella ruminicola and Anaerovibrio lipolytica after transport. Rumen concentration of acetic acid increased after transport, while rumen pH and concentrations of propionic and butyric acids were decreased. Body weight decreased by 3 days and increased by 15 days after transportation. Using real‐time PCR analysis, we detected changes in bacteria in the rumen of beef cattle after transport, which might affect the growth of cattle after transport.     

奶水牛瘤胃大口径瘘管安装手术及术后护理

瘤胃瘘管是用于研究反刍动物消化代谢、瘤胃微生态环境、生理生化等指标试验的手段之一,可广泛应用于反刍动物营养科研实验中。试验采用外科手术方法对 4 头奶水牛进行人造瘤胃瘘管安装,经约4周的术后护理。结果表明：术牛精神状态、体温、食欲、大小便等指标均表现正常。术后15d经检查发现,术牛的瘤胃壁与腹膜、腹肌及皮肤愈合粘连在一起,形成自然瘘口,没有出现刀口或腹腔感染的现象。说明该手术方法可操作性强,过程简单,用时短,术后瘘管密闭性好,创口恢复快、无感染;奶水牛能正常存活。     

Tracer studies of urea kinetics in growing pigs: II. The effect of starch infusion at the distal ileum on urea recycling and bacterial nitrogen excretion.

Six gilts, with an average BW of 70 kg, were fitted with a simple T-cannula at the distal ileum to study the effect of continuous starch infusion on urea kinetics by means of a radioisotope dilution technique. The pigs were fed twice daily 600 g of a cornstarch-based diet formulated to contain 16% CP by supplementation with isolated soy protein. Infusion of starch, compared with water, decreased (P < .05) plasma urea concentration, urea pool size, and entry, excretion, and degradation rates; urea turnover rate and urea space were not affected (P > .05). Expressed as a percentage of total entry rate, approximately 40% of urea was recycled into the digestive tract in both infusion treatments. The stimulation of microbial fermentation in the large intestine resulted in an increase (P < .05) in fecal N excretion, which was mainly due to an increased excretion of bacterial N. This increase could not be attributed to a greater secretion of urea into the large intestine and its subsequent utilization by the intestinal microflora. The increased bacterial N assimilation after starch infusion led to a reduction in ammonia absorption from the large intestine, which in turn was reflected by a reduced urinary N excretion. As a result, the overall N balance was not affected. In a second experiment, two barrows, with an average BW of 80 kg, were fed twice daily 1.4 kg of a cereal-based diet. The body urea pool of both pigs was labeled with a single injection of 1 g and 2 g of [15N]urea, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of slaframine on ruminant digestive function: liquid turnover rate and fermentation patterns in sheep and cattle

Two trials were initiated to determine if slaframine (SF) can be used to alter fluid digesta flow and fermentation patterns in the rumen. In trial 1, a preliminary experiment, four Dorset X Barbados Black-belly ruminal-cannulated wethers (avg weight 41.6 8.7 kg) given ad libitum access to a pelleted concentrate/hay diet were injected intramuscularly with 0, 12, 24 or 48 micrograms SF/kg body weight (BW) in a 4 X 4 Latin-square design. Ruminal fluid dilution rate was determined using a single intraruminal infusion of polyethylene glycol (7 g), followed by seven hourly ruminal fluid samples. The administration of 48 micrograms SF/kg BW increased (P less than .10) ruminal volume and outflow by 27 and 25%, respectively, compared with controls. In trial 2, two Hereford and two Angus ruminal cannulated steers (avg weight 568 +/- 93 kg) were injected with 0, 6, 12 or 24 micrograms SF/kg BW at 8-h intervals over a 24-h period in a 4 X 4 Latin-square design. Steers were fed a concentrate diet at twice maintenance in 24 equal portions daily. Ruminal fluid dilution was measured using a single intraruminal infusion of cobalt-ethylenediamine tetraacetic acid (20 g) administered 9 h after the initial SF injection. Ruminal fluid was collected each hour during 8 to 24 h after the initial SF injection and analyzed for pH, osmolality and volatile fatty acids (VFA).(ABSTRACT TRUNCATED AT 250 WORDS)