Abomasal Contents Research Articles

Pneumonia associated withTorulopsis glabratain an aborted bovine fetus

The second case of bovine abortion caused by Torulopsis glabrata observed in examining more than 5000 fetuses is reported. The yeast was cultured from fetal abomasal content and fetal lung; attempts to isolate viruses and bacteria were unsuccessful. The yeast was seen in association with diffuse fetal pneumonia characterized by presence of polymorphonuclear leukocytes and macrophages within bronchioles, alveolar lumina and alveolar septa. Macrophages containing many yeast cells were observed within bronchioles.

Digestion and absorption of starch, maltose and lactose by the preruminant calf.

1. Preruminant calves, some of which were equipped with re-entrant cannulas in the small intestine, were given liquid feeds in which various starches, maltose or lactose formed the sole source of carbohydrate.2. The sugars left the abomasum at the same rate as a water-soluble marker but the starches were greatly delayed. Little starch left the abomasum until about 5 h after feeding. Examination of abomasal contents 0.5 h after feeding showed the starch to be associated with the casein clot.3. Amounts of starch, maltose and lactose removed during the passage of digesta through the small intestine were about 60, 43 and 97% of intake respectively, with no marked difference with age between about 7 and 16 weeks.4. No change in blood glucose was apparent in calves given starch-containing feeds. The possible effect of the retention of dietary starch in the abomasum in minimizing blood glucose responses is discussed.

The effect of formaldehyde treatment of a casein supplement on urea excretion and on digesta composition in sheep

The urinary excretion of urea, the fate of an intravenous dose of urea, overall nitrogen metabolism and the composition of rurnen and abomasal samples were studied in crossbred sheep given a basal roughage diet to which supplements of starch, casein or formaldehyde-treated casein were added. Urea excretion was closely related to plasma urea level (r = 0.935) and to the filtered load of urea (r = 0.957). The amount of urea reabsorbed by the kidney increased as'the amount filtered increased; the relationship was improved when values obtained at urine flow rates less than 1 rnl/rnin were omitted. When sheep were given the starch and treated casein diets, the rate at which they cleared a small dose of urea from their plasma was greater than the renal clearance rate; only 75% of a large dose was recovered in the urine. The capacity to dispose of exogenous urea by extra-renal pathways was apparent only when rumen ammonia nitrogen levels were less than about 200 mg/l. Formaldehyde treatment reduced nitrogen digestibility but reduced urine nitrogen excretion to a greater extent so that nitrogen retention increased. Treatment was associated with reduced plasma urea levels, reduced rumen and abomasal ammonia levels, reduced total VFA levels, increased proportions of acetic acid and decreased proportions of isobutyric, isovaleric and n-valeric acids, and more protein in abomasal contents.

Corrigendum - The effect of formaldehyde treatment of a casein supplement on urea excretion and on digesta composition in sheep

The urinary excretion of urea, the fate of an intravenous dose of urea, overall nitrogen metabolism and the composition of rurnen and abomasal samples were studied in crossbred sheep given a basal roughage diet to which supplements of starch, casein or formaldehyde-treated casein were added. Urea excretion was closely related to plasma urea level (r = 0.935) and to the filtered load of urea (r = 0.957). The amount of urea reabsorbed by the kidney increased as'the amount filtered increased; the relationship was improved when values obtained at urine flow rates less than 1 rnl/rnin were omitted. When sheep were given the starch and treated casein diets, the rate at which they cleared a small dose of urea from their plasma was greater than the renal clearance rate; only 75% of a large dose was recovered in the urine. The capacity to dispose of exogenous urea by extra-renal pathways was apparent only when rumen ammonia nitrogen levels were less than about 200 mg/l. Formaldehyde treatment reduced nitrogen digestibility but reduced urine nitrogen excretion to a greater extent so that nitrogen retention increased. Treatment was associated with reduced plasma urea levels, reduced rumen and abomasal ammonia levels, reduced total VFA levels, increased proportions of acetic acid and decreased proportions of isobutyric, isovaleric and n-valeric acids, and more protein in abomasal contents.

FATE OF 75Se-SELENOMETHIONINE IN THE GASTROINTESTINAL TRACT OF SHEEP

A total of 30 wethers was used to study the movement of 75Se-selenomethionine in tissues and contents of various sections of the digestive tract after a single oral or intravenous dose of the selenocompound. After intravenous administration, 75Se-selenomethionine was detected in the upper part of the small intestine lumen after 3–5 h and to a lesser extent in the abomasum contents at 24 h. The highest specific activity (cpm/g of fresh tissue) in gastrointestinal tract tissue was found in the upper jejunum at 3 h postdosing. When the labeled selenocompound was given orally, the midjejunum tissue had the highest 75Se specific activity at 24 h. Supernatant and sediment fractions of gastrointestinal tract contents resulting from centrifugation at 30,000 × g were treated with 20% trichloroacetic acid. For both modes of administration, the trichloroacetic acid-soluble portion of the various gastrointestinal tract contents had higher 75Se activity in the supernatant than in the sediment. Up to 24 h, the acid-soluble part of the two centrifugal fractions was much higher for the upper part of the small intestine than for the fore-stomach contents.

Effects on abomasal function of Ostertagia circumcincta infections in sheep.

Sheep in which abomasal fundic pouches had been made were infected with Ostertagia circumcincta (150000 larvae in one sheep, 100000 in three sheep). Subsequently studies were made on pouch secretion, food intake, plasma pepsinogens and abomasal pouch secretory responses when the sheep first ate. A functional abomasal lesion was apparent within 4 days of infection judged by the changes in plasma pepsinogen levels and the sodium concentrations of abomasal contents. Whereas the secretory activity of the abomasal fundic pouches (never exposed to parasites) was maintained or increased, the pH and sodium concentration of contents taken from the infected part of the abomasum were indicative of either a failure to secrete or of a permeability reabsorptive lesion. Ultrastructural studies demonstrated that parietal cells of the pouches had the appearance of cells subjected to strong secretory stimuli, but those of infected abomasa were similar to cells of gastric mucosa subjected to agents suppressing secretion. Factors which might operate, on the one hand, to stimulate secretion from separated fundic abomasal pouches, and on the other to inhibit or modify the secretory activity of the fundic mucosa of the infected abomasa, are discussed.

On the relationship between abomasal electrolytes and some population parameters of the nematodes Haemonchus contortus and Nematodirus battus.

Possible relationships between the numbers and development and growth of Haemonchus contortus and Nematodirus battus during concurrent infections and the levels of abomasal pH and Na+ were investigated in 2- to 3-month-old and 8-month-old lambs. The percentage of Haemonchus in the fourth larval stage was found to be positively related to the levels of abomasal electrolytes, while the mean lengths of the worms in the total male and female populations and in the fifth-stage populations were negatively related to these parameters. The numbers of Nematodirus and the mean lengths of worms in the total and fifth-stage populations were negatively related and the percentage of worms in the fourth-stage positively related to abomasal pH and Na+ levels. It is suggested that the changes in abomasal physiology caused by massive infections of Haemonchus directly affect the growth and development of this abomasal parasite. It is also suggested that the changes in the abomasal contents entering the proximal part of the small intestine during such infections of Haemonchus alter the intestinal environment and that this alteration directly affects the course of development of concurrent infections of Nematodirus.

The effect of some molecules and ions on gastric function in the milk-fed calf.

1. The abomasum of the milk-fed calf has been examined using an adaptation of the Serial Test Meal method devised by Hunt & Spurrell (1951). The emptying process, acid secretion and pepsin secretion were studied.2. Using serial test meals of simple solutions instilled into the abomasum via a cannula, our investigation leaves no doubt that the osmolarity of the abomasal contents significantly modifies the rate of abomasal emptying.3. Hypotonic and isotonic solutions of sodium chloride and sodium bicarbonate increase abomasal emptying but bicarbonate is most effective.4. Increasing the concentration of solutes in the abomasal contents slows abomasal emptying. Sodium chloride, sodium bicarbonate, ammonium chloride and urea do not delay abomasal emptying until hypertonic concentrations are attained. Hypotonic solutions of potassium chloride, calcium chloride, glucose, lactose, hydrochloric acid and acetic acid delay abomasal emptying.5. The results obtained in the calf show that the abomasum is under restraint probably from duodenal receptors as is the simple stomach (Hunt & Knox, 1968) and that an osmoreceptor as postulated by Hunt (1956) is an important factor in this mechanism.6. Acid secretion is inhibited when hypertonic solutions are instilled into the abomasum.7. Pepsin secretion is not affected by simple solutions in the abomasum.8. Gastric function in the milk-fed calf appears to be controlled by mechanisms essentially similar to those already demonstrated in the simple stomach.

A Technique for Chronic Catheterization of the Sheep Abomasum

Summary A simple technique for implanting a catheter in the abomasum of the sheep for daily sampling of the fluid phase of the abomasal contents is described.

Digestion of concentrates in sheep. 4. The effects of urea on digestion, nitrogen retention and growth in young lambs.

1. The effects of adding increasing supplements of urea to mainly barley diets for early-weaned lambs were investigated in two experiments. In the first experiment the passage of nutrients along the alimentary tract was studied by taking samples of abomasal, ileal and rectal contents and using a marker technique. In the second experiment, feed consumption and rate of gain were recorded over the growth period up to 40 kg live weight, and nitrogen balances were carried out. In the second experiment a barley-fish meal diet was also included.2. The fermentation of organic matter in the rumen increased with the amount of urea in the diet and levelled off when the diet contained about 12% crude protein.3. Urea supplementation had significant effects in increasing N retention and rate of live-weight gain and in decreasing feed conversion ratio, but supplementation beyond about 12% crude protein in dry matter had no further effect on these measurements. In each instance results with the barley–fish meal diet were better than the results with any of the barley-urea diets.4. From the concentrations of diaminopimelic acid (DAPA) in abomasal fluid it was estimated that microbial protein was produced in the rumen at a rate of 15.6% g/100 g organic matter fermented. This ratio did not appear to alter significantly with urea supplementation, but the comparison depends on the assumption that the concentration of DAPA in the bacterial protein did not itself change with urea supplementation.5. Using results from both experiments, it was calculated that the retained N on the urea-supplemented barley diets was approximately 47% of the amount of protein N absorbed in the small intestine.6. It is suggested that barley diets for early-weaned lambs can with advantage be supplemented with non-protein N to increase the crude protein in the dry matter up to about 12%. When barley diets are given with a protein supplement the addition of non-protein N is unlikely to be beneficial unless the protein supplement is given in such a way that it is not subject to degradation to yield ammonia in the rumen.

Radioiodine Absorption and Secretion by the Calf Abomasum

The bidirectional passage of radioiodine between the blood and abomasum was investigated in 12 anesthetized calves. Ratios of abomasal venous to arterial 131I concentrations averaged 0.84±0.13 (sd) during 24 minutes and 0.72±0.13 at 24 hours after intravenous administration indicating 16 to 28% removal of circulating iodine by the abomasum. Recovery of 125I in abomasal contents 25 minutes after injection into the abomasum averaged 72±23%. Movement of iodine from the abomasal lumen to the blood was further indicated by rapid appearance of 125I in abomasal venous blood which plateaued between 2 and 3% of the 125I dose per liter within seven minutes. A negative relationship (r = 0.96, P<.01) was found between 131I uptakes by the thyroid and abomasum 24 hours after dosing.

Abomasal Nitrogen in Steers Fed Soybean Meal, Urea or Urea Plus Two Levels of Molasses

The quantity and quality of nitrogen reaching the abomasum of steers fed SBM, urea, urea and 2.5% molasses or urea and 10.0% molasses were determined using four abomasal fistulated steers in a 4×4 latin square. Total nitrogen reaching the abomasum, estimated by nitrogen:chromic oxide ratios was determined and separated into protein, bound-amino and free-amino nonprotein nitrogen and purine-pyrimidine nitrogen. Quantitative estimates revealed that only 79.4% as much nitrogen reached the abomasum in steers fed urea as in steers fed SBM. Addition of 2.5% molasses to urea increased daily abomasal nitrogen to 92.5% of that from SBM feeding, and addition of 10.0% molasses to urea was of no benefit over 2.5% molasses. While differences between means were not statistically significant (P>.05), significant treatment effects were recorded at P<.2. Abomasal nitrogen composition was similar on all rations with the urea ration showing somewhat lower quantities of purine-pyrimidine nitrogen. There were no differences due to ration treatment in the amino acid composition of abomasal contents.

A comparison of markers for estimating magnitude of rumen digestion.

1. Two experiments were carried out with sheep and cattle receiving high-concentrate rations to estimate the amount of digestion taking place in the rumino-reticulum and omasum. Two techniques were used for the collection of samples of abomasal contents. In the experiment with sheep, animals were slaughtered at different times after feeding and samples of digesta were collected. In the experiment with cattle, samples were collected through an abomasal fistula at 2 h intervals throughout the entire 24 h. Chromic oxide powder was incorporated into the ration.2. Digestion of DM in the rumen estimated by the chromic oxide ratio ranged from 36 to –7%. Estimates based on the lignin ratio ranged from 57 to 68%. Estimates based on lignin as the marker were more consistent within experiments.3. Starch digestion in the rumen based on the chromic oxide ratio ranged from 56 to 92% while estimates based on the lignin ratio ranged from 89 to 96%. The amount of starch digested, according to chromic oxide ratios, was up to 500 g more than estimated organic matter digested in sheep, and up to 2 kg more than organic matter digested in cattle, both impossible results. Estimates based on lignin were always less than estimated dry-matter digestion.4. In view of the untenable results obtained by using chromic oxide powder mixed in the ration as an indigestible marker, while lignin in the same samples always yielded credible results, it appears that chromic oxide is not always a suitable marker for estimating rumen digestion from abomasal samples.

EFFECT OF ADDED BULK ON GROWTH, NUTRIENT UTILIZATION, DIGESTIVE SYSTEM AND DIARRHEA IN CALVES FED MILK REPLACER

Liquid milk replacera with or without added sawdust, purified wood cellulose or oat hulls (3% of dry replacer), or whole milk were fed to dairy calves in metabolism cages to study growth, digestibility, physical, chemical and enzymatic changes in the digestive tract, and incidence of diarrhea. In a relatively draft-free room at 21–22 °C bulk tended to increase1 fecal dry matter (19.6 vs. 17.1%). Bulk, especially oat hulls, also tended to reduce incidence of diarrhea compared with milk replacer fed alone. Bulk had no effect on calf growth, digestibility of milk replacer nutrients or nitrogen retention. Oat hulls were the only bulk source which entered the rumen, causing development of this organ, and increasing the percent dry matter and lowering the pH of abomasal contents. It was concluded that bulk, especially in the rumen, may exert a beneficial effect on the digestive tract of calves consuming only milk replacer.

Abomasal Nitrogen in Steers Fed Soybean Meal or Urea

Quantitative and qualitative estimates of nitrogen in the abomasum were studied with four steers fitted with permanent abomasal fistulas and fed ground ear corn rations supplemented with SBM or urea. Significantly more total nitrogen was recovered in the abomasum of steers fed SBM than in steers fed urea. More of the nitrogen in the abomasum was in the form of protein and less as free amino and purine-pyrimidine nitrogen when SBM was fed than when urea was fed. Molar ratios of individual amino acids in abomasal contents were not significantly affected by source of supplemental nitrogen.

Calcium Iodate and Pentacalcium Orthoperiodate as Sources of Supplemental Iodine for Cattle

The nutritional availability of iodine from calcium iodate, pentacalcium orthoperiodate (PCOP), and sodium iodide was compared using six near-term pregnant cows. Nine days before expected parturition, three were orally dosed with 2mCi 125I-labeled calcium iodate and three orally with 2mCi 125-labeled pentacalcium orthoperiodate. Each animal was orally given 2mCi Na131I simultaneously with the 125I doses. One animal from each group was killed seven days after dosing and four were allowed to calve normally. Blood plasma radioiodine concentrations, thyroid uptake, and urinary and fecal radioiodine excretions were comparable for each of the iodine compounds during seven days after dosing. Calcium iodate and pentacalcium orthoperiodate were equally available as iodide for transfer to the unborn fetus as indicated by equal 125I and 131I concentrations in slaughter samples including maternal and fetal thyroids, abomasal content, placental fluids, cotyledons, and fetal bladder content and bile. Thyroid and plasma 125I levels equaled corresponding 131I values for four cows and calves during six days following parturition. It was concluded that calcium iodate and pentacalcium orthoperiodate are adequate supplemental iodine sources for cattle.

Absorption of volatile fatty acids, tritiated water and antipyrine from the abomasum of goats.

In conscious goats the abomasum was isolated temporarily from the rest of the gastro‐intestinal tract by means of balloons, or a double by‐pass or a snare around the pylorus. Abomasal contents, rumen fluid or a saline solution were given into the abomasum. Altogether forty experiments were done on four goats.The absorption of acetic acid, propionic acid, butyric acid, tritiated water (HTO) and antipyrine (AP) from the abomasum was measured. For comparison of the absorption rates, the data were given as clearance of the abomasal fluid and as water diffusion.At a mean abomasal fluid volume of 606 ± 201 ml., 513 ± 169 ml. water diffused out of the abomasum through the abomasal mucosa per hour. The antipyrine clearance was 214 ± 84 ml./hr. The volatile fatty acids (VFA) were absorbed considerably faster at acid than at neutral pH values; at pH 5·2 — 5·6 the VFA clearance was only 320 ml./hr.: at pH 3·5−4·0, however, it increased to 1130 ml./hr.The olive oil: water partition coefficients for acetic, propionic and butyric acid were measured in the pH range of 3·5 −6·2. With decreasing pH values the degree of dissociation of the acids decreases and the lipid solubility increases considerably. The permeability of the abomasal and ruminal mucosa for VFA also increases at lower pH values, but not as much as the olive oil : water partition coefficients of the acids.Absorption of VFA, HTO and AP from the abomasum is discussed in relation to the absorption of these substances from the rumen and the human stomach.

An electrophysiological study of some reticulo‐ruminal and abomasal reflexes in sheep

1. In halothane-anaesthetized sheep in which reticulo-ruminal (gastric) contractions were present, nervous discharges have been recorded electrophysiologically in sixty-four single efferent gastric units (grouped in seven types) dissected from the mid-cervical region of the left vagus. An examination was made of the reflex effects on the efferent discharges of the procedures given in paragraphs 2-5.2. Under isotonic recording conditions the total discharge was reduced but the peak frequency of most types of unit was enhanced compared with the discharge recorded under control isometric conditions.3. Abolition of reticular contractions by the use of preganglionic and post-ganglionic blocking agents resulted in an efferent discharge pattern similar to that recorded under isotonic conditions.4. Sudden deflation or inflation of the reticulum at the start of a reticular contraction had an effect that depended on the initial volume of the reticulum. It could be either excitatory and/or inhibitory.5. Acidification of the abomasal contents reflexly enhanced the discharge in three of ten efferent gastric vagal units. An abomasal pH less than 1.0 appears to be less important in providing an excitatory drive to the ;gastric centres' in halothane-anaesthetized sheep than in decerebrate sheep.6. It is estimated that the total reflex time is > 1.3 sec for reticulo-reticular reflexes and > 2.1 sec for reticulo-ruminal reflexes. The central reflex time is > 370 msec.7. It is concluded that a tonic afferent input from ;in series' reticular tension receptors during the quiescent period of the primary (reticulo-ruminal) cycle provides a reflex drive to the ;gastric centres' and largely determines the rate and amplitude of the reticular and ruminal contractions.8. The enhanced afferent input, during a reticular contraction under isometric recording conditions, modifies the size, form and duration of the later phases in the contraction sequence of the reticulum and rumen. The reflex effects are predominantly excitatory at low and moderate levels of reticular tension and inhibitory at high levels.

Post-ruminal Degradation and Absorption of Carbohydrate by the Mature Ruminant

Sheep that had been fed a high carbohydrate ration were killed 3, 6 or 24 hours post-feeding to determine the relative amount and form of carbohydrate reaching the abomasum. The carbohydrate concentrations in abomasum contents, 3 hours post-feeding, was equal to 55% of the ration concentration. More total carbohydrate, due to more starch, was observed in the abomasum 3 hours post-feeding than 6 or 24 hours post-feeding. Starch and maltose were hydrolyzed and absorbed as glucose from the small intestine. The rate of hydrolysis of maltose and absorption of glucose was appreciably faster than the rate of blood glucose clearance, whereas the rate of starch hydrolysis was only slightly greater than the rate of blood glucose clearance. The latter difference was detectable only when a large amount of soluble starch was administered into the abomasum of sheep fed a high concentrate diet.

Absorption and gastric secretion of iodine-131 and chlorine-36 in dairy calves.

Metabolism of I131 and Cl36 was investigated by simultaneous daily administration of the two radioisotopes to milk fed dairy calves. Plasma levels of I131 averaged 1/5 and abomasal I131 contents 3 times corresponding Cl36 values. Thus, net gastric secretion of iodine exceeded that of chlorine by 15 times. Percentages of daily administered I131 and Cl36, respectively, excreted during the last 3 days of dosing averaged 15.6 and 12.2% in urine and 31.5 and 0.4% in feces. Chlorine-36 in ingesta from the large intestine was completely water-extractable compared to less than 20% of the I131 in the same samples.