Effect of suckling an isotonic solution of sodium acetate, sodium bicarbonate, or sodium chloride on abomasal emptying rate and luminal pH in calves

OBJECTIVES: To compare abomasal emptying rates in calves after suckling milk replacer or 3 common orally administered electrolyte solution components. ANIMALS: 5 male calves < 35 days of age. PROCEDURES: Calves with a cannula fitted in the abomasal body were fed 2 L of milk replacer with or without parenteral administration of atropine (0.01 mg/kg, i.v., then 0.02 mg/ kg, s.c., q 30 min) or isotonic (150 mM) solutions of sodium acetate, NaHCO(3), or NaCl in a randomized crossover design. Abomasal emptying rates were determined via scintigraphy, acetaminophen absorption, ultrasonography, and change in abomasal luminal pH. RESULTS: Scintigraphic half-emptying time, time of maximal plasma acetaminophen concentration, ultrasonographic half-emptying time, and pH return time indicated similar abomasal emptying rates following suckling of isotonic sodium acetate, NaHCO(3), and NaCl solutions, whereas the emptying rate of milk replacer was significantly slower. Mean maximal abomasal luminal pH was highest following suckling of NaHCO(3) (pH(max)=7.85) and lowest following suckling of NaCl (pH(max)=4.52); sodium acetate (pH(max)=6.59) and milk replacer (pH(max)=5.84) yielded intermediate pH values. CONCLUSIONS AND CLINICAL RELEVANCE: Isotonic solutions of sodium acetate, NaHCO(3), and NaCl were rapidly emptied from the abomasum but varied markedly in their ability to alkalinize the abomasum. Sodium bicarbonate-containing orally administered electrolyte solution might increase the frequency of infection or severity of clinical disease in diarrheic calves treated for dehydration by causing prolonged abomasal alkalinization.     

Effect of suckling isotonic or hypertonic solutions of sodium bicarbonate or glucose on abomasal emptying rate in calves

OBJECTIVE: To determine and compare the abomasal emptying rates in calves suckling milk replacer or an isotonic or hypertonic solution of NaHCO(3) or glucose. ANIMALS: 5 male Holstein-Friesian calves that were < 30 days of age. PROCEDURES: Calves were fed 2 L of milk replacer or isotonic (300 mOsm/L) or hypertonic (600 mOsm/L) solutions of NaHCO(3) or glucose containing acetaminophen (50 mg/kg). Venous blood samples and transabdominal ultrasonographic abomasal dimensions were obtained periodically after feeding, and abomasal luminal pH was continuously monitored by placement of a luminal pH electrode through an abomasal cannula. Abomasal emptying rate was assessed by the time to maximal plasma acetaminophen concentration, ultrasonographic determination of the half-time of abomasal emptying, and the time for luminal pH to return to within 1 pH unit of the preprandial value. RESULTS: Hypertonic NaHCO(3) solution was emptied slower than an isotonic NaHCO(3) solution, isotonic glucose solution was emptied slower than an isotonic NaHCO(3) solution, and hypertonic glucose solution emptied slower than an isotonic glucose solution. CONCLUSIONS AND CLINICAL RELEVANCE: An electrolyte solution for oral administration with a high osmolarity and glucose concentration may lead to a slower resuscitation of dehydrated diarrheic calves because such solutions decrease the abomasal emptying rate and therefore the rate of solution delivery to the small intestine. Whether slowing of the abomasal emptying rate in dehydrated diarrheic calves suckling an oral electrolyte solution is clinically important remains to be determined.     

Vagal reflex inhibition of motility in the abomasal body of sheep by antral and duodenal tension receptors

Vagally-mediated regulation of motility in the abomasal body by duodenal and abomasal antral motility was demonstrated in acutely prepared anaesthetized sheep. The enteric plexuses between the abomasal body, antrum and duodenum were interrupted by transection. Antral contractions were more effective than duodenal contractions at causing inhibition of the abomasal body, and antral isometric conditions were more effective than antral isotonic conditions. Inhibition of motility in the abomasal body was reduced by unilateral cervical vagotomy, was abolished by bilateral cervical vagotomy, and was reversibly inhibited by cervical vagus cold block. The demonstration of vagal pathways in abomaso-abomasal reflexes confirms a functional homology of the mechanisms in the ruminant and animals with simple forms of stomach.Abbreviations b-t balloon-tipped - EMG electromyography - NANC non-adrenergic, non-cholinergic - o-t open-tipped     

Ultrasonographic measurement of abomasal volume, location, and emptying rate in calves

OBJECTIVE: To develop and validate an ultrasonographic method for measuring abomasal volume, location, and emptying rate in suckling calves. ANIMALS: 9 male Holstein calves < 40 days of age. PROCEDURE: Before and after calves were fed different volumes of milk replacer or 2 L of oral electrolyte solutions, ultrasonographic measurements of abomasal dimensions (width, length, and height) were obtained by applying a 3.5-MHz sector probe to the ventral aspect of the abdomen in the transverse and sagittal planes. Abomasal volume was calculated from the ultrasonographic measurements by modeling the abomasum as an ellipsoid and by use of a power exponential equation to calculate the half-time of abomasal emptying (t1/2). RESULTS: Preprandial abomasal volume was 20 to 137 mL. All 3 abomasal dimensions increased during feeding and after suckling, and the abomasum was symmetrically located about the midline of the ventral aspect of the abdomen. Strong linear relationships were identified between ultrasonographic and suckled volumes, between ultrasonographic and scintigraphic heights, and between ultrasonographic and scintigraphic lengths. Ultrasonographic t1/2 was linearly related to scintigraphic t1/2; the latter is regarded as the gold standard measure of gastric emptying rate. CONCLUSIONS AND CLINICAL RELEVANCE: Ultrasonographic evaluation of the abomasum appears to provide a practical, rapid, noninvasive, and accurate method for determination of abomasal volume, location, and emptying rate in suckling calves.     

Comparison of two oral electrolyte solutions and route of administration on the abomasal emptying rate of Holstein-Friesian calves

Dehydrated calves with diarrhea are routinely given an oral electrolyte solution (OES) by suckling or esophageal intubation. An important issue related to rehydration therapy is the rate of OES delivery to the small intestine. It is widely assumed that the glucose content of the OES does not impact the speed of resuscitation and that fluid administered by esophageal intubation provides a similar resuscitative response to that obtained by suckling. The aims of this study were to compare the abomasal emptying rate in calves suckling an OES containing a high or low glucose concentration and in calves administered a high-glucose OES by suckling or esophageal intubation. Seven male Holstein-Friesian calves were given the following treatments in random order: 2 L of a commercially available high-glucose OES ([glucose] = 405 mM) by suckling or esophageal intubation or 2 L of a commercially available low-glucose OES ([glucose] = 56 mM) by suckling. Abomasal emptying rate was determined by acetaminophen absorption, ultrasonography, and glucose absorption. High-glucose OES rapidly increased plasma glucose concentration after suckling but produced a slower rate of abomasal emptying than did low-glucose OES. Esophageal intubation of high-glucose OES produced the same initial change in abomasal volume as did suckling, but delayed the rate of OES delivery to the small intestine. Our results suggest that suckling a low-glucose OES provides the fastest rate of abomasal emptying and plasma volume expansion, whereas a high-glucose OES provides the most appropriate oral solution for treating hypoglycemic calves.     

Effect of pyloric blockade and infusion of histamine or pentagastrin on gastric secretion in horses

OBJECTIVE: To determine the origin of the nonacid (nonparietal) component of gastric secretions in horses induced by pentagastrin infusion. ANIMALS: 6 horses. PROCEDURE: A Latin square design was used, involving 6 horses, 3 treatments, and 2 duodenal intubation conditions (catheter with balloon to obstruct pylorus [B] or without balloon allowing movement of contents between stomach and duodenum [NB]). Each horse had an indwelling gastric cannula and a catheter positioned in the duodenum. Gastric and duodenal contents were collected during 15-minute periods. Each experiment consisted of serial collection periods: baseline; infusion of pyrilamine maleate (1 mg/kg of body weight, IV); not treated; and IV infusion of saline (0.9% NaCl) solution alone, saline solution containing pentagastrin (6 microg/kg x h), or saline solution containing histamine (30 microg/kg x h). Volume of samples was recorded, and electrolyte concentrations were measured. RESULTS: Pentagastrin and histamine stimulated maximal acid output; however, during NB conditions, pentagastrin-induced concentration of hydrogen ions was significantly less than during histamine or pentagastrin infusions during B conditions. The large volume produced in response to pentagastrin during NB conditions was accompanied by increased sodium ion output that was greater than for pentagastrin during B conditions, but both values were significantly greater than values for histamine during B or NB conditions. CONCLUSIONS AND CLINICAL RELEVANCE: Nonparietal secretions collected during IV infusion of pentagastrin are duodenal in origin. Reflux of duodenal contents into the stomach of horses is enhanced by pentagastrin. Flow of duodenal contents into the stomach could have implications in the pathogenesis of ulcers in horses.     

The Functional Structure of the Pylorus in the Ox

In spite of recent electromyographic experiments and myotomy on the pylorus, a detailed morphological study of that region is still lacking. In this study the pyloric part of the abomasum and the first 15 cm. of the duodenum have been investigated macro- and microscopically in 20 veal calves and 20 adult cattle. The circular muscle layer of the terminal part of the pars pylorica thickens into a proximal and a distal sphincter. Two U-shaped muscle loops, one on the visceral and the other on the parietal surface, are fixed by their base to the sphincter pylori. Together with longitudinal fibers of the abomasum and the duodenum, they may form a dilator pylori. A fibrous septum, which separates the muscular coat of the stomach from that of the duodenum is absent. Some longitudinal fibers of the abomasum are continuous with those of the duodenum. The loose mucosal folds in the pars pylorica and also the torus pyloricus may act as a mucosal plug in closing the pylorus. These findings are discussed in view of possible functional implications.     

Effects of wheat protein in milk replacers on abomasal emptying rate in calves

Diarrhoea is a condition with tremendous impact on calf health. Infectious agents play a dominant role; however, non‐infective factors may also contribute to pathogenesis of diarrhoea. One factor, the abomasal emptying rate, is mainly influenced by the composition of feed. The aim of the study was to assess the influence of different protein sources in milk replacers on abomasal emptying rate and clinical parameters. The effect of increasing age of the calves on abomasal emptying was also evaluated. The study compared abomasal emptying rates and clinical parameters in calves, which were fed either milk replacer containing only whey protein or one which partially contained wheat protein. Abomasal emptying rate was estimated by ultrasonography. Ten calves were used in the study over 18 days, and each calf was fed 3 periods of 3 days length using different milk replacers in an alternating crossover design. The abomasum was emptied significantly faster when the wheat protein containing milk replacer was fed (half‐emptying time wheat protein 49.1 ± 4.1 min, half‐emptying time milk protein 59.1 ± 7.4 min); however, clinical parameters and weight gain did not differ between the feeding regimes. Age did not significantly influence abomasal emptying rate. As milk replacers containing wheat proteins increased abomasal emptying rate, they may have a higher potential to initiate diarrhoea, especially if high volumes are fed. Thus, the feeding regimes are likely to be even more important when such milk replacers are used.     

A survey of abomasal ulceration in veal calves

Abomasal ulceration was found in 264 of 304 commercially reared veal calves at slaughter. The incidence and severity of lesions were greatest in loose housed calves with access to straw and fed milk substitute ad libitum. The majority of lesions were located in the distal pylorus. There was no evidence that the abomasal erosions and ulcers found in the majority of veal calves affected their growth rate or were deleterious to their welfare. It is suggested that pyloric ulceration may be related to the diet of veal calves.     

Assessment of the effects of erythromycin, neostigmine, and metoclopramide on abomasal motility and emptying rate in calves

OBJECTIVE: To determine and compare the effects of erythromycin, neostigmine, and metoclopramide on abomasal motility and emptying rate in suckling calves. ANIMALS: 6 male Holstein calves (15 to 40 days of age). PROCEDURE: Calves were monitored for 1 hour before being fed milk replacer (60 mL/kg; time, 0 minutes) and then were monitored for another 3 hours. Calves received 6 treatments in randomized order: erythromycin (8.8 mg/kg, IM) at -30 minutes; low-dose erythromycin (0.88 mg/kg, IM) at -30 minutes; erythromycin (8.8 mg/kg, IM) at -30 minutes and neostigmine (0.02 mg/kg, SC) at -30 and 90 minutes; neostigmine (0.02 mg/kg, SC) at -30 and 90 minutes; metoclopramide (0.1 mg/kg, IM) at-30 and 90 minutes; and placebo (2 mL of saline [0.9% NaCl] solution, SC) at -30 minutes. Abomasal volume was calculated from ultrasonographic measurements of abomasal width, length, and height. Abomasal motility and emptying rate were assessed by measuring luminal pressure and change in abomasal volume over time. RESULTS: Administration of erythromycin (8.8 mg/kg) increased the frequency of abomasal luminal pressure waves and the mean abomasal luminal pressure and decreased the half-time of abomasal emptying by 37%. Administration of metoclopramide, neostigmine, and low-dose erythromycin (0.88 mg/kg) did not alter abomasal motility, mean luminal pressure, or emptying rate. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that administration of erythromycin at the labeled antimicrobial dose (8.8 mg/kg, IM) exerted an immediate, marked prokinetic effect in healthy suckling calves, whereas administration of metoclopramide or neostigmine did not alter abomasal motility or emptying rate.     

Effect of Escherichia coli heat-labile enterotoxin on the myoelectric activity of the duodenum in weaned pigs

The objective of the present study was to elucidate the effect of subclinical doses of Escherichia coli heat-labile enterotoxin (LT) on the antro-duodenal myoelectric activities of weaned pigs. Twelve weaned pigs were surgically implanted with three pairs of electrodes on the antrum 3 cm before the pylorus, 5 and 20 cm after the pylorus on the duodenum, respectively. An infusion cannula was inserted into the duodenum between duodenal electrodes. Using a wireless telemetry recording system, an electromyography (EMG) tracing lasting at least 24 h was recorded as the control, then another 24-h EMG recording was performed with a bolus intraduodenal infusion of LT (0.1 and 0.5 microg/kg b.w.). After a 1- to 2-day break, a 5-fold higher dose of LT was administered using the same protocol. In the antrum, LT administration barely modified the EMG signal. However, in the duodenum it prolonged the duration of phase II and the migrating myoelectric complex (MMC) cycle when compared with the control. The number of duodenal MMC cycles was also significantly diminished. Moreover, the migrating velocity of phase III was increased. The migrating action potential complex (MAPC) was present both without and with LT, but occurred more frequently following LT administration. In conclusion, LT caused a dose-dependent, lagged alteration in the duodenal MMC in weaned pigs, involving a reduction of the MMC number by lengthening phase II, increased phase III migration velocity, and increased MAPC frequency. The disturbances did not, however, result in diarrhoea and may reflect the induction of a local protection mechanism of the gut to expel unwanted foreign content from the lumen of the upper gut.     

Effect of parenteral administration of erythromycin, tilmicosin, and tylosin on abomasal emptying rate in suckling calves

OBJECTIVE: To determine the effect of parenteral administration of erythromycin, tilmicosin, and tylosin on abomasal emptying rate in suckling calves. ANIMALS: 8 male Holstein-Friesian calves < 35 days old. PROCEDURES: Calves received each of 4 treatments in random order (2 mL of saline [0.9% NaCl] solution, IM [control treatment]; erythromycin, 8.8 mg/kg, IM; tilmicosin, 10 mg/kg, SC; and tylosin, 17.6 mg/kg, IM). Calves were fed 2 L of milk replacer containing acetaminophen (50 mg/kg) 30 minutes later. Jugular venous blood samples and transabdominal ultrasonographic abomasal dimensions were obtained periodically after suckling. Abomasal emptying rate was assessed on the basis of the time to maximal plasma acetaminophen concentration and ultrasonographic determination of the halftime of abomasal emptying. One-tailed Dunnett post tests were conducted whenever the F value for group was significant. RESULTS: Emptying rate was faster for erythromycin, tilimicosin, and tylosin than for the control treatment, as determined on the basis of time to maximal plasma acetaminophen concentration. Ultrasonography indicated that the half-time of abomasal emptying was significantly shorter for erythromycin than for the control treatment. Tylosin and tilmicosin accelerated the abomasal emptying rate, but not significantly, relative to the emptying rate for the control treatment. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of erythromycin, tilmicosin, and tylosin at the label dosage increased abomasal emptying rate in calves. The clinical importance of an increase in abomasal emptying rate in cattle remains to be determined.     

Effect of spiramycin and tulathromycin on abomasal emptying rate in milk-fed calves

Impaired abomasal motility is common in cattle with abomasal disorders. The macrolide erythromycin has been demonstrated to be an effective prokinetic agent in healthy calves and in adult cattle with abomasal volvulus or left displaced abomasum. We hypothesized that 2 structurally related macrolides, spiramycin and tulathromycin, would also be effective prokinetic agents in cattle. Six milk-fed, male, Holstein-Friesian calves were administered each of the following 4 treatments: spiramycin, 75 000 IU/kg BW, IM, this dose approximates 25 mg/kg BW, IM; tulathromycin, 2.5 mg/kg BW, SC; 2 mL of 0.9% NaCl (negative control); and erythromycin, 8.8 mg/kg BW, IM (positive control). Calves were fed 2 L of cow’s milk containing acetaminophen (50 mg/kg body weight) 30 min after each treatment was administered and jugular venous blood samples were obtained periodically after the start of sucking. Abomasal emptying rate was assessed by the time to maximal plasma acetaminophen concentration. Spiramycin, tulathromycin, and the positive control erythromycin increased abomasal emptying rate compared to the negative control. We conclude that the labeled antimicrobial dose of spiramycin and tulathromycin increases the abomasal emptying rate in healthy milk-fed calves. Additional studies investigating whether spiramycin and tulathromycin exert a prokinetic effect in adult cattle with abomasal hypomotility appear indicated.     

Hexamethonium: A probe to assess autonomic nervous system involvement in upper gastrointestinal functions in conscious sheep

Hexamethonium, which inhibits cholinergic transmission by preventing acetylcholine release, has been considered an ideal reference drug for the blockade of autonomic ganglia, Auerbach plexus and reflex gastrointestinal secretions. The degree of inhibition of ruminant gastrointestinal functions with this reference drug were as follows: cyclical contractions of the reticulo-rumen and abomasal motility > gastric acid secretion and duodenal migrating myoelectrical complexes. Although reduced at high dosages, the initiation of migrating myoelectric complexes was enhanced at clinically used dosages. The duration of the inhibition of reticular contractions was dose-related varying from 0.5 to 5 h for 1.25 to 20 mg/kg subcutaneously. Abomasal motility and acid secretion were similarly reduced but exhibited strong and long-lasting rebound effects. Inhibition of the reticulum by the blockade of muscarinic receptors by atropine was also dose-related lasting from 0.5 to 3 h for 0.5 to 2 mg/kg, whereas inhibition of the abomasal motor and secretory functions lasted from 1 to 6 h. These results suggest a higher degree of impingement of the parasympathetic pathways on abomasal acid secretion and motility than on the cyclical activity of the reticulum and only a modulatory role of the extrinsic neural activity on the cyclical motor events of the duodenum.     

Effect of erythromycin and gentamicin on abomasal emptying rate in suckling calves

BACKGROUND: Commonly used dosage protocols for antimicrobial agents may alter the rate of gastric emptying. HYPOTHESIS: Parenteral administration of erythromycin increases and gentamicin decreases the rate of abomasal emptying. ANIMALS: Five male Holstein-Friesian calves (8-15 days of age). METHODS: Calves received each of the following 4 IM treatments in random order: control, 2 mL of 0.9% NaCl; erythromycin, 8.8 mg/kg; low-dose gentamicin, 4.4 mg/kg; high-dose gentamicin, 6.6 mg/kg. Abomasal emptying rate was assessed by acetaminophen and glucose absorption. Calves were fed 2 L of cow's milk containing acetaminophen (50 mg/kg body weight) 30 minutes after each treatment was administered, and jugular venous blood samples were obtained periodically after suckling. The maximum observed plasma acetaminophen concentration (actual C(max)) and time of actual C(max) (actual T(max)) were determined, and pharmacokinetic modeling was used to calculate model C(max) and model T(max). RESULTS: Erythromycin increased abomasal emptying rate, as indicated by a shorter time to actual T(max) and model T(max) (P < .05). Abomasal emptying rate after injection of low-dose gentamicin was similar to that of control. Administration of high-dose gentamicin resulted in a longer time to actual T(max) (P= .021) but did not change model T(max) (P= .62). CONCLUSIONS AND CLINICAL RELEVANCE: IM injection of erythromycin increased abomasal emptying rate in dairy calves, whereas low-dose and high-dose gentamicin did not alter the rate of abomasal emptying as measured by acetaminophen kinetics and glucose absorption. The clinical relevance of these findings remains to be determined.     

Infusion of sodium bicarbonate in experimentally induced metabolic acidosis does not provoke cerebrospinal fluid (CSF) acidosis in calves

In a crossover study, 5 calves were made acidotic by intermittent intravenous infusion of isotonic hydrochloric acid (HCl) over approximately 24 h. This was followed by rapid (4 h) or slow (24 h) correction of blood pH with isotonic sodium bicarbonate (NaHCO(3)) to determine if rapid correction of acidemia produced paradoxical cerebrospinal fluid (CSF) acidosis. Infusion of HCl produced a marked metabolic acidosis with respiratory compensation. Venous blood pH (mean ± S(x)) was 7.362 ± 0.021 and 7.116 ± 0.032, partial pressure of carbon dioxide (Pco(2), torr) 48.8 ± 1.3 and 34.8 ± 1.4, and bicarbonate (mmol/L), 27.2 ± 1.27 and 11 ± 0.96; CSF pH was 7.344 ± 0.031 and 7.240 ± 0.039, Pco(2) 42.8 ± 2.9 and 34.5 ± 1.4, and bicarbonate 23.5 ± 0.91 and 14.2 ± 1.09 for the period before the infusion of hydrochloric acid and immediately before the start of sodium bicarbonate correction, respectively. In calves treated with rapid infusion of sodium bicarbonate, correction of venous acidemia was significantly more rapid and increases in Pco(2) and bicarbonate in CSF were also more rapid. However, there was no significant difference in CSF pH. After 4 h of correction, CSF pH was 7.238 ± 0.040 and 7.256 ± 0.050, Pco(2) 44.4 ± 2.2 and 34.2 ± 2.1, and bicarbonate 17.8 ± 1.02 and 14.6 ± 1.4 for rapid and slow correction, respectively. Under the conditions of this experiment, rapid correction of acidemia did not provoke paradoxical CSF acidosis.     

In vitro effects of cisapride, metoclopramide and bethanechol on smooth muscle preparations from abomasal antrum and duodenum of dairy cows

The objective of this study was to investigate the effects of cisapride (CIS), metoclopramide (MET) and bethanechol (BET) on contractility parameters from smooth muscle preparations of the abomasal antrum and proximal duodenum of cows. Smooth muscle preparations were harvested shortly post-mortem from 42 healthy dairy cows, and concentration-response curves were performed by cumulative application of the drugs. Cisapride and MET did not have any significant effect on the contractility parameters studied, while BET induced a significant, concentration-dependent increase in basal tone (BT), mean amplitude (Amean), and area under the curve (AUC) in smooth muscle preparations from the abomasal antrum, but not from the duodenum. The effect of BET on BT was more pronounced in specimens with longitudinal orientation while the maximal obtainable effect (Vm) in Amean was more pronounced in circular-oriented preparations. Atropine (1 x 10-5 m) significantly inhibited the effect of BET, whereas pre-incubation with hexamethonium or tetrodotoxin (TTX) had no effect, suggesting that the effect was mediated by cholinergic receptors on the smooth muscle. The results may be relevant to diseases or disorders associated with gastric emptying and gastric hypomotility. Further investigations are warranted to investigate the potential ability of BET to enhance abomasal emptying of adult dairy cows.     

Comparison of abomasal emptying in neonatal calves with a nuclear scintigraphic procedure.

The purpose of the present study was to demonstrate that nuclear medicine technology allows observation of the effect that milk clotting has on abomasal emptying in the living neonatal calf. Scintigraphic evaluation of abomasal emptying was carried out in 6 healthy male Holstein calves. The calves were fed 10% of their body weight daily as whole cow's milk that was divided equally and consumed as 2 feedings via a nipple bottle. One day before the nuclear scintigraphic procedure, the calves were randomly fed whole cow's milk, or an oral rehydration solution (ORS) containing bicarbonate and high levels of soluble fibre was fed for 3 consecutive feedings an hour before the portion of milk. For each calf, both feeding programs were repeated twice at a one-week interval. Immediately following administration of the 99mTC-sulfur-colloid-containing milk, the calves were imaged with the gamma camera positioned lateral and ventral to the abomasum. Additional right lateral and ventral views of the abomasum were collected at 15, 30, 45, 60, 90, 120, 150, 180, 210, and 240 min after administration of the radionuclide. Blood glucose determination were performed at one-hour intervals for 7 h after feeding milk to evaluate milk digestibility in both feeding programs. No significant differences in the results of the glucose absorption test or in the radionuclide counts of the abomasum were found between both feeding programs. Scintigraphic evaluation of abomasal emptying was found to be a useful technique for visualization of milk clotting and to test the effect of an ORS on milk digestibility.     

Ultrasonographic imaging of abomasal milk clotting and abomasal diameter in healthy and diarrheic calves

In case of diarrhea calves are treated with oral rehydration solutions (ORS), which are known to increase abomasal pH and inhibit milk clotting in vitro. Nevertheless, recent studies have shown that ORS with HCO₃^‐ ≤ 62 mmol/L do not interfere with abomasal milk clotting in healthy calves. However, in diarrheic calves, feeding ORS and milk simultaneously may disturb abomasal curd formation and exacerbate diarrhea due to faster abomasal passage of ingesta. Therefore, the aim of the present study was to ultrasonographically examine abomasal milk clotting and diameter after feeding milk and milk replacer (MR) with and without ORS to healthy and diarrheic calves. Abomasal curd formation and diameter in healthy and diarrheic calves were ultrasonographically imaged before and after feeding milk, MR and ORS prepared in milk or MR. Feeding mixtures of milk or MR with ORS did not cause any remarkable differences in the ultrasonographic images of abomasal content. Moreover, abomasal milk clotting was not disturbed due to diarrhea. Statistically significant differences of abomasal diameter after feeding between healthy and diarrheic calves indicated that abomasal emptying is delayed in diarrheic calves. Hence, further studies are needed to determine reasons for decelerated abomasal passage in calves suffering from diarrhea.