Ultrasonographic examination of the abomasum of 50 cows

Evaluation of multifactorial digestive disorders in a dairy herd at different stages of lactation

The manager of a large dairy herd (total confinement, total mixed ration feeding, 10130 kg milk sold per cow and year) requested a workup of a digestive disorder problem that had been ongoing for several years. The cows were at all stages of lactation, and the incidence proportion (events/100 cows at risk) of digestive disorders was approximately 5 to 10%. The clinical picture included an abnormal demeanor of varying severity and signs that differed among the cows. The latter included decreased milk production and physical activity, low body condition score, abnormal rumen motility and stratification, small intestinal dilatation, diarrhea, undigested fiber particles in the feces, fever and abdominal pain.The following approach was used to investigate the digestive disorder problem:1. The herd was assessed for production levels, housing requirements, feeding protocols and animal health management. The latter comprised evaluation of different animal scores, metabolic profile analysis, diagnosis of disease, culling records and slaughter data. The results revealed risk factors concerning the feeding and animal health monitoring, (e. g. in dry matter intake and silage quality management, disease detection and diagnosis in fresh cows). The assessment also identified a high occurrence of digestive disorders of unknown origin.2. Fifteen cows that represented the ongoing digestive disorder problem were selected to undergo clinical examination, hematological analysis, urinalysis, and ultrasonography of the ventral abdomen. The clinical examinations revealed different digestive disorders, which were mainly inflammatory in nature, in all the cows. Eight cows had localized reticuloperitonitis and 13 had left displaced abomasum with different degrees of displacement and adhesions between the abomasum and reticulum attributable to reticuloperitonitis.Our results revealed a multifactorial problem caused by several risk factors relating to animal health and feeding management protocols that resulted in different types of digestive disorders. The wires from damaged tires used to hold the pit silo tarps in place were identified as a possible traumatic cause of the reticuloperitonitis. Treatment, prevention and follow-up of the different conditions were discussed.

Ultrasonographic documentation of type-3 abomasal ulcer in a cow with left displacement of the abomasum

Background

Ultrasonographic documentation of perforated abomasal ulcer has not been published till now. This report describes the clinical, ultrasonographic and postmortem findings in a Jersey cow with type-3 abomasal ulcer and left displacement of the abomasum (LDA).

Case report

The main clinical findings were abnormal demeanour, rumen atony and tympany, positive foreign body tests, positive auscultation and simultaneous ballottement on the left side, abdominal guarding and loss of negative pressure in the abdominal cavity. The tentative diagnosis was peritonitis and LDA. Abdominal ultrasonography produced images typical of LDA, and in one location between the abdominal wall and abomasum there was a layer of fibrin, a fibrin clot, a break in the abomasal contour, suggestive of a perforated ulcer, and partial obstruction of this gap with fibrin. The diagnosis of perforated abomasal ulcer with subsequent peritonitis was confirmed during postmortem examination.

Conclusions

The examination of this case shows that under certain circumstances, ultrasonographic imaging of a perforated abomasal ulcer in a cow is possible. Antemortem diagnosis of type-3 abomasal ulcer is preferable to relying on exploratory laparotomy and/or post-mortem examination.

Diagnostic performance of ultrasonography in clinical management of dairy cattle identified with left-sided ping sounds

Objectives:

Left displaced abomasum (LDA) is a common postparturient condition of high yielding dairy cattle. The diagnosis of LDA is challenging and has historically been based on findings that are not specific to the condition. The objective of the current study was to investigate the diagnostic performance of ultrasonography (USG) in the clinical management of dairy cows identified with left-sided ping sound postpartum.

Materials and methods:

Cows with reduced appetite postpartum and had audible left-sided ping sounds on abdominal auscultation were eligible to be prospectively recruited onto the study. The results of clinical findings and abdominal USG were recorded along with milk β-hydroxybutyrate levels, pH levels of abomaso/rumenocentesis samples, and findings on exploratory laparotomy. The diagnostic performance of USG and other clinical investigations was assessed by calculating the test sensitivity and specificity using exploratory laparotomy as a gold standard test.

Results:

A definitive diagnosis of LDA was made in 23 cows, 8 cows were diagnosed with peritonitis, and 4 cows with frothy tympany. The USG findings that were consistent with LDA were present in all cattle diagnosed with LDA at exploratory laparotomy. The USG findings over the past three intercostal space characteristics of LDA, however, were also present in five cases subsequently diagnosed with peritonitis and in all cases diagnosed with frothy tympany on exploratory laparotomy. The pH of abdomaso/rumenocentesis samples yielded the highest diagnostic accuracy (97.14%) as a single test in the current study.

Conclusions:

USG over the left abdominal wall despite being a highly sensitive test for the diagnosis of LDA has limitations as a diagnostic tool due to suboptimal specificity.

Clinical, laboratory and ultrasonographic findings in 87 cows with type-4 abomasal ulcer

Background

This study evaluated the clinical, laboratory, ultrasonographic and pathological findings in 87 cows aged 2 to 10 years (4.5 ± 1.5 years) with type-4 abomasal ulcer.

Results

The most common clinical findings were in decreasing order compromised health status accompanied by partial or complete anorexia (100%), abdominal guarding (81%), congested scleral vessels (77%), ruminal atony (73%), tachycardia (68%), tachypnoea (65%), positive foreign body tests (58%), decreased skin surface temperature (53%), fever (49%), reduction in negative intraabdominal pressure assessed transrectally (39%), poorly subdivided plant fragments in faeces (35%) and arched back (28%). The principal haematological abnormalities were hypokalaemia (72%), haemoconcentration (69%), azotaemia (56%), metabolic acidosis (49%), hyperfibrinogenaemia (45%), leukopenia (35%) and hypoproteinaemia (29%). Other abnormalities were aciduria (56%), haematuria (44%), increased chloride concentration in rumen fluid (34%) and abnormal peritoneal fluid (98%). Of 75 examined cows, 65 (87%) had ultrasonographic evidence of local or generalised peritonitis. On postmortem examination all cows had a type-4 abomasal ulcer and generalised peritonitis. In addition, 36 cows had type-1 ulcers, 6 had type-2 ulcers and one cow had a type-3 ulcer.

Discussion

The clinical signs in cows with type-4 abomasal ulcer are associated with generalised peritonitis. An increased haematocrit, indicating shock-induced haemoconcentration is characteristic in contrast to cows with traumatic reticuloperitonitis. Ultrasonography is useful for visualising and assessing generalised peritonitis.

Conclusions

The diagnosis of type-4 abomasal ulcer based on clinical signs alone is difficult and therefore requires additional diagnostic procedures including the determination of the haematocrit and plasma protein concentration, abdominal ultrasonography and analysis of peritoneal fluid. In most cases, these steps lead to a correct diagnosis and allow timely euthanasia of the cow to prevent further suffering and unnecessary treatment costs.

Methods

The cows underwent a clinical, laboratory, ultrasonographic and postmortem examination.

Ultrasonographic findings in cows with left displacement of abomasum, before and after reposition surgery

Background

The natural incidence of left displacement of abomasum (LDA) in dairy cows was high. The diagnosis of LDA usually relies on characteristic physical exam findings but that transabdominal ultrasound is a useful technique that has been applied to the diagnosis of gastrointestinal diseases of dairy cows in equivocal cases.

Methods

Forty dairy cows with LDA were clinically and ultrasonographically examined to determine the position and the echogenic property of the abomasum. The cows were examined ultrasonographically on the left side, from the 9th intercostal space (ICS) to the 12th ICS as well as the ventral left abdomen before and after reposition surgery.

Results

The vital signs were within normal range in most of the cows and the ‘pinging’ were clearly heard in 37 cows. The abomasal gas cap was visualized from the 9th to 12th ICS in 37 cows and characterized by reverberation artifacts. The abomasal ingesta appeared as homogeneous hypoechoic fluid with scattered hyperechoic foci and were mainly visible in the median region and ventral region of the 9th to 11th ICS in 35 cows. The pyloric canal was detected from the ventral left abdomen wall in 30 cows and appeared as a loop with hypoechogenic wall and echogenic luminal contents in cross section.

Conclusion

These typical ultrasonograms, including reverberation artifacts, homogenous hypoechoic structures, are important diagnostic feature in ultrasonography of LDA. Furthermore, the circular acoustic image structure of the pyloric canal is an important characteristic of LDA, so it can be used as an important diagnostic basis of LDA.

Abomasal and Third Compartment Ulcers in Ruminants and South American Camelids

Abomasal ulcers are frequent incidental findings in necropsies of domestic ruminants and South American Camelids (SAC) or in slaughter animals and are a frequent cause of death in the most affected group of cattle, veal calves. Their true prevalence and significance is unknown owing to limitations in diagnosing the condition in live animals. This article discusses types of ulcers, possible causes of ulceration, and the clinical consequences, symptoms, and differential diagnoses, as well as further diagnostics in cattle, small ruminants and SAC. The limited treatment options and possibilities for prevention are reviewed.

Diagnostic Approach to the Acute Abdomen

The acute abdomen is a term used to characterize an animal presented as an emergency, in a more or less severe critical state, and for which medical and possibly surgical treatment will be necessary. To succeed, the clinician should use a systematic approach, have an excellent knowledge of the bovine abdominal anatomy, and have a good understanding of the pathophysiology of abdominal pain. Good clinical judgment, critical analysis, and good client communication skills are also essential. This article presents and discusses those necessary skills in the context of field practice.

Ascites in Cattle: Ultrasonographic Findings and Diagnosis

Ultrasonography enables the examiner to detect very small amounts of fluid in the peritoneal cavity and to determine its location, amount, and sonographic features. The pathologic process responsible for the ascites, for example, ileus, hepatic fibrosis, thrombosis of the caudal vena cava, or traumatic reticuloperitonitis, often can be identified. Abdominocentesis and analysis of the aspirated fluid allow differentiation of inflammatory and noninflammatory ascites as well as the diagnosis of uroperitoneum, hemoperitoneum, chylous ascites, and bile peritonitis.

Ultrasonographic examination of the forestomachs and the abomasum in ruminal drinker calves

BACKGROUND

The study investigated the ultrasonographic appearance of the reticulum, rumen, omasum and abomasum of calves with ruminal drinking syndrome.

METHODS

In ten milk-fed calves with ruminal drinking syndrome the reticulum, rumen, omasum and abomasum were examined by ultrasonography using a 5-MHz linear transducer before, during and after the ingestion of milk.

RESULTS

The reticulum could be imaged in eight of ten calves before feeding. The reticular wall appeared as an echoic line, similar to mature cattle, and reticular folds were seen in eight calves. The reticular content appeared as echoic heterogeneous fluid. Reticular contractions were biphasic with 1.0 ± 0.38 contractions per minute. The rumen had a mean wall thickness of 2.1 mm dorsally, 3.5 mm at the level of the longitudinal groove, and 3.2 mm ventrally. The ventral sac of the rumen of all calves contained echoic heterogeneous liquid. During feeding the milk entering the rumen could be seen as hyperechoic liquid in five calves. The omasum was seen on the right side as a crescent-shaped line medial to the liver in seven calves. Only the omasal wall closest to the transducer was seen as an echoic line with a mean thickness of 2.7 mm. The ultrasonographic appearance of the omasum did not change during or after feeding. The abomasum was seen immediately caudal to the xyphoid on both sides of the midline before feeding. The mean length at the ventral midline was 22.2 cm. The ingesta were heterogeneous in all calves and the abomasal folds were distinct in eight. The mean lateral expansion of the abomasum from the ventral midline to the left and right varied from 8.7 to 13.8 cm and from 4.3 to 11.3 cm. The milk entering the abomasum was observed in all calves, and signs of milk clotting were seen in all calves 15 minutes after feeding.

CONCLUSION

This study showed that ultrasonography is useful for detecting milk in the reticulum and rumen of calves with ruminal drinking syndrome.

Transabdominal ultrasonographic appearance of the gastrointestinal viscera of healthy camels (Camelus dromedaries)

The purpose of this study was to describe the ultrasonographic picture of the gastrointestinal tract in healthy camels (Camelus dromedarius). For this purpose, 22 camels were examined. The rumen and its glandular sacs were filling most of the left side of the abdomen. The rumen wall was smooth and echogenic. The ventral part of the reticulum could be best imaged in 17 (77%) camels from the left and right paramedian region just behind to the sternal pad. The reticulum in these animals had a thick wall (1.17±0.27 cm) that appeared as a half-moon-shaped structure with a biphasic contraction. The omasum was best viewed through the right 8th to 6th intercostal spaces in 18 (82%) camels. In the remaining 4 (18%), it was visualized through four consecutive intercostal spaces (right 9th to 6th). It had a wall thickness of 1.1±0.7 cm and a transverse diameter of 8.74±3.4 cm. The abomasum could be best visualized from the right 9th and 8th intercostal spaces in 14 (64%) camels, while it was observed in the 9th intercostal space in 3 (14%) animals and in the 8th and 7th intercostal space in 5 (22%) camels. Small intestinal structures were best seen low in the right paralumbar fossa. It was thin-walled (0.43±0.14 cm) and had a diameter of 2.62±0.47 cm. The cecum was imaged chiefly in the caudal right flank. It was thin-walled (0.37±0.05 cm), had a diameter of 13.8±1.6 cm. The proximal loop of the large colon appeared as thick, echogenic, continuous and slightly curved lines. It was thin-walled (0.51±0.08 cm) and had a diameter of 3.5±0.8 cm. The spiral colon was confined in all camels to the caudal ventral half of the abdomen. It appeared as structures with thick echoic lateral walls with a number of echogenic arched lines next to each other. Free peritoneal fluid pockets were imaged in two locations in 19 (86%) camels. Ultrasound-guided abdominocentesis was successful in 15 (68%) of the examined camels. This study provides the ultrasonographic appearance of the normal gastrointestinal tract in healthy camels that could be used as a reference for the interpretation of suspected digestive abnormalities.

Ultrasonographic imaging of normal and impacted omasum in Indian crossbred cows

Omasal impaction is a serious disease problem in cattle in India, but it is difficult to diagnose clinically. Ultrasonography has been proposed for the noninvasive evaluation of omasal disease. The objectives of this study were to compare the in vitro and in vivo ultrasonographic appearance of the omasum and to compare omasal appearance, limits, and size in clinically healthy cows with those in cows having confirmed omasal impaction. A 3.5 MHz curvilinear transducer was used to image and record the appearance of the omasum in vitro in a water bath, and its appearance, dorsal and ventral limits, and size in 10 healthy Indian Jersey/Red Sindhi crossbred cows. The results were compared with the ultrasonographic data collected from 5 cows with omasal impaction, as confirmed at necropsy. On moving the transducer dorsoventrally in each intercostal space and below the costal arch, the wall of omasum could be seen as an echogenic arc-like structure. The difference between mean dorsoventral extents of the normal and impacted omasums was statistically insignificant. These results suggest that ultrasonographic imaging may not be useful in the diagnosis of omasal impaction in Indian crossbred cows, however, additional studies may be warranted.

Ultrasonographic appearance of lymphomatous infiltration of the abomasum in cows with lymphoma

CASE DESCRIPTION

4 adult Holstein dairy cows were examined for anorexia and decreased milk production.

CLINICAL FINDINGS

Clinical signs included abdominal distension, normal to decreased ruminal motility, and decreased fecal output. Hypochloremia and high BUN concentration were also noted on serum biochemical analysis. Transabdominal ultrasonography revealed abnormal thickening of the abomasum with pyloric thickening and loss of the typical layered appearance of the pyloric wall. Results of cytologic examination of fine-needle aspirates of the abnormal portion of the abomasum were compatible with a diagnosis of lymphoma in 3 cows.

OUTCOME

The diagnosis of lymphoma involving the abomasum was confirmed by exploratory laparotomy, necropsy, or slaughterhouse reports. Two cows were euthanatized, 1 died 5 days after the diagnosis, and 1 was sent to the slaughterhouse, but the carcass was discarded because of generalized lymphoma.

CLINICAL RELEVANCE

Transabdominal ultrasonography is a noninvasive portable test that can be useful for the diagnosis of lymphomatous infiltration of the pyloric portion of the abomasum, which may result in obstruction. This can be especially useful to avoid unnecessary treatments when no typical signs of enzootic lymphoma are present. Percutaneous fine-needle aspiration of the abnormally thickened abomasal wall should be performed. These procedures can enable diagnosis of this neoplasm, which has a relatively poor prognosis, thus avoiding the unnecessary costs incurred by exploratory laparotomy.

Ultrasonography of the gastrointestinal tract in cattle

Ultrasonography is an ideal diagnostic tool for investigating gastrointestinal disorders in cattle. In animals with traumatic reticuloperitonitis, inflammatory fibrinous changes and abscesses can be imaged. Ultrasonography can be used to assess the size, position, and contents of the abomasum. This article describes the ultrasonographic techniques used for examination of the reticulum, rumen, omasum, abomasum, small intestine, and large intestine. The normal findings are presented followed by a description of the most important diseases of these organs.

Ultrasonographic imaging of abomasal curd in preruminant calves

The aim of this study was to determine whether ultrasonography could be used to evaluate curd formation in the abomasum of preruminant calves. Holstein-Friesian calves were fed one of three milk replacers: clotting (five calves), non-clotting (four calves) and pH-dependent clotting (clots form at pH 5.5, but not at pH 6.5; six calves). Ultrasonography was performed until 6h after feeding the milk replacers. In calves fed the clotting milk replacer, a large clot of curd was visualised by ultrasonography as a clearly outlined echogenic image and whey as an anechoic image. In calves fed the non-clotting milk replacer, abomasal contents were visualised as a uniform, entirely echogenic image, indicating the absence of curd formation. In calves fed milk replacer with pH-dependent clotting properties, several small curds and whey were visualised by ultrasonography. It was concluded ultrasonography can be used to visualise abomasal curd and to distinguish the presence and absence of curds in the abomasum of calves.

Ultrasonographic findings in cows with right displacement of the abomasum and abomasal volvulus

Seventeen cows with right displacement of the abomasum (rda) without abomasal volvulus, nine cows with abomasal volvulus and 10 clinically healthy cows were examined ultrasonographically. A 5.0 MHz transducer was used to scan the eighth to 12th intercostal spaces and the cranial and caudal aspects of the flank on the right side. The position, size and dorsal and ventral margins of the abomasum were determined at each imaging position. In both groups of diseased cows, the ventral abomasum contained fluid ingesta, which appeared hypoechogenic with diffuse echogenic stippling. The abomasal folds could be seen clearly as echogenic sickle-shaped structures within the ingesta. The dorsal abomasal gas cap varied in size and was characterised by reverberation artefacts, which appeared as echogenic lines running parallel to the body surface. Compared with the healthy cows, the abomasum was larger and located significantly closer to the midline of the dorsum in both groups of cows. Compared with the cows with rda, the abomasum in the cows with abomasal volvulus was significantly smaller in the eighth intercostal space and significantly larger in the 11th intercostal space. It was not possible to differentiate between rda and abomasal volvulus on the basis of the ultrasonographic findings.

Diagnostic ultrasonography in ruminants

The use of diagnostic ultrasound equipment is becoming widespread within various sectors of veterinary practice. Ultrasonographic examination has several advantages over other imaging modalities and it can be applied in hospital and ambulatory settings. It has the potential for widespread use in the diagnosis of disorders of several body systems in food animal species. This article describes its application to gastrointestinal, hepatobiliary, cardiothoracic, urogenital, and umbilical disorders. Normal and abnormal findings are portrayed and discussed. Accurate and timely use of this diagnostic modality requires a modest amount of training and practice, but it allows for relatively rapid, inexpensive, and noninvasive acquisition of clinically relevant data.

Ventral laparoscopic abomasopexy in 18 cattle with displaced abomasum

OBJECTIVE

To evaluate the feasibility and outcome of a technique for laparoscopic abomasopexy in cattle with displaced abomasum (DA).

STUDY DESIGN

Retrospective study.

ANIMALS

Dairy cattle (n=18).

METHODS

Retrieved data included signalment, clinical findings, treatments, and outcome. Laparoscopic abomasopexy was performed with the sedated cow in dorsal recumbency. The pexy site was determined after identification of the antrum and the greater curvature of the abomasum. Three or 4 absorbable sutures were passed through the body wall and abomasal wall for abomasal fixation. Wound complications, DA recurrence, food consumption, owner satisfaction, and long-term survival were assessed.

RESULTS

Left DA was diagnosed in 17 cows and right DA in 1 cow. Abomasal decompression was performed in 12 cows and abomasopexy was achieved in all cows. Surgical wounds healed without complication, except in 4 cows that had mild periportal swelling. Postoperative return to normal appetite occurred quickly except for 2 cows with concurrent diseases. Owner satisfaction varied from good to excellent. DA did not recur.

CONCLUSION

Ventral laparoscopic abomasopexy was successfully performed in 18 cows with DA. Abomasal decompression was necessary for adequate abomasal manipulation and identification of landmarks for pexy. An adequate return to food consumption and no recurrence of DA occurred (mean follow-up, 15.5 months).

CLINICAL RELEVANCE

Ventral laparoscopic abomasopexy is technically feasible and an effective method for surgical treatment of DA.

Development, advances and applications of diagnostic ultrasound in animals

Ultrasound has many industrial applications but it was first introduced as a medical diagnostic aid in the 1940s with its first veterinary application, the detection of ovine pregnancy, being reported in 1966. Since then, improvements in equipment quality combined with an increased awareness of the benefits of ultrasound as an imaging technique have led to its widespread use in the veterinary field. Recent advances in computer technology have significantly influenced equipment design and the miniaturization of transducers allows intra-operative and intra-vascular applications. Software advances have improved the ability to manipulate and process data, leading to an increased amount of information being obtained from each examination and the advent of 'remote diagnosis'. Ultrasound guided interventional techniques can now be used for diagnostic or therapeutic purposes. Many of these developments have been introduced by equipment manufacturers but have found specific applications in the veterinary field. Ultrasound is currently employed in a very diverse range of situations, not just as a diagnostic tool in the routine clinical workup of a range of species, but also for disease screening, conservation projects, commercial services, herd management and clinical research.

Ultrasonographic assessment of change in abomasal position during the last three months of gestation and first three months of lactation in Holstein-Friesian cows

OBJECTIVE

To determine changes in abomasal position and dimensions during the last 3 months of gestation and first 3 months of lactation via transabdominal ultrasonography and determine whether surgical correction of left-displaced abomasum (LDA) by right flank omentopexy alters abomasal position within the abdomen in Holstein-Friesian cows.

DESIGN

Observational study.

ANIMALS

20 heifers and 20 cows with no history of an LDA and 7 cows that had been treated for LDA via right flank omentopexy during an earlier lactation. Procedure-Ultrasonographic measurements were obtained 8 times during the last 3 months of gestation and first 3 months of lactation. Abomasal length, width, and volume were calculated from these measurements.

RESULTS

The abomasum was always wider than it was long and located predominantly to the right of the midline. The presence of a right flank omentopexy had no effect on the measured parameters. Abomasal length decreased and width increased during the last 3 months of gestation, resulting in a more transverse orientation of the abomasum within the abdomen. These changes appeared to be in response to cranial expansion of the gravid uterus. The abomasum returned to a more caudal and right sagittal position within 14 days after parturition.

CONCLUSIONS AND CLINICAL RELEVANCE

Abomasal dimensions, position, and volume change markedly during the last 3 months of gestation and first 3 months of lactation. Results permit detection of abnormal abomasal position in ill cows and indicate that the preferred location for abomasopexy is 20 cm caudal to the xiphoid process and 5 to 10 cm to the right of the ventral mid-line.

Ultrasound as a decision-making tool in abdominal surgery in cows

In many patients, abdominal ultrasonography is an excellent diagnostic and prognostic tool. It aids in deciding whether the animal should undergo surgical or medical treatment or be slaughtered. This is particularly true in cattle with traumatic reticuloperitonitis (in combination with radiography of the reticulum) or with a tentative diagnosis of left or right displacement of the abomasum. Ultrasound also is an excellent aid for identification of ileus of the small and large intestine, liver abscesses, cholestasis, various urinary tract disorders, and the different forms of ascites.

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.

Changes in the feed intake, pH and osmolality of rumen fluid, and the position of the abomasum of eight dairy cows during a diet-induced left displacement of the abomasum

During the last six weeks of the dry period, eight Holstein-Friesian cows were fed a restricted amount of grass silage; after calving, a mixture of maize silage and concentrates was offered in a feeding regimen designed to induce a displacement of the abomasum. In the first month after calving, the cows were monitored for the following variables: feed intake and composition, milk production, the position of the abomasum, and the pH and osmolality of the rumen contents. In five of the eight cows, a left displacement of the abomasum occurred between four and 21 days after calving in the absence of other diseases. The displacement was temporary, lasting between five and 36 consecutive hours and one or two days in two of the cows (floaters), and for three or more days in the other three. Before these three cows developed the displacement, their abomasum was 4.3 to 7.9 cm higher, its contents had a higher mean osmolality (+19.2 mosmol/kg), and the ratio of roughage to concentrates in their feed was lower (-0.87) than in the three cows that did not develop clinical signs of a displaced abomasum. There were no significant differences in these variables between the floaters and the healthy cows.

Ultrasonography in gastrointestinal disease in cattle

Ultrasonography is an ideal diagnostic tool for investigating gastrointestinal disorders in cattle. It is performed on standing non-sedated cattle using a 3.5 MHz linear transducer. In animals with traumatic reticuloperitonitis, inflammatory fibrinous changes, and abscesses can be imaged; however, magnets and foreign bodies are difficult to visualize because of the gas content of the reticulum. Ultrasonography can be used to assess the size, position and contents of the abomasum. Percutaneous ultrasound-guided abomasocentesis can be performed to evaluate the nature and chemical composition of its contents. In left displacement of the abomasum, the abomasum is seen between the left abdominal wall and the rumen. It contains fluid ingesta ventrally and a gas cap of varying size dorsally. Occasionally, the abomasal folds are seen in the ingesta. In cattle with right displacement of the abomasum, the liver is displaced medially from the right abdominal wall by the abomasum, which has an ultrasonographic appearance similar to that described for left displacement. Motility and diameter of the intestine are the most important criteria for ultrasonographic assessment of ileus. However, the cause of the ileus is rarely determined using ultrasonography. In cases with ileus of the small intestine, there is at least one region of dilatation of the intestine and motility is reduced or absent. In cattle with caecal dilatation, the caecum can always be imaged from the right lateral abdominal wall. The wall of the caecum closest to the transducer appears as a thick, echogenic, semi-circular line.

Position of the abomasum in dairy cows during the first six weeks after calving

The position of the abomasum in six cows was examined by ultrasonography at regular intervals for six weeks after they had calved. Its position was established by determining the distance between the margin of the left side of the abomasum and the ventral midline at two sites. During the last weeks of pregnancy, the abomasum was positioned in a small region of the left ventral side of the abdominal cavity. At parturition it was positioned high on the left side and then descended. The abomasum was furthest from the midline immediately after parturition. Its position was related to the interval after calving, the cow's feed intake, and the pH and osmotic pressure of the rumen fluid. There was considerable variation between the cows in the position of the abomasum, which was in part due to analytical variation, and in individual cows it had a circadian rhythm.

Ultrasonographic findings in cows with left displacement of the abomasum

Forty-eight cows with left displacement of the abomasum (LDA) and three clinically healthy control cows were examined ultrasonographically from the 11th and 12th intercostal spaces on the left side. In the controls, the rumen was immediately adjacent to the left abdominal wall, whereas in the cows with LDA the rumen was generally immediately adjacent to the left abdominal wall ventrally, but displaced by the abomasum more dorsally. The ultrasonographic findings were generally consistent in the cows with LDA. The ingesta that were visualised ventrally in the abomasum appeared echogenic to hypoechogenic and, in a few cows, the abomasal folds were visible as elongated, echogenic, sickle-shaped structures. The dorsal abomasal gas cap was characterised by reverberation artifacts from the abomasal surface.

Percutaneous ultrasound-guided abomasocentesis in cows

The goal of this study was to determine the optimal location for ultrasound-guided centesis of the bovine abomasum and to assess the safety of the procedure. In the first part of this study, the technique was applied to 50 clinically healthy cows which were slaughtered within two hours of the procedure. The abomasum and peritoneum were then examined for lesions. In all but one cow, the location for abomasocentesis was 10 to 27 cm caudal to the xiphoid and on the ventral midline or up to 10 cm to the right of it. No peritoneal lesions were observed in any of the cows. In all cases, the site of centesis was visible as a localised haemorrhage on the serosal surface of the abomasum. In 41 of the cows, a haematoma was visible on the mucosal surface of the abomasum. In the second part of the study, 10 cows were monitored clinically for 10 days after abomasocentesis, to assess the safety of the procedure. The appetite, general behaviour, attitude and rectal temperature of the cows remained normal. The haematocrit, total and differential leucocyte counts, and the concentrations of total solids and fibrinogen were determined daily and remained within their normal ranges. At slaughter minimal changes, such as localised reddening and adhesions between the site of the puncture in the abomasum and the abdominal wall, were visible in three of the cows.