Abomasal and Intestinal Disease in Cattle

What primary history information could indicate an abdominal problem?

abnormal abdominal shape, colic, not eating, “slab sided”, sunken eyes, sudden drop in milk yield, lagging behind

What distance exam findings can be helpful in determining nature and severity of abdominal problems?

posture (hunched back, sawhorse stance)

attitude (pained face, drooping ears, looking depressed)

behavior (not interested in food or water)

BCS

body symmetry/abdomen shape (distension, one sided or bilateral)

sunken eyes (indicator of dehydration)

abnormal urination or defecation

is the animal chewing cud?

severe horse-like colic (thrashing, rolling, kicking at abdomen)

fecal staining on hindlimbs

what can be evaluated on the left side of a cow showing abdominal issues?

rumen fill and strength/frequency of contractions

HR (HR >120 indicates severe problems and severe pain)

increased RR

moderate to severe dehydration (skin tent)

positive withers pinch test (can be negative for problems located aborally)

pings on percussion and splashing sounds on succussion

what physical requirements must be met for a “ping” sound to be audible?

gas-distended organ against the body wall, gas/fluid interface, gas under pressure

list some ddx for left-sided pings (in order of likelihood)

left displaced abomasum, rumen gas cap, pneumoperitoneum, physometra

list some ddx for right-sided pings (in order of likelihood)

right displaced abomasum (± torsion), cecal dialtion/volvulus, spiral colon/small intestinal gas (ileus, intussusception, hemorrhagic bowel syndrome), pneumoperitoneum, physometra

what are you assessing on the right side of the cow when you are concerned about abdominal pathology?

check for borborygmi — a distended abdomen with absent gut sounds is a warning sign!

• loud and frequent sounds could indicate abdominal discomfort linked to diarrhea

percuss and succuss the right flank

what can the feces (or lack of feces) indicate?

absence of feces — suggests intestinal obstruction

diarrhea — seen with RDA and LDA

frank blood or melena — abomasal ulceration or hemorrhagic bowel syndrome

undigested fiber particles >2cm — suggests hardware disease

what can be revealed on rectal examination of cattle?

• presence of absence of dilated intestinal loops

• quantity and consistency of feces

• intra-abdominal pressure (markedly reduced with pneumoperitoneum)

• roughness or abnormal texture of the peritoneum

what tests can be performed to assess the reason for pinging heard on percussion of the left flank?

• rectal palpation

• assessment of rumen fiber layer

• double auscultation

• orogastric tube sound transmission test

• rumen or abomasal fluid analysis

what is double auscultation and what do the findings suggest?

during a clear rumen contraction, move the stethoscope to the area of the loudest pin

• if the rumen is pinging, the contraction should be heard at similar volume

• if the abomasum lies between the rumen and abdominal wall (LDA), contraction sounds will be muffled or absent over the pinging area

what is the orogastric tube sound transmission test and what do the findings suggest?

place an orogastric tube and ask an assistant to gently blow air down the tube while you auscultate the area of the loudest ping

• loud bubbling sounds indicate the rumen is directly under the abdominal wall and producing the ping

• absent or faint sounds suggest another organ (eg displaced abomasum) lies between the rumen and body wall

what findings on rumen or abomasal fluid analysis can assist diagnosis?

chloride >30mEq/L indicates abomasal reflux into the rumen, supporting LDA diagnosis

what diagnostic findings can help you rule in or out abomasal displacement or other cranial intestinal obstruction?

ultrasound!

• free abdominal fluid - suggestive of peritonitis, organ rupture, or hemorrhage

• dilated intestinal loops consistent with obstruction or ileus, and abnormal organ positioning

• allows identification of organ position

what diagnostic findings suggest abomaso-ruminal reflux?

when running bloods, you may seen changes in serum biochem associated with obstruction of abomasal outflow or obstruction of cranial intestines:

• hypokalemia

• hypochloremia

• metabolic alkalosis (increased bicarbonate)

If metabolic acidosis and hyperkalemia were present instead, that would suggest decompensation and a poor prognosis

explain the mechanism of LDA development

accumulation of gas and lack of organ contractility → abomasum shifts to left of midline → organ becomes gas-distended → organ floats up on left between body wall and rumen → causes partial or complete outflow obstruction

what are the main causes of the abomasum displacing to the left or right?

• anatomical predisposition (think deep-bodied cows)

• mechanical factors — reduced rumen fill, especially in periparturient period

• abomasal atony is the most important factor! - reduced motility results in gas accumulation

• concurrent disease — hypocalcemia, metritis, mastitis, retained fetal membranes all reduce abomasal motility

what clinical signs would you expect in a cow with LDA?

sudden onset drop in milk yield, hypochloremia, hypokalemia, full left flank, hypocalcemia, diarrhea, high-pitched ping left flank, no fever, ketonuria

what other diseases are also linked to atony, hypoglycemia and high levels of VFAs in bloods?

cecal dilation and torsion, general volvulus, mesenteric torsion

when might we see intussusception in a cow?

intestinal ulceration, polyps, or preceding bouts of diarrhea can all affect intestinal contractility, leading to an oral segment or intestine to slide into adjacent aboral segments

what is mesenteric torsion?

severe, acute, often fatal emergency where intestines twist around their mesenteric root, cutting off blood supply

accompanied by severe colic signs, shock and severe abdominal prain and requires immediate surgery

what is hemorrhagic bowel syndrome (HBS)?

segmental bleeding (usually from an ulcer) leading to a large blood clot obstructing the intestinal lumen

in some cases Clostridium perfringens and Aspergillus fumigatus have been isolated

surgery often required to find the obstruction, break down the clot through the intestinal wall and carefully massage it forward

what clinical signs would you expect to see in a cow with HBS?

sudden onset drop in milk production, fluid sounds on succussion of right flank, ping on right flank, dehydration, dark tarry feces or clotted blood in feces, elevated HR, decreased rumen motility, hypocalcemia, colic

when should you suspect abomasal ulceration?

melena, sudden abdominal pain and distension due to generalized peritonitis in calves and adult cattle

very common found in South American camelids, occur les frequently in small ruminants

what causes right displaced abomasum (RDA)?

gas distension and atony of the abomasum leads to dorsal displacement of the greater curvature and the abomasum rotates counterclockwise 180°- 360° forming a torsion as the pylorus moves cranially, resulting in abomasal volvulus → leads to severe constriction of blood supply, complete in- and outflow obstruction and compromise of nerves

when can conservative management be used, and what does conservative management consist of?

selected cases like simple indigestion, spasmodic colic, or cecal dilation without torsion

• analgesia — meloxicam for flunixin given IV

• motility modification — buscopan can be given to see if colic and abdominal discomfort subside

• hydration — oral fluid therapy most effective, can add magnesium hydroxide or magnesium oxide to provide mild laxative effects