Small Intestinal Intussusceptions in Two Maternally Related Brown Swiss Dairy Cows
Mary Walker (OVC 2011)
Abstract
Two maternally related Brown Swiss dairy cows presented with signs of colic, anorexia,
decreased rumen motility and scant melenic feces of less than 24 h duration approximately one month
apart. Clinical signs along with surgical exploration of the right flank supported the diagnosis of small
intestinal intussusceptions. Fecal testing from one of the cows showed moderate growth of Clostridium
perfringens. Dietary analysis of the lactating cow ration showed a high quality feed with no macro- or
micro-nutrient imbalances.
However, the lactating dry forage ration was deficient in
quantity and effective fiber (length). We believe that the intussusceptions occurred secondarily to
changes in intestinal motility as a result of poor fiber content in the diet and recurrent subacute rumen
acidosis.
Case Description
Case 1
Podium, a third parity lactating Brown Swiss cow presented to the Ripley-Huron Veterinary
Clinic for signs of colic (shifting weight and kicking of hind limbs) and anorexia of 24 h duration. On
presentation, Podium was dehydrated, mildly tachypnic and tachycardic. Upon auscultation, no gas
pings, pongs or gas filled bowel were heard. The colic signs had decreased slightly according to the
owner. On rectal exam, no abnormalities were felt, but there were scant feces and evidence of melena in
the rectum. Hypocalcemia, severe hyperglycemia, hypokalemia and hypochloremia were present on
serum biochemistry. After 24 hours of supportive care, referral to the Ontario Veterinary College
Teaching Hospital (OVCTH). Surgical exploration was recommended due to lack of clinical resolution
and high genetic and production value of the cow.
At the OVCTH, transabdominal ultrasound showed decreased intestinal motility, dilated small
intestines, and free fluid in the peritoneum. Melena was found in the rectum and a tubular shaped
structure was palpable transrectally. A standing right flank laparotomy revealed a severe jejuno-jejunal
intussusception that was not manually reducible. Fibrin clots and free fluid in the peritoneum were
supportive of severe intestinal damage. A jejunal resection and anastamosis was attempted because of
Podium’s high value even though the prognosis for return to production was poor. Humane euthanasia
was necessary after rupture of the bowel during surgery. On post mortem, the intussusception was found
to be 25-30 cm long, meaning that it involved twice that length of the jejunum. Evidence of peritonitis
was evident as well, reinforcing the belief that Podiums prognosis for survival was poor, even after
surgical resection.
Case 2
Pebbles, a fourth parity lactating Brown Swiss presented with signs of anorexia, colic and
melena on rectal palpation of 12 h duration. Pebbles had reduced rumen motility, a drop in milk
production, and was moderately tachycardic. Biochemistry results showed severe hypocalcemia,
hyperglycemia, moderate hypokalemia, and mild hypochloremia. Pebbles was immediately referred to
the OVC for treatment because of similarities in clinical signs to Podium.
At the OVCTH, transabdominal ultrasound showed a decrease in intestinal motility and rectal
palpation demonstrated a full rumen, a complete lack of feces, but no melena was present. Blood gas
analysis showed metabolic alkalosis with hypocalcemia, hypokalemia and hypochloremia. Continuing
anorexia, lack of feces production, melena on rectal palpation, bradycardia and increasing recumbence
overnight indicated that surgical exploration was warranted. A standing right flank laparotomy exposed
an intussusception of the distal duodenum that could not be exteriorized. During surgery, a second
palpation of the intestines revealed that the intussusception had reduced itself based on an inability to
locate the lesion and decreased gas distension of the duodenum. The owners elected for recovery with the
knowledge that the extent of intestinal damage was unknown and the prognosis guarded.
Pebbles condition improved over the next two days as feed was gradually introduced and she
began to pass normal feces three days post surgery. Culture results showed 3+ growth of Clostridium
perfringens in feces produced post surgery. Pebbles was discharged four days after surgery. The owners
reported that she had effectively dried off, but gradually regained her full appetite and was doing well.
Discussion
An intussusception is a form of mechanical bowel obstruction where a section of intestine (the
intussusceptum) invaginates into an aboral segment of intestine (the intussuscipiens) 1,2. The cause of
intussusceptions is often idiopathic, but variation in motility along the length of the bowel is believed to
be an underlying cause1-4. Definitive causes of intussusceptions include foreign bodies, intramural or
abdominal masses, parasites, sudden diet change, drug induced changes in motility, and enteritis1-3. The
majority of bovine intussusceptions are of the distal jejunum, but they have also been reported in the
ileum, cecum, and colon3-6. This may be the first report of a duodeno-duodenal intussusception in bovids
based on the epidemiological study of North American veterinary teaching hospital case reports2. Longer
length and mobility of the mesentery of the jejunum may facilitate formation of intussusceptions2,3.
Regardless of location, it is an uncommon cause of obstruction in cattle (1.4 cases of
intussusceptions/1000 cattle admitted)2. They more commonly occur in young cattle as sequelae to
neonatal diarrhea1,2. Interestingly, Brown Swiss cattle seem to be over represented when compared to
Holstein cattle2.
Clinical signs in acute intussusceptions include colic signs as a result of distention of the
mesentery as the intussusceptum is propelled into the distal segment. With time, ischemia of the
invaginated segment causes desensitization of the nerves and colic signs may diminish 1,2. However,
distention of the intestines proximal to the obstruction become distended and cause chronic pain, which
may present as treading, or repeated recumbence and standing. If untreated, the affected bowel may die
and slough or rupture, leading to a severe peritonitis and possible toxic shock1,2. In the case of Podium,
decreasing colic signs led us to believe that her obstruction was resolving instead of being a sign of
decaying bowel and worsening prognosis.
Mechanical obstructions of the small intestine will lead to characteristic biochemical changes due
to sequestration of electrolytes in the abomasum and sequential dehydration1. Adults present with a
hypochloremic, hypokalemic metabolic alkalosis which develops from ion and fluid sequestration in the
abomasum and anorexia1-3. Rectal palpation may reveal distended loops of bowel, or the lesion itself may
be palpated1,2. Intussusceptions have a classical “target” sign on ultrasound, showing the outline of bowel
within bowel1,6. As in both of these cases, surgical exploration can be used to definitively diagnose the
obstruction.
Successful treatment requires fluid and electrolyte stabilization as well as surgical correction with
resection and anastamosis of the affected intestine if possible. Location of the lesion, secondary
peritonitis and intestinal stenosis will affect the prognosis for short term survival and return to production
long term1,2. A retrospective case study of 336 intussusceptions in cattle showed the overall survival rate
was only 35%2. Preventing intussusceptions is difficult because the cause is often unknown. Gradual
changes in diet and prevention of enteric disease may reduce the risk2.
Why two cows from the same herd developed small intestinal intussusceptions in a short time
period led to questions about internal parasites, bacterial overgrowth, and nutritional deficiencies.
Bacterial culture tested 3+ for Clostridium perfringens Type A.
We are unable to determine the
significance of this finding in the pathogenesis of the intussusceptions for a number of reasons. It is
possible that a high plane of nutrition in the diet allowed clostridial species to proliferate, perhaps
affecting intestinal motility, which then lead to an intussusception. Alternatively, clostridial species may
have proliferated secondary to decreased motility and damaged bowel after the intussusceptions occurred.
Since Clostridia can be isolated from symptomatically normal animals, a positive culture may have been
an incidental finding.
We suspect that this herd of cows suffered from recurrent bouts of subacute rumen acidosis
(SARA) because they were being fed a high plane of nutrition without enough roughage to act as a rumen
buffer. SARA is minimally defined as periods of moderately low rumen pH (between 5.6 and 5.2) due to
VFA accumulation and inadequate ruminal buffering8,9. It is more commonly found in early or midlactation dairy cows and is induced by a diet of highly fermentable forages and carbohydrates, and
deficient in coarse fiber or roughage. SARA may cause reduced fiber digestion, decreased feed intake,
milk fat depression, laminitis, diarrhea, and increased bacterial endotoxin production8.9.
Regular nutritional analyses of the farm’s lactating ration showed that the herd was being fed a
high quality haylage and grain diet to maximize production. However, the quantity of hay or roughage
fed did not meet the daily fiber requirement for a lactating dairy cow and it was suggested that the
haylage was chopped too finely to meet recommendations for optimal rumination10,11. Adequate fiber
content allows for optimal digestibility of the ration, maximal dry matter intake, stabilization of rumen
microbes, and maintenance of butterfat levels in the milk10.11. Effective fiber, or the physical length of
the fiber, is also important because the long fibers help form the floating rumen mat which promotes
eructation and saliva production.
We do not have definitive evidence of what caused two intussusceptions in such a short time
period. We suspect that underlying subacute rumen acidosis affected intestinal motility which lead to a
secondary intestinal intussusception. The producers have reported that they have increased the amount of
hay in the lactating ration and have replaced their haylage with a longer cut. No further animals have
shown any further signs of colic or other intestinal upset.
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