RDA/LDA

Question 1

What are the three causes for pings on the left side of a cow?

Answer 1

Rumen gas, left displaced abomasum, free gas in abdomen

Question 2

What position is a left displaced abomasum in?

Answer 2

Abomasal fundus and body are in the left dorsal abdominal quadrant, omasum is displaced ventrally and towards the left

Question 3

What is the pre-requisite for a left displaced abomasum?

Answer 3

Hypomotility of the abomasum

Question 4

What are some causes of abomasal hypomotility?

Answer 4

Endotoxemia, hypocalcemia, alkalemia, hyperinsulinemia, duodenal acidification, hypergastrinemia, histamine, prostaglandin

Question 5

What are predisposing factors for a left displaced abomasum?

Answer 5

Being female, dairy cattle, 5-6 years old, having calved recently, having birthed twins, large body size, spring season, consumption of a diet low in crude fiber and high in concentrates, small rumen volume

Question 6

Why do dairy cows early in lactation frequently get LDA?

Answer 6

Increased exposure to factors that induce abomasal hypomotility (hypocalcemia), presence of abdominal void after calving

Question 7

What is the classic presentation for an LDA?

Answer 7

5-6 year old dairy cow in first 2-4 weeks after calving

Question 8

What are clinical signs consistent with an LDA?

Answer 8

Poor appetite for grain and normal/good appetite for hay, poor milk production, “ping” on left abdomen, ketonuria, abdominal pain

Question 9

Why is medical management of LDA not recommended?

Answer 9

It has a high recurrence rate

Question 10

What does medical management of LDA entail?

Answer 10

Rolling a cow +/- tying her right hind leg to a post, erythromycin lactiobionate can be given but is not recommended

Question 11

What are the dangers associated with medical management of LDA?

Answer 11

Can induce abomasal volvulus or intestinal volvulus; can cause hip luxation or teat laceration

Question 12

What are the main objectives of surgery on an LDA?

Answer 12

To replace the abomasum to its normal anatomic position, to stabilize the abomasum in its normal anatomic location, and to minimize perioperative morbidity and mortality

Question 13

Describe the roll and toggle surgery for LDA

Answer 13

Cast cow into dorsal recumbency and identify a loud ping. Toggle the abomasum to the skin. Linked to more post-operative complications than open surgery (peritonitis, fixation of organs other than the abomasum, abomasal fistula or volvulus). Easiest/cheapest surgery

Question 14

Describe a right flank omentopexy for an LDA

Answer 14

Make an incision in the right paralumbar fossa and identify the dorsal abomasum and return it to the right ventral abdominal floor. Identify the pylorus and pexy the omentum 1.5” from the pylorus to the peritoneum and transversus abdominis. Advantages- can be done without an assistant, permits exploration of the abdomen and pelvic canal, relapse rate relatively low and possibly less traumatic to the abomasum.

Question 15

Describe an abomasopexy from the left flank for an LDA

Answer 15

Incise over the left paralumbar fossa and identify the dorsal abomasum. Place a row of nonabsorbable sutures on the greater curvature of the abomasum and push it into its normal position on the ventral abdominal floor. Have an assistant grab the free ends of the suture and pull them through the abdominal wall. Make sure no organs are trapped under the abomasum before tying the sutures. Advantages- theoretically stronger than an omentopexy, positioning of the abomasum may be superior. Disadvantages- need a large and high LDA, no opportunity for an abdominal exploration, higher complication rate because of risk of small intestinal entrapment and potential for abomasal fistula formation.

Question 16

Describe an abomasopexy from a paramedian approach for an LDA

Answer 16

Put the cow in dorsal recumbency and make a 6” incision 3 fingers cranial to the umbilicus and 3 fingers to the right. Identify the abomasum and suture along with the peritoneum and internal rectus sheath with absorbable suture. Advantages- theoretically stronger than omentopexy, no readily visible incision scar. Disadvantages- requires properly trained assistant and proper facilities, should not be used in cows in the last trimester of pregnancy or in cows with udder edema, possibly has increased post-operative complications (incisional infection and dehiscence)

Question 17

Describe a laparoscopic abomasopexy for an LDA

Answer 17

While the cow is standing, prepare a small 3” square area on the left flank. Make a stab incision and use a laparoscope to visualize the abomasum. Insert a trocar into the appropriate intercostal space and into the abomasal lumen and toggle suture through the trocar. Remove the trocar and the laparoscope and place the cow in dorsal recumbency. Make a stab incision in the right paramedian region and insert the laparoscope. Visualize the toggle suture and use forceps to grab the ends and fix it externally. Disadvantages- expensive, requires several assistants

Question 18

How can LDAs be prevented?

Answer 18

Provide plenty of forage during the dry period, gradually increase grain after calving, ensure adequate crude fiber during early lactation, treat/prevent diseases that cause abomasal hypomotility/atony, keep cow on feed

Question 19

What are the causes of right sided pings?

Answer 19

Abomasal volvulus, right displaced abomasum, gas in the spiral colon, gas in the cecum, gas in the rumen with massive ruminal distension, free gas in the abdomen, gas in the rectum and descending colon, gas in the proximal duodenum, gas in the uterus

Question 20

What are the most common causes of a large focal right sided ping?

Answer 20

Abnormality of the abomasum or large intestine

Question 21

Define a right displaced abomasum

Answer 21

Displacement of the abomasum to the anterior right abdominal quadrant with no vascular occlusion

Question 22

Define an abomasal volvulus

Answer 22

Unstable distended RDA that has rotated around the mesenteric attachment; causes vascular occlusion, lymphatic occlusion, and luminal obstruction

Question 23

What increases the likelihood of an abomasal volvulus?

Answer 23

Normal rumen volume following abomasal hypomotility

Question 24

What exam findings are consistent with an RDA?

Answer 24

Right sided ping anterior of the 13th rib that might change pitch during percussion, air-fluid interface on succession of right flank, tachycardia, dehydration, abnormal feces

Question 25

What exam findings are consistent with an abomasal volvulus?

Answer 25

Large right sided ping anterior of the 13th rib, dehydration, tachycardia, abdominal pain, tense abdomen, abnormal feces

Question 26

What lab findings are consistent with an RDA or abomasal volvulus?

Answer 26

Hypochloremia, hypokalemia, metabolic alkalosis, azotemia, increased SDH

Question 27

What is the mortality rate of abomasal volvulus without surgery?

Answer 27

100%

Question 28

What is the preferred surgical technique for an RDA or AV?

Answer 28

Right flank approach

Question 29

How do you identify whether the liver is displaced medially by the abomasum in an RDA or AV?

Answer 29

RDA- if no firm twist palpated in abomasum then liver is not displaced
AV- firm twist usually palpated indicating liver is displaced

Question 30

What are the three types of abomasal voluvulus?

Answer 30

Abomasal volvulus- firm twist located primarily at the omasal-abomasal junction (60%)
Omasal-abomasal volvulus- firm twist located primarily at the reticulo-omasal junction (40%)
Reticulo-omasal-abomasal volvulus- firm twist located primarily at the junction of the rumen and reticulum (rare)

Question 31

How do you surgically correct an RDA or AV?

Answer 31

RDA- decompress the abomasum
AV- correct the volvulus by rotating abomasum clockwise, success is indicated by easy exteriorization of the pylorus, do not remove abomasal fluid unless AV cannot be corrected

Question 32

What are prognostic indicators for pyloric omentopexy for AV?

Answer 32

Appetite, presence of diarrhea, absence of abdominal distension, heart rate <80bpm

Question 33

What are the survival rates of different types of AV with surgery?

Answer 33

AV- 90%
OAV- 55%
ROAV- 0%