Horse colon displacement can occur when a portion of the large colon becomes displaced from its normal position. Three common types include left dorsal displacement where the ascending colon is trapped in the renosplenic space, right dorsal displacement where the left colon moves laterally around the cecum, and retroflexion where the pelvic flexure is displaced cranially. Clinical signs include recurrent colic. Diagnosis involves rectal palpation and ultrasound. Treatment depends on the type but may include phenylephrine to reduce spleen size, rolling procedures, or surgery to reposition the colon. Recurrence rates are approximately 10%.

1. Horse colon displacement
Presented by :
Rajeev Kumar Mishra
L2015V38M
Department of veterinary Medicine
Credit seminar

2. Gastro Intestinal Tract of Horse
1. Mouth
2. Pharynx
3. Esophagus
4. Diaphragm
5. Spleen
6. Stomach
7. Duodenum
8. Liver, upper extremity
9. Large colon
10. Coecum
11. Small intestine
12. Floating colon
13. Rectum
14. Anus
15. Left kidney and its ureter
16. Bladder
17. Urethra
Source:-United States Department of Agriculture Leonard Pearson Rush Shippen Huidekoper Ch. B.
Michener W. H. Harbaugh

3. Colon
Descendingcolon
(Smallcolon)
Ascendingcolon
(Largecolon)
Transverse colon

4. Ascending colon
3-4 metres long, 20-30cm in diameter & 80 liters
capacity.
45% of the horse’s digestive tract, compared to 17% of Human.
Microbial digestion (fermentation) continues of Fibres
Absorption, B group of vitamins & Phosphorus.
Begins at cecocolic orifice & terminates at transverse colon

5. Continue….
• Begins at lesser curvature of the base of caecum.
Moves caudally up to pelvic inlet as Left ventral colon
Moves cranially up to Diaphragm as left dorsal colon
Passes caudally, on reaching medial surface of the base of ceacum it turns left
Transverse colon

6. Anatomical variation throughout colon
At pelvic region the diameter of colon decreases markedly and turns back.
Initial portion of unsacculation.
Right dorsal colon is closely attached to right ventral colon by a short intercolic fold
And to body cavity by common mesenteric attachment with base of ceacum, no such
attachment Is seen in left colon.
Transverse colon is fixed firmly to the most dorsal aspect of abdomen by fibrous
mesentery

7. Colonic Motility Pattern
• It is under the control of pacemaker located at pelvic flexure.
• The pacemaker sense either the size or the consistency of feed
particle.
Normograde peristalsis :- Left ventral colon to left dorsal colon
Retrograde Peristalsis :- from pelvic flexure to sternal flexure.

8. Etiology or predisposing factor
• Lack of mesenteric attachment to the body wall.
• Excess soluble carbohydrate diet, quick fermentation, excessive gas
accumulation.
• Abrupt change in diet.
• Altered colonic motility pattern.
• Parturition

9. Displacement of colon
Displacement of Ascending
colon

10. Displacement
of
colon
Left dorsal
displacement
Retroflection
Right dorsal
displacement

11. Left Dorsal Displacement
In a normal healthy horse, the spleen rests against the left abdominal
wall and is connected to the left kidney.
Left dorsal displacement is characterized by entrapment of
ascending colon in the renosplenic space.

12. NormalTwisted
Entrapment
Pelvic flexure
A large colon
With pelvic
flexure
Near diaphragm

13. When the colon is trapped in this position, it is known as a
“nephrosplenic entrapment.
Abnormal movement (motility) of the colon causes
dysfunction and gas accumulation within the colon, which
then floats up or is pushed up into the abnormal position.
Another hypothesis is that a feed impaction starts the
abnormal movement of the colon.

14. Spurgeon's Color Atlas of Large Animal Anatomy.
Prof. Pat McCarthy (Australian)

16. Per rectal examination
• If large colon is found to the left and slightly ventral to the left kidney
between the kidney and caudo dorsal border of the spleen.
• It can be suspected when large colon Is between spleen and body
wall or when spleen is displaced medially.
• In one study rectal examination was diagnostic in 72% of cases.

17. Ultrasonographic examination
Nephrosplenic Ligament Entrapment
• Dorsal spleen and left
kidney not visible in left
caudal abdomen
• Visualize ingesta or gas-
filled large bowel
• Spleen ventrally displaced
• Bright hyperechoic
reflection dorsal to the
spleen from the bowel
False negative diagnosis can result from a gas distended viscus near the left kidney.

18. Management
Withholding the feed.
Phenylephrine@ 3µg/kg/min for 15 Minute,
Reduces the spleen size by 25%
The Rolling procedure.

19. Phenylephrine
• Phenylephrine is a sympathomimetic amine Alpha-1 agonist.
Action
Peripheral vasoconstriction → increase in arterial blood pressure; this may lead to a reflex bradycardia,
particularly if hypertension occurs.
•Reduced cardiac output due to reduced heart rate and increased afterload.
•Splenic contraction.
•Mydriasis.
•Phenylephrine reduces femoral arterial and venous blood flow, therefore may reduce muscle perfusion
Hardy et al. (1994 ) made a study in 6 healthy horse and found that 3 & 6 µg/kg/min for 15 Minute, splenic are was reduced to
28 &17% of baseline measurement by 35 minute of end of infusion.

20. For a 600 kg horse
600*3*15=27000mg
1 ml of phenylepherin in 100 ml of NSS= 100µg/ml
Total required=27000/100=270ml
A 16 gauge needle has 52ml/min (maximum)
As we have to infuse for 15 min so
Per ml fluid 270/15= 18ml /min
This treatment
combined with
exercise, has a
reported efficacy of
92% (11 out of 12) in
horses with low
gaseous distension of
the colon

21. Side effect
• Bradycardia with atrioventricular block second degree.
• Increased blood pressure and haematocrit.
• The stroke volume remains stable, but the cardiac output decreases
with phenylephrine dose.
• However, one study showed that this treatment has an increased
risk (64 times higher) of internal bleeding (hem thorax, hem
peritoneum) in older horses over 15 years

22. • Venner et al. () showed that infusion of adrenaline to 1 mcg / kg /
min for 5 minutes in healthy horses results in a decrease of the size
of the spleen in 52% of its base value.
• Adrenaline is a nonspecific adrenergic agonist, risks associated with
its use are potentially larger and less predictable than those of
phenylephrine specific for α1 receptors.

23. Recurs in about 10% of horses.
Surgery
Ablation of
nephrosplenic
space
colopexy

24. Colopexy Cont ……….
Techniques involving suturing the dorsal and
ventral colon segments together.
Should not be used
A technique of suturing the lateral free band of the
LVC to the left body wall, approximately 6 cm to the
left of midline, is the currently recommended
technique.
Markel MD, Meagher DM, Richardson DW: Colopexy of the
large colon in four horses. J Am Vet Med Assoc 192:358, 1988
Markel MD: Prevention of large colon displacements and
volvulus. In Snyder JR, Markel MD (Eds): Advances in Equine
Abdominal Surgery. Vet Clin North Am Equine Pract 5:395,
1989

25. Right Dorsal Displacement
The left colons move laterally around the base of the cecum
lie between the cecum and the right body wall.
usually the arterial supply remains intact.
The pelvic flexure ends up positioned near the diaphragm.
some interference
with venous
drainage from the
affected colon.
most common form of this
displacement
• Clock wise displacement is more common than counter clock wise. cranial
caudal

26. • Pelvic flexure being placed lateral to caecum.
cranial
caudal

27. Spurgeon's Color Atlas of Large Animal Anatomy.

30. • Colon is palpated between caecum and right body wall.
• Rectal examination may reveal the taenia of the colon running
transversely across the pelvic inlet. It may not be possible to palpate
the ventral caecal band on rectal examination.
• The pelvic flexure cannot normally be felt and caecum is often
difficult to palpate.
Per rectal examination Not much significant.

31. In addition to clinical signs mentioned above, elevation of γ-glutamyltransferase (γ GT)
is often noted when moving right colon.
Generally in more chronic cases. It happens that initially diagnosed as mere stasis of
pelvic curvature and not responding to repeated administration of laxatives turn out to
be right movements .

32. • Large intestine distended with gas filled.
•
In the normal equine abdomen, the ascending colonic vasculature courses in the
mesentery along the medial aspects of the colon and should not be visible during
transabdominal sonographic examination
• Visualization of colonic mesenteric vessels on ultrasound provided a sensitivity of
67.7%, specificity of 97.9%, positive predictive value of 95.8%, and negative
predictive value of 81% for large colon right dorsal displacement or 180° large
colon volvulus, or both
Ultrasonographic examination

33. Ultrasound image obtained from a horse that presented for colic. Dorsal is to the right
of the image. Colonic vessels are identified in the right 13th intercostal space just
dorsal to the costochondral junctions with the probe oriented transversely to the spine.
Note large colon adjacent to the vessels, identified by a semi-curved appearance and
hyperechoic wall to gas lumen interface (arrow). Also note the echogenic mineralized
costal cartilage casting an acoustic shadow ventrally (asterisk) and a small amount of
free peritoneal fluid external to the mesocolon and vessels dorsally (double asterisk).
Right dorsal displacement of the large colon was confirmed at surgery.

34. Management
Surgery
surgery must be performed to locate the pelvic flexure, to exteriorize and decompress the left portion of
the colon and then to relocate the colon to its normal position by rotating it around the cecal base.
The twisting of the colon must be identified and corrected.
The prognosis for survival is good, provided that the colonic wall is not damaged during surgery.

35. Source:
 Merck Manual
 Equine Internal Medicine , By Stephen M. Reed
 Manual of Equine Practice, Reuben j. Rose.
 Blackwell's Five-Minute Veterinary Consult: Equine, 2nd Edition
• Equine Hospital Manual, Kevin Corley & Jennifer Stephen.