SGU LAS: Final Set 1
Terms in this set (91)
Squamous cell carcinoma is more common in what breeds of cattle?
**breeds with white faces with no pigment around the eyes
Squamous cell carcinoma around the eye needs to be differentiated from.....
sequlae of keratoconjunctivitis
What are common locations for squamous cell carcinoma in cattle?
at the dorso-lateral limbus.
How can you surgically manage squamous cell carcinoma if the limbus is involved?
prolapse the eye.
shave the lesion off the cornea/sclera with a blade.
How can you manage squamous cell carcinoma with extensive involvement of the eyeball but does not involve the bone?
What are dehorning methods in young animals?
dehorning paste: caustic material (potassium hydroxide) applied to horn buds.
hot iron: applied to area surrounding horn bud.
What are equipment options for dehorning adult cattle?
saws: hard-backed hand saw, electric saw, wire saw.
powered guillotine devices
What anesthetic methods are used for dehorning adult goats?
How is dehorning commonly done in adult goats?
with a saw
What are some possible dehorning complications?
scur formation: occurs when less than adequate amount of horn is removed.
sinusitis: increased incidence if rain occurs immediately following dehorning.
What part of the tongue will hold sutures better?
dorsal surface holds suture better vs ventral surface
What are clinical signs of cleft soft palate?
milk runs out of the nostrils when foal nurses
What technique is used to correct a cleft soft palate?
How is the palate closed following correction of a cleft soft palate?
3 layer appositional closure
What is the path of the esophagus in horses?
starts dorsal to cricoid cartilage.
stays dorsal to trachea until 4th cervical vertebrae.
crosses to the left of the trachea.
dorsal to the trachea in the thorax
What are the layers of the esophagus in the horse?
muscular layer: striated to the base of the heart, then smooth.
**note: no serosa!!!
What are some potential complications of esophageal surgery in the horse?
What are the most common locations for obstruction in the esophagus?
just anterior to the thoracic inlet
How is the esophagus closed following an esophagotomy?
suture mucosa and submucosa with non-absorbable suture; knots tied in the lumen.
musculature closed with absorbable suture.
subcutaneous tissue and skin closed.
What are some ways to prevent recurrence of esophageal obstruction with food?
stones in the feed bunk makes horse eat slower.
spread feed out in thin layer.
use hay nets.
don't feed ground grain.
What are some potential causes of esophageal strictures?
previous obstructions or perforations.
How are esophageal strictures classified?
based on layers of the wall involved:
mural - adventitia and muscle layers.
rings: only mucosa and submucosa.
annular stenosis: all layers
When is a partial esophageal resection indicated?
esophageal stricture involving only the mucosa and submucosa
What causes esophageal fistula?
secondary to esophageal perforation or surgery
What are indications for cervical esophagostomy?
feeding an animal with esophageal injury or an animal that can't swallow
True/False: most cases of equine colic can be managed medically
true - 90-95% of cases will respond to medical management
What are indicators that a case of horse colic needs to be surgically managed?
CRT >3 sec.
MM: congested or blue.
excessive fluid in stomach.
serosanguineous fluid from abdominocentesis.
distended bowel on rectal palpation
What is the preferred approach for surgical exploration of the equine abdomen?
What landmarks will help determine of there is a volvulus of the large colon?
palpate mesenteric attachment of the right dorsal colon and cecum
What should be done if you open the abdomen of a horse and there is ingesta free in the peritoneal cavity?
euthanasia is the only option - too much contamination
What are predisposing factors to gastric ulcers in horses?
use of NSAIDs
Where are gastric ulcers often found in the horse?
pylorus or anterior duodenum
True/False: gastric neoplasia is often not surgically removed in horses
True - poor surgical accessibility of the equine stomach
What is the definition of a simple small intestine obstruction?
obstruction which does not compromise the blood flow
In the case of small intestine obstruction, where would there be dilation?
anterior to the obstruction
What are some consequences of intestinal dilation?
lactic acid acidosis.
reflux of fluid into the stomach.
Are pedunculated lipomas more common in younger or older horses?
Clinical signs of anterior enteritis are similar to what other condition in the horse?
simple obstruction of the small intestine
What is the most common intussusception in horses?
*intussusceptions more common in foals
What is a volvulus?
twisting of a segment of bowel on its mesentery which obstructs blood flow and passage of intestinal contents
In the case of a volvulus, you may be able to save the bowel if surgery is done within how long?
In horses, what part of the intestine is usually involved in an internal hernia into the epiploic foramen?
jejunum passes into the omental bursa
What vessels border the epiploic foramen?
dorsal: posterior vena cava.
ventral: portal vein
What is Meckel's Diverticulum?
an embryonic anomaly: persistent omphalomesenteric duct
What is a mesodiverticular band?
persistent distal segment of a vitelline artery and associated mesentery
What is the concern with having a mesodiverticular band?
a triangular pocket is formed between the band, mesentery and jejunum which can trap loops of intestine and cause a volvulus
When is the best time to correct an umbilical hernia?
shortly after weaning (4-6mo)
How do umbilical hernias feel on palpation?
the area is firm, painful and becomes edematous
True/False: many umbilical hernias and foals and calves will correct themselves with time
true - if the ring is less than 3cm in diameter, there is a good chance that it will correct itself
What are some methods for correcting an umbilical hernia?
give it time.
apply external pressure.
injection of mild irritant.
How do hernia clamps correct an umbilical hernia?
force intestine back into the abdomen and clamp the hernia sac which will cause an inflammatory reaction and slough the hernia sac
Where are common places for impaction of the large colon in horse?
right dorsal colon
When is it indicated to do surgery in a case of impacted large colon in a horse?
excessive gastric reflux.
unresponsive to medical therapy for several days
What is usually the underlying cause of an impacted cecum?
a motility problem
What are common locations for enteroliths in the colon of a horse?
right dorsal colon.
What part of the horse colon is most likely to become trapped dorsal to the nephrosplenic ligament?
True/False: horses with a nephrosplenic ligament entrapment often do not show pain
While surgically correcting nephrosplenic ligament entrapment, what are some ways to prevent recurrence?
close the nephrosplenic space.
perform a colopexy.
large colon resection
What are the most common places to find torsion of the large colon in the horse?
diaphragmatic and sternal flexures
What is the term for when bowel is twisted around the mesenteric axis?
Volvulus is more common in horses after what event?
after a mare just foaled
True/False: horses with a volvulus rarely show pain
false - extremely painful
How much of the large colon can be removed without causing major problems in the horse?
up to 90%
Rectal prolapse occurs most frequently in what farm species?
What are some predispoing factors for rectal prolapse?
estrogens in the feed - relax anal region.
high protein diets.
antibiotic feedings - irritates anal region.
multiple bull housing
What type of anesthesia is used for correcting a rectal prolapse?
caudal epidural (not in pigs).
lumbosacral epidural (common in pigs)
When is amputation of the rectum indicated?
evagination of the rectum
Rectal rupture is most commonly a problem in what farm species?
What is the most important thing you can do to prevent rectal ruptures in the horse?
when doing a rectal, if the animal strains, allow the hand to be pushed caudally
What are the grades of rectal ruptures?
1 = through mucosa and submucosa.
2 = through muscularis; mucosa intact.
3 = through mucosa and muscularis.
4 = through mucosa, muscularis and serosa
How do you manage a grade 3 rectal rupture?
manual removal of feces.
temporary colostomy to divert feces.
glue rectal sleeve to plastic ring which is sutured in rectum cranial to the tear
How is ultrasound used to diagnose obstruction to milk flow?
use rectal linear probe.
place teat in small plastic container filled with water and put the ultrasound probe on the side of the container
Teat lacerations that are how old will respond well to primary closure?
Which has a worse prognosis: longitudinal or transverse teat lacerations?
transverse - more damage to blood supply
Which has a worse prognosis: proximal or distal teat lacerations?
distal lacerations involving the streak canal...more likely to result in necrosis of the distal teat
At what point is surgical management required for teat laceration?
if the laceration involves the teat lumen
True/False: all teat lesions are considered markedly contaminated
true - will need antibiotics
Is sedation used for teat laceration repair?
yes - may use xylazine, ketamine, butorphanol
What is the preferred position for cattle with teat laceration?
right lateral recumbency with head and feet tied.
*note: depending on which teat is involved, it may be necessary to be in left lateral
What is the appropriate way to milk a cow following repair of teat laceration?
drain milk with a teat tube at milking time.
*if no indication of mastitis, may choose to not milk the affected quarter for 3-5 days.
**hand milking is contraindicated!
What are some potential complications of teat laceration repair?
teat cistern fibrosis.
What commonly occurs when a teat laceration heals by second intention?
a fistula develops but will usually completely heal by 4 months in a non-infected wound
If a fistula develops due to a teat laceration, when should you dissect out the fistulous tract?
after the fistula is completely healed
What is the most common congenital anomaly involving the teats?
When do supernumerary teats pose a problem?
if they are too close to normal teats.
if they produce milk
What should be done with supernumerary teats?
remove when heifer is about 6mo. - use local anesthetic and remove with serrated scissors.
in older animals - remove with emasculatome or surgically excise
How can you tell if a cow has a tight streak canal?
reduced flow of milk
What should be evaluated in a cow if there is reduced flow of milk?
evaluate teat with ultrasound to be sure there is not a flap of mucosa in the rosette of Furstenberg
What is the treatment for a tight streak canal?
cut the sphincter with a Hug knife.
*usually done before morning milking
What is the aftercare for surgical correction of a tight streak canal?
routine morning milking.
forceful hand milking every 1-2 hours until afternoon milking.
introduce melting teat stent of povidone iodine in wax into the streak canal after each milking for 5-6 days
What is the treatment for obstruction in the area of the rosette of Furstenberg?
blind excision through the streak canal.