FORM & FUNCTION (Developmental Anomalies)

Question 1

Defects in neurulation/neural tube:

Answer 1

-anencephaly
-spina bifida

Question 2

Anencephaly:

Answer 2

-parts of the brain and skull is missing

Question 3

Spina bifida:

Answer 3

-improper formation of the spinal cord

Question 4

Anomalies of fetal membranes:

Answer 4

-hydrops
>hydrallantois
>hydramnion

Question 5

Hydrops:

Answer 5

-excessive accumulation of fetal fluids in either amnion or allantois in cattle

Question 6

Hydrallantois:

Answer 6

-present around 6-9 months gestation with up to 40x excess fluid
-clinically present as progressive distension of the right abdominal wall
-thought to be a result of placental abnormalities

Question 7

Hydramnion:

Answer 7

-in cows 8-10x normal fluid level associated with malformation of the digestive system
-rare in sheep, pigs, dogs, cats and not reported in horses

Question 8

Persistent or patent urachus:

Answer 8

-umbilical cord ruptures as fetus passes through the birth canal
-ruptured umbilical arteries retract within the abdomen and elastic fibers in their walls seals their lumina prevent haemorrhage
-urachus closes around the same time
*a failure to close urachus=leakage of urine at umbilicus and provide an opportunity for infection

Question 9

Diaphragmatic hernia:

Answer 9

-when fusion fails, there is a persistent opening between thoracic and abdominal cavities
-when abdominal viscera pass through this opening into the thoracic cavity=congenital diaphragmatic herniation

Question 10

2 types of congenital diaphragmatic hernia:

Answer 10

1. Pleuro-peritoneal herniation
2. Peritoneal-pericardial herniation

Question 11

Pleuro-peritoneal herniation:

Answer 11

-failure of one or both pleuro-peritoneal folds to develop or fuse with mesoesophagus and septum transversum
-usually occurs on left side
-most common in humans
-results in viscera (stomach and intestines) being present in the pleural cavity

Question 12

Peritoneal-pericardial herniation:

Answer 12

-domestic animals, particularly dogs and cats
-result of defect in development of septum transversum leading to improper communication between peritoneal and pericardial cavities
-herniation of viscera (liver, pyloric region of stomach and intestines) into the pericardial cavity

Question 13

Gastroschisis:

Answer 13

-failure of ventral body wall to close in the abdominal region
-can lead to movement of abdominal contents (intestines) outside of the body cavity through a fissure between umbilicus and sternum

Question 14

Congenital umbilical hernias:

Answer 14

-associated with abdominal ventral body wall defect (ex. gastroschisis)
-protrusion of viscera occurs around the umbilicus due to lack of muscular body wall in that region

Question 15

Congenital umbilical hernia in different species:

Answer 15

-found in small animals, pigs and cattle
-one of the most common developmental defects in pigs
-common in calves (especially Holstein Friesian cattle) with frequency of 4-15%

Question 16

Schistosomus reflexus (SR):

Answer 16

-congenital fatal anomaly
-primarily observed during embryonic development in ruminants
-leads to significant dystocia that is less difficult in large ruminants compared to smaller ones

Question 17

SR presentation:

Answer 17

-head, limbs, and tail are in close proximity resembling a distinctive ventral convex curvature (result of acute angulations of spinal column)
-limb fusion/stiffness (ankylosis)
-failure to close all or part of the ventral wall of the feta body resulting in exteriorized viscera

Question 18

SR calf birth:

Answer 18

-unable to pass through birth canal
-must be removed by caesarean section or fetotomy
>leads to recovery of the cow for later breeding