Food Animal Congenital Abnormalities

What is arthrogryposis?

Congenital ankylosis or contracture of the limbs.

What other congenital abnormalities may accompany arthrogryposis?

-Cleft palate

-Scoliosis

-Kyphosis

What is the inheritance pattern of arthrogryposis in Charolais cattle?

Autosomal recessive

What toxins or plants are associated with bovine arthrogryposis?

-Lupines

-Hemlock

-Tree tobacco

What is the important gestational exposure period for lupine-induced arthrogryposis?

40-70 days of gestation

What viral infections are listed as causes of arthrogryposis?

Akabane virus and bluetongue virus

T/F: Arthrogryposis is always a genetic condition.

False

1 multiple choice option

What is another name for arthrogryposis multiplex?

Curly calf syndrome

What breed is associated with arthrogryposis multiplex?

Angus

What is the inheritance pattern of arthrogryposis multiplex?

Lethal autosomal recessive

What are characteristic findings of arthrogryposis multiplex?

-Small-for-gestational-age calves

-Markedly decreased muscle mass

-Arthrogryposis

-Scoliosis

-Torticollis

T/F: Calves with curly calf syndrome typically have marked muscular hypertrophy.

False

1 multiple choice option

An Angus calf is born small for gestational age with severe limb contractures, scoliosis, torticollis, and markedly decreased muscle mass. What is the most likely diagnosis?

Arthrogryposis multiplex (curly calf syndrome)

What is bovine arachnomelia syndrome?

An inherited skeletal disorder producing severe skeletal abnormalities and a characteristic "spidery" appearance of the limbs.

What is the inheritance pattern of bovine arachnomelia syndrome?

Monogenic autosomal recessive

Which breeds are associated with bovine arachnomelia syndrome?

Brown Swiss and Fleckvieh/Simmental cattle

What is the term for the abnormally long, slender limbs in bovine arachnomelia?

Dolichostenomelia

What skeletal abnormalities are characteristic of bovine arachnomelia?

-Spidery limbs

-Marked thinning of the diaphyses

-Abnormally shaped skull

T/F: Calves affected with bovine arachnomelia are commonly stillborn.

True

1 multiple choice option

A stillborn Brown Swiss calf has extremely long, thin limbs, markedly thin long-bone diaphyses, and an abnormal skull. What is the most likely diagnosis?

Bovine arachnomelia syndrome

What type of disorder is bovine citrullinemia?

An autosomal recessive inherited disorder of the urea cycle.

Which breed is associated with bovine citrullinemia?

Holstein

What enzyme is nonfunctional in bovine citrullinemia?

Argininosuccinate synthetase (ASS1)

What metabolic process is impaired in bovine citrullinemia?

Normal conversion of ammonia to urea

What substances rapidly accumulate in bovine citrullinemia?

Ammonia and citrulline

T/F: Calves with bovine citrullinemia are abnormal at birth.

False

1 multiple choice option

What signs develop within approximately 24 hours in calves affected by bovine citrullinemia?

-Depression

-Aimless wandering

-Head pressing

-Apparent blindness

-Teeth grinding

What signs of bovine citrullinemia typically develop by 4-5 days?

-Proprioceptive deficits

-Ataxia

-Recumbency

-Convulsions

-Collapse

-Death

What CNS lesion may occur with bovine citrullinemia?

Mild-to-moderate diffuse astroglial swelling in the cerebrocortical gray matter.

What hepatic lesion may occur with bovine citrullinemia?

Mild-to-severe hepatocellular hydropic degeneration.

A Holstein calf is normal at birth but within 24 hours develops head pressing, apparent blindness, wandering, and bruxism. Several days later it becomes ataxic, recumbent, and convulses. What inherited disorder should be suspected?

Bovine citrullinemia

T/F: Citrullinemia primarily produces neurologic disease because ammonia cannot be normally converted to urea.

True

1 multiple choice option

What type of skeletal developmental abnormality commonly underlies inherited bovine dwarfism?

Chondrodysplasia.

What is Dexter bulldog dwarfism?

A homozygous lethal/autosomal recessive form of severe disproportionate dwarfism in Dexter cattle.

When are fetuses with Dexter bulldog dwarfism generally aborted?

Around 7 months of gestation.

What gene is associated with Dexter bulldog dwarfism?

The ACAN (aggrecan) gene

What physical abnormalities occur with Dexter bulldog dwarfism?

-Extreme disproportionate dwarfism

-Short vertebral column

-Severe micromelia

-Large abdominal hernia

-Relatively large head

-Retruded muzzle

-Cleft palate

-Protruding tongue

Why can the Dexter dwarfism mutation create a breeding problem?

The short-legged phenotype is desired by some breeders, despite the homozygous state being lethal.

T/F: Dexter bulldog dwarfism is characterized by proportionate dwarfism in otherwise normal calves.

False

1 multiple choice option

What is the inheritance pattern of dwarfism described in Aberdeen Angus cattle?

Autosomal recessive

What gene is affected with dwarfism in Aberdeen Angus?

PRKF2

How do Aberdeen Angus calves affected by dwarfism initially appear?

Normal at birth

What happens to Angus calves affected by dwarfism over their first few months of life?

They fail to grow and develop abnormally short legs with thick bodies.

What skeletal process is diminished in Angus dwarfism?

Endochondral ossification

An Angus calf appears normal at birth but several months later has failed to grow and develops short legs and a thick body. What disorder should be considered?

Inherited dwarfism of Aberdeen Angus

Which breed is associated with brachyspina syndrome?

Holstein

T/F: Brachyspina syndrome is considered lethal.

True

1 multiple choice option

What reproductive finding is common with brachyspina syndrome?

A stillborn calf following a slightly prolonged gestation.

What happens to the vertebral segments in brachyspina syndrome?

They show disorganization and irregular ossification separated by cores of cartilage, making individual vertebrae difficult to identify.

What two internal-organ abnormalities are commonly associated with brachyspina syndrome?

Renal dysplasia and intestinal atresia

What abnormalities may inconsistently occur with brachyspina syndrome?

Brachygnathism and caudal dislocation/compression of the brain.

What is complex vertebral malformation (CVM)?

An autosomal recessive lethal disorder causing severe axial skeletal and other congenital abnormalities.

Which breed is primarily affected by complex vertebral malformation?

Holstein

What famous Holstein lineage is associated with CVM?

Carlin-M Ivanhoe Bell

What reproductive outcomes occur with CVM?

Embryonic death, abortion, and perinatal death.

What skeletal abnormalities occur with CVM?

-Hemi- or misshapen vertebrae

-Ankylosis especially of the cervicothoracic vertebrae

-Scoliosis

-Symmetric arthrogryposis of the lower limbs

What nonskeletal abnormalities may occur with CVM?

Craniofacial dysmorphism and cardiac anomalies.

A Holstein herd experiences embryonic losses, abortions, and perinatal deaths. Affected calves have abnormal cervicothoracic vertebrae, scoliosis, symmetric lower-limb arthrogryposis, and cardiac defects. What is the diagnosis?

Complex vertebral malformation

What is another name for fawn calf syndrome?

Congenital contractual arachnodactyly

Which breed is associated with fawn calf syndrome?

Angus

What is the inheritance pattern of fawn calf syndrome?

Nonlethal autosomal recessive

What underlying tissue abnormality occurs in fawn calf syndrome?

Reduced elasticity of the connective tissue of muscles.

What limb abnormalities characterize fawn calf syndrome?

-Elongated limbs

-Proximal limb contracture

-Distal limb hyperextension/hyperlaxity

What spinal abnormality may accompany fawn calf syndrome?

Congenital kyphosis

What happens to many of the musculoskeletal abnormalities associated with fawn calf syndrome as the calf grows?

They improve significantly with age

What do adult cattle affected with fawn calf syndrome tend to look like?

Tall and skinny, with persistently poor muscle development.

T/F: Fawn calf syndrome is generally lethal shortly after birth.

False

1 multiple choice option

An Angus calf has normal birth weight and is able to stand and nurse but has elongated limbs, proximal joint contractures, distal hyperextension, and kyphosis. The abnormalities gradually improve with age. What is the diagnosis?

Fawn calf syndrome/congenital contractual arachnodactyly

Which breed is associated with crooked tail syndrome?

Belgian Blue

What gene is associated with crooked tail syndrome?

MRC2

What are the major clinical characteristics of crooked tail syndrome?

-Tail deviation

-Growth retardation beginning around 1 month of age

-Shortened/broad head

-Extreme muscular hypertrophy

A Belgian Blue calf develops growth retardation by one month of age, has a deviated tail, a short broad skull, and marked muscular hypertrophy. What syndrome is most likely?

Crooked tail syndrome

What does DUMPS stand for?

Deficiency of Uridine Monophosphate Synthase

What breed is associated with DUMPS?

Holstein

What is the inheritance pattern of DUMPS?

Lethal autosomal recessive

What is the major reproductive consequence of DUMPS?

Early embryonic mortality during implantation

What additional fetal outcome may occur with DUMPS?

Fetal mummification

T/F: DUMPS typically results in live calves with severe neurologic disease.

False

1 multiple choice option

Which breed is associated with developmental duplication?

Angus

What is the inheritance pattern of developmental duplication?

Autosomal recessive

What structure is most commonly duplicated with developmental duplication?

A forelimb

From where may a duplicated structure originate with developmental duplication?

The neck or back

What obstetric complication can developmental duplication cause?

Dystocia

Which breed is associated with inherited congenital myoclonus?

Hereford

What is another name given for inherited congenital myoclonus?

Idiopathic epilepsy

What is the inheritance pattern of inherited congenital myoclonus?

Autosomal recessive and incompatible with life.

What is the hallmark manifestation of inherited congenital myoclonus?

Spontaneous and stimulus-responsive myoclonic spasms present prenatally that prevent affected calves from rising at birth.

What environmental stressors may trigger seizures in congenital myoclonus?

Heat, cold, and weaning

What neurotransmitter system is implicated in bovine inherited congenital myoclonus?

A severe disturbance in glycine-mediated neurotransmission in the spinal cord.

A Hereford calf cannot rise because of severe stimulus-responsive myoclonic spasms. Between episodes, the calf appears phenotypically normal. What inherited condition is most likely?

Inherited congenital myoclonus

What breed is associated with the microdeletion in the maternally imprinted Peg3 domain described in the presentation?

Finnish Ayrshire

Microdeletion in the maternally imprinted Peg3 domain leads to lack of expression of what paternal gene?

MIMT1

What reproductive outcomes occur with a Peg3-domain defect?

Late-term abortion and stillbirth.

What is the characteristic of a fetus with a microdeletion in the maternally imprinted Peg3 domain?

Half the normal average birth weight for the breed with non-inflated lungs.

Which breed is associated with limber leg?

Jersey

What is the inheritance pattern of limber leg?

Simple lethal autosomal recessive.

Why are calves with limber leg unable to stand?

Their ligaments, muscles, tendons, and joints are incompletely formed.

What striking joint finding can occur with limber leg?

The shoulders and hips can rotate in essentially any direction without discomfort.

T/F: Limber-leg calves are always obviously malformed at birth.

False

1 multiple choice option

What is perosomus elumbis?

A congenital anomaly characterized by partial or complete agenesis of the lumbar, sacral, and coccygeal regions.