Cranial nerve disorders in sheep and goats

Cranial nerve disorders in sheep and goats are most often caused by infectious diseases, trauma, toxicity, or nutritional problems. The damage can be to a single nerve or to multiple nerves together.

1. Infectious diseases that cause damage to the cranial nerves

A. Listeriosis (Listeria monocytogenes) – most common

•   Infection of the brainstem → damage to nerves III–XII.

•   Typical signs:

•   Head tilt (torticollis)

•  Facial paralysis (nerve VII) – drooping ear, open eye

•  Increased salivation (nerve V / VII)

•  Inability to chew properly

•   Ataxia, walking in circles

B. Other bacteria

•   Pasteurella, Histophilus, Trueperella — may cause meningitis/encephalitis → nerve damage.

•   Signs: depression, fever, unresponsiveness, vision/hearing damage.

C. Viruses

•  CAE virus in goats (rarely causes cranial nerve palsy, more likely myelitis, but possible).

•  PPR virus in endemic areas – may damage the nervous system.

2. Toxicity

A. Lead poisoning

•   Optical nerve damage (II) → sudden blindness

•   Spasms, depression, head pressure on the wall

B. Neurotoxic plants

   •  Heliotropium, Lupinus – may affect nerve and muscle function.

3. Trauma

•   Skull injuries → fractures in the area of ​​the base of the skull.

•   Facial nerve (VII) injury – inability to blink, drooping ear.

•   Trigeminal nerve (V) injury – difficulty chewing.

4. Nutritional deficiencies

A. Vitamin B1 (thiamine) deficiency – PEM

•   Most often causes cortical blindness, but can also involve CN II, III, IV.

•   Signs: “kicking” eyes, twitching, temporary blindness.

B. Mineral deficiencies (e.g. copper)

•   May cause general neurological impairments, sometimes including CN.

Common Nerves Affected

CN II (Optical Nerve)

– Blindness, unresponsive pupils

— Mainly listeriosis, lead, PEM

CN V (Trigeminal Nerve)

– Difficulty chewing, facial numbness

— Listeria, trauma

CN VII (Facial Nerve)

– Eyelid/ear droop, drooling

— Listeria, trauma, otitis media

CN VIII (Balance and Hearing)

– Head tilt, rotation, ataxia

— Listeria, otitis media

CN IX–X (Swallowing/Voice)

– Difficulty swallowing, drooling, abnormal breathing sounds

— Listeria, tetanus (less common in goats)

Diagnosis

Neurological examination to target the affected nerve

Blood count + culture

Cerebrospinal fluid aspiration

Imaging (X-ray/CT in case of trauma)

General treatment

Depends on the cause:

•  Listeriosis: Mainstay of treatment – ​​high dose penicillin/ampicillin + anti-inflammatories.

•  Meningitis: Broad spectrum antibiotics.

•  Lead: Chelation therapy (Ca-EDTA).

•  Trauma: Steroids/NSAIDs and support.

•  PEM (B1): Immediate thiamine injection.

*It is always advisable to consult a qualified veterinarian.