Livestock dermatology

Question 1

What are common dermatological problems in cattle + sheep?

Answer 1

• Infectious
  – Parasitic
  – Bacterial
  – Fungal
  – Viral
• Neoplastic
• Nutritional
• Toxic
• Physical
• Congenital

Question 2

What is general approach to skin condition in livestock?

Answer 2

• Signalment + history =
  – Incidence & onset
  – Location (soil type etc.)
  – Animal(s) affected
• Full clinical examination =
  – BCS
  – TPR
  – Rumination
  – Lameness etc.
  – Skin lesions & lymph nodes - Visual and manual assessment (wear gloves!), Distribution & description (depth & tissues affected)
• Diagnosis =
  – Differentials
  – Sample collection
  – Response to treatment
• Dermatological signs may be manifestation of systemic disease
  – May be sign of underlying issue (nutritional deficiency, immunosuppression etc.)
• E.g. poor coat condition

Question 3

What are physical skin conditions? What do they indicate?

Answer 3

• Rub mark injuries =
  -indictive of environment / housing issues

Question 4

What housing issues can cause skin damage?

Answer 4

• Cubicle design and bedding = Hock, stifle, pelvic, spinal and neck lesions
• Feed barrier = Neck rubbing- reduced DMI?
• Cleanliness = General management, routines, building design, SARA

Question 5

What are ectoparasites that affect livestock indoor/outdoor?

Answer 5

• Indoors = lice + mites
• Outdoor = flies + ticks

Question 6

What are the lice in cattle? Where do they effect?

Answer 6

• Sucking = Linognathus vituli + Haematopinus eurysternus - can cause anaemia in calves
• Chewing = Bovicola bovis
• Mainly seen on back + neck = hairloss

Question 7

What are the mites that affect livestock? What is seen?

Answer 7

• Chorioptes bovis - hairloss of Legs, feet, tail base, caudal surface of udder
• Sarcoptes scabei - hairloss of neck + face
• Psoroptes bovis - hairloss of Legs, feet, tail base, caudal surface of udder

Question 8

How are mites diagnosed?

Answer 8

• Skin scrapes - edge of lesions
• examine under low power (x100) - liquid paraffin

Question 9

How are ectoparasites treated?

Answer 9

• Pediculosis & mange = Check underlying health status, management & husbandry
  – Mild infestations may not warrant treatment.
  – Often self limiting/ winter housing specific
  – Check your diagnosis (especially if psoroptic mange suspected)
  – Treatments informed by clinical assessment
• Psoroptic mange = injectable MLs
• Chorioptic mange = Pour on MLs
• Sarcoptic mange = injectalble or pour on MLs
• Louse =
• chewing = pour-on MLs
• sucking = injectable MLs

Question 10

What is ringworm of calves? Dx? Tx?

Answer 10

• Trichophyton verrucosum
• Dx = clinical signs, history, Culture + microscopy (hairpluck at edge of lesion)
• Tx = Clean + disinfect housing, UV light + spontaneous resolution

Question 11

What causes pustular impetigo?

Answer 11

• Staphylococcal infections
• wounds
• udder + perineum
• poorly applied ear tags

Question 12

What causes abscesses + cellulitis? Tx?

Answer 12

• Actinobacili (Trueperella pyogenes) = oral cavity entry
• lower jaw + popliteal LNs
• Penetrating injuries (dirty needles)
• Non-resolved / infected hygromas + haematomas
• Tx = Open + drain, parenteral Ab (Gram +ve anaerobes)

Question 13

What causes lumpy jaw + wooden tongue?

Answer 13

• Lumpy jaw = Actinomyces bovis
• Wooden tongus = Actinobacillus lignieresii

Question 14

What causes Streptothricosis (rain scald)? Tx?

Answer 14

• Dermatophilus congolensis
• wet weather
• Tx = topical disinfectant, oxytet / penicillin + move to dry environment

Question 15

What causes warts? Tx?

Answer 15

• Bovine viral papillomatosis
• possibly spread by flies
• Can persist in immunocompromised animals
• Usually self-limiting
• Surgical removal sometimes needed (penile / teat warts)

Question 16

What are other viral skin lesions?

Answer 16

• Stomatitis/ mamillitis & vesicular diseases
  – Generally self limiting
  – Mild to painful
• Bovine papular stomatitis (muzzle and lips)
• Bovine herpes mamillitis (teats & udder)

– May indicate systemic disease =
* Ulceration of mouth and nose =
1. Mucosal disease = PI with cytopathic BVDv
2. Malignant Catharral fever (MCF), IBR etc.

– FMD?
* Pyrexia (>40oC), depression, lameness
* Vesicles on muzzle, tongue, nostrils udder & feet

Question 17

What causes poor growth rates + brown tinged coat w spectacles?

Answer 17

• Copper deficiency
• Molybdenum toxicity

Question 18

What causes photosensitisation? What is seen? Tx?

Answer 18

• Primary caused by photodynamic agents in diet = St John’s Wort
• Secondary (hepatogenous) = liver damage + accumulation of phylloerythrin - ragwort
• CS = unpigmented skin affected = sloughing + serous ooze, secondary bacterial infections
• Tx = Symptomatic, house animals away from sunlight

Question 19

What are physical causes of skin damage in sheep?

Answer 19

• Rubbing – Due to pruritis/irritation
• Wool break – Nutritional/condition/stress, Systemic disease
• Trapping (eg. fence wire)/ fleece grabbing
• Dog attacks – Consider underlying structures (eg. joints, abdomen etc.)

Question 20

What is Prevention / Tx of scab in sheep?

Answer 20

• Px = Good biosecurity (fences), Adequate quarantine measures
• Tx = Whole flock, OP dip, Injectable MLs, Avoid previous housing + pastures

Question 21

What are Ddx for scab? what does this indicate?

Answer 21

• Bovicola ovis
• heavy infestation indicates underlying flock health issue =
• investigate health + nutrition + reduce stocking density
• SHEAR / Dip

Question 22

What is seen with Orf? Tx?

Answer 22

*Affects mouth, feet + teats - hungry lambs, mastitic ewes
* Self limiting - 1-4wks
* Tx = antibiotics for 2ary infections, Scabivax - only if present on farm

Question 23

What are other skin diseases in sheep?

Answer 23

• Ringworm = lambs, face
• Photosensitisation = non-pigmented skin
• CLA = Corynebacterium pseudotuberculosis - CULL
• Scrapie = Notifiable - intense pruritis + wool break + neuro signs

Question 24

When are biting / nuisance flies + ticks seen? What is their primary pathology + What diseases can they be a vector for?

Answer 24

• Summer months
• Primary pathology =
• Blood feeding species
• Secondary infections
• Myiasis
• Disease vectors =
• New Forest disease, BVDv, Summer mastitis
• Tick borne disease - babesiosis, Q-fever
• Bluetongue + schmallenberg

Question 25

What can be done for fly control?

Answer 25

• Regular inspection
• Risk forecasting (NADIS blowfly alert)
• Identify risk areas
  – Outdoors- trees & shaded pastures
  – Indoors- Good hygiene (e.g. muck out)
• Routine topical treatments (SPs, IGRs, 3-MLs)
• Insecticide-impregnated ear tags, tail bands etc.
• Environmental controls

Question 26

What are external threats outside the UK?

Answer 26

• Aujesky’s disease (“pseudorabies”) = notifiable
  – Contagious viral disease, Extreme pruritis & self-injury
• Besnoitiosis
  – Besnoitia besnoiti (apicomplexan parasite)
  – Present in France, Italy, Spain & Portugal
  – Cattle are intermediate hosts
  – Mechanical transmission = Flies & needles
  – Clinical disease = 1-3 weeks acute to chronic progression
• Pyrexia, fever-like symptoms and wasting
• Various dermal lesions with lymphadenitis and cyst formation
• Lumpy skin disease = notifiable
  – Transmission = Biting flies, ticks, needles, Cattle movement
  – Skin nodules, emaciation, lymphadenitis, nasal discharge, mastitis & fever (10-14 days)
  – Control with biosecurity (national & local) & vaccination