Sheep

Question 1

Outline the clinical signs + gross pathology of abortion by Chlamydia (Chlamydophila) abortus in sheep.
(sep 2016)

Answer 1

• abortion often no premonitory signs, may get RFM
• PM (Gross) – placenta acutely inflamed, intercotyledonary allantochorion oedematous, thickened and leathery. Degeneration and necrosis of foetal cotyledons and thick yellow deposits on chorion

Question 2

Outline the treatment + control of abortion by Chlamydia (Chlamydophila) abortus in sheep.

(sep 2016)

Answer 2

• Antibiotics – reduce (but not eliminate) abortions. As soon after 95-100 days gestation repeat every 10-14 days.
• Vaccination – Inactive vaccine preparation available for use during outbreak
• Isolate aborting ewes until discharges dried up
• Disposed of infected bedding and clean and disinfect
• Discourage foster lambs and do not use lambs as replacements
• Vaccination – based on risk High risk (yearly or biannually), low risk (ewes vaccinated just once)
• Biosecurity – keep closed flock
• EAE monitoring / accreditation can be undertaken.

Question 3

Definitive diagnosis of abortion by Chlamydia (Chlamydophila) abortus in sheep.
(sep 2016)

Answer 3

Laboratory – Smears from placenta and foetal skin stained with modified ZN stain reveal intracellular inclusion bodies acid fast cocci

Serology – antibody in foetal fluid or precolostral lamb FAT or CF. Paired serology at abortion and 3-4 weeks later (rising titre)

Question 4

Action for severe hypothermia (<37oC) in lambs

sep 2016

Answer 4

> 5hr old (feed, dry, heat, feed)

• if can’t lift head/swallow, glucose
• if can, stomach tube
• then dry lamb and place in heat box, before next stomach tube

<5hr old (dry, heat, feed)
- dry lamb, then warm in heat box, then stomach tube

If vigorous suck after stomach tube, return to ewe

Question 5

Action for mild hypothermia (37-39oC) in lambs

sep 2016

Answer 5

dry and feed (no heat)
stomach tube (no glucose)

If vigorous suck after stomach tube, return to ewe

Question 6

Aetiologies of polyarthritis in 10-14d.o. lambs

sep 2016

Answer 6

Usually bacterial infection most likely Erysipelothrix rhusiopathiae.
(Others Histophilus spp. e.g. H.ovis, E. coli, Strep dysgalactiae, Strep spp, Staph, also Chlamydia, Mycoplasma!)

Question 7

Causes of polyarthritis in 10-14d.o. lambs (NOT aetiology, but how are lambs infected?)
(sep 2016)

Answer 7

Bacteria enter through broken and softened skin

Likely to become infected soon after birth, via the umbilical cord

Also at tail docking, castration or marking and ear notching.

Erysipelothrix – ubiquitous survives in soil, faeces and water, also found in the tonsils and pharynx of ewe

Question 8

Sheep, 11 clostridial diseases

sep 2016

Answer 8

C. perfringens

1. Type A = enterotoxaemia, gas gangrene, sudden death
2. Type B = LAMB DYSENTRY, enterotoxaemia
3. Type C = STRUCK, enterotoxaemia
4. Type D = pulpy kidney, enterotoxaemia
5. C. tetani
6. C. botulinum
7. C. chauvoei = BLACK LEG/quarter
8. C.novyi type B = BLACK DZ, infectious necrotic hepatitis
9. C. sordelli = sudden death
10. C. septicum = MALIGNANT OEDEMA/BRAXY
11. C.haemolyticum = RED WATER DZ

Question 9

Sheep, clostridial disease vaccination protocol

sep 2016

Answer 9

Ewe, 2-6wk pre-lambing

Maternal Ig lasts 12 wk protection

Can vaccinate lambs from 2w.o. (6-8wm usually) (2 injections, 4-6wk apart)

YEARLY BOOSTER

Question 10

You are approached by a client who wishes to establish a flock of pedigree Texel sheep. What advice would you give regarding biosecurity in purchasing and running such a flock? 8 points
(sep 2016)

Answer 10

1. Purchase sheep from known sources and health history and status to reduce risk of infection. Never bring in sheep without knowing their vaccination history
2. Limit purchases to ewe lambs and gimmers not older sheep
3. Quarantine all new arrivals for at least 30 days and preferable until after lambing. Opportunity to detect disease in sheep.
4. Isolation of sheep prevents contact between groups of sheep after arrival on farm.
5. Gives time for appropriate treatments Vaccination, hoof trimming, footbaths, SCOPS worming strategy
6. Movement control includes vehicles, animals and people traffic.
7. Cleaning and disinfection of vehicles and people entering the farm.
8. Biocontainment: aim to prevent/reduce movement of infectious disease on the farm

Question 11

Diseases widely present in national sheep flock

sep 2016

Answer 11

1. Parasites (PGE, fluke, ectoparasites)
2. Contagious causes of abortion (EAE, Salmonella Abortisovis, Campylobacter fetus subsp. fetus (intestinalis) C. jejuni)
3. Foot problems (footrot, contagious ovine digital dermatitis)
4. Respiratory tract (Sheep pulmonary adenomatosis,
5. Other: caseous lymphadenitis, Scrapie, Maedi-visna, Johnes disease, orf, infectious keratoconjunctivitis

Question 12

If giving Footvax vaccine to sheep, to treat for , which drug can never be given again in this animals lifetime?

Answer 12

1% cydectin, or 1% MOXIDECTIN

2% moxidectin or oral drench are fine!

Question 13

5 Preventions of mastitis in dry period

sep 2016

Answer 13

• Dry Off: Abrupt cessation of milking,
• DCT – Aim to prevent new and cure existing mastitis infections. Antibiotic or teat sealant. Parenteral antibiotics may be used (useful Staph aureus mastitis) Choice based on SCC and clinical mastitis records
• Ensure diet is optimal so immune system is not compromised (Vitamin E/Se)
• Environmental cleanliness 60% of clinical mastitis in first 100 days after calving are due to infections picked up during the dry period.
• External teat sealents,

Question 14

Drying off/dry period summary for feeding cows

sep 2016

Answer 14

3 stages

1. Involution
2. steady state
3. colostrogenesis

6-8wk total
Ideally 2.5-3.5 BCS

Split into 2 blocks of 3 weeks (early and late)

Early

• reduce nutritional density of diet (hay/straw ideal)
• avoid getting too fat! (risk fatty liver –> ketosis –> reduced intake early lactation, dystocia)
• low Ca, high Mg and Ph
• selenium and biotin

Late (CRITICAL PERIOD)

• increase in energy and protein demand with foetus, but reduced DMI!
• increase energy density of food
• may need DUP source for high yielders (protein that survives rumen!)

NO WEIGHT LOSS, can gain up to 0.5BCS

Question 15

3 reasons why nutrition is important during dry period in cows to prevent reproductive dz?
(sep 2016)

Answer 15

1. avoid -ve energy balance
2. poor nutrition can cause uterine disease (ca2+, mg, ph)
3. avoid getting too fat, dystocia risk

Question 16

3 ways prevention of lameness with nutrition in dry period in cows
(sep 2016)

Answer 16

• Nutrition to avoid toxaemias (metritis or mastitis) in early lactation associated with coriosis (laminitis)
• Foot trimming at dry off
• Nutrition: Biotin???

Question 17

Impact of BVD on a cattle herd depends on…

may 2016

Answer 17

• the BVD status of the herd (if BVD is endemic there may be little consequence if infection introduced. If naïve then consequences could be grave)
• timing (if introduced in seasonally calving herd at critical time in stage of gestation, production of many PIs. Otherwise could be just sporadic)

Question 18

BVD infection in cattle, clinical consequences in calves, adults, breeding animals and PIs (may 2016)

Answer 18

Calves: BVD immunosuppressive, usually increases severity of other infections such as scours and pneumonia. Type 2 cause of high mortality disease signs such as thrombocytopaenia

Adults: Causes a mild self resolving diarrhoea, often unnoticed by the farmer, may have milk drop and transient pyrexia

Breeding animals: Cause of infertility by early embryo death. Abortion. Depending on timing of infection production of PI calves (which can subsequently be poor doers), congenital abnormalities (cataracts, retinal problems, cerebellar hypoplasia), or normal calves.

PI animals will eventually succumb to mucosal disease

Question 19

Diagnosis for BVD in cattle (may 2016)

Answer 19

Bulk milk serology can give an indication of the extent of the problem
PCR on bulk milk will detect if there are PIs or recently infected cows in the milking herd Serology of individuals will only show exposure to virus, or if young calves, maternally derived antibody.
PI will be antibody negative
PCR for BVD antigen will show presence of virus, could be acute infection or PI animal Ear notching of claves at ear tagging is available to detect PIs.

Question 20

Control of BVD in cattle (may 2016)

Answer 20

Key to control is identification and removal of PI animals
Good vaccination is available
Biosecurity is important especially in naïve herds to prevent reintroduction
Monitor by blood sampling or bulk milk serology. Use of groups of cohorts (sentinels) such as first lactation cows can be useful for checking dynamics of infection.

Question 21

A farmer with a flock of 500 mule ewes lambing in April requests assistance because he is experiencing a high perinatal lamb mortality. What are the possible causes of this problem (10 marks)? (may 2016)

Answer 21

• Conditions Physical abnormalities, scouring, trace elements (Se, I and Cu), watery
mouth
• Problems with ewes (mastitis metritis, listeria)
• Managemental: Trauma: Dystocia, housing handling, Colostrum intake: Quality,
topping up hungry lambs
• Environmental outside (weather/exposure), Cleanliness indoors
• Infectious causes: Clostridial diseases, Schmallenburg, Border diseases, weak lmabs
due to abortive agents
• Hypothermia/starvation – check ewes body condition score - ?? producing enough
milk

Question 22

A farmer with a flock of 500 mule ewes lambing in April requests assistance because he is experiencing a high perinatal lamb mortality. Describe your approach to the diagnosis of the problem indicating any diagnostic tests you would carry out (10 marks). (may 2016)

Answer 22

Useful to sub-divide into Still births, dead within 48 hours,
• PM examination of dead lambs particularly useful:-
o General external exam for physical abnormalities, e.g cleft palate, atresia ani, hairy shaker, microphthalmia, skeletal defects, signs of predation, status of birth coat, hooves examined to see if lamb has walked
o Internal examination to check lungs for aeration (lamb viability from birth) ?float in water if unsure. Check for organ autolysis - tissue degradation may indicate uterine death. Lamb death from dystocia may show haemorrhage, liver rupture, localised subcutaneous oedema (esp. Distal extremities), rib fractures.
o Lamb starvation/Exposure may present as changes in pericardial/perirenal brown fat. No milk clots in stomach, no evidence of milk absorption in GI tract (in lacteals).
o Presence of meconium, presence may indicate abnormal intestine function. o Other causes detected include infections (check navel, umbilical arteries) o Other congential abnormalities,
o Iodine deficiency diagnosed by checking and weighing thyroid
• Check nutrition of ewes, milk production,

Question 23

A farmer with a flock of 500 mule ewes lambing in April requests assistance because he is experiencing a high perinatal lamb mortality. Draw up an action plan to reduce or prevent further losses (10 marks). (may 2016)

Answer 23

Reduce risk of abortion, still birth, weak lambs, Vaccinate EAE/Toxo
• Assistance of lambing, hygiene lamb survival
• Birth weight, lambing problems, mis-mothering, colostrums intake at least 50ml/kg in
first 6 hours
• Weather: Turn out, avoid exposure and starvation,
• Protocols for treating lambs: Feeding and glucose injections

Question 24

5 measures of failure of passive transfer (FPT)? (may 2016)

Answer 24

• ZST
• Total protein
• Sodium sulphite turbidity
• ELISA
• GGT

Question 25

Ideal colostrum management for calves (may 2016)

Answer 25

• Test colostrum for IgG content (Brix refractometer, hygrometer) only feed good quality) • 2-3 litres clean and fed by stomach tube • Repeated • Needs to be fed within 6 hours or at least 24 hours

Question 26

Indications for digit amputation in cow (may 2016)

Answer 26

* Deep digital sepsis where more conservative approaches have failed * If both claws affected likely to be hopeless prognosis

Question 27

3 anaesthesia options for digit amputation cattle (may 2016)

Answer 27

• GA possible (would not be first choice) • IVRA o Turniquet, 20-30ml i/v Local anaesthetic (Procaine licenced) o 10 minutes before onset, 1 hour maximum, 30 minutes minimum time left on • Nerve block and local infiltration also described

Question 28

Describe digit amputation surgery cattle (may 2016)

Answer 28

* Usual method is by wire * Ideally incision made first as a guide for the wire * Distal portion of P1 removed, or through P2 * If deep infection then tendon sheath may be split for drainage * Disarticulation of P1 / P2 joint described

Question 29

After care and further use prognosis for cow post-digit amputation (may 2016)

Answer 29

After care: • Bandage placed on, necessary to prevent bleeding • Replace bandage after 4-7 days • Bandage wound for 10-14 days • Antibiotics and NSAIDs Future use: • Salvage procedure may get 18 months out of cow (at least until end of lactations0 • Problems if has lesion on the remaining claw

Question 30

Herpes viruses in cattle and their diseases (may 2016)

Answer 30

BHV-1 - Infectious bovine rhinotracheitis (IBR) = Respiratory: Pneumonia, conjunctivitis - Infectious pustular vulvovaginitis (IPVV) = Reproductive: Infertility, abortion, venereal spread lesions - Infectious pustular balanoposthitis (IPBP) - Also Neurological signs associated with BHV-1 (formally designated BHV-5)  BHV-2 Bovine herpes mammilitis = Severe erosive lesions on teat skin OHV-2 Malignant catarrhal fever (formally BHV-3) = Severe system illness and daeth BHV-4 Metritis (cases of mastitis also reported)  BHV-5 = See BHV-1 BHV-6 Bovine leukotrophic virus = Has been associated with metritis Allerton virus causes pseudo-lumpy skin disease Not found in UK 

Question 31

Explain the development and diagnosis of freemartinism in cattle (may 2016)

Answer 31

• Vascular anatomoses of adjacent chorioallantoic sac of heterozygous foetus in multiple pregnancies (bull and heifer twinning) • Fusion of placental blood vessels transfer of hormones o Mullerian inhibition substance o Testosterone • Affects females development spectrum from absence of female tract to almost normal Diagnosis • Abnormal internal and external genitalia (masculinisation) • Suspected in male/female twins (11/12 affected) • Prominent clitoris with tufts of hair • Short vagina in in calves 4cm cf 12-14cm in normal • Rectal exam in older animal reveals absence of tract • Male appearance when older • Blood sample reveals XX/XY cell population in white blood cells (due to transfer of heamopoetic cells) • Bulls (of twin) may also have reduced fertility

Question 32

Risk factors for hypomagnesaemia cattle (may 2016)

Answer 32

``` Risk factors: • Lush green grass • Starvation • Reduced voluntary intakes • Stress o Climate o Handling o Milk yield o Parturition Spring: Increased gut motility, decreased Dry matter intake (Autumn: Inadequate nutrition, changeable weather) ```

Question 33

Clinical signs and treatment for hypomagnesaemia in cattle (may 2016)

Answer 33

Signs: Acute: Hyperaesthesia, alert posture, muscle tremors, staggering gait, animal falls, paddling leg movements, opisthotonus, diarrhoea, urination, nystagmus, foaming at the mouth, pricked ears, retracted eyelids, exaggerated blink reflex, decreased heart rate, loud heart sounds Treatment: MgSO4 s/c (Not i/v will kill) Can give CM40 or 100ml MgSO4 mixed with 400ml Ca2+ Sedatives: Xylazine, or pentabarbitone (Caution off licence)

Question 34

Briefly describe the clinical signs, diagnosis and control of Ovine Pulmonary Adenocarcinoma (adenamatosis) Jaagsiekte. (may 2016)

Answer 34

Clinical signs: Early – rapid shallow respiration – occasional coughing especially if animal forced to move Later – RR increased dyspnoea, breathing noisy, head held low and loss of condition Diagnosis: If hind limbs raised (wheelbarrow) 125-500ml watery discharge pours from nostril PM – excess pulmonary fluid (frothy), early lesions smooth rounded swellings. Lungs heavier than normal Control: Retro-virus In utero infection does not occur Feed lambs colostrum and milk from free source Slaughter as soon as signs present

Question 35

Briefly describe the clinical presentations that may be caused by Listeria monocytogenes infection in sheep. (may 2016)

Answer 35

Reproductive: Abortion and weak lambs born, foetus oedematous autolysed, metritis / placentits. Foetus abomasal erosions, small necrotic foci in liver Meningoencephalitis: Pyrexia, possible facial paralysis, depression, head pressing, slow prehension, circling, death Septicaemia: New born lambs often found dead Risk factors: Often caused by poor quality silage with poor fermentation or soil contamination Close grazing with soil ingestion can be a cause Pregnancy Young animals – route through teeth emergence

Question 36

If you suspected anthelmintic resistance in a sheep flock, outline the investigation and tests you would use to confirm this. (may 2016)

Answer 36

Check: • Efficacy of dosing regime • Dosing equipment • Correct dosage / correct estimates of weight • Correct diagnosis o DDx Deficiencies / coccidiosis Methods: • Drench tests (post-dosing faecal egg counts) o 10 sheep FEC before drench o FEC ! 7 days later 2-LV ! 10-14 days 1-BZ ! 14-16 days 3-ML • FEC reduction test o Anthelmintics tested against a control group o AR suspected if FEC of test group is less than 95% • Larval development tests o Egg hatch assays

Question 37

- biphasic fever, depression, ataxia, muscular incoordination, tremors, posterior paralysis, coma, and death. ZOONOTIC

Answer 37

Louping-ill! Acute viral disease spread via Ixodes richness tick (like babesia in cattle...)

Question 38

Sheep scab (sep 2014)

Answer 38

Psoroptes ovis - also affects cattle and rabbit ears (P.cuniculi) - ppp = 10-15d - 16-18d survival off host - adult lives 20d - Ag in mite poo cause allergic reaction within hrs of infection - alopecia (care when scraping, as mites are in lolly areas!!!) - fitting! can be fatal - ozzey serum, scabby skin, yellow crusty look between wool - can be asymptomatic when small population hiding in skin folds... - NOTIFIABLE IN SCOTLAND but all cases in UK farmer is OBLIGED TO TREAT - primarily a winter disease (esp. with nutritional challenge and pregnancy see worse cases) - dz peaks at 6-8wk post-initial infection - treat with either organophosphate dip, or clear drench (marcolytic lactones, which also treat round worms)

Question 39

Iodine deficiency in lambs

Answer 39

Can cause neonatal mortality 1-7d.o., or stillbirth PM = enlarged thyroid glands

Question 40

Causes of lamb mortality 1-7d.o.

Answer 40

``` Trauma Hypoxia Low iodine/selenium/VitE/copper Septicaemia Diarrhoea sudden death (aspirate, starve, FMD!) ```

Question 41

Lamb diarrhoea causes

Answer 41

Salmonella E.coli Lamb dysentry (C.perfringens type B) Rotavirus