Sheep Flashcards
Describe the ‘ram effect’
Introduction of ram triggers brain to produce LH (2 forms: pulsing-> follicle growth; and surge-> ovulation). Basically it triggers cycling (as long as environmental conditions eg light are also correct)
Why should you encourage farmers to do PMs on sheep that died suddenly?
Could have died from something that is a risk to other animals
What should you ask when taking a history of a sheep that died suddenly?
Clinical signs of other sheep Age Season (ie parasites) Proximity to lambing (ie metabolic disease) Indoors or grazing Changes in management? (Eg diet, transport) Weather changes Recent treatments Vaccination history Anthelmintic treatments Recent gathering or handling?
Why should you look at a sheep/ flock before doing a clinical exam?
To look for neurological signs eg ataxia, head tilt
Give some causes of sudden death in neonatal lambs
Birth trauma eg rib fractures, dystocia Starvation Hypothermia Clostridial disease (dysentry, tetanus) Neonatal infections (meningitis, septicaemia, watery mouth) Intestinal torsion Predators
At what age should you blood sample lambs to test colostrum transfer?
2-7 days old
Give some causes of sudden death in growing lambs
Infections (clostridial disease, pasteurellosis) Urolithiasis Parasitic gastroenteritis Fluke Rumen acidosis Plant poisoning
Give some causes of sudden death in adult sheep
Metabolic disease (eg hypocalcaemia) Parasitic disease (eg fluke) Plant poisoning Infection Clostridial disease
Give some common causes of plant poisoning in sheep
Yew
Acorn
Laurel
Rhododendron
Give some clinical signs of plant poisoning in sheep
Abdominal pain (strong indicator)
Neurological signs
Sudden death
How do you treat plant poisoning in sheep?
Supportive treatment
Rumenotomy to remove poison material
What is the causative agent of pneumonic pasteurellosis?
Mannheimia haemolytica (normal inhabitant of nasopharynx)
What are the 2 types of pasteurellosis in sheep?
Pneumonic and systemic
Give the clinical signs of pneumonic pasteurellosis in young and old lambs
Young lambs: severe septicaemia
Older lambs: pneumonia
What enhances pneumonic pasteurellosis in sheep?
Disease is associate with other factors eg stress, poor colostrum status
How do you treat pneumonic pasteurellosis?
Long active Oxytetracycline or amoxicillin
How do you control pneumonic pasteurellosis?
Vaccination from 3 weeks old, booster ewes before lambing to protect lambs aswell
(Heptavac P)
What is the causative agent of systemic pasteurellosis?
Biebersteinia trehalosi (normal inhabitant of URT)
What clinical sign is seen with systemic pasteurellosis?
Sudden death in 6-10 month old lambs
What is the treatment for systemic pasteurellosis?
Long acting Oxytetracycline
Vaccination
Why is diagnosis of clostridial diseases in sheep done at post mortem?
Mostly causes sudden death
Give some trigger factors of clostridial diseases in sheep
Changes in management
Injury/trauma/insult
Endoparasites
Poor hygiene
Which clostridium causes lamb dysentry?
Cl. perfringens B
Which clostridium causes pulpy kidney in sheep?
What age of sheep are affected?
What are the clinical signs?
Cl. perfringens D
Lambs aged 4-10 weeks old, or finishing lambs 6 months +
Sudden death, may see ataxia and/or opisthotonus
Which clostridium causes abomastitis in sheep?
What age of sheep are affected?
What are the clinical signs?
Cl. sordelli (‘sore belly’)
4-10 weeks old, creep fed (high levels of concentrates in feed)
Sudden death or bloat due to displaced, distended abomasum
Which clostridium causes blackleg in sheep?
Cl.chauvoei
Which clostridium causes botulism in sheep?
Cl.botulinum C
Which clostridium causes tetanus in sheep?
Cl.tetani
What causes lamb dysentery?
Cl.perfringens type B
How can you control clostridial disease in sheep?
Vaccinate ewes 4 weeks before lambing (also protects lamb), annual booster
Start lambs own vaccination course from 3 weeks old
Vaccine: Covexin 8 and 10 or Bravovoxin 10 or Heptavac P
Give some notifiable diseases of sheep
Anthrax
Bluetongue
Foot and Mouth
Scrapie
What causes Anthrax?
Bacillus anthracis
If a sheep had foot and mouth disease, where would you see blisters?
Tongue, teats, coronary band, dental pad
How is Bluetongue spread?
Culicoides imicola
Give some clinical signs of Bluetongue
Fever Swelling of head and neck Lameness Mouth ulcers Drooling Skin haemorrhages Respiratory problems Tongue swelling (rare)
What are the 2 forms of scrapie?
Classical and atypical (rare)
Describe classical scrapie in sheep
Infectious neurological disease of sheep
Fatal, chronic, progressive TSE
Prion disease: prions accumulate in brain -> neuro dysfunction: excitable, nervous, depressed, aggressive, trembling, ataxia, high step ataxia, wide back legs, pruritus, wool loss due to scratching
2-5 years old
If you suspect scrapie who should you report it to?
AHVLA
How do you treat sheep scab?
Macrocyclic lactones or organophosphate dip
Give some problems caused by nutrition seen around lambing time
Metabolic disease: -Pregnancy toxaemia or twin lamb disease -Hypocalcaemia -Hypomagnesaemia Ewe: -Mastitis -Dystocia (over feeding) Lamb Mortality/Morbidity: -Low lamb birth weight -Poor colostrum -Poor milk production
Briefly describe pregnancy toxaemia in sheep
Lack of glucose availability due to consumption by foetus. Hypoglycaemia -> neurological signs
Hyperketonaemia
Why are molasses given to ewes carrying triplets?
They are very high in energy
What is ‘milk fever’?
When does it occur in sheep and cows?
Hypocalcaemia
Sheep: before lambing
Cows: after calving
Where should you not inject magnesium into sheep?
Veins -> death
What is meant by ‘flushing the ewe’?
Feeding the ewe so she is gaining weight about 2 weeks before tupping
Increasing the BCS by 0.5 will improve the number of eggs produced#
White muscle disease in lambs and calves is caused by a deficiency in what?
Selenium
How should a ewe’s BCS change during mid-pregnancy?
Maintain BCS or decrease by 0.5 as this is when the placenta develops. Care: if underfed -> small placenta -> low birth weights
What are the aims of feeding a ewe in late pregnancy?
To support foetal growth
To support mammary tissue development and colostrum production
To maintain ewe health and prevent pregnancy toxemia (ketosis)
To ensure lambs are born strong, healthy and of proper birth weight
When should we start feeding ewes cake during pregnancy?
90 days to lambing
What major events happen in a ewe when there is 90 days to lambing?
Uterus is expanding -> rumen capacity decreases
70% of foetal growth occurs
Colostrum development begins
What should you measure in a ewe’s blood 3 weeks before lambing?
BOHB (ketone bodies), albumin, urea
Give some problems with fat ewes
More prone to pregnancy toxemia Fat ewes experience more dystocia More likely to prolapse Large fetuses can cause dystocia Oversized lambs have a higher mortality Fat is expensive to put on
When are lambs weaned?
12-16 weeks old
Give some clinical signs of pregnancy toxaemia in sheep
Separate from group Inappetant Apparent blindness Tremors of face and ears Can progress to recumbency Dead foetuses Death BOHB >3mmol/L