Small ruminants Flashcards
Outline the steps involved in undertaking a flock or herd investigation
- History: event timeline, determine losses, treatments
- Examination of env: pasture (soil type, availability, water supply), indoors (hygiene, ventilation, overcrowding)
- Examination of animals: at a distance, clinical exam, PM exam
- Use of ancillary aids: parasite tests, haematology, biochem, histopath, etc
- Data analysis and decision making: tentative diag, prognosis, therapy
- Reporting and further monitoring
MCQ: the average normal resting heart rate for an adult ewe is:
a. 20-30 beats/min
b. 30-40 beats/min
c. 40-60 beats/min
d. 70-90 beats/min
e. 100-120 beats/min
d. 70-90 beats/min
What % of ewes should be scanned in lamb after a 5 week, seasonal joining if ewes are in CS 3 or better?
95%
What type of clovers can cause permanent infertility?
Sub clover and red clover
When are the three main times that repro loss may occur and when are they diagnosed?
- Failure to get in lamb/early embryonic loss –> diag at scanning
- Second half preg +/- frank abortion –> diag before lambing, often at marking
- Neonatal losses 1-5 days –> diag at marking
For each BCS >1.5 to 4 you can expect…
- 5% increase in conception rate
- increase in lamb birthweight and survivability
- increase in lamb weaning weight
How can you increase BCS for reproductive gains?
- Change lambing time –> pasture availability
- Some level of supp with grain
- Flushing: provide nutritional spike in lead up to joining
Aside from decreased lambing %, what other signs of clover disease may you see?
- Dystocia secondary to uterine inertia and fibrotic labia
- Increased rates of pre-lambing vaginal prolapse
- Teat elongation and inappropriate lactation
- Urolithiasis in wethers
What is the rate of embryonic mortality in the first 18 days?
20-30%
What are the signs of abortion
- Ewes scanned in lamb detected as likely not in lamb at pre-lambing treatments, skinny, no udder dev
- Frank abortion
- If not scanned at marking: not lactating, lactating but no lamb (udder involuting)
What are the three most common causes of abortion?
Campylobacter, Listeriosis, Toxoplasmosis
Answer the following about Campy:
a. What species cause abortions?
b. What % lamb loss do they cause?
c. How is it transmitted?
d. How can it be prevented?
a. C. fetus fetus, C. jejuni
b. 10-60%
c. Ingestion, direct contact with discharges from vagina, aborted foetuses, placenta, crows and magpies can carry
d. Infect ewe hoggets while not pregnant, vaccine (2 doses 3-8 wks apart, yearly booster pre-joining)
What are some of the clinical signs of Campy?
- Abortion mid to late preg
- Stillbirths
- Births of premature apparently normal but not viable lambs
- Ewes no signs of sickness
- Retention of foetal membranes and dev metritis (rare)
How are sheep infected with Toxoplasma?
Ingestion of feed or water contaminated with cat faeces (very resistant in env)
Describe the clinical signs of Toxoplasma at different stages of pregnancy, including how you would distinguish from Campy
- If not preg: no signs
- If early preg: no signs, foetal death and resorption
- If mid preg (d60-120): stillbirth, weak lambs, mummification (distinguish from CAMPY), abortion
- If late preg (>d120): normal offspring (immune)
What are the two species that cause Listeriosis and what specific symptoms do they cause?
Listeria monocytogenes: abortion, lamb septicaemia, meningoencephalitis
Listeria ivanovii: abortion and enteritis
What is the source of Listeriosis infection?
Survive for a long time in soil and on decaying vegetation (disease in wet, muddy conditions)
What are the two species of Salmonella that cause abortions?
S. typhimurium and S. bovis-morbificans (systemic)
What causes hairy shaker disease?
Ovine pestivirus
What are the clinical signs of ovine pestivirus at different stages of preg?
Not preg: mild fever, immunity
<50d: foetal death, resorption, abortion, ewes show no signs
50-85d: foetal death and abortion, “hairy shakers”
Describe some of the risk factors of preg toxaemia
- Very fat ewes (BCS<4)
- Very skinny ewes
- Twins
- Older ewes
- British breeds + crossbreds
- Anything that decreases feed intake e.g foot abscesses, cold weather, transport
- Anything that increases energy req: twins, cold, shearing, GI parasites
Describe the clinical signs of preg tox
- Dullness
- Loss of appetite
- Lag behind mob
- Recumbency
- Stargaze
- In coma and die
Describe the clinical signs of hypocalcaemia
- Sudden onset
- Affected ewes become isolated and stiff gait with muscle tremors
- Soon ewes become weak and recumbent
- Fatal if not treated
Describe the treatment and prevention of hypocalcaemia
- Calcium borogluconate
- Magnesium sulphate
Describe the differences between preg tox and hypocalcaemia
- Preg tox is usually a low number over a longer period after precipitating event vs hypocal can be very large no all at once
- Demeanor: preg tox = very depressed vs hypocal = BAR but unable to get up, frogs legs sitting position
- Response to Tx: poor for preg tox, good for hypocal
What kind of pastures are high risk for hypomagnesemia?
- Lush grass dominant pastures or rapidly growing fodder crops in late winter are low in Mg
- Fertilisers rich in potassium and nitrogen
- Acid soils may decrease Mg availability
Describe some of the clinical signs of hypomagnesemia
- Often found dead in paddock 1-4 wks post lambing
- Ataxia, muscle tremors, tetanic signs
- Collapse, convulsions with severe limb paddling, froth at mouth
- Death w/in 4-6 hrs
Describe the treatment and prevention of hypomagnesemia
- Treat ASAP
- Mg + Ca IV/SC therapy followed by SC Mg salts
- Prevent by min. stress and handling in first wks of lactation
- Hay with Mg oxide (causmag)
Question: describe a simple post-mortem technique that your client could perform to determine whether a dead lamb:
1. Was born alive or still-born
2. Managed to get up is feet and walk
3. Died before or after all its reserves of energy were exhausted
- Lungs inflated or not
- Has “slippers” on
- Amount of BAT
List the 3 major causes of perinatal lamb mortality
- Starvation, mismothering, exposure (SME)
- Dystocia
- Predation
List some of the minor causes of perinatal lamb mortality
- Death in utero/prematurity
- Infectious diseases
- Trauma –> stood on by ewe
- Trace element deficiencies
Describe how you will investigate perinatal lamb loss
- Estimate losses
- History: nutrition, trace element supp, lambing paddock, pre-joining exams of ewe, breed, age
- Lamb PM: weight, sex
What may indicate hypothermia in a PM exam?
Yellow subcut oedema of extremities
Explain primary vs secondary predation
Primary: lamb appears normal but suffered fatal injury
Secondary: lamb is abnormal –> more susceptible