Ddx for a down sheep
- hypocalcaemia
- pregnancy toxaemia (twin lamb dz)
- scrapie
- lameness
- respiratory dz
- listeria
- hypomagnasaemia
- carb overload causing acidosis
- copper poisoning (most often found dead)
- rhododendron poisoning (particularly in smallholdings)
- clostridia (botulism) (sheep less susceptible but still can get infected)
Ddx that can happen anytime, and will likely be relatively slow onset to point of recumbency
- scrapie
- resp dz
- listeria
Ddx that can happen anytime, but always worth checking the feet and limbs of a recumbent animal
- lameness
Ddx that can happen anytime, and will likely be relatively slow onset to point of recumbency, initial signs of pruritic and nervous signs
- scrapie
Ddx that can happen anytime, and will likely be relatively slow onset to point of recumbency, initial signs of pyrexia and respiratory stridor expected
- resp dz
Ddx that can happen anytime, and will likely be relatively slow onset to point of recumbency, neurological and some unilateral facial paralysis expected
- listeria
Hypocalcaemia - risk factors, when does it occur?
- occurs in late pregnancy
- older and thinner ewes more prone
- carrying multiple foetuses increases risk
- any stressor can trigger the condition
Hypocalcaemia management
- 25-40ml 40% calcium + borogluconate over 30-60s IV
- typically eructation seen after 1-2mins, stand after 5mins then urinate/defecate and re-join flock
- normal serum levels are slightly lower than cattle:
– Ca 2.6mmol/l
– P 1mmol/l
– Mg 1.3mmol/l
Pregnancy toxaemia - when does it occur? Risk factors? CS?
- occurs in late pregnancy
- older or thinner ewes are more prone
- carrying multiple foetuses increases risk
- any stressor can trigger the condition
- ewe separated from flock
- ewe drowsy or comatose
- ewe not eating: rumen compressed by foetuses in abdomen just can’t get food in properly
- nervous system signs due to ketone bodies in the brain: tremors, blindness
- lying on their side: long duration (3-4d)
- die few days later
- normal blood glucose = 50-80mg/dl
Nutrition during late pregnancy needed for
- developing foetus
- udder development and colostrum production
- prevent milk fever
- compensation for reduced feed intake
Why shouldn’t you feed ewes loads during late pregnancy?
- perversely increases pregnancy toxaemia risk as deregulates insulin response
- increases milk fever risk as deregulated PTH response
- vaginal prolapses more likely
- dystocia more likely: fat in pelvic canal with oversized foetus
- feed = money
Pregnancy toxaemia management
- IV glucose
- oral glucose
- induce parturition (steroids, PGF2a)
- encourage eating: minerals in molasses, yeasts (promote rumen function) and propylene glycol drench, vitB12, consider minerals
Hypomagnesaemia
- staggers
- is more common post-partum
- seen when moved onto fast growing spring pasture
– sometimes pasture with high potassium fertiliser which inhibits uptakes
– just as with cattle
– is an emergency, as with cattle
– volumes of IV magnesium to kill a sheep are obviously less, so even more care with administration
Managing staggers
- increasing gut transit times, by feeding higher fibre diet can help to increase absorption of available Mg, and reduce the incidence of dz
- routine soil analysis shows the Mg level of soil, use of Mg limestone rather than Ca limestone maintains the levels
- modify bagged fertiliser applications so K applications are carried out later in the season
- a regular supply of Mg in the diet e.g. offer free access to minerals
How do steroids induce/help parturition?
- matures lambs lungs
- increases surfactant
- encourages them to breathe when born
