Pre-lambing Nutrition and Periparturient Diseases

Question 1

Tupping

• target BCS
• affects

Answer 1

• BCS 2.5 -3.5
• affects ovulations and pregnancy rate
• inadequate cobalt decrease lamb viability at birth

Question 2

First Trimester

Answer 2

• stress in first 21 days can cause early embryonic loss

Question 3

Second Trimester

Answer 3

• BCS 2.0 -3.0 (allowed to drip 0.5)
• US at days 50-105
• Placental development: affects foetal size and lamb birthweight

Question 4

Lambing

Answer 4

• BCS 2-3
• 75% of foetal growth
• DM intake decreases to 1.8-2% of liveweight

Question 5

Weaning

Answer 5

• BCS 2.0 - 2.5

Question 6

Pre lambing metabolic profile

• when
• numbers
• indicators (3)
• Timing (2)

Answer 6

• 2-4 weeks pre-lambing
• 5 ewes per group
• 10-15 if unscanned
• Albumin: indication of not enough energy
• Urea: will go up if just eaten a lot of protein
• BHB: will tell you how much ketones has gone up and how close to preganncy endotoxaemia she is
• Earlier gives more time for intervention to work
• Later is more likely to find issues as the ewes are under more metabolic stress.

Question 7

Ewe energy requirements (6)

Answer 7

• Ewe appetite reduces by about 30% approaching lambing
• Maintenance for ewe is 8-11MJ
• Late pregnancy is 19MJ (twins 1.8 x maintenance)
• Peak lactation is 30MJ
• Intake varies from 1kg DM to just under 3kg DM
• If a ewe loses 1kg it will provide only 1 day of energy if carrying twins
–Has to get 4 times the energy to regain that 1 kg

Question 8

Pregnancy toxaemia

• causes of disease (3)
• pathogenesis

Answer 8

• inadequate energy intake coupled with excessive energy drain
• Rumen size is restricted due to uterine size, this reduces feed intake whilst demand is increased due to increasing foetal size
• Altered insulin levels and sensitivity along with a reduced ability to metabolise ketones during late pregnancy

• Primary disease: hypoglycaemic encephalopathy
• Initially reversible
• Later compounded by
                –	Hyperketonaemia
                –	Ketoacidosis

Question 9

Pregnancy toxaemia

• CS (11)
• progression
• subclinical disease (5)

Answer 9

• Inappetant (separation at feeding time)
• Generally slower than other ewes
• Dull, weak and lethargic
• Neurological signs: Blindness, inco-ordination, head tilt, head pressing, “Star gazing”
• Tremor, convulsions
• Depression, recumbence, D+, death

Progression of 2-16 days

subclinical disease: 
• Common occurrence
• ↓ Lamb birthweight
• ↓ Lamb viability
• Mothering ability
• Colostrum quality

Question 10

Pregnancy toxaemia

• profile (7)

Answer 10

• Low glucose (3mmol/l )
• Frequently high urea
• Frequently low calcium
• Liver enzymes elevated
• Low insulin
• High growth hormone (interacting with prolactin, placental lactogen, oestrogens and progesterone)

Question 11

Pregnancy toxaemia

• Tx (5)
• response
• Px (6)

Answer 11

• IV glucose
• Source of glucogenic precursers (propylene glycol)
• encourage eating
• Fluids: to correct ketoacidosis
• remove lambs/abort

often poor response to treatment

Px:
Group ewes according to feed requirements, feed appropriately and manage concurrent disease:

• Scan ewes & use raddle marks
• Appropriate concentrate feeding from 6 weeks before lambing
• Provide good quality roughage (hay, silage) that can be accessed by all ewes
• Regular condition scoring
• Control concurrent disease

Question 12

Hypocalcaemia

• cause
• when
• association with other electrolytes/hormones/enzymes

Answer 12

• Sheep get hypocalcaemia prior to lambing, cattle don’t (4 weeks prior- 1 week post.
• ↑ Demand-foetal bone (no relationship with foetal number)
• ↓ Availability
• Peak 1-3wk pre partum
• high oestrogens/low magnesium and anion/cation diets all have an effect on calcium
• Calcium is bound to albumin: look at together

Question 13

Hypocalcaemia

• Early CS (5)
• Late CS (3)
• Px (3)

Answer 13

Early:
• Staggering gait
• Weakness
• Tremor (shoulder)
• Sluggish PLR (papillary light reflex)
• Tachycardia

Late
• Tachypnoea
• Recumbency
• Death (<24h)

Px:
• Avoid stress in late gestation: Transport, Dog worry, Change of feed, (Change of weather)
• Adequate Ca dietary intake- acidotic diet
• Supplement if feeding root crops and cereals

Question 14

Hypomagnesaeemia

Answer 14

• Lack of available magnesium
• Ineffective homeostatic mechanisms
• Pasture must have Mg > 0.2% of DM (but if too high won’t eat grass: unpalatable)

Risk factors:
• High levels of Potassium in grass
• Rapidly growing grass (gut transit)
• Cold/wet stressful weather
• Lactating ewes with twins

Question 15

Hypomagnesaeemia

• CS (11)
• Tx (2)
• Px

Answer 15

• Sudden death
• Anxiety, hyperaesthesia/tachycardia
• Unsteady gait, staggering
• Apparent blindness
• Nystagmus
• Recumbency (+ paddling)
• Opisthotonus
• Hypersalivation (frothing at mouth)
• 50 ml 25% MgSO4, SC multiple sites (skin necrosis: not IV- causes cardiac dysrhythmias)
• Also CBG, IV or SC

• Mg supplementation
– Rumen bolus
– In concentrates
– Mg licks (variable intake)
– Top dressing pastures with calcined magnesite
– Drinking water
– Do not use potash (high potassium) fertilisers in spring

Magnesium is usually bitter when supplemented: very unpalatable