Flock Metabolic & Nutritional Conditions

Question 1

why is nutrition important in sheep

Answer 1

If nutrition is inadequate we see disease in sheep

This most evident when there is high metabolic load-late pregnancy/lamb growth

Failure to correctly manage the nutrition of sheep almost guarantees disease

Question 2

what is the BCS for tupping

Answer 2

2.5-3.5

Question 3

what nutrition changes can be done at tupping

Answer 3

flushing? affects ovulation rate and preg rate (care with red clover)

inadequate cobalt (vit B12) reduces lamb viability at birth

Question 4

what occurs during the first trimester in flock management

Answer 4

stress in the first 21 days post fertilization may cause early embryonic loss

in effect this is 6 weeks post start of tupping for the flock

Question 5

what is the BCS of ewes in second trimester

Answer 5

2-3

Question 6

what effect does nutrition have in the second trimester

Answer 6

placental development

effect on fetal size and lamb’s birthweights

Question 7

what BCS changes can occur in the second trimester

Answer 7

can drop 1/2 unit

Question 8

what day does US scanning occur in second trimester

Answer 8

50-105 days

Question 9

what should BCS be at lambing

Answer 9

2-3

Question 10

what occurs during third trimester

Answer 10

75% of fetal growth

Question 11

what is nutrition critical for in the third trimester

Answer 11

nutrition is critical for ewes and lambs (birthweights, colostrum)

Question 12

when should concentrates be fed

Answer 12

concentrates possibly required during last 6-8 weeks

Question 13

what are ewes grouped according to during lambing

Answer 13

group ewes according to energy need

Question 14

how much does DMI drop in the last trimester

Answer 14

DM intake decreases to 1.8-2.0%

Question 15

what should BCS be during weaning

Answer 15

2-2.5

Question 16

how can you monitor the nutritional status of the ewe (4)

Answer 16

1. BCS
2. weighing
3. metabolic profiles
4. lamb birth weights

Question 17

when would you do a pre lambing metabolic profile

Answer 17

2-4 weeks pre lambing

Question 18

how many ewes per group woud you sample for pre lambing metabolic profile

Answer 18

5 ewes per group representative (not outliers)

10-15 if unscanned

Question 19

what bood values would you test for a metabolic profile

Answer 19

albumin

globulin

urea

BHB

Question 20

what can albumin indicate

Answer 20

Alb long term measurement of protein level in diet

Question 21

what can globulin indicate

Answer 21

Globulin up in chronic disease, albumin will decrease in response to maintain osmotic pressure

Question 22

what can urea indicate

Answer 22

Urea gives short term measure of rumen degradable protein

Question 23

what can beta hydroxybutyrate indicate

Answer 23

ketone

both NEFAs and volatile fatty acids produced from rumen metabolism can be used to form ketones.

ketones are excreted into the circulation, taken up by other tissues (e.g. skeletal muscle, mammary gland), where they are oxidized to yield energy or, in the case of the mammary gland, incorporated into milk fat.

increase in ketones in the blood =4 ketosis

Increased BHB concentrations in blood indicates stimulation of lipolysis (all species) or excess absorption of butyrate (ruminants) from feeding spoiled silage (also called alimentary ketosis

Question 24

how do you ensure the timing of metabolic profiles is appropriate

Answer 24

Earlier gives more time for intervention to work but later is more likely to find issues as the ewes are more under stress

But remember most flocks lamb over a 6 week period (majority of sheep lamb in the first 21 days)

Question 25

what are the energy requirements of an ewe

Answer 25

Maintenance for ewe is 8-11MJ Late pregnancy is 19MJ (twins 1.8x maintenance) Peak lactation is 30MJ

Question 26

what is the intake of an ewe

Answer 26

1kg DM to just under 3kg

Question 27

what are periparturient diseases

Answer 27

Abortion Pregnancy toxemia Hypocalcemia Hypomagnesemia (Listeriosis) (Septicemia) (Johne’s, Ovine pulmonary adenocarcinoma (OPA; Jaagsiekte) and all the other usual suspectS)

Question 28

what is the timing of clinical disease in sheep compared to dairy cows

Answer 28

Hypocalcemia typically post parturition in cattle Hypomagnesemia is similar Pregnancy toxemia is post parturient in cattle (increased milk yield demands)

Question 29

what is pregnancy toxemia

Answer 29

metabolic disease ## Footnote Caused by inadequate energy intake coupled with excessive energy drain

Question 30

what is the cause of pregnancy toxemia

Answer 30

Rumen size is restricted due to increasing uterine size, this reduces feed intake Energy derange is increased due to increasing fetal size Altered insulin levels and sensitivity along with a reduced ability to metabolize ketones during late pregnancy

Question 31

what is the clinical disease of pregnancy toxemia

Answer 31

hypoglycemia encephalopathy

Question 32

what is pregnancy toxemia compounded later by (2)

Answer 32

1. hyperketonemia 2. ketoacidosis

Question 33

what are the clinical signs of pregnancy toxemia

Answer 33

Inappetent (separation at feeding time) Dull, weak and lethargic Neurological signs: * Blindness, incoordination, head tilt, head pressing (star gazing) * Tremor, convulsions * Depression * Recumbence Diarrhea Death Progression relatively slow (2-16 days)

Question 34

what would be seen on biochem with pregnancy toxemia

Answer 34

Low glucose (\<3.0 mmol/L) High ketones (BHB \>3mmol/L) Frequently high urea (dehydration) Frequently low calcium Liver enzymes elevated Low insulin High growth hormone (interacting with prolactin, placental lactogen, estrogens and progesterones)

Question 35

what is the treatment of pregnancy toxemia (9)

Answer 35

1. Glucose (parentally) * IV glucose will cause an infected thrombus * Source of glucogenic precursors (propylene glycol 120ml BID in first 24hrs then 60ml BID) 2. Fluids (oral) 3. Calcium? 4. Anything to encourage eating * Grass? * Social eaters? 5. Treat concurrent disease 6. Pyrexia, lameness, pneumonia etc 7. Remove lambs (abort/caesarean) 8. Steroids 9. Insulin? (illegal to use in food producing animals in UK and EU) * Bovine somatotropin (BST)? (illegal to use in food producing animals in UK and EU)

Question 36

what ewe is at risk for pregnancy toxemia

Answer 36

Any ewe with an energy intake/requirement mismatch: Late pregnancy Twins/triplets Older ewes Fat ewes/thin ewes Often a group problem (iceberg disease) Concurrent disease Fluke, Johnes etc

Question 37

how do we determine whether this is a flock or individual problem

Answer 37

We need to understand whether this is an individual animal issue or a flock issue * Frequently a poor response to treatment * Treat early and aggressively to improve chances of success * Intervene to solve the flock issue — MOST IMPORTANT

Question 38

what is the subcinical disease of pregnancy toxemia

Answer 38

Decrease birthweight Decreased lamb viability Decreased mothering ability Decreased colostrum quality

Question 39

how do you prevent pregnancy toxemia (6)

Answer 39

Group ewes according to feed requirements, feed appropriately and manage concurrent disease 1. Provide good quality roughage (grass \> silage \> hay) that can be accessed by all ewes 2. Appropriate concentrate feeding if necessary from 6 weeks before lambing 3. Control concurrent disease 4. Scan ewes and use paddle marks (with resultant, informed, management changes) 5. Regular condition scoring 6. Metabolic profiling

Question 40

what is hypocalcemia

Answer 40

Demand exceeds supply: * Increased demand: fetal bone (no relationship with fetal #) * Decreased availability

Question 41

when does hypocalcemia occur

Answer 41

peak 1-3 week pre partum

Question 42

what are the causes of hypocalcemia

Answer 42

Decreased food intakes (+ oxalates) Frequently associated with stress (ex. snow)

Question 43

does hypocalcemia present as a individual or group problem

Answer 43

group problem

Question 44

what can contribute to hypocalcemia

Answer 44

high estrogens/low magnesium and anion/cation diets

Question 45

what are the early clinical signs of hypocalcemia

Answer 45

Staggering gait Weakness Tremor (shoulder) Sluggish pupillary light reflex Tachycardia

Question 46

what are the late clinical signs of hypocalcemia

Answer 46

Tachypnea Recumbency Death (\<24h)

Question 47

how is hypocalcemia treated

Answer 47

50ml 40% calcium borogluconate IV There may be benefits in giving magnesium at the same time as the ewe may also have low magnesium and there may also be benefits to giving phosphate (stimulates PTH) Response is not as good/dramatic as that seen in cows Supportive treatment, including pregnancy toxemia prevention

Question 48

how is hypocalcemia prevented

Answer 48

Avoid stress in late gestation: * Transport * Dogs * Change of feed * Change of weather Adequate calcium dietary intake — acidotic diet Difficult to achieve while meeting the energy requirements of ewes Supplement if feeding root crops and cereals

Question 49

what is the etiology of hypomagnesemia

Answer 49

Lack of available magnesium * +/- hypocalcemia Absence of readily mobilized Mg store Ineffective homeostatic mechanism Diet must have Mg \> 0.2% of DM Remember most of the mobile magnesium is intra-cellular not extra-cellular

Question 50

what are risk factors of hypomagnesemia (2)

Answer 50

1. decrease supply 2. increased demand

Question 51

what causes a decreased supply of magnesium

Answer 51

High levels of potassium in grass (and low sodium) Rapidly growing gas (decrease gut transit time) Cold/wet stressful weather * Grass disproportionally absorbs K+ and Mg2+ * Ewes don’t eat as much

Question 52

what causes increased demand of magnesium

Answer 52

lactacting ewes with twins

Question 53

what are the clinical signs of hypomagnesemia

Answer 53

Mostly sudden death Anxiety, hyperesthesia/tachycardia Unsteady gait, staggering Apparent blindness Nystagmus Recumbency (+ paddling) Opisthotonus Hypersalivation (frothing at mouth)

Question 54

how is hypomagensemia diagnosed

Answer 54

Clinical signs and history * Otherwise the ewe will die Pre-treatment blood to confirm diagnosis if there is a treatment failure Anterior or posterior chamber Mg2+ level as part of a PM (this is easy)

Question 55

how is hypomagensemia treated

Answer 55

50ml 25% MgSO4 SC multiple sites (skin necrosis, not IV) * Better absorption Also calcium borogluconate IV or SC Often poor response to treatment observed Treatment response may be slower as it is probably the intra-cellular CSF levels that have to return to normal for c/s to resolve Into the cerebral tissues before resolution of clinical signs Takes an hour usually to return to any form of normality

Question 56

how is hypomagnesemia prevented

Answer 56

Mg supplementation:

Question 57

how is mg supplemented

Answer 57

Rumen bolus * Not commonly used In concentrates * Works well * 50% variation in the flock of intakes Mg licks/buckets (variable intake) * More common, less effective Top dressing pastures with calcined magnesite Drinking water Do not use potash fertilizers in spring Magnesium is usually bitter when supplemented