Trace Element Deficiencies

Question 1

What is the function of cobalt in the body?

Answer 1

Incorporated into vit B12 cobalamin which converts propionate to succinate in the TCA cycle. Improves rumen function and metabolic function.

Question 2

Whata re the requirements of cattle and sheep for cobalt?

Answer 2

0.1-0.2 mg/kg/DM
Sheep > cattle (high S content in wool)
Growing > adults

Question 3

What are the clinical signs of cobalt deficiency?

Answer 3

Decreased lamb vitality
Anorexia
Ill thrift
Ocular discharge from medial canthus
Anaemia
Carry collapsed animals at gathering
Poor quality wool

Question 4

How is cobalt deficiency diagnosed?

Answer 4

CS, hx, flock location
Liver biopsy
Serum B12 (take sample within 4hrs of being taken off pasture otherwise levels will increase)
Normochromic normocytic anaemia
Response to supplementation
Interaction with PGE

Question 5

How is cobalt deficiency treated?

Answer 5

Short term supplements - injectable B12, oral Co salts, given every 2 weeks

Question 6

What is the function of selenium?

Answer 6

Component of glutathione peroxidase (protects cell membranes)
Non-specific humoral and cell mediated immune responses
Anti-oxidant
Se containing enzyme activates thyroid hormone

Question 7

What are the requirements for selenium?

Answer 7

2mg/kgDM
Requirements are higher when - legumes are fed (high level of inflam mediators), S intake is high, diet high in heavy metals, low vit E

Question 8

What are the clnical signs of selenium deficiency?

Answer 8

Low fertility in ewes
Still born/weak lambs
Older lambs - sudden onset, semi-flaccid paralysis, pharyngeal paralysis
WMD - severe non-inflammatory degeneration and necrosis of skeletal and cardiac muscle (fast growing lambs

Question 9

How is selenium deficiency diagnosed?

Answer 9

Flock hx/location
Response to supplementation
Blood GSPHx (historical measure)
Liver biopsy (good immediate measure)

Question 10

How is selenium deficiency treated?

Answer 10

Short term supplements - oral/injectable sodium selenite
Long term supplements - orla bolus
Repeat tx can be toxic

Question 11

What are the signs of selenium toxicity?

Answer 11

Acute - CV collapse, dyspnoea, recumbency, d+, death

Chronic - non-specific, dull, ill thrift, anaemia, birttle hooves

Question 12

What is the function of iodine?

Answer 12

Thryoid hormone

Question 13

Describe the pathogenicity of iodine deficiency

Answer 13

Occasional cause of high perinatal lamb mortality
Associated with grazing pasture/crops with high thiocyanate goitrogens e.g. brassica, white clover (block iodine uptake by thyroid)

Question 14

What are the clinical signs of iodine deficiency?

Answer 14

Goitre
Scant wool
Weak lambs
High mortality in absence of goitre - starvation and hypothermia

Question 15

How is iodine deficiency diagnosed?

Answer 15

Difficult

PM - ratio of thyroid weight to body weight

Question 16

How is iodine deficiency treated?

Answer 16

IM iodised oil pre-tupping
Oral dosing - 280mg potassium iodide @ 8 and 4 weeks prior to lambing
Sustained release ruminal bolus

Question 17

What is the function of copper?

Answer 17

Growth and development

Maintenance of bone, CT, brain, heart and other organs

Question 18

Describe the pathogenesis of copper deficiency

Answer 18

Follows mild winters due to less supplementary feeding

Associated with some soils and crops - molybdenum + S = Cu binding = less absorption

Question 19

What are the clinical signs of copper deficiency?

Answer 19

Congenital - small, weak lambs, depressed corneal/pupillary reflex, head tremor, poor coordination
Delayed (enzootic ataxia) - progressive hindlimb weakness from 2-4 months, decreased muscle tone and pelvic limb reflexes (muscle atrophy)
Growing lambs - 10% decreased growth rate, steely wool, anaemia, d+

Question 20

How is copper deficiency diagnosed?

Answer 20

CS, flock hx/location
Liver copper assay (can correct if find abnormality in growing lambs)
Response to supplementation (?)
PM - brain and spinal cord for hsitopath
[Cu] in plasma

Question 21

How is copper deficiency treated?

Answer 21

Sway back - euthanase
Bolus - gelatine with CuO wire
Drench/inject
Licks
In feed (most concentrates have low Cu content)

Question 22

What are the clinical signs of copper toxicity?

Answer 22

Acute - 24hrs post supplementation - severe GE, colic, d+, collapse, death
Chronic - acute haemolytic anaemia, jaundice, anorexia, d+

Question 23

What are the causes of ill thrift in lambs?

Answer 23

Poor ewe nutrition
Parasites
Trace element deficency
Lameness
Neurological disease
Resp. disease
Joint ill
Foot rot
Rickets
Fracture