Trace Element Deficiencies Flashcards
What is the function of cobalt in the body?
Incorporated into vit B12 cobalamin which converts propionate to succinate in the TCA cycle. Improves rumen function and metabolic function.
Whata re the requirements of cattle and sheep for cobalt?
0.1-0.2 mg/kg/DM
Sheep > cattle (high S content in wool)
Growing > adults
What are the clinical signs of cobalt deficiency?
Decreased lamb vitality Anorexia Ill thrift Ocular discharge from medial canthus Anaemia Carry collapsed animals at gathering Poor quality wool
How is cobalt deficiency diagnosed?
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
How is cobalt deficiency treated?
Short term supplements - injectable B12, oral Co salts, given every 2 weeks
What is the function of selenium?
Component of glutathione peroxidase (protects cell membranes)
Non-specific humoral and cell mediated immune responses
Anti-oxidant
Se containing enzyme activates thyroid hormone
What are the requirements for selenium?
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
What are the clnical signs of selenium deficiency?
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
How is selenium deficiency diagnosed?
Flock hx/location
Response to supplementation
Blood GSPHx (historical measure)
Liver biopsy (good immediate measure)
How is selenium deficiency treated?
Short term supplements - oral/injectable sodium selenite
Long term supplements - orla bolus
Repeat tx can be toxic
What are the signs of selenium toxicity?
Acute - CV collapse, dyspnoea, recumbency, d+, death
Chronic - non-specific, dull, ill thrift, anaemia, birttle hooves
What is the function of iodine?
Thryoid hormone
Describe the pathogenicity of iodine deficiency
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)
What are the clinical signs of iodine deficiency?
Goitre
Scant wool
Weak lambs
High mortality in absence of goitre - starvation and hypothermia
How is iodine deficiency diagnosed?
Difficult
PM - ratio of thyroid weight to body weight
How is iodine deficiency treated?
IM iodised oil pre-tupping
Oral dosing - 280mg potassium iodide @ 8 and 4 weeks prior to lambing
Sustained release ruminal bolus
What is the function of copper?
Growth and development
Maintenance of bone, CT, brain, heart and other organs
Describe the pathogenesis of copper deficiency
Follows mild winters due to less supplementary feeding
Associated with some soils and crops - molybdenum + S = Cu binding = less absorption
What are the clinical signs of copper deficiency?
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+
How is copper deficiency diagnosed?
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
How is copper deficiency treated?
Sway back - euthanase Bolus - gelatine with CuO wire Drench/inject Licks In feed (most concentrates have low Cu content)
What are the clinical signs of copper toxicity?
Acute - 24hrs post supplementation - severe GE, colic, d+, collapse, death
Chronic - acute haemolytic anaemia, jaundice, anorexia, d+
What are the causes of ill thrift in lambs?
Poor ewe nutrition Parasites Trace element deficency Lameness Neurological disease Resp. disease Joint ill Foot rot Rickets Fracture
