Trace elements in cattle

Question 1

What trace elements can cows be deficient in?

Answer 1

• Selenium
• Iodine
• Manganese
• Cobalt
• Zinc
• Copper

Question 2

What trace element are toxic to cattle?

Answer 2

• Copper
• Selenium
• Iodine
• Cobalt
• Cadmium
• Lead

Question 3

What element are often in excess in cattle?

Answer 3

• Iron
• Sulphur
• Molybdenum
• Aluminium
• Selenium

Question 4

What are specific syndromes of trace element deficiencies?
+ General impact of deficiencies?

Answer 4

• Copper = swayback, coat colour, falling disease
• Selenium - white muscle disease, cardiomyopathies
• Cobalt = reduced growth, wool changes ‘pine’
• Iodine - weak neonates
• Iodine + selenium = stillbirth / weak calf syndrome
• Reduced growth + production + Immunity

Question 5

What are different sources of trace elements?

Answer 5

• Free access minerals
• Mineral blocks / buckets
• Boluses - dietetic under feed regs
• Drenches
• ‘Supplements’
• Water – esp. bore hole
• Authorised Veterinary products
• Grass
• Forages
• Straight feed materials
• Compound feeds (complete & complementary)
• Blends (supplemented or not)
• In-feed minerals

Question 6

What animals are at risk of trace element deficiencies?

Answer 6

• Animals grazing (+not getting much concentrates)
• beef cows + calves
• fattening cattle
• New Zealand style dairy cows
• Dairy heifers prior to first calving if at pasture

Question 7

How are trace element deficiencies diagnosed?

Answer 7

• HISTORY – at pasture with no supplements
• Blood samples
  – Se – GSHPx – tells us about 60 days ago
  – Cu – tells us how much is being transported
  – Does not tell us how much is in liver – liver biopsy needed
  – Caeruloplasmin
  – Co – Vitamin B12
  – Iodine –Plasma Inorganic Iodine (& thyroid weight & histopathology)

Question 8

Where is copper stored? What can toxicity cause? What are predisposed breeds?

Answer 8

• Stored in liver
• Toxicity = haemolytic crisis = jaundice + death
• Predisposed to toxicity = Texel + North Ronaldsey
• Predisposed to deficiency = Scottish blackface = swayback

Question 9

What is the availability of copper in different forages?

Answer 9

• Grass silage = 49%
• Maize silage = 87%
• Whole crop silage = 69%

Question 10

What is copper bound to in the rumen?

Answer 10

• Molybdenum - thiomolybdates (w sulphur)
• Iron
  = deficiency

Question 11

How can you check liver copper status?

Answer 11

• Liver biopsy
• Liver from cull cows

Question 12

How can you supplement copper?

Answer 12

• Pasture dressing
• S/C injections
• Intra-ruminal bolus

Question 13

How can over supplementation occur?

Answer 13

• Multiple supplementary feeds =
• Compound feeds
• Supplemented blends
• Free access minerals
• Licks
• Boluses
• Drenches

Question 14

What are the consequences of zinc deficiency?

Answer 14

• Appetite and feed intake
• Immune status
• Teratogenic effects - congenital abnormalities
• Immune function effects - endometritis, mastitis
• Hoot, horn + hair integrity
• Teat keratin plus

Question 15

What are symptoms of selenium deficiency?

Answer 15

• White muscle disease (other muscle myopathies)
• Ill thrift
• Retained placenta and (resulting endometritis)
• Impaired immune function (mastitis)
• Poor fertility
• High S and/or Ca reduce Se absorption (Pb also)
• Selenium dependant enzyme, iodothyronine deiodinase, crucial for thyroid function, converts thyroxine to T3, is inhibited in selenium deficient cattle

Question 16

What is seen with selenium toxicity?

Answer 16

• Acute (Blind Staggers)
• Chronic (Alkali disease) = Dullness, lack of vitality, rough coat and hair-loss, soreness/sloughing of hooves, stiffness / lameness, sudden death
• Areas of high Se or Se accumulator plants or inappropriate / careless supplementation

Question 17

What are signs of iodine deficiency?

Answer 17

• Reproductive symptoms
  – Lowered conception rates, irregular oestrus/anoestrus
  – Retained placenta
  – Cystic ovaries
  – Abortions
  – Still births, birth of weak and/or hairless calves (thyroid in fetus)
  – Loss of libido in males

Question 18

How is iodine deficiency diagnosed?

Answer 18

• T4, T3, TSH, TRH, TSR, Plasma
• Histopath
• PME <3% of BW

Question 19

What are signs of cobalt deficiency?

Answer 19

– Poor appetite
– Reduced growth
– Anaemia
– Skin thins with poor hair quality

Question 20

How is cobalt deficiency diagnosed?

Answer 20

• Cobalamin
• Vitamin B12
• liver biopsy