Trace Element Deficiencies

Question 1

What are the two types of trace element deficiency? Define them

Answer 1

Primary - soil/plant deficiency

Secondary - lack of absorption in animal

Question 2

What are the four main trace elements essential for farm animals?

Answer 2

Copper (Cu) - Selenium (Se/VitE) - Iodine (I) - Cobalt (Co)

Question 3

Which trace element is the only one that is normally secondarily deficient?

Answer 3

Copper

Question 4

Why is Cobalt essential in farm animals?

Answer 4

Essential component of Vit B12 in rumen - Vit B12 part of co-enzyme involved in propionate - propionate involved in glucose pathway

Question 5

What would a deficiency of Cobalt show as in a farm animal? What other clinical signs are there?

Answer 5

Deficiency of glucose - poor thrift - associated with concurrent parasitism - eye discharges - anaemia

Question 6

Why is Selenium essential in farm animals?

Answer 6

Helps protect cells against free radicals - Maintains resistance to infections

Question 7

What would the clinical signs of Se deficiency be?

Answer 7

White Muscle Disease

Question 8

Sub-clinically what does Se deficiency look like?

Answer 8

Poor growth - embryonic deaths - increased disease susceptibility - reduced milk yield

Question 9

Why is copper so essential in farm animals?

Answer 9

Essential part of many enzymes
Cytochrome oxidase (myelin formation) - Caeruloplasmin (iron release into plasma in erythropoiesis) - Lysyl oxidase (elastin and collagen synthesis) - Tyrosinase (pigmentation)

Question 10

What are the clinical features of Cu deficiency?

Answer 10

Poor thrift - diarrhoea - poor coat - swayback (gait deficiency) - bone fragility

Question 11

Why is Iodine essential to farm animals?

Answer 11

Required for thyroid hormone synthesis

Question 12

What are the clinical signs for I deficiency?

Answer 12

Goitre in new born

Question 13

What is a sub-clinical sign of I deficiency?

Answer 13

Increased peri-natal mortality

Question 14

Which deficiency causes which species and age of that species to have poor thrift?

Answer 14

Cobalt - weaned lambs
Selenium - any species
Copper - usually catlle

Question 15

What ways can you supplement trace element deficiencies?

Answer 15

Oral dosing or in-feed - Injection - Slow release rumen capsule - Addition to fertiliser

Question 16

What elements are toxic in overdose?

Answer 16

Copper and Selenium

Question 17

You visit a mixed-species livestock farmer who has 30 adult Red deer hinds. The farmer reports that over the past week one of the hinds has started “running funny and her back legs wobble from side to side”. The wobble is getting progressively worse and now the hind sometimes falls over as she runs. Which trace element is it deficient in?

Answer 17

Copper - Swayback

Question 18

You are contacted by a beef cattle farmer who has a group of 80 eight-month-old Hereford x steers grazing on pasture. The steers are failing to gain weight as rapidly as expected (in fact some of them don’t seem to be growing at all) and a number have diarrhoea.

Answer 18

Copper and/or Selenium (Cobalt not associated with cattle)

Question 19

You are contacted by a farmer who has a pedigree Texel flock. They are worried because in the last few days 4 of a group of 60 five-week-old ram lambs have developed a sudden-onset stiffness and unusual gait which seems to be affecting all legs. The lambs are reluctant to move their necks or put their heads up to suckle. 2 of the lambs have now become recumbent.

Answer 19

Selenium - suggestive of White Muscle Disease

Question 20

When assessing the needs of sheep (or other grazing livestock) for trace elements, why is it preferable to test the levels in the animal rather than the levels within the plants fed to the sheep?

Answer 20

Trace element levels within plants can vary markedly - Absorption will vary within the animal - Requirements of animal vary depending to physiological status and age