Nutrition

Question 1

Vit A (retinol)

Answer 1

Fat soluble
Used for vision (rhodopsin) and for epithelium
- Deficiency, e.g. causes night blindness and rough scaly skin.
- Occasionally causes retained foetal membranes or infertility.
- Excess can be toxic

Question 2

Vit B

Answer 2

: Function mainly as enzyme co-factors e.g pyruvate dehydrogenase

• Deficiency often causes poor growth & nerve problems.
• Formed by rumen and colon microbes
• Vitamin B deficiencies include:
• Thiamine (B1) deficiency affects the nervous system – cerebrocortical necrosis (CCN, aka polioencephalomalacia, PEM) in sheep – Bracken poisoning
• Riboflavin (B2) deficiency causes curly toe disease in chicks
• Pantothenic acid (B5 deficiency causes goose-stepping in pigs

Question 3

Vit C

Answer 3

Synthesised by most animals

- Not synthesised by primates, guinea pigs, capybaras and bats

Question 4

Vit D

Answer 4

Important in Ca2+ homeostasis and normal mineralization of bone.

• Deficiencies in pigs and poultry leading to poor bones
• Excess is toxic

Question 5

Vit E

Answer 5

An antioxidant (Se as cofactor so can compensate for low vit E with selenium)
Stored food likely to be deficient as oxygen reacts with it
- Deficiency (like that of Se) causes nutritional myopathy
- White muscle disease in calves
- Stiff lamb disease
- Cardiac myopathy (mulberry heart disease) in pigs.
- Grazing goats are more susceptible to Vitamin E deficiency

Question 6

Vit K

Answer 6

“Sweet clover disease” is sometimes seen in cattle: coumarin is converted to dicoumarol by moulds.
Dicoumarol antagonises vitamin K causing haemorrhage / anaemia.
Formed by rumen/colon microbes so ruminants don’t get primary deficiencies
Involved in prothrombin -> haemorrhage

Question 7

Calcium

Answer 7

• Milk Fever or periparturient paralysis in cattle – affected animals exhibit transient hyperexcitability followed by flaccid paralysis (all three muscle types). Bent neck in milk fever
• Hypocalcaemia can follow total Ca depletion or excess plasma protein binding
• Hypercalcaemia (e.g. excess PTH or vitamin D) results in metastatic calcification.

Question 8

Cobalt

Answer 8

Co is required for B12 synthesis (pernicious anaemia, i.e. slow onset).

• In dogs (and cats), some GI disease can lead to bacterial metabolism (destruction) of cobalamin and a low-grade anaemia.
• Cobalt deficiency -> pine

Question 9

Copper

Answer 9

• Cytochrome oxidase deficiency interferes with pigmentation
• Swayback (poor myelination) in lambs. Stringy / steely wool
• Teart pastures are high in molybdenum (Mo) which forms a complex with copper and makes in unavailable
• Note that sheep are prone to copper poisoning when kept indoors
• Sheep get copper poisoning if eating pig feed (pigs tolerate it)

Question 10

Iodine

Answer 10

• Goitre – neck swelling as thyroid gland increases in volume.
• Brassica. Goitrin interferes with iodination of tyrosine and thyroxine production.

Question 11

Iron

Answer 11

Anaemia from deficiency. Needed in neonatal pigs as deficient in milk

Question 12

Magnesium

Answer 12

• Hypomagnesaemic tetany , lactation tetany, grass staggers.

Question 13

Potassium

Answer 13

• Deficiency causes hyperpolarisation of excitable cells

- Excess hypopolarises – main effect on excitable cells especially the heart.

Question 14

Selenium

Answer 14

An antioxidant

- Deficiency results in myopathy (like vitamin E deficiency) and stiff lamb disease

Question 15

Sodium

Answer 15

• Reduced height of action potentials and also low osmotic pressure of ECF.
• Also occurs in Addison’s disease (lack of aldosterone).

Question 16

Zinc

Answer 16

• Parakeratosis (abnormal keratin, scaly appearance) in pigs.