Australasian Veterinary Examination, formerly the National Veterinary Examination Fodder Production & Grassland Management: practice questions

Question 1 · easy

Which temperate legume spreads by stolons and is the classic grazing partner of perennial ryegrass in New Zealand and north-west Europe?

1. White clover (Trifolium repens)
2. Subterranean clover (T. subterraneum)
3. Red clover (Trifolium pratense)
4. Lucerne (Medicago sativa)

Question 2 · hard

Sheep grazing a pure Brachiaria decumbens pasture develop jaundice and dermatitis of unpigmented skin. What is the mechanism?

1. High nitrate forms methaemoglobin, which reacts with light in the skin
2. Hypericin is absorbed unchanged and makes the skin itself photodynamic
3. Saponin crystals in bile ducts block phylloerythrin excretion
4. Dhurrin releases cyanide that damages skin capillaries in direct sunlight

Question 3 · medium

Which pair correctly matches a temperate grass endophyte alkaloid with its disease?

1. Lolitrem B in tall fescue - facial eczema
2. Ergovaline in ryegrass - kale anaemia
3. Sporidesmin in ryegrass - ryegrass staggers
4. Ergovaline in tall fescue - fescue toxicosis

Question 4 · hard

Several ewes fed poorly fermented, soil-contaminated big-bale silage develop facial paralysis and circle to one side. Which organism and silage defect are most likely involved?

1. Pasteurella multocida, inhaled from silage with low pH and no soil present
2. Clostridium tetani, multiplying in silage that was too acidic and too dry
3. Listeria monocytogenes, multiplying in silage with high pH and soil contamination
4. Salmonella Dublin, spread to sheep in silage made from well-fermented, low-pH maize

Question 5 · hard

A farmer believes that resting each paddock for 30 days between grazings will 'starve out' all infective nematode larvae. What is the correct advice?

1. Larvae die within 48 hours on pasture, so even a 3-day rest is enough to clean it
2. Larvae survive only on paddocks fertilised with nitrogen, so stop the fertiliser
3. Larvae can survive only in dung pats, so harrowing the paddock removes all risk
4. Larvae can survive weeks to months on pasture, so a 30-day rest does not clean it

Question 6 · medium

Cattle grazing bracken-infested hill pasture for many months develop haematuria with bladder tumours. Which bracken toxin is responsible?

1. Lolitrem B
2. Thiaminase
3. Mimosine
4. Ptaquiloside

Question 7 · hard

Pregnant mares grazing endophyte-infected tall fescue are at risk of which syndrome?

1. Haematuria and bladder tumours
2. Prolonged gestation and agalactia
3. Haemolytic anaemia with Heinz bodies
4. Goitre and alopecia of the foal

Question 8 · medium

Horses kept for many months on pasture of high-oxalate tropical grasses such as setaria or buffel develop shifting lameness and swollen facial bones. What is the condition?

1. Primary photosensitisation from hypericin
2. Equine grass sickness (dysautonomia) from neurotoxins
3. Laminitis caused by bracken thiaminase
4. Nutritional secondary hyperparathyroidism ('big head')

Question 9 · hard

'Clover disease', with infertility of ewes grazing certain subterranean clover pastures in Western Australia, was caused by:

1. Coumarin converted to dicoumarol
2. Pyrrolizidine alkaloids from Senecio
3. Cyanogenic glycosides such as dhurrin
4. Phyto-oestrogens such as formononetin

Question 10 · medium

Cattle fed large amounts of kale develop haemolytic anaemia with Heinz bodies. Which compound is responsible?

1. Glucosinolate goitrogens
2. Lolitrem B
3. S-methylcysteine sulphoxide
4. Ergovaline