NAVLE Food-Animal Production Medicine & Herd Health: practice questions

1 · Herd health programmes · medium

Which blood test and timing are most appropriate for herd monitoring of subclinical ketosis in dairy cows?

1. Non-esterified fatty acids in cows at mid-lactation, around 150 days in milk, with 1.2 mmol/L as the ketosis cut point
2. Beta-hydroxybutyrate in cows in the first two weeks after calving, with 1.2 mmol/L as a common cut point
3. Beta-hydroxybutyrate in heifers at first service, because ketosis is mainly a disease of heifers
4. Serum calcium in dry cows eight weeks before calving, with 2.5 mmol/L as the ketosis threshold

2 · Fertility management · easy

To achieve a 365-day calving interval with a 282-day gestation, by about how many days after calving must a cow conceive?

1. 83 days
2. 78 days
3. 282 days
4. 60 days

3 · Mastitis control · easy

Which group lists only contagious mastitis pathogens?

1. Streptococcus uberis, Streptococcus agalactiae and Pseudomonas from soil
2. Escherichia coli, Klebsiella species and Streptococcus uberis from bedding
3. Staphylococcus aureus, Streptococcus agalactiae and Mycoplasma species
4. Staphylococcus aureus, Escherichia coli and Klebsiella species from water

4 · Mastitis control · hard

A herd has a bulk SCC of 480,000 cells/mL, few clinical cases, and many cows with SCC above 200,000 at two successive recordings. Cultures grow Staphylococcus aureus. Which control measure is most specific to this problem?

1. Changing from straw to sand bedding to reduce coliform exposure between milkings
2. Pre-milking teat dip only, since pre-dipping is the main control for contagious mastitis
3. Treating every high-SCC cow in lactation for eight weeks, as Staph. aureus cures readily in lactation
4. Milking infected cows last or with a separate unit, and culling chronically infected cows

5 · Calf health · medium

Housed dairy calves aged 3–8 weeks have recurrent pneumonia. The shed is humid, smells of ammonia and has no air inlets at eave level. What is the primary intervention?

1. Give all calves a long-acting antimicrobial injection monthly until they are weaned
2. Improve ventilation through inlets and outlets without creating draughts at calf level
3. Close the remaining gaps to keep the calves warm and stop any air movement
4. Increase stocking density so the calves generate more body heat in winter

6 · Lameness control · medium

A farmer estimates 5% of his cows are lame, but independent mobility scoring finds 24% scoring 2 or 3. How should the vet interpret this?

1. The difference proves that lameness in this herd is caused by a single infectious agent
2. It fits the common finding that farmers underestimate lameness, so regular independent scoring is needed
3. The independent scorer must have made an error, because farmers see their cows every day and know them best
4. Most of the scored cows are only stiff after milking and do not count as lame in any system

7 · Performance records and KPIs: calving interval, SCC, ADG and FCR · easy

Which record is required by law for food-producing animals in many countries?

1. A record of the weather on each day that animals were treated with medicines
2. A daily record of each cow's rumination time and step count taken from electronic collars and pedometers
3. A record of every visitor's home address and vehicle colour kept for ten years
4. A medicines record listing the product, batch, dose, animals treated, date and withdrawal period

8 · Performance records and KPIs: calving interval, SCC, ADG and FCR · easy

Which of these is a leading indicator of dairy herd fertility?

1. Lifetime milk yield
2. 21-day pregnancy rate
3. Age at culling
4. Calving interval

9 · Pig and poultry flock medicine · medium

A sow herd has late-term abortions, increased stillbirths and weak-born piglets, and nursery pigs have respiratory disease. Which virus is the leading suspect?

1. Porcine parvovirus alone
2. Transmissible gastroenteritis virus
3. Porcine reproductive and respiratory syndrome virus
4. Porcine circovirus type 2 alone

10 · Pig and poultry flock medicine · easy

Which pig herd KPI is calculated as sows farrowing divided by sows served?

1. Litters per sow per year
2. Pre-weaning mortality
3. Farrowing rate
4. Non-productive days