DL: Poor weight gain

Question 1

Which 3 reasons may account for poor weight gain if all animals in a herd are affected?

Answer 1

underfeeding, TE, parasites

Question 2

How often should sheep be dosed against worms?

Answer 2

ideally this should be based on FEC

Question 3

How long after liver fluke infection (metacercaria) in later summer/early autumn would it take to produce a FEC to indicate infection?

Answer 3

about 8 weeks

Question 4

Why might you have size variation in lambs? 2

Answer 4

variation in time it takes to develop adaptive immunity

parasite burden

Question 5

How do you test parasite resistance to anthelmintics? 2

Why not a FEC?

Answer 5

FECRT or drench test

FEC will not necessarily be lower if the parasites in question are resistant to the anthelmintic (!).

Question 6

When do you most commonly see Co deficiency? Effect?

Answer 6

late summer/early autumn after weaning when animals are at pasture.

Causes diarrhoea

Question 7

How can you confirm/disprove parasite resistance to anthelmintics?

Answer 7

Post Mortem worm count – if the animals are being dosed correctly then only resistant worms will be found in the GI Tract – will confirm/disprove parasite resistance.

Question 8

How much do 10 individual FEC cost?

Answer 8

Approx. £94 +VAT for 10 individual FECs

Question 9

How much does a pooled FEC cost?

Answer 9

£17.70 +VAT

Question 10

What are the reference parasite ranges in FEC?

What should be considered in addition to this? 3

Answer 10

Low 750 eggs/gram.

Also consider: grazing/anthelmintics/time of year

Question 11

How much does it cost to do a Se test?
Cost?
Reference range?

Answer 11

Test for glutathione peroxidase

Cost £12 + VAT for testing 3 samples,

Reference range: low 3

Question 12

How do you test Co levels?
Cost?
Reference range?

Answer 12

Test for Vitamin B12

Cost is approx. £40 + VAT for testing 7 blood samples for serum vitamin B12

Reference range: Low 500.

Question 13

What does FEC reflect?

Answer 13

reflects active adult worms in the GIT, this is a pretty reliable and accurate test

Question 14

What would you do if you discover a sheep flock’s poor thrift is due to Benzimidazole resistance by Trichostrongylus?

Answer 14

Dose immediately with different anthelmintic (e.g. moxidectin,, kills larvae persistently for 2 weeks) and after a couple of days move to uncontaminated pasture, determine if resistance of parasite to anthelmintic is present (undertake a drench test or FECRT).

Question 15

True/False: some Benzimidazoles are only effective against liver fluke and not nematodes

Answer 15

True

Question 16

When is it worth doing an individual versus a pooled FEC?

Answer 16

If individual, can the additional cost be justified? If you can benefit, do the individual test, otherwise do the composite sample. In most cases, the extra cost of the individual test is not worth it.