Bovine ostertagiosis

Question 1

Parasitic gastro-enteritis (PGE)

Answer 1

Disease associated with a number of nematode species (singly or in combination)

Characterised by:
diarrhoea / weight loss (clinical disease)
poor weight gain (sub-clinical disease)
seasonal appearance
hypoalbuminaemia (low blood albumin)

Question 2

Economic importance of PGE

Answer 2

Considerable economic importance in grazing livestock
Potential welfare problem (esp. organic farms)

Losses associated with the cost of:
replacement stock
disruption of breeding programme
impaired productivity
treatment of clinically affected stock
prophylaxis

Question 3

Bovine PGE

Answer 3

Involves Ostertagia worm localised in the abomasum. Disease: ostertagiosis

Ostertagia ostertagi is the primary pathogen of cattle; adult worms 1cm long, cotton like, brown

Question 4

Ostertagia ostertagi

Answer 4

Pasture: free-living stages (eggs and larvae)

Pre-patent period: 3 wks to 6+ months

Final host (abomasum: parasitic stages (larvae and adult worms)

Question 5

Control (type 1 disease)

Answer 5

Use clean pasture:
New leys, pasture not grazed by cattle last year - BUT not always available

Delay turnout until after spring mortality in L3 - BUT uneconomical use of pasture, supplementary feeding?

Dose ’n’ move to aftermath (mid-July):
This will not control early season disease
Increased anthelmintic resistance risk?

Question 6

What if there’s no alternative grazing available?

Answer 6

Intra-ruminal anthelmintic devices
-Minimise pasture contamination, e.g. Autoworm; but expensive

Question 7

Control (type 2 disease)

Answer 7

Cattle exposed to LOW challenge at pasture in late autumn
-UNLIKELY to require treatment at housing
Cattle exposed to MEDIUM / HIGH challenge at pasture in late autumn or cattle of UNKNOWN origin
-LIKELY to require treatment at housing