Ruminant Parasite Case

Question 1

Scouring lambs in May on a Leicestershire farm

(lambs born in March outside and outside now grazing and being fed creep)

What history do you need to ask?

Answer 1

• Worming history.
• Rotated paddocks.
• Other grazing.
• What does It look like?
• How long has it been going on for?
• What % of flock are affected?
• Lambing protocol
• Medication history

Question 2

Scouring lambs in May

on a Leicestershire farm

(lambs born in March outside and outside now grazing and being fed creep)

What are your differentials?

Answer 2

• Coccidiosis
• Nematodirosis
• Teladorsagaiosis
• Parasitic gastroenteritis – Should always be investigated in any weaned lamb

Question 3

Scouring lambs in May

on a Leicestershire farm

(lambs born in March outside and outside now grazing and being fed creep)

How would you get a diagnosis?

Answer 3

• Faecal sample – FEC and worm count
• History and clinical signs
• Post mortem

Question 4

Upland flock 1200 ewes lambing in March-April on an 800 acre farm in the peak district (no cattle or arable crops on the farm)

What parasites are potentially important in this system:

Answer 4

• Nematadirous Batus
• Haemonchus Contortus
• Coccidia

Question 5

What testing would you want to do to decide when treatments are required?

Answer 5

• FEC
• Faecal worm test
• Sedimentation – fluke
• Baermann apparatus – lungworm larvae

Question 6

What can we do to limit pasture contamination but minimise selection for anthelmintic resistance

Answer 6

• Rotation
• Pooled (MOB) faecal egg count – track the rise to predict when treatment required
• Targeted selected tretatment – work out how much per day (any under perofrming may benefit from treatment)
• Narrow spectrum as possible

Question 7

What non-chemical control measures can you suggest?

Answer 7

•Avoid parasite with rotational grazing

Question 8

•List your differential diagnoses for diarrhoea in a group of housed yearling cattle?

Answer 8

+ Ostertagia

Question 9

•What diagnostic tests could you use to rule in/out type 2 Ostertagiosis?

Answer 9

Cattle are exposed to low challenge at pasture in late autumn so are unlikely to require treatment at housing. Cattle exposed to medium/high challenge in late autumn or animals of unknown origin are likely to require treatment at housing using an anthelmintic active against hypobiotic larvae

Type 2 = Previous grazing seasons

• Faecal examination, worm egg count is definitive if there are >1000 e.p.g. (eggs per gram) in type 1 disease and variable or sometimes zero in type 2 disease.
• Response to worming
• Diagnosis is based upon the grazing pattern and history of previous anthelmintic treatments. Faecal egg counts are generally high in type I but can be absent in type II disease. Blood tests can be used to determine whether there is significant parasitic damage to the abomasal lining.

–Grazing pattern

–Previous anthelmintic treatments

–Faecal egg counts

–Blood tests

Question 10

• A further two heifers die despite your treatment with Ivermectin. As the farmer is grumbling about the loss you remind them that “prevention is better than cure” and agree to help them develop a parasite control plan to reduce the risk of disease occurring again next year.
• What does your plan involve?

–Consider anthelmintic and management changes

Answer 10

More difficult to treat hypobiosis but drugs such as ivermectin will kill the hypobiotic L4

In some cases very frequent drenching may be required around calving (Type II)

Frequent drenching may be required during the first grazing season (Type I), especially or animal raised on pasture on which calves grazed previous seasons

Where vaccination of cattle for lungworm is undertaken planned anthelmintic treatments during late summer (July to September) can work to control PGE but mistakes can happen and failure to treat at the scheduled time may result in disease and costly weight loss in the cattle. No real challenge during their first grazing season at pasture, and failure to develop immunity, renders cattle susceptible to lungworm during their second season at pasture especially if weaned beef calves graze the same fields every year (for example rented ground away from the main farm etc). Nematode control strategies aimed at suppressive management of O. ostertagi, in particular those using persistent acting macrocyclic lactone anthelmintic regimes, prevent exposure of naïve cattle to D. viviparous and disease is often seen in older animals during their second, third or subsequent grazing seasons.

Health planning by the farmer’s veterinary surgeon is very important to prevent PGE and lungworm disease and may include both strategic anthelmintic treatment and lungworm vaccination. A detailed knowledge of the individual farm set-up is essential to tailor the best control programme for PGE and lungworm especially involving beef calves during their second grazing season.