Bursate Nematodes 4

Question 1

Why are small ruminants most problematic when it comes to PGE?

Answer 1

1.
2.
3. Goats are considered to be a minor species by the veterinary community (less work towards anthelmintics for them)

Question 2

Non-chemical control strategies

Answer 2

• stocking densities
  -mixed grazing
  -rotational grazing
  -monitoring of egg counts and growth rates
  -bulk milk tank monitoring

Question 3

Anthelmintics Classes - Nematodes

Answer 3

Levamisole - old drug (not effective against inhibited Ostertagia larvae)
Benzimidazoles - old (resistance is widespread)
Macrocyclic lactones / avermectins - newer (prolonged release formulations)

Monopantel (small ruminants) “Zolvix” - NOT LICENSED IN USA
Derquantel (small ruminants) - NOT LICENSED IN USA

Question 4

General rules for strategic use of anthelmintics:

Answer 4

• Targeted (selective) TX
• Consider which drug classes to use
• Never underdose
  -Never dose unless you can describe the benefit in terms of the epidemiological effect and / or the effect on individual animals

Question 5

Strategic dose

Answer 5

Dose the ewes just before lambing, (if ewes in poor body condition) dose at housing of calves

Question 6

Targeted dose

Answer 6

When FEC indicate potentially problematic pasture contamination levels - to some of a cohort of animals

Question 7

Targeted treatment

Answer 7

Only to animals displaying clinical signs or reduced growth (more stable shed in small ruminants)

Question 8

Beef Cattle

Answer 8

• If good pasture management, it is likely no anthelmintic TX may be required in suckler herds over the summer
  -In the autumn/at weaning, suckler calves should be monitored and an anthelmintic dose might be required depending on pasture hygiene
  -Consider a dose at housing if any indications of poor control
  -Be vigilant for Type 2 Ostertagiosis

Question 9

Dairy Herds

Answer 9

-spring born calves at highest risk
-monitor FECs (pooled) and growth rates
-dosing most vulnerable claves may be necessary depending on pasture management

Question 10

Eprinomectin in cows

Answer 10

Topical avermectin - no milk withdrawal period

Question 11

Small Ruminants vs Cattle

Answer 11

-multifactorial (Teladorsagia, Trichostrongylus, others)
-Continued age susceptibility
-peri parturient rise in egg production
-high protein decreases clinical effects
-Nematodirus (cold) & Haemonchus (warm)