Skip Ribbon Commands Skip to main content
Share This


Surveys of anthelmintic use on deer farms coupled with known information about parasites in weaner deer suggest that for effective parasite control the following recommendations are important:

  • Available products are effective
  • Initial treatment needs to be at weaning or if weaning is delayed then it’s better to commence early ie before weaning rather than delay commencing the programme.
  • Regular treatments are necessary from approximately weaning to late winter/spring.
  • The interval between treatments is difficult to assess but as a rule of thumb
    • Pour-ons should be given at 6-8 weekly intervals. The actual timing will depend on product, stocking rates, pasture contamination, climate conditions
    • Oral drench treatments should probably be given at no greater than 4-weekly intervals
    • Treatment intervals should not be extended beyond those recommended as to do so will lead to poor parasite control and poor growth weights.
    • Adult drenching recommendations are not clearly defined, much more trial work is required.
      Stags in their second winter appear to be at risk to subclinical parasitism
    • Monitoring of deer groups by faecal egg and lungworm larvae counts will provide information on an individual farm and lead to better drenching recommendations for that farm
    • The pepsinogen blood test is currently being used as a monitoring test but only limited information is available

Life Cycle of Dictyocaulus viviparus in Red Deer


A. First-stage larvae passed in faeces
B. Infective larvae penetrate intestinal mucosa and migrate via lymphatic and blood circulation to lungs
C. Development to fifth stage and maturation to adulthood in lungs
D. Adult worms inhabit bronchial tree and lay eggs
E. Eggs coughed up and swallowed; hatch to L1 larvae in faeces
F. Infective larvae consumed with herbage

Deer Parasites

Ostertagia - Type
Ostertagia leptospicularis*
Skrjabinagia kolchida
Spiculaopteragia spiculoptera
Apteragia qua drispiculata
These are true deer parasites
*probably the most widespread and representative of the Ostertagia types found.

**probably more common in South Island
Capillaria bovis
Trichuris ovis
Oesophagostomum venulosum
Cattle/Sheep parasites which appear to be a well adopted to deer.
Eleaphostrongylus cervi True deer parasite.
Dictyocaulus viviparus True deer parasite.
Ostertagia circumcincta
Cooperia spp.
Trichostrongylus axei
Haemonchus contortus
May be found in deer. Possibly opportunists available through mixed grazing with sheep and cattle.

Parasite Control in Deer

Increasingly various researchers are finding that control of parasites in deer requires a similar approach as in other animals, otherwise productivity is affected and parasite control is incomplete.

The objectives of parasite control are:

  • Removal of exisiting parastie burden
  • Reduce reinfection challenge to the animal
  • Reduction in the level of pasture contamination
  • Essentially the effect of parasitism can be viewed as clinical prarsitism (the effects can be seen) or subclinical parasitism (the efects are not seen but they can be measured).

The most serious and important parasites in young growing deer are lungworm. They cause clinical and subclinical losses.

Gut parasites are of increased concern in farmed deer and these parasites can cause clinical problems in deer. Gut parasites may be an important "routine" cause of subclinical loss.