Parasites and Deer

Table of Contents

  1. Introduction
  2. Deer Internal Parasites and their Biology
  3. Timing of Treatments
  4. Anthelmintics
  5. Summary
  6. References

Introduction

A common question of deer farmers is "What wormer should I use and what dosage?" The follow-up concerns are: "When is the best time to treat?" and "What is the appropriate withdrawal time for meat from treated animals?".

The term deer refers to the farmed deer species and includes white tail, fallow, sika, red, red deer/elk hybrids and elk.

In the 1995 Alternative Livestock Survey of Ontario Deer Producers, conducted by OMAFRA, 76% of respondents reported that they treated immature deer and 79% reported treating adult deer at least once a year. In addition, 60% of respondents indicated that they used ivermectin.(1) There are no anthelmintics approved for use in deer in Canada. Therefore, all treatments are off-label (extra label) use and require a client-patient-veterinarian relationship. Veterinarians are required to re-label medications used for an off-label treatment indicating the species and group of animals to be used on, the dosage and the withdrawal time for medications before slaughter.

Veterinarians can integrate procedures into their herd health management programs which ensure that clients are aware of their responsibilities with regard to withdrawal times for meat.

Deer Internal Parasites and their Biology

Various reports indicate that the following parasite species affect deer. The prepatent period, as indicated, is the time from ingestion of infected larvae to the first appearance of faecal larvae or eggs.(2)

 Parasite  Prepatent Period (days)
 Cooperia  17
 Ostertagia  20
 Trichostrongylus  21
 Oesophagostomum  
 Dictyocaulus viviparus (lungworm)  24-25


A 1996 study in southern England of red deer showed that mixed ostertagid infections were dominant, with very small infections of Trichostrongylus axei, Cooperia punctata and Oesophagostomum species. There was a widespread increase in egg counts of hinds in the summer which may be analagous to the post parturient (eg. after lambing) increases seen in sheep and other host species. These infections peaked in September to November. Many of the calves had patent infections by September. Anthelmintic treatment (worming) of adult deer, at turn out in May, delayed the beginning of the summer egg count rise but had little effect on subsequent pasture larval counts. Movement to other pastures in July did, however, reduce the infection to which calves were exposed. Ostertagia infections seem to be similar to infections in cattle, where L3 and hypobiotic L4 are continuously available to replace dying adult worms whose life expectancy is about 30 days. Hypobiosis is where larvae are held in an inhibited state and will mature and replace the adults when the adults are removed or die. The effects of treatment with fenbendazole and ivermectin administration to adults in May were disappointing, presumably due to the constant presence of hypobiotic larvae.

The authors conclude that parasitism had no adverse affects on adult deer hinds and that calves should be weaned, treated and moved to clean pasture or housed before the rut in September. The moving of mobs to new pasture in mid July could help delay exposure of the calves to large numbers of parasitic larvae.(3)

Waldrup et al. suggest that there appears to be a variation in susceptibility to parasites between red deer and elk even though they are only different subspecies of Cervus elaphus. Parasitism had a greater effect on live weight gains in elk/red hybrid weaner hinds than in red deer weaner hinds.(4)

Researchers indicate that the use of oral anthelmintics at the recommended dosages for cattle have poor results in the treatment of deer. The authors indicate that efficiency may be affected by abomasal acidity. Therefore, they suggest that injectable or pour-on products be used to overcome this problem.(5)

Timing of Treatments

Lancaster, from his studies with red deer in the UK, indicates adult animals should be treated with a single dose anthelmintic given at the end of April unless lungworm is a problem or unless you have a high worm burden in the autumn.

Yearlings should be treated like adults.

Calves should be treated after weaning in the fall and moved to a clean pasture or housed. This will prevent the late summer/early autumn parasite peak.(6)

Anthelmintics

There are no approved anthelmintics in Canada for use in deer. Therefore, all usages are "off-label".

The following will give veterinarians guidelines when recommending anthelmintics. The withdrawal times are those; as published in the Registered Animal Remedies for Use in Deer, by the Ministry of Agriculture and Fisheries, New Zealand, or as published, for cattle in Canada, in the Compendium of Veterinary Products, unless otherwise specified.(7,8)

Febantel (Rintal, Bayer NZ) has been used orally at a rate of 7.5 mg/kg. Plasma levels were undetectable by 30 hours. It was highly effective against mature lungworms and moderately effective against immature lungworms.(9)

Withdrawal Times: Meat

New Zealand
 Deer  21 days
Canada
 Cattle  no products licensed

Ref. (10)

Fenbendazole was administered in feed pellets to red deer at the rate of 10 mg/kg. over a 3 day period.(11) Canadian products include Panacur® and Safe-Guard® by Hoechst.

Withdrawal Times: Meat

New Zealand
Deer Fenbendazole 14 days
Panacur® 21 days
Canada
Cattle   Panacur® 8 days
Safe-Guard® 13 days


Oxfendazole is licensed in New Zealand for oral administration in deer. The withdrawal times vary between 10, 11, and 14 days, depending on the product.

Albendazole was used in fallow deer at 3.8 mg/kg and 7.5 mg/kg. It did not reduce faecal worm egg output in fallow deer.(12) Canadian products include Valbazen® by Pfizer.

Withdrawal Times: Meat

New Zealand
 Deer  7 days
Canada
 Cattle  27 days


Pour-on Ivermectin

Waldrup indicates that, by doubling the cattle dosage of pour-on ivermectin to 1000 ug/kg, adult abomasal nematodes were controlled but encysted Ostertagia-type larvae were only reduced by 40%.(13) Ivomec® pour-on is registered for use in both cattle and deer in New Zealand.

Withdrawal Times: Meat

 
Dosage
 500 ug/kg
 1000 ug/kg
New Zealand  Deer
 28 days
 not reported
Canada  Cattle
 49 days
 not reported

Ivermectin Injection, at the normal cattle dose rate (200 ug/kg), is very effective against lungworm and adult abomasal parasites, but is only moderately effective (84%) against immature (late L4) abomasal parasites. Doubling the dose rate of injectable ivermectin to 400 ug/kg improved the efficiency to over 95%.

A mild subcutaneous reaction is common for a day after the treatment.(14) Ivermectin injection is not approved for use on deer in either New Zealand or Canada.

The half life of ivermectin in the plasma of red deer is known to be shorter than in cattle; seven days in deer versus 8.3 days in cattle. (15) Plasma concentrations for ivermectin used at 200 ug/kg were undetectable by 14 days. However, 40% of deer in which 400 ug/kg was used, still had detectable levels by 14 days.(16)

Example: Ivomec ® given subcutaneously to fallow deer 1 cc per animal.(17)

Withdrawal Times: Meat  

 
Dosage
200 ug/kg
400 ug/kg
New Zealand  Deer
not approved and not reported
Canada  Cattle
 49 days
-


Moxidectin Pour-on

Mackintosh and his colleagues investigated the use of moxidectin pour-on in deer (sold as Vetdectin ® by Cyanamid of New Zealand and Cydectin® by Ayerst in North America). The 0.5% pour-on moxidectin, when used at the rate of 1 ml./10 kg. (0.5 mg/kg) body weight, had a persistent activity against reinfection with lungworm for 35 to 42 days while ivermectin showed a persistent activity for 21-28 days.(18)

Middelberg et al. showed that moxidectin was highly effective in eliminating D. viviparous, haemonchus, ostertagia, trichostrongylus, and oesophagostomum. Moxidectin reduced D. viviparus infections by 99.74%.

Example: red deer weaner fawns were treated as follows;

  • hind red fawns weighing 30.6 to 39.4 kg. - 4ml. dose
  • stag red fawns weighing 36.2 to 47.6 kg. - 5ml. dose

Ref.(19)

Withdrawal Times: Meat

 
Dosage (500 ug/kg)
New Zealand    Deer 21 days
Australia  Deer 7 days
Canada   Cattle 36 days

Ref.(20,21)

Eprinomectin is marketed as Ivomec-Eprinex ® by Merial. For cattle, it is used as a pour-on, given at 500 mcg/kg or 1 ml. per 10kg (22 lb.). Its activity is reported to include the 4th stage inhibited larvae. It has persistence against lungworm for 21 days and hornflies for 7 days. There are no withdrawal times when used in cattle in Canada for either meat or milk. In New Zealand, a 14 day withdrawal time is used for deer.(22)

Withdrawal Times: Meat

 
Dosage (500 ug/kg)
New Zealand  Deer 14 days
New Zealand  Cattle 14 days
Canada  Cattle 0 days

Doramectin is marketed as Dectomax® by Pfizer. Currently, there is no published research for use on deer.

The pour-on formulation is used at the rate of 500ug/kg. It is reported to have a 99.9% efficacy on L4 ostertagia larvae. The persistent protection for lungworm is 42 days, for ostertagi 28 days and cooperia 21 days.

Withdrawal Times: Meat

 
Dosage (500 ug/kg)
New Zealand  Deer no studies reported  
Canada  Cattle pour-on 55 days
injectable 40 days

Ref.(23)

Summary

  1. Observations in Canada and in New Zealand would indicate that clinical parasitism (deaths or severe disease) is not a common problem.(24)
  2. In a study on fallow deer, light worm burdens do not have a measurable effect on body carcass weight.(25) However, sporadic clinical losses will occur, particularly for lungworm infections.
  3. There are very efficient wormers now available to practitioners and their clients.
  4. Worming programs, starting at weaning, work reasonably well but pre weaning faecal samples should be evaluated to learn when problems may be occurring.
  5. Red deer weaners in late winter have higher growth rates when wormed.
  6. Stags in their second winter should be evaluated and could benefit from worming, due to the risk of subclinical infections.

There is a significant role which can be played by veterinarians in advising on parasite programs, including the strategic use of anthelmintics (wormers) and the monitoring of parasites levels. A good herd program will; reduce costs, reduce risks of resistance, and reduce drug residues.

Plan for the inevitable! When deer are handled, they get excited and accidents happen. At some time, an animal will sustain an injury which will require a decision of either humane slaughter or humane euthanasia. Producers have to be fully aware of their responsibilities to protect human health and prevent drug residues.

References

  1. Wright R.G., Tapscott B., 1995 Alternative Livestock Survey of Ontario Deer Producers. (1995) Ontario Ministry of Agriculture, Food and Rural Affairs.
  2. Mackintosh C.G., Qureshi T., Waldrup K., Labes R.E., Taylor M., Murphy A., Johnstone P., Persistence of Moxidectin Activity Against Nematodes in Red Deer. NZVA Deer Branch Conference Proceedings . (1997) p.149-154.
  3. Connan R.M., Observations on the Epidemiology of Gastrointestinal Nematodes of Red Deer in Central Southern England.. Veterinary Record (1996) 139: p.228-232
  4. Waldrup K.A., Mackintosh P.D., Johnstone P.D., Labes R.E., The Effects of Parasitism on Weaner Deer: Parallel Studies with Red Deer Hinds and Wapiti Hybrid Hinds. Proceedings of a Deer Course for Veterinarians (1994) No.11, p.193-202.
  5. Waldrup K.A., Mackintosh C.G., Fading Elk: Syndrome Research. Proceedings of a Deer Course for Veterinarians (1992) No.9, p.170-174.
  6. Lancaster M.B., Andrews S.J., Observations on the Output of Nematode Eggs in Faeces and on the Subsequent Pasture Infestation with Third Stage Larvae Produced by a Herd of Farmed Red Deer (Cervus elaphus). Veterinary Record Dec 21/28, (1991) p.549-551.
  7. Ministry of Agriculture and Fisheries New Zealand, Registered Animal Remedies for Use in Deer as of 06 May 98, Wallaceville Research Centre, New Zealand.
  8. Compendium of Veterinary Products, North American Compendiums Ltd., 5th. edition, 1997.
  9. MacKintosh C.G., Mason P.C., Manley T., Baker K., Littlejohn R., Efficacy and Pharmacokinetics of Febantel and Ivermectin in Red Deer (Cervus elaphus). New Zealand Veterinary Journal (1985) 33, p.127-131.
  10. Ministry of Agriculture and Fisheries New Zealand, Registered Animal Remedies for Use in Deer as of 19 Dec 1994, Wallaceville Research Centre, New Zealand.
  11. Connan R.M., Observations on the Epidemiology of Gastrointestinal Nematodes of Red Deer in Central Southern England, Veterinary Record (1996) 139: p.228-232.
  12. Waldrup K.A., Rhodes C.G., Labes R.E., Wilson P.R., Gastrointestinal Helminthosis in Fallow Deer (Dama dama) and their Response to Treatment with Anthelmintics. Australian Veterinary Journal (1991) Vol 68 No.2
  13. Waldrup K.A., Mackintosh C.G., Fading Elk: Syndrome Research. Proceedings of a Deer Course for Veterinarians (1992) No. 9, p.170-174.
  14. MacKintosh C.G., Waldrup K., Labes R., Taylor M., Efficacy of Ivermectin Pour-on Formulations in Young Red Deer (Cervus elaphus). Proceedings of a Deer Course for Veterinarians (1992) No. 9, p.155-161.
  15. MacKintosh C.G., Mason P.C., Manley T., Baker K., Littlejohn R., Efficacy and Pharmacokinetics of Febantel and Ivermectin in Red Deer (Cervus elaphus). New Zealand Veterinary Journal (1985) 33, p.127-131.
  16. Andrews S.J., Ferrari M.M., Pow D.E., Lancaster M.B., Nematode Egg Output and Plasma Administration to Red Deer (Cervus elaphus elaphus) Veterinary Record (1993) 132, p.161-163.
  17. Mylrea G.E., Mulley R.C., English A.W., Gastrointestinal Helminthosis in Fallow Deer (Dama dama) and their Response to Treatment with Anthelmintics. Australian Veterinary Journal. (1991) Vol 68 No.2.
  18. Mackintosh C.G., Qureshi T., Waldrup K., Labes R.E., Taylor M., Murphy A., Johnstone P., Persistence of Moxidectin Activity Against Nematodes in Red Deer. NZVA Deer Branch Conference Proceedings (1997) p.149-154.
  19. Middlelberg A., Wilson P.R., The Proceedings of a Deer Course for Veterinarians No. 11, Queenstown, New Zealand, June (1994), p.203-205.
  20. Mackintosh C.G., Personal Communication, April 24, 1998.
  21. Jacobs S., Personal Communication, Ayerst, May 20,98.
  22. Product Data: Ivomec-Eprinex ®
  23. Pfizer Animal Health, Personal Communication.
  24. Wilson P.R., Audig'e L.J.M., Morris R.S., On-farm Internal Parasite Control: Luck or Design. NZVA Deer Branch Conference Proceedings (1997).
  25. Rehbein S., Haupt W., Schaschke R., Rosigkeit H., Investigation on the Efficacy of Ivomec Pour-on Against Lungworms and Gastrointestinal Nematodes in Encysted Fallow Deer and Influence of Regular Anthelmintic Treatment on Performance. Zeitschrift-fur-Jagdwissenschaft (1993) 39, 1, p.1-14.

For more information:
Toll Free: 1-877-424-1300
E-mail: ag.info.omafra@ontario.ca
Author: Dr. Bob Wright - Veterinary Scientist, Equine and Alternative Livestock/OMAFRA
Creation Date: February 2000
Last Reviewed: 28 September 2015