Deer Health Flashcards
What are the five main diseases of farmed deer in NZ?
- Yersiniosis (bacterial infection)
- facial eczema (toxin)
- Leptospirosis (zoonosis)
- internal parasites
- copper deficiency
What bacteria causes Yersiniosis?
Yersinia pseudotuberculosis
What triggers outbreaks of Yersiniosis in deer?
stress, particularly at pre-rut weaning. such as:
- separation from mothers
- cold, wet, windy weather
- underfeeding or a sudden feed change
- transportation
- a heavy internal parasite burden
- mixing with strange deer
What are the clinical signs of Yersiniosis in deer?
- deer are dull, don’t eat, and stand apart from the rest of the mob
- green, watery diarrhea that turns dark and bloody as the disease progresses
- scouring causes rapid dehydration and weakness
- some deer may be found dead without having shown any signs
What are the prevention methods for Yersiniosis?
- vaccination
- reduce the stress of weaning
When does passive immunity to Yersiniosis wane in deer?
12 weeks
When should you vaccinate for Yersiniosis in deer?
- should be at least 12 weeks old for the first vaccination, with a booster 3 to 4 weeks after
- max protection not reached until 10 days after the second dose
- first dose before weaning, second at weaning
- give two doses before transport
How do you reduce weaning stress in deer?
- wean fawn back into the same paddock
- ensure good pasture quality and shelter
- reduce parasite burden
- provide older nanny hinds
- use long range weather forecast to choose weaning dates
What causes facial eczema?
Pseudopithyomyces chartarum, which is a fungus
Explain the process of how facial eczema may spread
- Pythomyces chartarum releases spores in warm, humid weather
- spores stick to the grass and are consumed when stock graze
- spores contain sporidesmin A toxin, which concentrates in bile and urine and causes damage to the bile ducts and bladder lining
- this results in a build up of phylloerythrin, which is a natural photo-active product of chlorophyll breakdown and causes photosensitization in pale areas
What are the clinical signs of facial eczema in deer?
- deer stand or lie down away from the mob
- may seek shade
- can be extremely restless
-frequent shaking of the head and ears - frequent licking of the lips and nostrils
- tending to rub affected parts on the ground or fence (muzzle, eyes, ears)
- may be signs of impaired sight and frequent urination
- excretion of the toxin can cause hemorrhagic lesions and ulcers in the urinary tract
- abdominal pain from duodenal ulcers
- photosensitivity is only seen in extreme cases
- can lead to scouring, protein loss, and ill thrift
What are methods to prevent facial eczema?
- monitor pasture spore counts, feed alternative silage once the spore count reaches 20,000/gm pasture
- spray pasture with carbendazim fungicide (150gm/ha)
- minimise dead litter
- don’t make stock graze too low
What are the ways to treat deer with facial eczema
- take deer off of the toxic pasture and supply alternative feed
- house them in a dark shed, especially during daylight hours, or provide effective shade
- severe cases may require vet treatment with fluids and vitamins, or euthanasia
Why is zinc treatment potentially ineffective in deer?
- boluses not tested, and deer are difficult to bolus
- water treatment is unreliable because deer drink small amounts
What causes Leptospirosis?
- Leptospira interogans
- Leptospira borgpetersenii
What are the common serovars of L. interogans and L. birgpetersenii?
- pomona
- hardjobovis
- tarassovi
- copenhageni
- icterohaemorrhagiae
Which host species carries what serovars of Leptospirosis?
- cattle/deer: hardjobovis
- pigs: pomona and tarassovi
- black rat: ballum
- Norway rat: copenhageni
Which serovars are deer a secondary host for?
- L. interrogans serovar pomona
- L. interrogans serovar copenhageni
When should fawns be vaccinated for Leptospirosis?
- as soon as possible after they reach 12 weeks of age
- before they become exposed to the disease, which can make them a carrier and isn’t cured by vaccination
What are the methods of prevention of Leptospirosis in deer?
- avoid direct or indirect contact with unvaccinated dairy cattle or deer
- ensure deer are not exposed to effluent or run-off from pig or dairy cattle farms
- minimize run-off from neighboring farms
- control rodents, wild deer, wild pigs, and possums
- vaccinate all deer on the farm
- buy in only vaccinated deer or treat and vaccinate all incoming deer
What are the most common parasites in deer?
- lungworm
- Ostertagia type gut worms
What are the signs young deer may have internal parasites?
- decreased growth rates (gut worms)
- increased death rates (lungworms)
How frequently should you drench deer to prevent internal parasites?
- every 28 days from weaning, 4 or 5 times
- may need to start pre-weaning
Define refugia
A refuge for worms so that non-resistant (susceptible) worms remain in the population base, which means they can reproduce to restock refugia and may also breed with resistant worms to increase their susceptibility. The ideal refugia is when the reservoir of susceptible larvae on pasture significantly outnumber resistant larvae
