Ruminant Dermatology Flashcards
What fly infestation is seen?
a. face fly
b. deer fly
c. horn fly
d. horse fly
e. stable fly
A
What fly is likely affecting this cow based on location?
a. face fly
b. deer fly
c. horn fly
d. horse fly
e. stable fly
C
What fly is likely affecting this cow based on location?
a. face fly
b. deer fly
c. horn fly
d. horse fly
e. stable fly
E
Where do face flies lay their eggs? What unique aspect affects control measures?
newly deposited manure - hatch within a day and complete their lifecycle within 14-21 days
strong fliers - can fly several miles to find a new meal/mate
What face fly commonly affects ruminants? Where are they most commonly found? What are they a vector for?
Musca autumnalis
feed on secretions of eyes, muzzle, and open wounds with spongy mouthparts
pinkeye
What is the main way of controlling face fly infestation?
insecticidal fly tags placed in ears a few weeks before peak fly season (July-Aug)
When are fly tags for controlling face flies removed? Why?
fall - decreases fly resistance due to low concentration of insecticide left at this point
Are fly takes used for controlling face flies placed in both ears? What breed commonly does not require any tags?
depends on susceptibility and prevalence.incidence of disease
Bos indicus - larger ears make tags not as useful
Other than fly tags what are other options for face fly control?
- dusting/dusting bags
- oilers, back rubbers
- whole animal sprays
- oral insecticides incorporated into mineral blocks or feed (Rabon, Methoprene (IGR), Dimilan)
- biological control with Pteromalid wasps that deposit their eggs within the pupa case of flies and larva feed on developing flies (not as effective in pasture situations)
How long do most insecticidal fly tags last?
variable - depends on fly resistance
What horn flies commonly affect cattle? Where do they lay their eggs?
Hematobia irritans - disease vector with sabre-like proboscis, which allows transfer of blood-borne disease
fresh manure (same control as face fly!) —> overwinter in puparium near or under manure pats
How do horn flies act?
adults stay on host continually, unless laying eggs —> good weather = sides and back, bad weather = ventrum
- swishing tail can spread flies to nearby cows in the herd
How much blood can horn flies take from their host? When are control measures performed?
500 flies = 7 mL blood loss/day (>200 flies on a cow starts affecting economics)
pour-on ivermectin products and tag when 200 flies are present per head —> recommended to start just as horn flies start appearing in the spring
What part of the environment is commonly affected by horn fly control measures? What alternative is preferred to avoid this?
dung beetles —> ivermectin kills
cydectin does not affect them
Why are multiple measures of fly control recommended for herds?
flies commonly become resistant to the pyrethroid/OP found in the ear tags
- pour-ons
- dusting
- fly traps
What is a stable fly? What are their preferred feeding sites?
Stomoxys calcitrans —> biting house fly with sabre-like mouthparts (transmits blood-borne disease)
lower extremities and flanks during the day - only on the host when feeding
How can stable flies be controlled? What are they linked with spreading?
- clean environment
- eliminate breeding sites
- UV zapper and other predatory systems
- insecticides (pour-ons, dust bags)
- feed additives
HIV
In what 5 ways can breeding areas of stable flies be controlled?
- remove manure and rotting vegetation
- clean up spilled silage and broken bales
- fix leaky water and pipes
- provide drainage around silage pits and pens
- remove decaying spilled grain
What kind of hosts do lice prefer? How do they complete their life cycle?
highly host specific - bovine lice will not feed on humans
takes 3-4 weeks and spends it entirely on the host —> eggs hatch in 8 days, so long-term treatment is not necessary
Once treated, when should cattle with lice be retreated? How does this compare with different types of lice?
14 days
- BITING lice feed on epithelial and cutaneous debris, so topical treatments are enough
- SUCKING lice feed on blood and tissue fluid, so systemic treatments are needed