Selecting for fly strike resistance? Is it a selectable trait or not?

[Coximus]

As the title says -
Obviously excluding the wool shedding element,
I am referring say to a skin element, or some other mechanism that deters, or prevents strike?

I say this today having gone through my logs to find that since I stopped Preventative treating the summer mob-grazed flock (as they are moved after not more than 72 hours, so handled through a race easily, and on small paddocks usually 2ac or so catching them is no issue) - that their is a definate pattern, the same ewes and their relatives getting struck, often in similar places, and none of these had messy bums - thats a once strike offence in my outfit.

I've found that one group, all related off one hard hill farm, of swaledales has often been struck and survived before I find out - The strike causing a patch of damage but not spreading - yet animals from another source nearby go down fast and get covered in it as youd expect.

My Rarebreed Hebrideans tend to only get struck round the udders but it rarely spreads, and they again are usually only noticed at handling.

Yet Tex x's tend to get eaten alive in 24 hours after it starts.

As I cant identify any specific trait, other than after the fact survival, is their any other way of measuring this?

Is it skin thickness? Skin Tightness? Skin toughness?
Is it a smell? The greasyness?

 

[Nithsdale]

It's not the skin as such.. but the wool type.

 

[glensman]

As the title says -
Obviously excluding the wool shedding element,
I am referring say to a skin element, or some other mechanism that deters, or prevents strike?

I say this today having gone through my logs to find that since I stopped Preventative treating the summer mob-grazed flock (as they are moved after not more than 72 hours, so handled through a race easily, and on small paddocks usually 2ac or so catching them is no issue) - that their is a definate pattern, the same ewes and their relatives getting struck, often in similar places, and none of these had messy bums - thats a once strike offence in my outfit.

I've found that one group, all related off one hard hill farm, of swaledales has often been struck and survived before I find out - The strike causing a patch of damage but not spreading - yet animals from another source nearby go down fast and get covered in it as youd expect.

My Rarebreed Hebrideans tend to only get struck round the udders but it rarely spreads, and they again are usually only noticed at handling.

Yet Tex x's tend to get eaten alive in 24 hours after it starts.

As I cant identify any specific trait, other than after the fact survival, is their any other way of measuring this?

Is it skin thickness? Skin Tightness? Skin toughness?
Is it a smell? The greasyness?

@Global ovine should be able to answer your question.

 

[Tim W]

Yes, i am convinced that there is some linkage (through wool type or not I don't know)
Record, select, cull ---improve

 

[andybk]

its always the same ones affected first as a rule , have killed out any struck last couple of years , there dosnt seem to be a common wool type have had tight and loose coated affected , it maybe the scaring from a previous strike creates a break in coat to allow fly easy access another year or the scarring stays damp longer ,

 

[Tim W]

it maybe the scaring from a previous strike creates a break in coat to allow fly easy access another year or the scarring stays damp longer ,

Agree --- if you keep a struck animal you're asking for trouble

 

[It was already broken.]

Definite genetic propensity to get strike. Not always the weaker animals which I used to think. I would say the texel x mules are the least likely in my case.

 

[Poorbuthappy]

@NZDan

 

[David.]

Certain sheep are serial offenders, must have "victim" stamped on them.

 

[jemski]

I'm pretty sure it's something to do with their sweat glands and smell....

 

[jemski]

And I'm pretty sure it's definitely heritable.

 

[NZDan]

Oz and NZ have done some research, it's very repeatable and very heritable. The basics of it are cull cull cull. It's easy fixed if you stop whole mob treatment and just treat and cull individual animals.
I'll edit this. It's easy diminished if your ram breeder stops whole mob treatment and just treat and cull individual animals

 

[Coximus]

Well I just removed 18 animals for it today. It's a 1 strike and out policy anyway for me but good to.knos...

 

[Keepers]

Is it not to do with how open the fleece is?

So with breeding for a "tight skin" look in our fat lambs have we not selected for a higher tendency towards strike.
Whereas the more open/loose fleeces are less prone to attracting flies due do not holding as much heat in as the tighter ones?

 

[tepapa]

Fancy tight skinned sheep are definitely more prone as are texels on the whole. Should think its to do with sweat and breath ability of theh wool to dry.
When out shearing you often see the same sheep maggot year after year with scars from last time.

 

[NZDan]

Is it not to do with how open the fleece is?

So with breeding for a "tight skin" look in our fat lambs have we not selected for a higher tendency towards strike.
Whereas the more open/loose fleeces are less prone to attracting flies due do not holding as much heat in as the tighter ones?

Yes but no, Iol

 

[llamedos]

Moisture is the key, followed by the scent that the flies pick up, and once the first fly has laid her eggs she then gives off a scent which attracts other females to the same site.

 

[Pan mixer]

I think that some ewes are more prone to it as they are too thick (in the mind and possibly the body) to bite out the maggots.

 

[johnflimston]

I heard it was to do with the lanolin, shedders don't have it so even if grading up ewes have wool they are less likely to get struck.

 

[Tim W]

I heard it was to do with the lanolin, shedders don't have it so even if grading up ewes have wool they are less likely to get struck.

I have a presentation somewhere explaining this-----the more hair follicles and less wool follicles= the less lanolin & sweat and therefore the less attractive to flies
(Dr Rolf Minhorst did the presentation)