[Backinwellies]

A follow up to a previous post (where 2 completely opposing opinions were given)  .... and an annual debate ......   

How Do Clic and Crovect work?  .... and which is best when?  ..... only real info please not personal experience 

[twizzel]

Crovect only prevents strike on the bits of wool it’s sprayed on. Lasts 6-8 weeks. Treats for ticks I think too and lice.


Clik spreads throughout the wool so protects the whole body. Clik lasts 16 weeks, click extra 19 weeks, clikzin 8 weeks. They all work in the same way (spread and cover the whole body). Clik wont stop flies laying eggs, but they will hatch and die before they get to the damaging stage.


An elanco rep told me crovect pre shearing and to treat established strike, Clik after shearing to protect for rest of season.

[SallyintNorth]

To clarify, the liquid in the Crovect bottle can be used for :

- lice
- ticks
- flystrike prevention
- active flystrike

BUT, the method of application differs for each. 

So it's *not* "one treatment covers all ectoparasites", but it *is* "one bottle can meet [almost] all my ectoparasite needs".  (Covers biting/chewing lice but doesn't cover sucking lice.)

[SallyintNorth]

For those concerned about environmental impact and residues in food (and wool)...

Both products are very harmful to aquatic life (albeit cypermethrin is not very persistent in the environment) and treated sheep should be kept away from watercourses for at least an hour after treatment.  Unused product and empty containers should be disposed of appropriately.

The Defra info sheet about Clik/Clikzin stipulates that treated sheep should be handled as little as possible in the weeks after treatment, protective clothing should be used if handling is unavoidable, and treated sheep should not be shorn for 3 months.  No equivalent warning for Crovect (although many of us prefer to not shear for a minimum of one month, and the Natural Fibre Company stipulate 3 months.)

Accirding to the Defra info sheet, Cypermethrin, the active ingredient in Crovect, has no tendency to accumulate in animal tissues, whereas figures are given for the half life of dicyclanil, the active ingredient in Clik/Clikzin, in the liver (13 days) and kidneys (10 days) with unchanged dicyclanil being found in muscle, fat and wool. 

Crovect accordingly has a milk withdrawal period of 5 days but Clik/Clikzin must not be used in animals producing milk for human consumption at all.  Crovect has a meat withdrawal period of 8 days, Clik/Clikzin 40 days. 

The info sheet for dicyclanil also specifically mentions that use of this product harms dung flies.  No such statement appears in the Cypermethrin sheet.

The Cypermethrin sheet mentions that an overdose can cause neurological symptoms, from which the animal (or presumeably human) will generally recover within a week.  Whereas the dicyclanil sheet lists no known symptoms arising from overdosing at up to 5 times the recommended rate.

You can read these sheets for yourself if interested. Cypermethrin (Crovect).  Dicyclanil (Clik/Clikzin).

[SallyintNorth]

I made a checksheet to compare these factors, for ease.  Either save the pic and open it in your own app, or I've done my best to make a table of the info in the post below.

[SallyintNorth]

Product name	Crovect	Clik et al
Active ingredient	Cypermethrin	Dicyclanil
Precautions at treatment	Wear protective clothing	Wear protective clothing
	Keep animals away from watercourses for one hour	Keep animals away from watercourses for one hour
Impact of overdose	Neurological symptoms, will clear within one week	None
Precautions post treatment		Handle as little as possible for several weeks.  If handling unavoidable, wear protective clothing
		Do not shear for 3 months
Environmental warnings	Toxic to aquatic insects and crustaceans - but is not very persistent in the environment	Serious risk to aquatic life
		Harms dung flies
Active ingredient accumulates in tissues	No	Yes
Metabolised before excretion	Yes	No, or only partly
Milk withdrawal	5 days	May not be used in animals producing milk for human consumption
Meat withdrawal	8 days	40 days

 

[SallyintNorth]

:bookmark: Clik vs Crovect - environmental issues and residues

[shep53]

Sally has given a very good explanation , you could look at the active ingredients  in wikipedia for more in depth .  If you read the data sheets you get all the relevant information  as sally says crovect covers many insects , just applied in different ways at different dose rates  , when fan sprayed to prevent blowflies   crovect sticks to the wool and does not spread , when applied as a pin stream down the spine for lice & ticks  it travels all over the body via the lanolin . For headfly a small amount is applied via a t-bar and stays in place on the top of the head  the same for blowfly treatment the small amount stays in the treated area  again via t-bar  .  Clik  etc  has a product called fleece bind  so when applied via fan spray it spreads and sticks to the fleece  and if the sheep is damp or very light rain after application it spreads more

[Badger Nadgers]

There's also Alphacypermethrin (Dysect/Zemasect), which I think of as "super crovect"