Ten weeks before they are due to lamb is the optimum time to copper ewes, or so it says on the label. We don't rightly know at which date each ewe is going to lamb so tend to go from ten weeks from the start of the lambing, which does actually give a bit of lea way if necessary.
So why would you copper ewes? Copper deficiency causes something called swayback in the lambs when they are born and once born with swayback there is no way of curing the problem (or not that I am aware of).
Swayback (sometimes called swing back) is exactly what the word suggests, the lambs show swaying in their backs, sometimes so severe it almost looks like a paralysis of the back end with hips and rear legs trailing behind them. Milder cases often don't show unless the lamb is stressed. For instance they can trot along merrily with their mother in the fields and possibly appear almost normal, set the dog around and try to gather them up and the lamb will start wobbling on the back end, the back legs will tip over as it rushes and panics and the signs of swayback become only too obvious.
Treating sheep with copper is a preventative approach to the problem. Not all the lambs will suffer from swayback but those that do have a difficult existence and are unable to be put forward for sale, it's often kinder to put them down at birth and adopt another lamb onto the ewe. Therefore, it is kinder all round to prevent the problem from arising in the first place, especially when the cost could work out at less than 20p per lamb.
There are some sheep which don't suffer from copper deficiency. Hill ewes, running on black ground (heather) do not suffer from the deficiency, obviously heather must naturally harbour copper enabling the sheep to have sufficient in their system. Pure bred Texel sheep are also able to retain copper in their systems and so don't require coppering.
These are important facts to know because not only do sheep suffer from copper deficiency but they can also suffer from copper poisoning, the last thing you would want to do is administer copper to animals which don't require it. Over the years through trial and error it has become apparent to farmers and shepherds which sheep are susceptible to either complaint. Basically, those running on green ground or less acidic ground are the ones often vulnerable to copper deficiency.
One farm I work on has a black heather hill, the farmer took the tenancy for this farm a few years back and knew the ewes wouldn't need coppering, he kept the older ewes in the field ground and started a fresh flock of in-bye sheep which were retired off the hill, ewes which had never had any trouble with a deficiency of copper, within a couple of years he was having swaybacked lambs born to these ewes, not many but too many. That in-bye flock is now inoculated with copper and no swayback lambs are born anymore. The hill ewes are still fine as they are still out on the heather. Lesson learnt.
A few lambings back there was trouble in the shed I was lambing in. Hired to do a night lambing on mule ewes which were housed in a shed and things started to go wrong. A few sheep were 'going off' pre lambing. Odd ewes were beginning to go dour, lethargic. Now there are a number of reasons for such things, mild twin lamb disease was suspected, however after lambing down more ewes were going off - lying around, not interested in their lambs. The nearest thing I could put it down to was milk fever.
There is nothing more frustrating, you want to do a good job, do the best for the sheep and nothing seems to work, a truly disheartening position to be in. At the time lamb prices were very poor, sheep had little value and vets bills were high. Eventually the farmer succumbed, I whinged sufficiently until he was either going to sack me or call in the vet, I was lucky the vet was called in.
Blood tests were taken from a cross section of the sheep, healthy ones, poorly ones, in between ones. A couple of days went by and the results came through - mild copper poisoning! The problem was rectified by turning the sheep out onto grass during the day and the feed merchant was notified and swallowed humble pie. The wrong sheep feed had been delivered with the last order and it contained copper. It was a hugely frustrating time for Shep but an interesting one too. A situation I had never come across before - a learning curve.
So, in January ewes are finding themselves being either injected with a copper solution or having copper boluses administered orally. Some administer these boluses at tup time as they are slow releasing and cover the copper problem for six months, others wait until the ten weeks before lambing to administer them.
The above ewes are a prime example of the in-bye type sheep living on green ground which require copper. The ugly whiter faced things in the foreground are the bluefaced leicesters, the browny faced ones are mules and one white faced one towards the rear left corner is a texel cross which wouldn't have been coppered.
Above we have a 'gun' used for the administration of copper bullets. The nozzle of the gun is put into the sheep's mouth and pulling the trigger operates a spring which then shoots the bullet to the back of the throat, care has to be taken as you don't want to damage the sheep's throat and you don't want her to spit the bullet out either. The bullets are full of small copper filings and the coating 'melts' when in contact with moisture (can be difficult to use on wet days). The bullet finds itself in the stomach where the coating dissolves leaving the copper filings to be slowly absorbed into the bloodstream.
The other option is to inject a copper sulphate solution by means of an automatic syringe (see below) attached to a bottle of the solution. This is injected directly into the muscle, again taking care not to inject in a site which may cause tendon or nerve damage. There is a plate of muscle either side of the tail head which many years ago a vet student who was lambing with me advised was one of the best places to inject as there is nothing sitting in there which could be damaged, however, on lean sheep this is not always the ideal place due to it being a small area of muscle. Everyone has their preferred sites.
Occasionally syringes break down, bullets get spat out and aren't noticed until they are on the ground, or sheep break out of the dosing pen and mix with others. It's a shepherd's worst nightmare and one thing we dare not do is treat the whole lot again in the hope of catching the ones which were missed. We would not like to inadvertently poison the sheep. When such problems arise fingers are crossed and it is hoped the one or two which somehow missed treatment will be the one or two which weren't likely to give birth to a swaybacked lamb.
