Copper and Sheep

We normally think of copper as a soft metal that has the useful property of being able to conduct electricity. It is also an essential trace element that is important because of the way it is present in the sheaths that surround nerves. If there is a shortage in the body nerves do not develop properly. If there is an excess in the diet irreversible liver damage can occur.

Getting the right Balance

It is important for sheep to get the right balance of copper in their diet. Hill sheep on improved pastures can suffer a shortage as the mineral is not taken in fast enough by plants from the soil. Through most of the year this is not a problem for sheep. If there is a shortage when the nervous system of the developing lambs is forming there can be permanent damage to the way that nervous impulses are transmitted to the hind limbs. Essentially most of the messages do not reach the muscle fibres and the lamb is weak on the hind end or is not able to stand. This is what we know as Sway Back.

No Treatment Option

This is a good example of a condition that you have to prevent as it is not possible to treat it once the spinal cord of the lamb has formed in the second half of pregnancy. A blood test from six to eight pregnant ewes will tell us if there is a problem with copper intake. The condition can be rectified using either copper injections or getting the ewes to swallow a bolus containing the mineral. This must be done before the spinal cord forms in the last eight weeks of pregnancy. 

Copper Toxicity

Most minerals when given in excess will remain in the intestinal tract and pass harmlessly through the body. Unfortunately sheep absorb all of the copper in their diet and process the excess with their liver. This can lead to serious toxicity problems. The liver is not able to function properly the animal becomes anaemic and the membranes around the eye will become jaundiced. Ewes will show signs of copper toxicity if they are fed concentrate with excessive levels over a prolonged period. Diets for pigs have high concentrations of copper included and should be avoided. Texel sheep are particularly sensitive to excessive levels of copper and care should be taken if they are on concentrate rations for long periods.

Tuberculosis and Goats

We are all too familiar with the problems that tuberculosis will cause to our cattle herds and the relentless progression of the disease. We have got used to deer having the disease and have come to rely on the game dealers that dress the carcasses to be conscientious and report any tubercular lesions that they might find.

In the summer of 2008 there was a serious outbreak of tuberculosis in goats involving 22 animals on four different farms. All of these reactors had come from a single goat herd that was dispersed to different parts of the country. Prior to this there has only been one reported incident of bovine tuberculosis in goats in the past fifty years. Tuberculosis is becoming a serious concern in goats, there is no official testing system, although reactors can be identified using the intra dermal tuberculin test that we use on cattle. If you have any goats that develop pneumonia that does not respond to conventional treatments you should be aware of the possibility of tuberculosis and have your herd investigated.

Action Needed

In many ways it should not be me who is telling you this, but DEFRA have been slow to react to the changing disease situation and do not seem to appreciate the risks to human health. Many adults and children have close contact with goats. Milk from small scale goat herds is not usually pasteurised. These are inquisitive animals that like to investigate things with their mouth and nose and can readily pass on any infections they are carrying. At the moment DEFRA will not usually finance tuberculin testing in goat herds, though they do insist that we send them a copy of the results.

Investigating Itchy Sheep

This winter so far has been colder than those of recent years and it has been noticed that there are more flocks trying to cope with sheep scab. For some reason sheep with scab seem to start rubbing around the time that they are due to lamb. This is the time when you are busy and they are most difficult to treat. Sheep with scab tend to get severe flaking on the skin and they will readily damage themselves. Lice will also cause itching, but it tends to be milder and there will be limited wool loss at first. We can usually tell fairly easily what is making your sheep rub if you can bring in some wool samples. The best samples are to pluck wool on the edge of the lesions away from the head. Pull several handfuls of wool from each ewe and mix them in a bag for us to examine at the surgery. We have found that young lambs do not usually get scab from the ewes and it is better not to treat them less than two weeks of age unless they are showing lesions.

Horses with Scabs

From time to time we have problems when horses get ringworm. Often the lesions are fairly innocuous, but they are readily spread to other animals in the group and the people who handle them. Sometimes it is not until somebody who has been in contact with the animals starts to get lesions that it is realised where the infection has come from. Hoses tend to get ringworm on their head and neck. The lesions are not usually itchy, there will be crusting on the hair follicles near the skin and some hair loss.

Treatment Options

It is not easy to control ringworm as many of the better drugs are not now licensed for treating animals. Imaverol is still available. It is an emulsion that needs to be diluted with water then sponged or sprayed onto the animal every three days for two weeks. It is better to cover the whole of the body surface the first time not just the lesions. Also when you get to the last wash it is important to drench any tack and wash rugs that have been on affected animals as they will pass the infection back to the horse when the drugs have worn off. There is one company that still has a product license for a powder that is mixed in with the feed to treat ringworm. This has been phased out for treating all other animals because of concerns about liver disease and foetal anomalies in both the treated animals and those caring for them. We are not able to recommend this course of treatment anymore because of these concerns.

Have Your Say

A comprehensive description of the history of bovine TB in England since 1980 is being compiled by researchers at Reading University. They would welcome your contribution by visiting www.survey.bris.ac/reading/btb5  Or follow the link from our web site.

Back to Newsletters