Pneumonia Treatments

Over the years there have been many developments in the different ways that we have been able to treat pneumonia in cattle. At first the standard treatment was oxytetracycline to limit the growth of bacteria that thrive when there is damaged tissue in the lungs. This was thought to work well until a long acting preparation was brought out which meant that one injection could be given to control the disease and you did not have to stress the animal to give daily treatments. Soon it was realised that in many ways it would be better to stop the animals getting the problem in the first place rather than to try and treat it once it occurred.

Early Vaccines

The first vaccines gave limited immunity, but even so they were an essential tool on some farms where losses were heavy. As several pathogens are active on most farms, as soon as action was taken to control one of the viruses or bacteria one of the others would become more active and cause disease. The drugs used to treat the disease have improved considerably as well. Antibiotics have been developed to target the bacteria that invade the lungs some of these are very sophisticated as they are taken to the diseased tissues by white blood cells that are responsible for eliminating the infection. In some countries intra muscular injections for meat producing animals are banned so they have been developed to be given as a single low volume subcutaneous injection that will deliver treatments levels for several days.

Because pneumonia is a complicated disease it was soon realised that it is not only the bacterial infection that does the damage but the reaction of the calf to it. Cattle have only a limited respiratory capacity. Reaction to infection causes inflammation and fluid to accumulate in the lungs this will block airways and stop parts of the lung functioning for gas exchange. Also animals with pneumonia develop temperatures that stops them eating.

Other Drugs

It was soon realised that anti inflammatory drugs have a role to play to limit this damage. At first cortico steroids were use, these seemed to give good results at first, but after three or four days calves deteriorated and succumbed to the infection. This was because conventional steroids have an adverse effect on the immune system and allow the viruses and bacteria to multiply unchallenged. The next generation of steroids were developed to reduce inflammation, but not to damage the immune system so that the calf could not fight off infections. These are the non steroidal anti inflammatory drugs. At first these would only work for twenty four hours and as they were irritant they were given by daily intravenous injections. As time went on drugs with specific properties that target the damage to the lungs and help to bring down the body temperature were found. These too can now give good results if given by a single subcutaneous injection.

Ideal Combination

The ideal drug to treat pneumonia is one that maintains the airway, reduces the temperature so that the calf starts feeding again and combats the bacterial infection that starts as soon as there is damage to the lungs. Some years ago Schering Plough introduced a product that combined oxytetracycline with finadyne there non steroidal anti inflammatory drug. This gave good results at first particularly for young calves in the early stages of pneumonia. After a time it was found that other drugs were more effective and it was eventually withdrawn. This was I think partly because of the choice of antibiotic and because ox tetracycline is only absorbed slowly after subcutaneous injections so it could not be used at all in some countries. Now they have found a way of combining their pneumonia antibiotic florfenicol with finadyne in a single dose subcutaneous injection. This looks promising as both drugs have a proven track record. It might well be that this will become the first choice drug to use now that micotil is under restrictions because of safety concerns.

Sheep and Copper

When sheep are in their third month of pregnancy the spinal chord of the lambs are starting to develop. This can only happen properly if there is sufficient copper in the blood stream of the ewe. Some sheep notably Black Faced ewes find it difficult to absorb enough copper from their feed to allow their lambs to develop properly. That is why some lambs are born with swayback and struggle to survive. The problem with copper is that too much can be as harmful as not enough. In excess it can overwhelm the liver and stop normal metabolic functions. If you are not sure that you have got things just right blood copper levels can be monitored from sheep when they get to the second half of their pregnancy so that supplements can be given before the lambs develop too far for the changes to the spinal column of the developing lambs to be repaired.

Testing Barren Ewes

Have you got more barren ewes than you were expecting? The tendency is to blame the rams, or maybe the weather if it was still very hot when the ewes first went to the ram. Often the explanation is that the ewes did become pregnant for a short time, then the pregnancy was lost to the Toxoplasma parasite. It may then be too late for it to clear up and for the ewe to get in lamb again. Intervet are again sponsoring blood samples from barren ewes to discover if toxoplasma is involved. They only do this because they are confident that when you get the results you will make a note in your new diary for next summer to order some of their vaccine to stop it happening again next year. It is an expensive business keeping and feeding barren ewes. Toxoplasma sometimes only affects one of the foetuses in the uterus. It will affect the overall lamb numbers. It is the barren ewes that are the most useful indicators of how active the infection is in the flock.

Bird Flu

Another year has passed and there have been no significant developments in our poultry flocks as far as Avian Influenza is concerned. Hopefully that will continue to be the case as our near neighbours in Europe have not been so lucky. There is still a great deal of hysteria concerning this disease. It is an infection that we can contain if it were to get established here.This has happened in the past almost unnoticed and there is no reason why it should not happen again. The real concern is if it were to mix with the human flu virus and transmit between people in countries where there is closer contact between people and poultry. That is the aspect of the disease that we are not prepared for.

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