It is hard to avoid issues related to clostridia and pasteurella bacteria in Irish sheep flocks.
“Clostridia are everywhere, especially in the soil, but bacteria are also present in areas such as the intestinal tract. Unfortunately, they are largely unavoidable, but thankfully they cannot multiply in fresh air. They are capable though of enveloping into spores and can stay there [in the environment] for years," William Fitzgerald from the Department of Agriculture Regional Veterinary Laboratory in Limerick said.
This, he said, is the reason why some flocks can go for years without experiencing any losses and then suddenly be faced with an outbreak.
Table 1 details the most common clostridial diseases and the causative bacteria species.
Pulpy kidney disease was highlighted as the most prevalent disease in sheep flocks in southern and northern Irish veterinary labs.
“We had 42 cases [in the veterinary laboratory service] in 2014, and 56 cases in 2015. This is only the tip of the iceberg when you consider how many deaths, that would be confirmed, are going to the knackery,” said William.
Pulpy kidney is typically seen in fast-growing lambs and is common in lambs usually over one month of age that are suckling ewes with a high milk yield or in lambs consuming high-concentrate diets. Lambs rarely show any symptoms, with a tell-tale sign often being lambs found dead.
Giving an overview on other common clostridial diseases, William said black disease is most prevalent late or early in the year due to its association with liver fluke infestation.
He said that bacteria picked up in the soil multiply in damaged areas of the liver and produce a powerful toxin, which results in the death of sheep. This is characteristic of many clostridia species which invade dead or dying tissue, multiplying rapidly and causing death.
There has been growth in recent years in cases of abomasitis, which William says is essentially a replica of braxy, but is caused by different clostridia species.
Abomasitis has been seen in young lambs from three to 10 weeks of age and in finishing lambs aged six to 12 months. The exact route of infection is not fully known, with the disease showing the same signs as braxy.
Braxy is associated with yearling or adult sheep and generally occurs when animals are grazing during ground frost. Frozen grass damages the lining of the stomach, giving clostridia an opportunity to infect the damaged tissue.
William said other diseases such as metritis (infection of the womb), lamb dysentery, malignant oedema and big head of rams are also significant contributors to mortality, but are not encountered to the same level in laboratory diagnosis as those mentioned above.
Pasteurella
Pasteurellosis, often known as septicaemic pasteurellosis, is also a significant contributor to lamb mortality. Like clostridia, the bacteria responsible are commonly found in the tonsils and throat of healthy sheep.
When sheep are healthy, these bacteria are kept at bay. However, if the sheep come under stress, brought on by factors such as exposure to very poor weather, poor ventilation, inadequate handling or transportation and excessive heat or overcrowding, bacteria can gain entry to the lungs and multiply, causing
damage.
In the worst cases, bacteria can multiply to a level that they can enter the blood stream and release toxins causing septicaemia. Pasteurella is also associated with mastitis and respiratory disease.
The process of infection occurs within a short time frame, which leads to many cases being identified by post-mortem, with animals often presenting no signs of sickness and found dead.
William says that those that do present signs of sickness are generally at an advanced stage, with low rates of success with treatment.
Maintaining a high standard of hygiene and adhering to manufacturers' product guidelines is part and parcel of ensuring maximum protection.
Vaccination
Given the difficulty in identifying disease onset and the very small chance of making a recovery, vaccination remains the optimum method of control. Table 2 details the vaccination programme for clostridial and pasteurella vaccination outlined at last week’s conference.
Explaining its importance, William said that as colostrum is the only source of antibodies against disease that the young lamb has, it is important that ewes are treated in the recommended time frame to maximise colostrum antibody levels. However, he cautioned farmers that this is only half the battle, with the work carried out of little use if ewes are not managed to produce sufficient colostrum or lambs consume insufficient volumes (50ml per kg bodyweight in first four to six hours). “The sooner a lamb gets colostrum, the more benefit they’ll get from it.”
Moving on to lambs, William says protection gained through passive transfer of colostrum can last anywhere from six to 12 weeks, though for some diseases he said it can be as short as two weeks.
However, he said the regional veterinary labs are seeing greater issues at a younger age and as such his advice is not to delay giving the first treatment and administer at three weeks of age.
“Once a lamb gets to six weeks of age, they’ll enter a point in the danger zone of increasing risk. If vaccinating from three weeks, you are trying to get the lambs’ own immune system working and prepared for when it meets a challenge,” he says.
There are vaccines that can be given at two weeks, but he says it is common practice that they are administered around three weeks of age.
The importance was also stressed of administering a booster shot four to six weeks after the initial treatment. It is vital to read the full instructions that come with vaccines – the manufacturers recommendations will be tailored for their particular product.
“In reality, giving one treatment is not enough to get protection. It will stimulate the immune response, but this can be overcome with a heavy challenge. The booster shot will give an extra lift and ensure lasting protection.”
The advice is to try to cover as wide a spectrum as possible when considering product choice.
How long will the vaccine last once opened?
It varies. It is important to handle and store vaccines correctly. It’s very important to check with each individual vaccine and follow the manufacturer’s recommendations as there are variations between vaccines in this regard.
If I use a product that vaccinates 10 clostridial diseases, should I treat for pasteurella after birth?
Realistically yes, to cover all bases.
What time frame does an animal need to be administered for post-mortem?
Ideally, as soon as possible, but it depends on environmental temperatures. We have been able to make a diagnosis in animals that were dead 24 to 48 hours, but the sooner we get them, the better the chance of making an accurate diagnosis.
Can the vaccine be administered up to two weeks pre-lambing?
You can administer it, but it leaves a shorter time frame for ewes to develop antibodies in colostrum. Also, ideally, you want to keep handling of heavily pregnant ewes to a minimum.
Failing to administer the full primary course (two shots administered four to six weeks apart): This is a common recurrence that leads to inadequate protection.Administering lower volumes: This is essentially false economy, as while it reduces the cost, sheep may not develop an adequate antibody response with the vaccination being worthless.Incorrect storage: Vaccines are sensitive to temperature changes and must be stored as per manufacturers’ instructions.Inadequate product selection: It is highly advisable to select a product that covers the maximum number of clostridia.Technique and cleanliness: Adequate time should be taken to ensure the vaccine is delivered hygienically and as per manufacturers’ guidelines.
Top tip
Lambs should receive 50ml colostrum per kilogramme bodyweight in the first four to six hours of life and 200ml/kg bodyweight inside the first 24 hours. Read more
Sheep management notes
It is hard to avoid issues related to clostridia and pasteurella bacteria in Irish sheep flocks.
“Clostridia are everywhere, especially in the soil, but bacteria are also present in areas such as the intestinal tract. Unfortunately, they are largely unavoidable, but thankfully they cannot multiply in fresh air. They are capable though of enveloping into spores and can stay there [in the environment] for years," William Fitzgerald from the Department of Agriculture Regional Veterinary Laboratory in Limerick said.
This, he said, is the reason why some flocks can go for years without experiencing any losses and then suddenly be faced with an outbreak.
Table 1 details the most common clostridial diseases and the causative bacteria species.
Pulpy kidney disease was highlighted as the most prevalent disease in sheep flocks in southern and northern Irish veterinary labs.
“We had 42 cases [in the veterinary laboratory service] in 2014, and 56 cases in 2015. This is only the tip of the iceberg when you consider how many deaths, that would be confirmed, are going to the knackery,” said William.
Pulpy kidney is typically seen in fast-growing lambs and is common in lambs usually over one month of age that are suckling ewes with a high milk yield or in lambs consuming high-concentrate diets. Lambs rarely show any symptoms, with a tell-tale sign often being lambs found dead.
Giving an overview on other common clostridial diseases, William said black disease is most prevalent late or early in the year due to its association with liver fluke infestation.
He said that bacteria picked up in the soil multiply in damaged areas of the liver and produce a powerful toxin, which results in the death of sheep. This is characteristic of many clostridia species which invade dead or dying tissue, multiplying rapidly and causing death.
There has been growth in recent years in cases of abomasitis, which William says is essentially a replica of braxy, but is caused by different clostridia species.
Abomasitis has been seen in young lambs from three to 10 weeks of age and in finishing lambs aged six to 12 months. The exact route of infection is not fully known, with the disease showing the same signs as braxy.
Braxy is associated with yearling or adult sheep and generally occurs when animals are grazing during ground frost. Frozen grass damages the lining of the stomach, giving clostridia an opportunity to infect the damaged tissue.
William said other diseases such as metritis (infection of the womb), lamb dysentery, malignant oedema and big head of rams are also significant contributors to mortality, but are not encountered to the same level in laboratory diagnosis as those mentioned above.
Pasteurella
Pasteurellosis, often known as septicaemic pasteurellosis, is also a significant contributor to lamb mortality. Like clostridia, the bacteria responsible are commonly found in the tonsils and throat of healthy sheep.
When sheep are healthy, these bacteria are kept at bay. However, if the sheep come under stress, brought on by factors such as exposure to very poor weather, poor ventilation, inadequate handling or transportation and excessive heat or overcrowding, bacteria can gain entry to the lungs and multiply, causing
damage.
In the worst cases, bacteria can multiply to a level that they can enter the blood stream and release toxins causing septicaemia. Pasteurella is also associated with mastitis and respiratory disease.
The process of infection occurs within a short time frame, which leads to many cases being identified by post-mortem, with animals often presenting no signs of sickness and found dead.
William says that those that do present signs of sickness are generally at an advanced stage, with low rates of success with treatment.
Maintaining a high standard of hygiene and adhering to manufacturers' product guidelines is part and parcel of ensuring maximum protection.
Vaccination
Given the difficulty in identifying disease onset and the very small chance of making a recovery, vaccination remains the optimum method of control. Table 2 details the vaccination programme for clostridial and pasteurella vaccination outlined at last week’s conference.
Explaining its importance, William said that as colostrum is the only source of antibodies against disease that the young lamb has, it is important that ewes are treated in the recommended time frame to maximise colostrum antibody levels. However, he cautioned farmers that this is only half the battle, with the work carried out of little use if ewes are not managed to produce sufficient colostrum or lambs consume insufficient volumes (50ml per kg bodyweight in first four to six hours). “The sooner a lamb gets colostrum, the more benefit they’ll get from it.”
Moving on to lambs, William says protection gained through passive transfer of colostrum can last anywhere from six to 12 weeks, though for some diseases he said it can be as short as two weeks.
However, he said the regional veterinary labs are seeing greater issues at a younger age and as such his advice is not to delay giving the first treatment and administer at three weeks of age.
“Once a lamb gets to six weeks of age, they’ll enter a point in the danger zone of increasing risk. If vaccinating from three weeks, you are trying to get the lambs’ own immune system working and prepared for when it meets a challenge,” he says.
There are vaccines that can be given at two weeks, but he says it is common practice that they are administered around three weeks of age.
The importance was also stressed of administering a booster shot four to six weeks after the initial treatment. It is vital to read the full instructions that come with vaccines – the manufacturers recommendations will be tailored for their particular product.
“In reality, giving one treatment is not enough to get protection. It will stimulate the immune response, but this can be overcome with a heavy challenge. The booster shot will give an extra lift and ensure lasting protection.”
The advice is to try to cover as wide a spectrum as possible when considering product choice.
How long will the vaccine last once opened?
It varies. It is important to handle and store vaccines correctly. It’s very important to check with each individual vaccine and follow the manufacturer’s recommendations as there are variations between vaccines in this regard.
If I use a product that vaccinates 10 clostridial diseases, should I treat for pasteurella after birth?
Realistically yes, to cover all bases.
What time frame does an animal need to be administered for post-mortem?
Ideally, as soon as possible, but it depends on environmental temperatures. We have been able to make a diagnosis in animals that were dead 24 to 48 hours, but the sooner we get them, the better the chance of making an accurate diagnosis.
Can the vaccine be administered up to two weeks pre-lambing?
You can administer it, but it leaves a shorter time frame for ewes to develop antibodies in colostrum. Also, ideally, you want to keep handling of heavily pregnant ewes to a minimum.
Failing to administer the full primary course (two shots administered four to six weeks apart): This is a common recurrence that leads to inadequate protection.Administering lower volumes: This is essentially false economy, as while it reduces the cost, sheep may not develop an adequate antibody response with the vaccination being worthless.Incorrect storage: Vaccines are sensitive to temperature changes and must be stored as per manufacturers’ instructions.Inadequate product selection: It is highly advisable to select a product that covers the maximum number of clostridia.Technique and cleanliness: Adequate time should be taken to ensure the vaccine is delivered hygienically and as per manufacturers’ guidelines.
Top tip
Lambs should receive 50ml colostrum per kilogramme bodyweight in the first four to six hours of life and 200ml/kg bodyweight inside the first 24 hours. Read more
Sheep management notes
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