The winter and spring of 2018 will not be forgotten for quite some time. There is huge variability between farms but on average there has been a much higher incidence of health issues and lamb mortality. The latter can be linked to numerous factors from ewes in poorer body condition to higher losses in outdoor lambing systems or young lambs succumbing to the elements.
Weather remains stop-start with a sharp contrast between daytime and night time temperatures. Grass supplies remain tight, not helped by variable growth rates, with those on marginal lands facing the greatest challenge. As such there are still a number of health issues that farmers need to be mindful of.
Nematodirus warning
The Department of Agriculture released their nematodirus warning on Thursday of last week. The forecast highlights peak hatching of eggs taking place in the last week of April for most of the country with the southwest experiencing suitable hatching conditions (warm spell) a week earlier.
The warning advises farmers to carry out routine treatment of lambs with a risk of exposure in the first week of May in the south of the country and second week of May elsewhere. The forecast is keen to also highlight a potential higher risk in 2018 with animals under higher stress levels than normal.
The parasitic scour which is caused by nematodirus battus has a characteristic yellow-green scour and can strike quickly. The risk is especially heightened where causative factors occur at the same time. These include:
A warm spell, preceded by a cold spell, which has occurred this year and is likely to have led to a large hatch of eggs at the same time. Lambs grazing ground that was grazed by last year’s lamb crop. This was unavoidable for most this year, given the low growth rates and tight grass supplies. Lambs under stress including triplet suckling lambs, foster lambs, pet lambs and those suckling yearling hoggets, aged ewes and ewes in poor body condition and yielding poorly. Lambs aged between six and 12 months with a significant grass intake. This again is likely, given the nutritional stress lambs have been under. Concurrent infection such as coccidiosis. Treatment is straightforward and includes pre-emptive treatment with a benzimidazole or white drench product. Where there is an age gap between lambs, treatment should be staggered or repeated where necessary.
Failing to take action can lead to high mortality rates and stunting of lambs caused by damage to the lamb’s gut.
Grass tetany
Another ailment which is currently causing issues is grass tetany, a metabolic disease caused by low-magnesium blood levels. Swards were grazed tight this spring which is a positive in promoting high-quality regrowth. One potential downside of high-quality leafy grass – which has grown at a rapid rate and contains high nitrogen and low fibre levels – is poor absorption of magnesium. This is particularly a risk where swards have received significant applications of potassium (via slurry or chemical fertiliser), which is antagonistic to magnesium uptake.
The risk is highest when animals are grazing such swards and faced with one of a number of stress factors, many of which are also commonly occurring at present.
These include animals being under nutritional stress, going from bare to lush pastures, bad weather including significant variation in temperature and any other stress inducing factors such as flocking sheep, transport or concurrent disease.
Animals must consume sufficient levels of magnesium on a daily basis and prevention centres on helping to ensure this happens. Offering ewes access to high-mag lick buckets is the most common form of prevention.
It is also important to boost magnesium levels in advance of a known risk period with a two- to three-day period often required to ensure blood magnesium levels are adequate. Feeding concentrates containing magnesium, administering magnesium bullets or the addition of magnesium to water are other preventative routes, while pasture dusting is an option rarely used. Swift treatment by administering magnesium intravenously is essential to improve the chances of a successful recovery.
The Irish Farmers Journal’s Tullamore Farm has faced significant challenges with grass tetany over the last week with three ewes affected. The ewes were grazing a lush sward which had received 2,000gls of slurry in March and between 60 and 70 units of nitrogen.
Meal was reintroduced on a short-term basis with ewes already having access to lick buckets.
Clostridial vaccine
Sheep farmers vary in their approach to clostridial diseases. Some implement the optimum control programme of vaccinating dams to promote passive transfer of immunity via colostrum and follow this by vaccinating progeny at 10 to 12 weeks of age.
Vaccinating
Others do not vaccinate ewes and instead rely on vaccinating lambs at a young age while some farmers that have not experienced any problems steer away from any form of protection.
The chosen route should take into account risk factors but it should also be noted that it is common for outbreaks to occur in flocks that previously had no issues.
Passive protection is influenced greatly by colostrum management and is dependent on animals receiving adequate colostrum from their dam in the first 12 hours of their life. If this was an issue this spring, then vaccinating lambs earlier should be considered.
Passive immunity can last anywhere from two weeks to 12 weeks with veterinary advice generally coming down on the side of lambs being covered for 10 to 12 weeks.
The exception to this is where there is a history of an earlier challenge and in this case it is worth consulting your vet to implement the optimum level of protection. Vaccination should not take place under the age of three weeks as it can interfere with passive immunity.
Clostridial disease vaccines generally provide a level of cover following vaccination but full protection does not kick in until two weeks after a primary course consisting of two doses administered about four weeks apart is given.
Coccidiosis
The greatest risk with coccidiosis is in lambs aged between three and eight weeks, with clinical symptoms most evident in lambs aged six to eight weeks. Lambs develop resistance to coccidia with age (10 weeks and older) but at this stage great harm can be done with lambs finding it difficult to recover and a risk of permanent damage being done. High-risk factors at present include ewes and lambs continuing to receive concentrate supplementation or lambs being creep fed in troughs that do not prevent contamination.
The characteristic symptom is a bad scour which can be blood stained and as such black in colour. Lambs can be seen straining and performance will quickly suffer with high mortality levels common during an outbreak. Treatment is via oral drenches.
Orf
Orf remains an issue with outbreaks in some flocks this spring. This is not surprising given lambs suckling ewes with wet and dirty udders and the associated consequences of cracks appearing and delivering a greater potential for orf to establish. Orf is a virus that generally runs its course with no direct treatment available.
Some farmers will try administering tablets or homeopathic treatments, but where lesions are significant it is useful to administer antibiotic treatment to prevent secondary infections from occurring. Lambs should be segregated and lambs with difficulty suckling may need to be brought indoors or receive artificial feeding. The orf vaccine, Scabivax Forte, will help provide protection to other lambs but it will take immunity a couple of weeks to develop. It should not be administered where there is no history of infection on the farm. Care should be taken where handling and treating lambs with orf as it can cause nasty skin lesions in humans.
Mastitis
The incidence of mastitis seems to have died down from the high prevalence encountered a few weeks ago. While a good number are linked to ewes under nutritional stress or issues such as ewes getting sore teats and not standing for lambs to suckle, there have also been outbreaks with mastitis spreading to a number of animals in a group.
Treatment options depend on the type of mastitis present. The characteristic symptoms of peracute or gangrenous mastitis is severe depression, ewes ceasing eating, dehydration and a swollen mammary gland that turns from warm at the start of the infection to a blue discolouration. In the worst-case scenario the mammary gland can become rotten and fall away.
Acute mastitis can be identified by a warm, swollen, red gland that can possess normal- or abnormal-looking milk. The gland is typically painful to touch and leads to ewes often walking lamely in trying to avoid touching the gland with their leg.
The other forms are chronic mastitis which often go unnoticed and subclinical mastitis which is also hard to identify. The first sign is often lambs thriving poorly or sucking continuously. This form can progress to clinical forms described above.
Treatment of all forms generally includes administering a course of antibiotics with veterinary advice to segregate affected animals from the flock. If multiple cases arise, it is advised to collect a sample for laboratory analysis and to allow a targeted treatment programme. Non-steroidal anti-inflammatory drugs with pain relieving action are also prescribed by some vets.
The winter and spring of 2018 will not be forgotten for quite some time. There is huge variability between farms but on average there has been a much higher incidence of health issues and lamb mortality. The latter can be linked to numerous factors from ewes in poorer body condition to higher losses in outdoor lambing systems or young lambs succumbing to the elements.
Weather remains stop-start with a sharp contrast between daytime and night time temperatures. Grass supplies remain tight, not helped by variable growth rates, with those on marginal lands facing the greatest challenge. As such there are still a number of health issues that farmers need to be mindful of.
Nematodirus warning
The Department of Agriculture released their nematodirus warning on Thursday of last week. The forecast highlights peak hatching of eggs taking place in the last week of April for most of the country with the southwest experiencing suitable hatching conditions (warm spell) a week earlier.
The warning advises farmers to carry out routine treatment of lambs with a risk of exposure in the first week of May in the south of the country and second week of May elsewhere. The forecast is keen to also highlight a potential higher risk in 2018 with animals under higher stress levels than normal.
The parasitic scour which is caused by nematodirus battus has a characteristic yellow-green scour and can strike quickly. The risk is especially heightened where causative factors occur at the same time. These include:
A warm spell, preceded by a cold spell, which has occurred this year and is likely to have led to a large hatch of eggs at the same time. Lambs grazing ground that was grazed by last year’s lamb crop. This was unavoidable for most this year, given the low growth rates and tight grass supplies. Lambs under stress including triplet suckling lambs, foster lambs, pet lambs and those suckling yearling hoggets, aged ewes and ewes in poor body condition and yielding poorly. Lambs aged between six and 12 months with a significant grass intake. This again is likely, given the nutritional stress lambs have been under. Concurrent infection such as coccidiosis. Treatment is straightforward and includes pre-emptive treatment with a benzimidazole or white drench product. Where there is an age gap between lambs, treatment should be staggered or repeated where necessary.
Failing to take action can lead to high mortality rates and stunting of lambs caused by damage to the lamb’s gut.
Grass tetany
Another ailment which is currently causing issues is grass tetany, a metabolic disease caused by low-magnesium blood levels. Swards were grazed tight this spring which is a positive in promoting high-quality regrowth. One potential downside of high-quality leafy grass – which has grown at a rapid rate and contains high nitrogen and low fibre levels – is poor absorption of magnesium. This is particularly a risk where swards have received significant applications of potassium (via slurry or chemical fertiliser), which is antagonistic to magnesium uptake.
The risk is highest when animals are grazing such swards and faced with one of a number of stress factors, many of which are also commonly occurring at present.
These include animals being under nutritional stress, going from bare to lush pastures, bad weather including significant variation in temperature and any other stress inducing factors such as flocking sheep, transport or concurrent disease.
Animals must consume sufficient levels of magnesium on a daily basis and prevention centres on helping to ensure this happens. Offering ewes access to high-mag lick buckets is the most common form of prevention.
It is also important to boost magnesium levels in advance of a known risk period with a two- to three-day period often required to ensure blood magnesium levels are adequate. Feeding concentrates containing magnesium, administering magnesium bullets or the addition of magnesium to water are other preventative routes, while pasture dusting is an option rarely used. Swift treatment by administering magnesium intravenously is essential to improve the chances of a successful recovery.
The Irish Farmers Journal’s Tullamore Farm has faced significant challenges with grass tetany over the last week with three ewes affected. The ewes were grazing a lush sward which had received 2,000gls of slurry in March and between 60 and 70 units of nitrogen.
Meal was reintroduced on a short-term basis with ewes already having access to lick buckets.
Clostridial vaccine
Sheep farmers vary in their approach to clostridial diseases. Some implement the optimum control programme of vaccinating dams to promote passive transfer of immunity via colostrum and follow this by vaccinating progeny at 10 to 12 weeks of age.
Vaccinating
Others do not vaccinate ewes and instead rely on vaccinating lambs at a young age while some farmers that have not experienced any problems steer away from any form of protection.
The chosen route should take into account risk factors but it should also be noted that it is common for outbreaks to occur in flocks that previously had no issues.
Passive protection is influenced greatly by colostrum management and is dependent on animals receiving adequate colostrum from their dam in the first 12 hours of their life. If this was an issue this spring, then vaccinating lambs earlier should be considered.
Passive immunity can last anywhere from two weeks to 12 weeks with veterinary advice generally coming down on the side of lambs being covered for 10 to 12 weeks.
The exception to this is where there is a history of an earlier challenge and in this case it is worth consulting your vet to implement the optimum level of protection. Vaccination should not take place under the age of three weeks as it can interfere with passive immunity.
Clostridial disease vaccines generally provide a level of cover following vaccination but full protection does not kick in until two weeks after a primary course consisting of two doses administered about four weeks apart is given.
Coccidiosis
The greatest risk with coccidiosis is in lambs aged between three and eight weeks, with clinical symptoms most evident in lambs aged six to eight weeks. Lambs develop resistance to coccidia with age (10 weeks and older) but at this stage great harm can be done with lambs finding it difficult to recover and a risk of permanent damage being done. High-risk factors at present include ewes and lambs continuing to receive concentrate supplementation or lambs being creep fed in troughs that do not prevent contamination.
The characteristic symptom is a bad scour which can be blood stained and as such black in colour. Lambs can be seen straining and performance will quickly suffer with high mortality levels common during an outbreak. Treatment is via oral drenches.
Orf
Orf remains an issue with outbreaks in some flocks this spring. This is not surprising given lambs suckling ewes with wet and dirty udders and the associated consequences of cracks appearing and delivering a greater potential for orf to establish. Orf is a virus that generally runs its course with no direct treatment available.
Some farmers will try administering tablets or homeopathic treatments, but where lesions are significant it is useful to administer antibiotic treatment to prevent secondary infections from occurring. Lambs should be segregated and lambs with difficulty suckling may need to be brought indoors or receive artificial feeding. The orf vaccine, Scabivax Forte, will help provide protection to other lambs but it will take immunity a couple of weeks to develop. It should not be administered where there is no history of infection on the farm. Care should be taken where handling and treating lambs with orf as it can cause nasty skin lesions in humans.
Mastitis
The incidence of mastitis seems to have died down from the high prevalence encountered a few weeks ago. While a good number are linked to ewes under nutritional stress or issues such as ewes getting sore teats and not standing for lambs to suckle, there have also been outbreaks with mastitis spreading to a number of animals in a group.
Treatment options depend on the type of mastitis present. The characteristic symptoms of peracute or gangrenous mastitis is severe depression, ewes ceasing eating, dehydration and a swollen mammary gland that turns from warm at the start of the infection to a blue discolouration. In the worst-case scenario the mammary gland can become rotten and fall away.
Acute mastitis can be identified by a warm, swollen, red gland that can possess normal- or abnormal-looking milk. The gland is typically painful to touch and leads to ewes often walking lamely in trying to avoid touching the gland with their leg.
The other forms are chronic mastitis which often go unnoticed and subclinical mastitis which is also hard to identify. The first sign is often lambs thriving poorly or sucking continuously. This form can progress to clinical forms described above.
Treatment of all forms generally includes administering a course of antibiotics with veterinary advice to segregate affected animals from the flock. If multiple cases arise, it is advised to collect a sample for laboratory analysis and to allow a targeted treatment programme. Non-steroidal anti-inflammatory drugs with pain relieving action are also prescribed by some vets.
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